Hydrological effects of urbanization

Hydrological effects of urbanization Report of the Sub-group on the Effects of Urbanization on the Hydrological Environment,

of the Co-ordinating Council of the International Hydrological Decade

Prepared under the chairmanship of M. B. McPherson

The Unesco Press Paris 1974

I

Studies and reports in hydrology 18

TITLES IN THIS SERIES

1. The use of analog and digital computers in hydrology: Proceedings of the Tucson Sympo- sium, June 1966 / L’utilisation des calculatrices analogiques et des ordinateurs en hydrologie: Actes du colloque de Tucson, juin 1966. Vol. 1 & 2. Co-edition IAHS-Unesco / Coédition A I S H - Unesco.

2. Water in the unsaturated zone: Proceedings of the Wageningen Symposium, June 1967 / L’eau dans la zone non saturée: Actes du symposium de Wageningen, juin 1967. Edited by /Edité par P.E. Rijtema & H. Wassink. Vol. 1 & 2. Co-edition IAHS-Unesco / Coédition A I S H - Unesco.

3. Floods and their computation: Proceedings of the Leningrad Symposium, August 1967 1 Les crues et leur évaluation : Actes du colloque de Leningrad, août 1967. Vol. 1 & 2. Co-edition IAHS-Unesco- WMO / Coédition A I S H - Unesco.OMM.

4. Representative and experimental basins: A n international guide for research and practice. Edited by C. Toebes and V. Ouryvaev. Published by Unesco.

4. Les bassins représentatifs et expérimentaux : Guide international des pratiques en matière de recherche. Publié sous la direction de C. Toebes et V. Ouryvaev. Publié par l’Unesco.

5. *Discharge of selected rivers of the world / Débit de certain cours d’eau du monde. Published by Unesco / Publié par l‘Unesco. Vol. I: General and régime characteristics of stations selected / Caractéristiques géné- rales et caractéristiques du régime des stations choisies.

Vol. II: Monthly and annual discharges recorded at various selected stations (from start of observations up to 1964) / Débits mensuels et annuels enregistrés en diverses stations sélectionnées (de l’origine des observations à l’année 1964).

Vol. III: Mean monthly and extreme discharges (1965-1969) / Débits mensuels moyens et débits extrêmes (1965-1969).

6. List of International Hydrological Decade Stations of the world / Liste des stations de la Décennie hydrologique internationale existant dans le monde. Published by Unesco /Publié par 1’ Unesco.

7. Ground-water studies: An international guide for practice. Edited by R. Brown, J. Ineson, V. Konoplyantsev and V. Kovalevski. (Will also appear in French, Russian and Spanish / Paraîtra également en espagnol, en français et en russe.)

8. Land subsidence: Proceedings of the Tokyo Symposium, September 1969 / Affaisement du sol : Actes du colloque de Tokyo, septembre 1969. Vol. 1 & 2. Co-edition IAHS-Unesco 1 Coédition AISH- Unesco.

9. Hydrology of deltas: Proceedings of the Bucharest Symposium, May 1969 / Hydrologie des deltas : Actes du colloque de Bucarest, mai 1969. Vol. 1 & 2. Co-edition IAHS-Unesco / Coédition AISH- Unesco.

10. Status and trends of research in hydrology / Bilan et tendances de la recherche en hydrologie. Published by Unesco / Publié par l’Unesco.

il. World water balance: Proceedings of the Reading Symposium, July 1970 / Bilan hydrique mondial : Actes du colloque de Reading, juillet 1970. Vol. 1-3. Co-edition IAHS-Unesco- WMO I Coédition AISH-Unesco-OMM.

12. Results of research on representative and experimental basins: Proceedings of the Wellington Symposium, December 1970 / Résultats de recherches sur les bassins représentatifs et expérimentaux : Actes du colloque de Wellington, décembre 1970. Vol. 1 & 2. Co-edition I A H S - Unesco / Coédition A I S H - Unesco.

13. Hydrometry: Proceedings of the Koblenz Symposium, September 1970 / Hydrométrie: Actes du colloque de Coblence, septembre 1970. Co-edition I A H S - Unesco- WMO / Coédition A I S H Unesco-OMM.

14. Hydrologic information systems. Co-edition Unesco- WMO. 15. Mathematical models in hydrology: Proceedings of the Warsaw Symposium, July 19711

Les modèles mathématiques en hydrologie : Actes du colloque de Varsovie, juillet 1971. Vol. 1-3. Co-edition IAHS-Unesco- WMO / Cogdition AISH-Unesco-OMM.

16. Design of water resoyrces projects with inadequate data: Proceedings of the Madrid Sym- posium, June 1973 1 Elaboration des projets d’utilisation des resources en eau sans données suffisantes : Actes du colloque de Madrid, juin 1973. Vol. 1-3. Co-edition U n e s c o - W M O - I A H S / Coédition Unesco- O M M - A I S I I .

17. Methods for water balance computations. An international guide for research and practice. Published by Unesco.

18. Hydrological effects of urbanization. Report of the Sub-group on the Effects of Urbanization on the Hydrological Environment. Published by Unesco.

Published by The Unesco Press Place de Fontenoy, 75700 Paris

Printed by La Néogravure, Paris

The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the publishers concerning the legal status of any country or territory, or of its authorities, or concerning the frontiers of any country or territory.

ISBN 92-3-101223-1

0 Unesco 1974 .

Printed in France

Preface The International Hydrological Decade (IHD) 1965-74 was launched by the General Confer-

ence of Unesco at its thirteenth session to promote international co-operation in research and studies and the training of specialists and technicians in scientific hydrology. Its purpose is to enable all countries to make a fuller assessment of their water resources and a more rational use of them as man's demands for water constantly increase in face of developments in population, industry and agriculture. In 1974, National Committees for the Decade had been formed in 108 of Unesco's 131 Member States to carry out national activities within the programme of the Decade. The implementation of the programme is supervised by a Co- ordinating Council, composed of thirty Member States selected by the General Conference of Unesco, which studies proposals for developments of the programme, recommends projects of interest to all or a large number of countries, assists in the development of national and regional projects and co-ordinates international co-operation.

Promotion of collaboration in developing hydrological research techniques, diffusing hydrological data and planning hydrological installations is a major feature of the programme of the IHD which encompasses all aspects of hydrological studies and research. Hydrological investigations are encouraged at the national, regional and international level to strengthen and to improve the use of natural resources from a local and a global perspective. The programme provides a means for countries well advanced in hydrological research to exchange scientific views and for developing countries to benefit from this exchange of information in elaborating research projects and in implementing recent developments in the planning of hydrological installations.

General Conference authorized the Director-General to collect, exchange and disseminate information concerning research on scientific hydrology and to facilitate contacts between research workers in this field. To this end Unesco initiated two series of publications; Studies and Reports in Hydrology and Technical Papers-in Hydrology.

is aimed at recording data collected and the main results of hydrological studies undertaken within the framework of the Decade, as well as providing information on research techniques. Also included in the series are proceedings of symposia. Thus, the series comprises the compilation of data, discussions of hydrological research techniques and findings, and guidance material for future scientific investigations. It is hoped that the volumes will furn- ish material of both practical and theoretical interest to hydrologists and governments participating in the IHD and respond to the needs of technicians and scientists concerned with problems of water in all countries.

As part of Unesco's contribution to the achievement of the objectives of the IHD the

The Studies and Reports in Hydrology series, in which the present volume is published,

Contents Foreword

PART I INTERNATIONAL SUMMARY

1 Introduction 2 Summary of findings 3 Research and development 4 References

PART II CASE STUDIES OF HYDROLOGICAL EFFECTS OF URBANIZATION IN SELECTED COUNTRIES

1 Federal Republic of Germany 2 The Netherlands 3 Sweden 4 United States of America 5 Union of Soviet Socialist Republics

PART III ILLUSTRATIVE SPECIAL TOPIC STUDIES

Urban runoff Effects of lignite mining on the urban water cycle in the Federal Republic of Germany Effects of industrial waste water and sludge on the self- purification of rivers in the Federal Republic of Germany Some aspects of solid waste disposal in the Federal Republic of Germany Waste water dilution in rivers, lakes and reservoirs Synthetic detergents and water quality in the United Kingdom The effect of opencast mining on the water balance of an area Water management in the Netherlands and the effect of urbanization, particularly runoff, in polder areas

ANNEXES

I Respondents to questionnaire sent by the Secretariat of the International Hydrological Decade to the National Committee for the_I.H.D.

Urbanization, Warsaw, 8-10 November 1973 II Participants in International Workshop on the Effects of

III Terminology

13 16 29 37

45 69 95 11 3 137

153

177

193

273

275 278

Foreword Among the numerous studies undertaken by the International Hydrological Decade was an investigation initiated in 1965 by the Working Group on the Influence of Man on the Hydrological Cycle and supported by the Food and Agricultural Organisation (FAO) I charged with agricultural and urbanization aspects of the subject. The Coordinating Council in 1970 decided to form a Sub-group on the Effects of Urbanization on the Hydxological Environment, supported by Unesco, to assist the Working Group and :o investigate more intensively industrial and urbanization aspects.

1973. Members were: The Sub-group met in three sessions, 28-3C dune 1971, 2-5 May 1972 and 12-13 November

Professor S Inokuti* (Japan) Dr V V Kuprianov* (USSR) Professor G Lindh (Sweden) Mr M B McPherson (USA), Chairman Mr T Waldmeyer (UK) Mr R Zayc, 1971-1972; and Dr H Massing, 1972-1973 (Federal Republic of Germany) Ir. F C Zuidema* (Netherlands) The Sub-group was assisted Gy Mr J Jacquet (France), who represented the IHD Working

Group on Representative and Experimental Basins. Mr N A Bochin of Unesco/IHD served as Technical Secretary of the Sub-group through its first two sessions, and was succeeded by Mr F H Verhoog in that capacity.

The Sub-group provided the IHD Coordinating Council with a Summary Statement on the Hyd- rological Effects of Urbanization in 1971, assisted the Working Group on the Influence of Man on the Hydrological Cycle on the part of its 1972 report dealing with urbanization through Ir. F C Zuidema, and prepared the report which follows.

In 1972 the IHD Secretariat circulated to all national committees for the IHD, a questionnaire on research and development needs. Respondents, identified in Annex I, were among the participants at an International Workshop on the Hydrological Effects of Urbanization held in Warsaw, Poland, 8-10 November 1973, Sponsored by the Polish Academy of Sciences , U.S. National Science Foundation, Unesco/IHD, and the American Society of Civil Engineers. al Summary', was reviewed at the Workshop and the many invaluable observations and suggestions made by participants have been taken into account in the following report. participants are identified in Annex II. Annex III contains definitions of terminology used throughout this report.

Part II of the report contains 'Case Studies' for Sub-group members' countries and Part III is a group of 'Illustrative Special Topic Studies' prepared by individual members and associates from their countries.

This report is a result of the wise decision of the IHD Coordinating Council to give a greater attention than originally planned to the effects of urbanization. With the rapid growth of urban areas and associated industrialization around the world, present and projected, this attention is particularly appropriate. One of the major findings of this report is that the field of urban hydrology is almost devoid of modem research investment and there has been relatively little study to date of the effect of urban man upon natural hydrological conditions, in spite of the significant economic and environmental importance of urban settlements in nearly every nation. extensive research and development in individual countries and the formulation of improved mechanisms for international cooperation on research subjects of widespread general interest.

questionnaire respondents, so many similarities were found in problems and effects that it is concluded that the findings of this report are more universally representative than the small sample of nations involved would suggest.

Responses are summarized later in this report.

A draft of Part I of this report, 'Internation-

Workshop

It is earnestly hoped that this report may inspire more

While only relatively few nations were represented by the Sub-group, as augmented by

* Members also of the FAO/IHD Working Group on the Influence of Man on the Hydrological Cycle.

Part I International summary

by the

IHD/Unesco Sub-Group on the Effects of Urbanization on the Hydrological Environment

as revised by the International Workshop on the Hydrological

Effect of Urbanization, Warsaw, 8-10 November 1973 and as completed by the Sub-Group in Warsaw

12-13 November 1973

CONTENTS

1-1 Iritroduction 13 1-1.1 Purpose and scope 1-1.2 Urbanization 1-1.3 Environmental effects 1-1.4 Urban hydrology 1-1.5 Urban hydrological research and development

1-2 Summary of findings

1-2.1 Urban hydrological system 1-2 - 2 Urbanization indices 1-2.3 Climatic effects 1-2.4 Changes in surface and groundwater flows 1-2.5 Water supply and water conservation 1-2.6 Water quality and pollution effects 1-2.7 Other hydrological implications 1-2.8 Conclusions

1-3 Research and development

i6

29

1-3.1 General status, conclusions and recommendations 1-3.2 Current activities 1-3.3 Inquiry on research needs 1-3.4 Major research and development needs 1-3.5 International co-operation 1-3.6 Recommendations for international action

1-4 References

I

37

Introduction

I - 1 INTRODUCTION

1-1.1 Purpose and scope

The objectives of this report are to describe the effects of urbanization together with its environmental impacts on the hydrological cycle aqd to recommend research needed by the managers of all types of water systems to minimize the environmental stresses. This report is primarily directed to researchers in hydrology. and a special summary is directed to water managers.

Man's impact on the hydrological regime is, on the whole, nowhere more intensive than in urban areas. The effects of urbanization on the human environment transcend by far the considerations of the hydrological cycle. Expected massive increases in urbanization over the next several decades clearly suggest that present problems will probably be alarmingly compounded. Although water is a necessity, an economic reality, an amenity, and an aesthetic component in urban settlements, research on urban water resources has lagged behind large catchment research in nearly every nation. Needed research is complex and will take considerable time , with much larger financial commitment than previously encountered.

Satisfactory assessment of contemporary hydrological effects is thwarted by a dearth of suitable information. Therefore, it has been necessary to use indirect means in this report to define principal effects and to identify necessary research.

was simply not feasible. As an expedient, extensive case studies were made for a few countries, to highlight both similarities and pronounced differences, complemented by supplementary information from other countries, and a canvass was made of a much larger sample of nations to determine relevant current research anã to identify outstanding research needs.

to account. The case studies reported in Part II are from economically and technologically advancea countries, and hence the hydrological effects identified here have been experienced in countries of that type. moving in the same direction, the observations offered may be regarded as precursors of occurrences that may be expected sooner or later almost everywhere. The findings from the selected case studies are summarized in the next chapter. It is hoped that they will give impetus to case studies in developing nations and that such case studies will focus upon the special needs and interests of such nations.

topics in urban hydrology, with the purpose of indicating what has been accomplished and documenting justification for much of the more urgently needed research and development recommended in this report. Some of the findings from these special studies are incorporated in the next chapter.

It is important to note that this report largely pxovides information and does not include an analysis of existing international publications.

Terminology used in this report is defined in Annex III of Part I.

While surveys of scores of nations would surely have been desirable and appropriate, this

An advantage of the case study approach is that inherent interrelations can be taken in-

However, because most of the developing nations appear to be

Part III explores in detail, via state-of-the-art studies, some of the most important

1-1.2 Urbanization

'The movement of people from rural to urban areas tends to proceed concomitantly with the mechanization of agriculture. The pressure of the surplus population, the extension of employment in industry, and better education, medical facilities, and culture in the cities have led to a growing migration to the urban and industrialized areas in developing and developed countries alike. It has coincided with an unprecedented increase in world population , thus putting an almost insuperable burden on metropolitan areas.

Africa, Asia and Latin America) , the main problem is urban. . . .. . -. ' (WHO Expert Committee, 'Although both rural and urban areas suffer because of this rapid change (especially in

1965a) - Industrialization is included in urbanization because the latter can be reqarded as

human activities involving change in land occupancy and use resulting from the conversion of rural lands to industrial uses and to urban, suburban and industxial communities. Also, there are instances where the effects of water pollution from large-scale mining operations are comparable to those from industries. Urban areas affect, and are affected by, such sometimes distant human activities. Among the obvious effects are increased population

13

Introduction

densities and increased concentrations of residential, industrial and commercial buildings and facilities, with resultant increases in areas that are impervious (impermeable to infiltration). Hydrological impacts then include the effects of these changes on the natural drainage, runoff, groundwater, sediment, water quality, water demands, and on measures utilized for the disposal of wastes and surplus waters and for the supply of water, Kammerer, 1961) Among the hydrological problems associated with urbanization are the continually increasing demands for water for various uses, changes in the physical environment that alter the natural water balance, and the disposal of wastes that may contaminate streams and groundwater. Of course, there are wide differences in both the distribution of population density and of natural water occurrences around the world.

by a continuous increase in the ratio of urban to rural dwellers, and it is expected that by the year 2000, half of the world's population will be urban. (United Nations, 1967). By then, three-quarters of the world's population will be in the less-industrialized countries. In the interval, urban growth is likely to be at least twice as rapid as total population growth, and to house this population will require building in one generation more structures than have been built in the whole of human history.

Paradoxically, the land occupied by urban population in nearly all countries is only a small fraction, often of the order of less than 5%, of the total land area. The geographic concentration of human activities in urban agglomerations intensifies local competition and conflict over all resources, including water in its many aspects.

its per capita income. (Davis, 1965) 'In general, the later each country became industrialized, the faster was its urbanization'.. . . . . . It is the underdeveloped countries - 'representing three-quarters of humanity - that are mainly responsible for the rapid urbanization now characterizing the world as a whole'...... and in these countries, 'it is virtually impossible to create city services fast enough ...... It is even harder to expand agridult- ural land and capital fast enough to accommodate the enormous natural increase on farms. The problem is not urbanization, not rural-urban migration, but human multiplication. It is a problem that is new both in its scale and its setting, and runaway city growth is only one of its painfull expressions, ' (Davis, 19651,

national population in urban places. influence on the environment than ever before. urban development and partly as a consequence of the stronger relationship between the urban and the rural worlds. Communication between the different urban concentrations increasingly opens up the countryside. Intensification of land use and increasing exploitation of natural resources are also directly related to the urbanization process. ...... In economically advanced societies, each individual today requires five to ten time more space for housing, employment and recreation than he did in 1900.' (Benthem, 1971)

Australia. Although Australia is a large continent of some 7700-million square kilometers with a population of only 13-million people, it is highly urbanized in some areas. of its population live in urban areas and two-thirds of these people are concentrated in only 12 urban centres. The question of the effect of urbanization on the hydrological cycle in Australia is therefore an important one.

(S'avini and

(FAO, 1973) On a world-wide scale, total population growth during this century has been accompanied

Currently, the degree of urbanization of a country reflects directly the magnitude of

A large majority of the countries of Western Europe have a large part of their total 'Urbanization in its present form has a much greater

This is partly due to the large amount of

The concentration of large populations in a small national space is exemplified by

Over 83%

1-1.3 Environmental effects

Urban settlements are characterized by an accelerating concentration and growth in man's activities, such as energy consumption, modification in land occupancy, traffic congestion, public demands for services and use of water. As a consequence, the natural environment is essentially changed. ative and qualitative aspects of the water cycle. These changes are leading to an increasingly critical situation.

A man-made environment evolves with subsequent changes in the quantit-

Hydrological effects of urbanization which are discussed later, include: - The agglomeration of settlements and industries is accompanied by rising water needs - Growing amounts of waste waters place a burden on rivers and lakes and endanger the-r which often exceed the natural resources in these areas;

ecology ;

14

Introduction

- Conversion of only 20% of a natural catchment can result in a doubling of the peak rate of runoff for that area;

- Replacing natural ground surfaces with impervious coverings reduces the infiltration of rain water;

- Extensive use of groundwater lowers the water table , adversely affects agriculture and forestry, diminishes the base flows of streams and aggravates the pollution problem;

- Changes in the local micro-climates of cities have been observed; and

- Increasing amounts of all kinds and varieties of wastes resulting from urbanization and the increasing lack of places for their disposal complicates the water quality problem.

'The crisis of human settlements stems from man's failure to understand the effects of urbanization, from indifference to the consequences of his intervention in the natural environment , or from his inability to take the necessary preventive or corrective actions, ' (Secretary General , UN , 1971).

centrated and profound influence on man, (Secretary General, UN, 1971).

health and urban-specific diseases to a change in social behaviour.

tries (united Nations, 1971) , therefore, the less industrialized countries should note the difficulties experienced in developed countries in more comprehensive planning of their developnient that takes into account environmental considerations.

the future health and well-being of humanity, '

concludes that all growth projections end in collapse and that a possible remedy would be an all-out effort to end exponential growth, and this prescription is independently supported by a group of some of the most distinguished scientists of the United Kingdom (Anon, 1972). On the other hand, assuming that for every scarce material a substitute can be found, that new technology can keep pollution under control and that an infinite energy source can be developed, recalculation of Club of Rome scenarios indicates that the world would come to a rather acceptable steady state (Boyd, 1972). It therefore appears that there are possibilities ranging between stability and collapse, but it is clear that attainment of stability will require conscious effort and is unlikely to emerge as a product of chance.

plentiful materials for scarce materials , strive for still higher productivity , reduce the amount of material wasted in processing, and reduce power consumption per unit of production. However, the fundamental ecological problem is how to protect the environment without unduly interfering with economic growth. One of the most vexing difficulties is in attempting to internalize the costs of pollution abatement within the cost structure of goods and services. Also, improved technology is not necessarily without flaws because new developments have a nasty habit of creating unforeseen side effects.

In most countries , economic growth, population growth, non-agricultural water use and pollution are intertwined. Water in its many manifestations plays a vital role in the extremely complex processes of urbanization , and thus affects national health and growth. For example, in some countries the demand for water-based recreation is literally exploding, placing heavy stresses on facilities that are currently available.

1-1.4 Urban hydrology

In turn, it is in urban settlements that the overburdened environment has its most con-

These influences have physical, psychical and social effects ranging from endangered

Problems of urban settlement are common to industrialized and less industrialized coun-

'The reduction and ultimate elimination of these problems is an essential condition for

A study (Meadows , Meadows, Randers and Behrens , 1972) conducted for the Club of Rome (United Nations, 1971)'

Meanwhile , as conditions of scarcity increase , industries can be expected to substitute

Urban hydrology is a distinct branch of the broad field of hydrology because the complex interactions of human activity in concentrated settlements , with air , water and land must be collectively taken into account. That is, the impact of man on the water cycle is greatest per unit of area in urban places. Man is capable of transforming his local environment in an almost endless variety of ways, over a matter of a few years , whereas nature moves largely on a timetable of eons. Thus, urban hydrology contends with the dimension of dynamic change because urban development everywhere has been in continuous states of expansion and flux. Urdan water resources management utilizes the social and biological sciences as well as the

15

Summary of findings

natural sciences. The impact of 'urbanization may extend beyond urban boundaries.

1-1.5 Urban hydrological research and development

Problems of urban hydrology have been of world-wide concern for several years, but there have been few compilations of background information and even fewer comprehensive investigations of specific urban situations. Although the general outlines of the effects of urbanization on the hydrological cycle can now be described in part, there is an urgent need for improved understanding, in detail, of interactions between urban stresses on the environment, the water regime, and the efforts made to manage, conserve, and improve our water resources.

to obtain them. In the meantime, water managers face the need to make immediate working decisions on a day-to-day basis. Consequently, while there is the need for new and expanded research in the future, there is also an urgent need to make the best possible use of existing information-and data. Careful analysis of the existing data will provide a useful measure of information needed by water managers throughout the period before results are available from new and more rationally organized research programmes.

Chapter 3. It should be noted that none of the recommendations is for strictly new areas of research. Each of the areas recommended is an extension of work that has already been begun. It is the synthesis of the information and data in these earlier stuäies, regardless of how inadequate they may seem at this time, which should proceed simultaneously with the initiat- ion of newer investigations based on improved understanding of data requirements, improved concepts , and improved instrumentation.

One of the major observations made during the preparation of this report is that the problems of urban hydrology are remakably similar in all parts of the world. Three important deductions may be made from this observation. The first is that data requirements and analytical and integrating procedures will be similar in many investigations, with due allowance for local conditions. Opportunity to intensify regional , continental, and world-wide cooperation among water scientists and water managers concerned with urban problems. apparent to institutions concerned with these problems that their problems will be resolved much more readily to the extent they expedite and implement the exchange of information among those working in the field. In this connection it is necessary to remember that the institutional arrangements for dealing with water in many countries are complex and fragmented, making it difficult to develop rational comprehensive water research programmes. This frag- mentation makes it even more important to emphasize the need to encourage the widespread exchange of information.

was a need for research to establish the nature of the effects of urbanization on basic hydrological processes. Today, the broad nature of these effects is beginning to be understood. However, just as it was more than a decade ago, more research and investigations are needed to better our understanding of the detailed effects of urbmization on order to facilitate and improve providing urban areas with the basic water they require.

However, no matter how vital it may be to have new information and data, it takes time

A detailed discussion of additional research and development needs is given in Part I,

The second is that such similarity of effort provides an excellent

The third is that it should be,

More than a decade ago (Savini and Kammerer, 1961) , it was possible to say that there

the adequacy of planning to alleviate or prevent undesirable consequences while

1-2 SUMMARY OF FINDINGS

The contents of this chapter are based on selected national case studies, which are collected in Part II. The following points will be described: urban hydrological system; urbanization indicators; climatic effects; changes in surface and groundwater flows; water supply impact and water conservation; water quality and pollution effects and other hydrological implications.

1-2.1 Urban hydrological system

A schematic representation of the hydrological cycle is given in Figure 1. Because agrarian activity has only a modest effect on the hydrological cycle, Figure 1 has been designated as the 'pre-urban hydrological system' in order to visualize the water components for a typical large sector of the land prior to its urbanization. The complexities imposed on the system

16

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18

Surmnary of findings

of Figure 1 by urbanization can be appreciated by comparing it with Figure 2, an 'urban hydrological system'. The latter illustrates the local water balance changes brought about by the drastic changes in land use that accompany urbanization.

Figure 2 is a simplified summary of a particular hydrological system.* Representation of water quality aspects , not shown in Figure 2 , would be still more complicated.

Of considerable hydrological importance is the relative location of an urban centre in the river basin of which it is a part, as well as the degree and character of its hydrological overlap with other urban centres, and their distance from a large lake or an ocean. Because early commerce utilized waterways for transportation , the great majority of metropolises are located on or near major water bodies. Hence, they frequently occupy low-lying ground, and tend to be located near estuaries of major streams or the junction with their tributaries , or along a coast. The advantages of superior water transport, water supply and waste-assimilation capacity through self-purification afforded by many of these locations have since been partly offset by increases in flooding damages and pollution that have accompanied more intensive urbanization. Further , growth in water-using industries and in mining enterprises has strained capabilities for enlarging community water supplies , and aggravated thermal and chemical pollution. Because total water withdrawals for domestic and industrial uses are expected to climb dramatically over future decades, present problems can be regarded as merely a prologue of what is to come. Also, in some locations , such as Kobe, Yokohama and Southern California, the sprawl of urban development into the steep foothills of nearby mountains has posed a new set of special problems there and at points 'downstream'.

1-2.2 Urbanization indices

The findings summarized here are based mainly on the five national case studies in Part II and only to a limited extent on some of the special topic studies of Part III. A draft of this chapter was distributed to participants of the 1973 Warsaw International Workshop on the Hydrological Effects of Urbanizatior, and their comments on this chapter have been taken int.0 consider ation.

In feudal times, the limits of urban areas were clearly bounded by the walls of cities and towns, which formed fortresses for defence against invaders. These and newer communities today are characterized by a seemingly endless sprawl beyond their densely occupied commercial centres - Population density tends to diminish exponentially with the distance from urban centres and the cessation of urban densities and the beginning of rural densities can be only subjectively defined. Additionally , the peripheral populations around two or more centres may overlap, and even nearby but separated urban areas may have obvious economic or cultural ties. Such complications have plagued demographers and economists in their attempts to specify definitions of 'urban areas' , 'metropolises' , 'megalopolises' and related features of urbanization. Each country has its own definitions, which best describe that nation's demography .

lations. The case studies include whatever data are available for around 1970 and expect- ations for about the years 1980 and 2000. Population is generally reported for communities of 50-thousand or more, 100-thousand or more, a half a million or more, and one million or more persons , together with total national populations. Where appropriate, available data on population density are also reported, and comparisons are usually drawn between the coll- 'ective size of urban areas and the total national area. Also where appropriate, qualitative

The five case studies in Part II are all of nations that have predominantly urban popu-

*Notes: In Figure 2, 'Water Systems' is intended to include treatment and distribution facilities of community systems and self-supplied industrial process systems. Because usually only a small percentage of industrial cooling water is from groundwater sources, only surface water withdrawals and returns of this type are represented. Provision of flow-detention storage for overland runoff is considered to be a part of 'Storm Drainage'. The term'Mani- pulated' , used twice in Figure 2, would include: runoff management, such as in the deliberate provision of local storage, of the 'Urban Land Surface' ; and recreation, transportation, flood control measures and property-value enhancement in connection with 'Bodies of Surface Water'. Water-borne carriage of human wastes is assumed. Management of seawater intrusion is not included. Some connections/functions shown are not necessarily typical of a particular metropolis.

19

S m a q of findings

divisions into principal national climatic-topographic regions have been made for existing and expected communities with populations exceeding about 50-thousand persons.

The immediately preceding parameters were selected as indicators of urbanization for the purpose of putting the national case studies in Part IL on a reasonably common demographic footing.

1-2.3 Climatic effects

Localized climatic changes produced by larger urban settlements have been noted (Secretariat , WMO, 1971), but knowledge of effects is limited, (Chandler, 1970). These effects are often called micro-scale phenomena and are unplanned or inadvertent as opposed, for example, to deliberate attempts to modify precipitation, (Neiburger, 1969) . Some climatic changes , for example thermal inversion , can make life unpleasant on occasions.

electricity is only part, coupled with changes in land heat-transfer characteristics due to urban development, have resulted in measurable and even rather large differences in the micro- climates of cities compared with their environs -

The tremendous growth in the rate of total energy consumption, of which generation of

Four physical mechanisms contribute to the micro-climates of urban areas: 1.

2. Built-up areas are obstacles to the wind, changing the natural flow and turbulence

3. The water vapour balance in A city is upset by the change from moist to dry surfaces; 4. The city emits heat, water vapour and pollution to the atmosphere. In addition,

Evaluation of climatic changes in urban areas can be made by analysis of the following

A. Air temperature. This climatic element has higher values for urban areas than for the country. The difference for the annual average temperature varies between 0.5 and 2OC, (Alison, Drosdow, and Rubenstein, 1956). This is caused by the following factors : 1. A much smaller latent heat flux; 2. The different physical properties (such as the albedo, the specific heat and the

thermal conductivity) and the different structures of the urban surface; 3. The energy generated by combustion processes (house heating, factories , auto-

mobiles and human metabolic heat). For Vienna the artificial heat supply pes annum is one-sixth to one-fourth that provided by direct solar radiation, and for Berlin and Amsterdam, the ratio is one-third (Kratzer, 1956 and Zuidema, 1974). At Amsterdam it is found that in Winter the energy generated by human activity exceeds the solar energy (Zuidema, 1974) - The pall of dust and carbon dioxide over a city influences not only the incoming solar radiation (especially the shorter lengths of the spectrum such as the ultraviolet rays) by additional flux divergence, but also reduces the net outgoing longwave radiation. For Boston the city values of solar radiation aver- , aged 15% lower than those in the suburbs. The solar radiation in Toronto, Canada averaged 3% higher on Sundays than on weekdays. In Winter the ultraviolet radiation in the centre of Leicester, England, amounts to 70% of that on the outskirts (Mann, 1966). The characteristic warmth of a city is called the urban heat island, the size and intensity of which changes fram day to day. It is at a maximum at night and as for most climatological elements there is evidence of a weekly cycle. A 1968 international symposium on urban climates (Secretariat, WMO , 1970) discussed the interrelations between micro-scale phenomena and noted characteristics such as the 'heat island' effect and difference in precipitation between cities and their environs.

The natural radiation balance is disturbed by chan*ges in the properties of the underlying surface.

of the air;

Vegetation is replaced by large areas of concrete and brick;

traffic is a source of local turbulence.

elements :

4-

B. The water vapour content of the air. The urban water vapur pressure is mostly below the value of the country because the precipitation is quickly discharged. Because the air temperature is normally higher, it can be understood that the relative huniidity will be smaller. However, in the night the vapour pressure is often higher in the city. Por American cities it has been found that the difference amounts to 8% in summer and 28 in winter because of the emission of water vapour by

20

Swmnary of findings

C.

D.

E.

combustion processes (Zuylen , 1971). Due to the relatively large area of open water near Amsterdam, no difference has been found between the city and the surrounding rural area (Zuidema, 1974). Fog. roundings , due to an increased amount of condensation nucleii, Pollution and fog vary from city to city, but fog frequency is lower in relatively clean cities, due to a higher temperature. Cloudiness and precipitation. It may be stated that due to an abundance of condensation nucleii , turbulence and convection , an increased cloudiness has been observed in urban regions. However, it is questionable whether this increased cloudiness is sufficient to cause an increased precipitation. Results of research into this problem appear to be very contradictory. Several investigators have found a weekly cycle that must be related to human activities. For instance, for Paris (Zuylen, 1971; Zuylen, 1973; Dettwiller, 1970) and for Rochdale, England (Alisson , Drosdow, and Rubenstein, 1956) there is convincing evidence that the amount of precipitation during working days exceeds that of weekends. At Amsterdam, rainfall is higher than the surrounding area, and this is distributed evenly throughout the year. The wind. Because of the high aerodynamic roughness of urban development, the mean wind velocity in the city is smaller than in the country. For Moscow the city values of the yearly wind velocity averaged 0.9 m/sec. lower than that of a nearby rural station. The disturbance manifests itself through locally distributed turbulent movement. Moreover, during periods of calm weather the city heat island may cause a local low inducing a country breeze and by consequence upward currents over the city itself.

In very polluted urban regions the frequency of fog is higher than in the sur-

Although average changes in climatic elements caused by urbanization have been quantified, Table 1, there is, as yet, insufficient evidence to draw any firm conclusion in regard to these various factors.

Table 1. Average changes in climatic elements caused by urbanization (Landsberg, 1970)

El emen t Comparison with rural environment

Contaminants - condensation nucleii and particles 10 times more gaseous admixtures

Cloudiness - 5 to 25 times more

Cover 5% to 10% more fog, winter 100% more fog, summer 30% more

Precipitation - totals days with less than 5 mm snow f al 1

winter summer

Radiation -

Relative Humidity -

5% to 10% more 10% more 5% more

2% less 8% less

global 15% to 20% less ultraviolet , winter 30% less u1 tr avi ole t , s umme r 5% less sunshine duration 5% to 15% less

annual mean to 1 C more winter minima (average) 10 to 20c more he at degree -days 10% less

annual mean 20% to 30% less extreme gusts 10% to 20% less calms 5% to 20% more

Temperature - O O

Wind Speed -

21

Summary of findings

Heat releases into the atmosphere and into water bodies ‘are to a large extent (perhaps two-thirds) concentrated in the densely populated urban areas that constitute only a fraction of the land area of the world ...... The effects of urban and regional heat sources on continental and global climate are uncertain‘ , (Anon,, 1971).

I-2.4 Changes in surface and groundwater flows

Urbanization substantially alters precipitation-runoff relations compared with those €or natural drainage. Despite a number of studies that have been made, the time/space relationships of the urban runoff process are still not very well quantified. As a result, generalizations can be made only at extreme hazard and those that follow are offered as tentative observations.

The increase in the impervious area that accompanies urbanization tends to reduce the volumes of infiltration and evapotranspiration of a catchment. Surface detention storage characteristics can be drastically changed, as street runoff ‘collection arrangements and underground drainage conduits facilitate rapid removal of water from the surface of the ground. i d 1 these factors collectively change the surface runoff regime, a change which is often reflected in an alteration in the amount of groundwater recharge.

receiving streams can be diminished as a consequence of the increase in impervious area diversions and bed recharge, and can be raised by the discharge of effluents that originated as imported water. Local runoff can also be increased as a result of the greater local precipitation produced by urbanization. Over-exploitation diminishes the overall yield of groundwater supplies as water levels and pressures in groundwater reservoirs progressively decline. Evapotranspiration can be reduced in respect of impervious surfaces and increased where cultured ground-growth is extensively irrigated. \iater yield can be enhanced by human intervention, such as groundwater recharge, successive multiple reuse, desalination and weather modification. The yields of portions of aquifers may be increased by leakage from water distribution systems or be decreased by drainage into foul, storm and combined sewers.

surfaces, means for collecting drainage at the surface, and underground conduits for artificial drainage, are thought to result in the faster, greater runoff peaks than would normally be experienced in the absence of urbanization. The cumulative effect of increased surface water volume and localized flood peaks may be to accentuate mainstream flooding. Flooding can be aggravated by the occupance of flood plains and associated flood-prone areas by dwellings and other structures.

that urbanization results in increases of surface runoff volumes and peak flows and decreases in base flows.

A management problem that occurs in many coastal countries is the intrusion of salt water into well fields subjected to heavy groundwater withdrawals ; serious intrusion have occurred along seacoasts and estuaries.

ial plains composed of geologically young deposits, where serious land subsidence has occurred as a consequence of intensive groundwater withdrawal for industrial and municipal use and/or natural gas exploitation, (Anon, 1970). Areas of subsidence are more susceptible to inundation from surface runoff, aggravated by high tides in coastal areas. Probably the best- known incidence of subsidence related to groundwater withdrawal is the sinking of Venice. Subsidence of half a metre to a metre have occurred in some Swedish cities (Lindh, 1972). Because no a priori data exist, it is not possible to evaluate the role of impermeable urban surfaces in lowering groundwater levels by way of reduced natural recharge, but this reduction must have a bearing on subsidence occurrences. 90% of their volume when drained.

‘Related phenomena are the acceleration of sinkhole development in certain limestone areas from groundwater withdrawal, and those landslides induced by slipping of ground that previously had stable slopes. Soil collapse and a resulting land subsidence can be facilit- ated when water is added in large amounts, particularly in loess deposits.

Land reclamation causes drastic changes in the immediate hydrological vicinity, (Zuidema, 1974). The outstanding example is the polder development in the Netherlands, where a large inland bay has been separated from the North Sea by a dam, divided i-ito parts by dikes, arid drained for agricultural and urban uses. About one-third of the Netherlands is at an eleva-

Both local runoff and catchment annual discharge are generally increased. Base flows of

The volume of flood runoff increases as the degree of urbanizatiori increases. impervious

ïn several countries, including Sweden (Ernfors and Isgard, 1970) , it has been observed

As elsewhere, many of the large cities and their environs in Japan are located on alluv-

I-’eat formations, for example, may lose

22

Summary of findings

tion below the normal range of tides, and another third extends only 10 m above this level. Lust about every conceivable water management problem is encountered in polder development, from defence against salt water intrusion to the control of groundwater and surface water pollution.

i-2.5 Water supply and water conservation

Water availability has affected the viability of ancient civilizations and the economic vit- ality of modern nations. In general, there appears to be a loose relationship between the extent of urbanization and the abundance of national water supplies.

domestic purposes , (Peixoto and Kettani, 1973) . uses are given in Table 2.

nation, the Federal Republic of Germany expects an increase from 540 m3 in 1970 to 820 m in the year 2000, for domestic, industrial and agricultural uses.

Flater is a necessity for development, though only a small portion of it is used for

Recent estimates by the USSR State Hydrological Institute, of principal global water

As an indication of growing demands per capita in cubic metres/year in a developed 3

Table 2. Present and projected water use, cubic kilometres

1 9 7 0 2 0 0 0 Continent

Domes tic Indus tri al Agricultural Domes tic Indus tri al Agricultural

Europe 30 160 125 77 32 4 320 Asia 40 50 1300 200 360 2 300 Africa ? 3 120 42 50 2 60 North America 40 267 206 77 9 20 300 South America 4 12 64 40 170 120 Australia and Oceania 1 8 12 4 22 40

Totals 119 500 1827 4 40 1846 3340

Table 2 indicates that the water demand of the more developed continents will increase less than those of continents which include most developing countries. Table 3 shows the relative increase of water consumption in the period 1970-2000 for domestic and industrial use.

Table 3. €%elative increase of water demands to the year 2000 (1970=100) for mostly developiilg and mostly advanced continents.

Domestic Indus trial

Mostly developing continents 500-1050 700- 17cO Mostly advanced continents 200- 400 200-350

Table 3 suggests Large increases and the redistribution of the four principal water uses (domestic, industrial, agricultural and cooling water) by the year 2030 compared with an estimated total global runoff of 47 O00 km3/year. municipal, most energy and the majority of industrial needs are in or near urban areas, strongly indicates a massive acceleration in the hydrological effects of urbanization, especially in developinq countries. Perhaps over 40% of the reauirements in the year 2000 or over 2300 km3/ year, will be for urban areas, which would represent a four-fold increase over requirements in 1970. above figures. water resources will have to be improved, such as by more extensive re-use, in certain regions of a number of nations.

(Lvovich, 1974). This plus the fact that all

A growing competition between urban and agricultural water uses is also suggested by the Farming efficiences will have to be raised (Penman, 1970)and husbandry of urban

23

Summary of findings

On a local scale, the intensive concentration of large numbers of people in urban areas is characterized by water demands exceeding the yields of the parts of catchments in the immediate vicinity. affected in the acquisition of its water supply. water from distant sources, but little is known about the effects of such water transfers on the regional water balance and associated water quality,

'Urban water supply is a critical factor in public health and economic development in m s t parts of the world, particularly in the developing countries. water resources a high priority should therefore be given to metropolitan use', Committee , 1965b) .

Figure 3 illustrates the subsystems involved in waste water re-use and emphasizes the environmental impacts beyond the water system. ment of urban water resources can be significant.

ponding increase in the volumes of waste water. posal problem parallels that of the water supply problem.

Noting the continuously changing composition of urban waste waters and resultant alterations in the character of receiving waters, the need for more water re-use is foreseen in the U.K. 'The combined effect of increasing abstractions from and discharges into our rivers is to accelerate the rate at which the quality of their water is being changed. If these trends continue unabated, and at present we see no indication otherwise, we shall before the turn of the century be compelled to re-use water much more than we do now. Concurrent with these changes is a greater use of our rivers, estuaries and inland lakes and reservoirs for recreation and as general amenities'. (Department of the Environment, 1971). The report also notes existing and potential adverse effects on groundwater quality. It expresses the universal concern on the public health implications of the increasing variety and incidence in water supplies for community use, of heavy metals and other trace elements, and exotic organic substances , to which could be added pathogenic organisms.

Reclaimed waste water has been used directly as a potable water supply in South Africa, (Cillie, VanVuuren, Stander and Kolbe , 1967; Henzen, VanVuuren and Stander, 1973) as a source o5 recreational water in the USA (Parkhurst, 1967) , and for industrial water supply in Japan (Kubo, 1973). In the UK there axe instances of water shortage being alleviated by supplying high quality effluents to industry. Artificial recharge with treated waste water effluents to augment groundwater supplies is widely used , Sciences, 1973). However, a variety of pollution problems can be encountered (WHO Expert Committee, 1968) that offset the advantage of recharge. In addition, the natural dissolved mineral content of water tends to increase in concentration with each successive re-use unless removed prior to each re-use.

questionnaires to experts in many countries throughout the world , requesting information on re-use of waste water practices. Replies from 30 countries were received. An analysis of the replies indicates that re-use of waste water for agricultural purposes is by far the largest use (18 countries), while the re-use of waste water for industrial purposes is on the increase , particularly for cooling purposes. Increased re-use of treated waste water is also being practiced for recreational purposes, such as fishing, and even bathing, as well as for irrigation of public parks, golf courses, etc. The only example of direct re-use to supplement domestic water supplies is reported from South Africa.

There are significant public health implications in the re-use of reclaimed waste water (WHO, 1973; Shuval, 1969). If waste water is to be used to supplement domestic water supply, the most stringent quality requirements , both chemical and bacteriological , must be applied and enforced. (WHO , 1973 , Anon. , 1972a) . Furthemore , it is recommended that extensive research be carried out on the possible health effects of consuming reclaimed waste water. This will make possible the establishment of acceptable criteria for the re-use of effluents for potable purposes , (WHO , 1973) .

Too often overlooked as measures for conserving water are reductions in user waste, the possibility of metering , and leakage reduction in water transmission and distribution systems. It can be stated that judiciousl-y applied 'conservation' measures will make it possible to use water of first quality for domestic purposes, while waters of secondary quality can be used for other purposes. In any event, the adequate treatment of waste water is imperative both

The larger an urban complex the greater the hydrological region that may be Large demands often are met by bringing

(Lindh , 1972) .

In the allocation of (WHO Expert

hs competition for water grows, the practice of re-use will necessarily increase sharply.

The role of waste water reclamation in the manage-

As water abstractions for domestic and industrial uses increase there will be a corres- That is, the scale of the waste water dis-

(International Association of Hydrological

Tñe World Health Organization (WHO Expert Committee, 1968; WHO, 1973) submitted informal

24

25

Summary of findings

for pollution control and for supplementing water resources for other beneficial use ( M O , 1973) .

Because water is qenerally regarded as a 'free good' , the price charged for it too seldom reflects true total cost and , except for outright shortages, incentives for conservation do not often exist. 'In most countries the price charged for water is well below its real cost to the economy, in contrast to other production inputs, in which, with some notable exceptions , real costs still regulate man's economic behaviour . No wonder, therefore , that the introduction of water-conserving facilities and of water substitutes has never risen to an economically justifiable level' , (Wiener, 1972).

1-2.6 Water quality and pollution effects

Major streams pass through many metropolitan areas. Advances in relevant methods of runoff analysis were considered at the International Symposium on Mathematical Models in Hydrology at Warsaw, Poland, in July, 1971, and earlier by Dawdy and Kalinin (1970). Some streams are estuarine when they reach metropolitan areas, and methods of analysis in this situation have also progressed considerably in recent years, particularly with regard to water quality parameters (Orlob, 1972). Progress in stream water quality analysis has been greatly enhanced by the growing use of automatic monitoring (WHO, 1971). In some areas where groundwater is used for water supply, deterioration of its chemical quality has been recorded due to overpumping, especially in coastal aquifers where sea water intrusion takes place.

Major causative sources of water quality degradation in urban areas include: agricul' tural storm runoff; soil erosion; combined sewer overflows; industrial process effluents; heated effluents from electric power plants; community waste water treatment plant effluents; natural drainage from marsh lands; leakage from septic tanks and cesspools; urban storm runoff; contamination from surface of roadways , spills and leakage from oil and chemicals; contamination from mining activities; and waste water discharged because of inadequate or malfunctioning systems of sewerage. Such degradation inhibits and/or makes more costly: use and re-use of urban surface water and groundwater supplies; water-oriented recreation; waterfront use , aesthetic improvements; aquatic life; commercial fisheries; shipping and navigation; waterfowl and sport fish propagation; and a number of other uses and cervices.

'In the absence of careful planning, urban centres are particularly susceptible to communicable diseases , particularly those which may be water-borne. . . . . . . The lack of sewerage and sewage-treatment facilities in many metropolitan areas of the world is a major cause of communicable diseases , including cholera , typhoid, diarrhoea, dysentery , filariasis , haemorraghic fever , infectious hepatitis , etc. , (WHO Expert Committee , 1965) .

elements and from myriad synthetic organic chemicals disposed of by industries also pose serious threats to public health. For example, mercury residues have been reported in many types of agriculturally produced food and in wildlife , including fish, (Ackefors , Lofroth and Rosen, 1970). High levels of mercury were found in algae collected at a site on an estuary flushed by fresh river water, whereas no mercury was detectable in algae from a fully marine sector beyond (Jones, Jones and Stewart, 1970). An extensive bibliography (with abstracts) of the worldwide literature on metals as pollutants was given by Sinha (1972). While residuals from synthetic detergents in domestic waste waters (even after treatment) have caused problems of foaming and excessive enxichment of receiving waters, these effects are not as menacing as the possibility that these substances, even in very low dosages, can stimulate the entry of various other chemicals from the intestine into the blood of a human being; this raises the potential toxic effect of the other chemicals, (Mozhaev, Osintseva, Yurasova, Lin'kov and Litvinov, 1972).

Most developing countries are situated in tropical and semi-arid regions . . . . . . the developing countries are those that have the greatest rate of population growth and a very high rate of urbanization and industrialization. Since water pollution is caused by the activities of man, it occurs to the greatest extent where urban populations are growing rapidly and where water resources are limited' , (WHO Expert Committee, 1968). This is not to suy- gest that developed nations have solved their water pollution problems - far from it. For example, the Rhine River, which drains a major portion of the heart of Europe in its 1300 km journey to the North Sea, is subjected to many types of pollution that have defied acceptable international control for decades, (Montgomery and Merklein , 1972) . According

As noted in the preceding section', water pollution from heavy metals and other trace

lLJidespread and serious water pollution has occurred in developing countries. . . . . . .

26

to a 1967 study (Bundesminster des Innern, 19711, the natural self-purification capacity of the lower Rhine River had been reduced-by 30% over only a few years as a result of toxides. The Netherlands has severe problems caused by the residual accumulated in the river in its passage to the sea.

the last two decades, and many inferences on its significance have been made, (Shigorin, 1965; Wilkinson, 1956; Kurzweil, 1968; Weibal, Anderson and Woodward, 1964; Negulescu and Rabinovici, 1964; Pravoshinski and Gatillo, 1968; Kinosita and Sonda, 1969; Soderlund, Lehtinen and Priberg, 1971; Muller, 1971; Field and Struzeski, 1972). Findings from measurements in two separate storm sewer systems in Sweden showed that by comparison with treated waste water, storm water runoff contained considerably greater amounts of suspended solids, but lesser amounts of BOD, phosphorous and nitrogen, (Soderlund and Lehtinen, 1973). The results also indicated that the pollution potential of flows from separate storm sewer systems is probably as great as the pollution potential from combined sewer systems. from Stockholm in one year and deposited in receiving waters, it has been estimated that there were 30 O00 kg of lead, 6000 kg of oil and 130 000 kg of sodium chloride, plus other contam- inantsr EIad the snow been allowed to melt where it accumulated. these contaminants would have passed throuqh the drainage svstems and possibly into groundwater supplies. There is widespread agreement that as pollution from point-source waste water effluents is progressively reduced by higher deyrees of treatment, it will become increasingly necessary to reduce pollution from storm sewer discharges and combined sewer overflows. Because of the 4udd.en and brier occurrence of these flows arid the larqe number of outfalls involved, this reduction will be very costlv, per- hams eaualiina or exceeding the cost of waste water treatment for the same area.

Natural and artificial lakes and slow-moving streams serve as inadvertent sinks for tributary contaminants. The danger of accelerated eutrophication continues to grow as stresses on natural water resources increase. In a number of countries there are instances where accelerated eutrophication is inhibiting uses, such as recreation, and where the main sources are urban. For example, a third of the phosphate input associated with the accelerated eutrophication of water bodies in the Federal Republic of German, originates from leaching of fertilizers from the soil, a third is from human metabolism and the remaining third is from detergents; that is , two-thirds is of distinctly urban origin.

Highly industrialized nations are strongly dependent on the instantaneous availability of energy of numerous types from various sources. Transformation of fuels into electrical power requires the production of thermal energy as an intermediate product. Because typically well over half of the thermal energy content is not converted into electrical energy, it must be necessarily released into some reservoir, such as the atmosphere, streams, and water bodies; this can result in thermal pollution. Waste heat is also released into waters from other industrial processes, but the predominant source is cooling water for generation of electricity.

transferred primarily to the atmosphere. Increased temperatures from waste heat raise the rate of evaporation from streams and other open water surfaces. Other consequences of changes in water temperature regimes are generally associated with the resulting acceleration of chemical and biochemical processes. Thermal pollution can damage aquatic life and recreational use of water by adversly affecting its oxygen content. On the other hand, there are some beneficial uses of heated water, (Mathur and Stewart, 1971), such as for fish farming or agriculture in colder climates.

of water pollution. In most countries the amount of electrical power generated roughly doubles every ten years. The trend towards large nuclear plants, which discharge one and a half times as much thermal load in water per unit of power as fossil-fuel plants, adds to the increasing threat to aquatic systems. Emerging conflicts between electrical power needs and environmental protection have been recognized, as for example, in Western Europe (Future Shape of Technology Foundation, 1971).

Field research on pollution from urban surface runoff has been undertaken over at least

ïn approximately 850 O00 m3 of snow removed

Heat is not conserved in the hydrological cycle, unlike many pollutants, but is ultimately

Waste heat from electrical power generation can be one of the most serious emerging sources

1-2.7 Other hydrological implications

Many of the world's major metropolitan centres are on or near ocean coasts and estuaries, and the muta1 dependency and interaction between marine ecology and the marine urban environment is becoming increasingly appreciated. Major causes and forms of marine pollution, including

27

Smmury of findings

disposal of domestic and industrial wastes, have been outlined, existing legal and administrative controls have been examined, and present needs and future solutions have been reviewed, by the Office of Legal Affairs of the United Nations, (Hardy, 1971). Nevertheless, an important aspect that deserves geater attention is the effects o€ pollution on biological equilib- rium and bioproduction, such as in the study of the north Adriatic and northern African coastal waters, (Stirn, 1971). Also, the coastal fisheries of many nations are a significant source of their food, and the navigation canals of Europe that connect with the seas are an essential means of transport and provide substantial recreational opportunities for many people.

sources; streams that have natural outlets at the seas; ships and small craft anchored in ports and along the coast; and drainage canals, (Anon, 1971). Pollution effects are: the presence of aesthetically unpleasant impurities of a malodorous nature; a direct danger to public health by infection; an indirect danger by infection from pollution of shellfish and other seafood; the poisoning of marine fauna; and the lowering of productivity in coastal waters, (Anon, 1971b).

In certain circumstances, the presence of nutrients can increase the productivity of aquatic life and lead to biological instability. Most chemical pollution problems are toxicological, and some of the most difficult problems in the marine ecosystem are associated with chronic intoxications that have low-level cumulative effects which can result ir! tremendous build-ups of toxic constituents in the environment before they are even detected, (Halstead, 1971). One of the most seriously stressed coastal zones is the southern part of the North Sea (Shaler, 1971).

Another pollution problem that seems to become increasingly severe is oil pollution, mostly caused by accidents occurring on land or at sea. weight is oil, (LJNESCO, 1970), the biota of most coastal areas are threatened by possibilities of accidental spills.

pollution by increasing water turbidity and disturbing oxygen-depleting benthal deposits.

there is only a modest degree of erosion in well-established urban sectors, field measurements in small catchments in England indicated that during the construction of buildings the concentrations of suspended sediment are from 2 to 10 times as great as for undisturbed conditions, and occasionally are 100 times as great, (Walling and Gregory, 1970). Some research measurements in the USA show that for areas undergoing suburban development the sediment loads can be as much as 5 to 500 times greater than in rural areas, (Powell, Winter and Bodwitch, 1970). Sediment from erosion impairs water quality, reduces reservoir storage, and damages recreational waters, quantitatively and qualitatively , such as by accelerating eutrophication - Effectiveness of mosquito-control works can be seriously reduced by erosion-deposition occurrences. The biological viability of aquatic biota is generally affected adversely by suspended matter. Public safety can be threatened by erosion caused by large flows over the flood plains that imperil structures and buildings, including the collapse of levees and dams.

some cold-climate urban areas, salting of streets and highways, to melt ice and snow, results in localized concentrations of leachates in the soil, (Pionk and Nicks, 1970) .

whereas on the urban fringe and in open countryside the amount declines to about 132 tonne/ sq km/year and 70 tonne/sq km/year, respectively, (Brown, 1970). According to computations in the USSR, based on data from field observations, precipitation brings 5 to 10 tonnejsq km/ year of dissolved matter to rural areas and 20 to 30 tonnejsq kmjyear to urban areas, (LVOV- ich, 1964). Pollutants transmitted from the atmosphere to the ground can form one of the most severe effects of urbanization on hydrological processes.

A number of hydrological effects of mining activities that affect urban areas are noted in Parts II and III of this report. Notable among these activities is open cast mining near settlements because of extensive amounts of land involved and the drastic changes that open cast mining can produce, in the local water balance. Judicious management can minimize unfavourable effects and there axe instances where abandoned pits have been reclaimed for water- based recreation and for landscape enhancement as, for example, in the Federal Republic of Germany. Even deep underground mining, such as for coal, can lower groundwater levels due to heavy pumping used to de-water tunnels and shafts. The more serious effects of mining include

Basic sources of coastal pollution are discharges from: adjacent urban and industrial

Because half the world's ocean cargo

Periodic dredging of ship and boat navigation channels in ports and canals aggravates

Urbanization and associated human activities have accelerated land erosion. Although

Various solutes, such as herbicides and insecticides, enter aquifers and streams. In

In English industrial areas, atmospheric deposition may exceed 395 tonne/sq km/year,

28

Research und BeveZopment

contamination of waters by saline drainage and by the unused residuals that accumulate in spoil heaps and are leached by precipitation. In addition, acids can be formed in abandoned underground mines as a result of exposure of rock surfaces to air and water, and when these acids seep into surface waters their biota may be destroyed.

matter and nutrients be recycled within the ecological system where economically feasible. For example, it may be feasible to return wastewater to the land or use it productively in aquatic system, (The Institute of Ecology, 1972). Possibilities exist for much more extensive land-disposal of treated waste water, which has the advantages of reducing surface water pollution, increasing groundwater recharge and utilizing nitrates and phosphates for crop production instead of promoting algal growth.

mineral content of waste water is substantial, amounting to up to about 50 kg per capita of dry solids annually, not including industrial wastes , (WHO Scientific Group, 1967) . Disposal difficulties are being encountered in some countries because available land sites are remote making transportation to them costly, and because new regulations in some cases prohibit further practice of disposal at sea.

Land sites utilized for the disposal of solid wastes can be a source of groundwater and surface water contamination. A Study in Sweden revealed that the biological pollution level of water after its passage through a domestic waste dumping site on land can be 10 times as great as for municipal waste water, (Lindh, 1972). There are numerous cases where the dual objectives of solid wastes disposal and filling of low-lying land were met, but there are strong suspicions that several of these may have contaminated the underlying groundwaters.

balance of the groundwater above the permafrost zone.

To offset the adverse effects of water pollution, it has been suggested that organic

Waste water treatment removes solids which also require disposal, and the organic and

Experience has shown that urbanization in permafrost regions affects the heat and water

1-2.8 Conclusions

From the summary findings given in this chapter and from the questionnaire on research development needs, Section 3.3, conclusions and recommendations on urban hydrological research have been derived. These are given in Section 3.6, where it is noted that such research projects can be executed as international activities.

1-3 RESEARCH AND DEVELOPMENT

1-3.1 General status and basic conclusions and recommendations

Although many nations have immediate needs for advanced knowledge in the field of urban hydrology, research and development has been inadequate and there has been relatively little study to date of the effect of urban man upon natural hydrological conditions. Evaluations of the effects of urbanization on the hydrological system encounter a substantial increase in complexity over pre-urban conditions. Approaches to urban water resources development generally, and urban hydrology specifically, are too often over-simplified by using techniques developed for non-urban applications. Urban water research that has been conducted has been many-sided, mostly disjointed, and usually pursued over a short period of time compared with traditional hydrological practice, despite the fact that most urban areas are almost constantly undergoing change. As a result, this report is necessarily restricted to the citation of tendencies because few meaningful general quantitative conclusions are available from research findings .

and effects are simi Zar in technoZogicaZZy and economicaZZy advanced countries. Further, many probZems confronting the devezoping nations have at one tinte or another azready been encounteredby many deveZoped nations. uZt from exchanging information and increased internationa2 co-operation in research and deve Zopment . there is a need for more comprehensive and more systematic investigation of hydrological changes in urban areas. More metropolitan-scale water-balance inventories and their analysis should be undertaken as a means for improving overall water resources planning and management, and subsequent inventories should be made periodically to document change and to provide a

The most significant concZusion of this report is that most urban hydroZogicaZ probZems

This strongZy suggests that great benefits wouZd res-

Because of the increase in complexity of water problems brought about by urbanization,

29

Research and development

better understanding of the hydrological effects of progressive urbanization. This call for more water-balance inventories is the direct result of a clear recognition of the interrelation, interdependence and interconnection of the elements of the water resources of a metropolis. That is, a total resource systems approach is necessary if sub-system phenomena truly are to be characterized, because of the complex linkages involved. Also, metropolitan land- use constantly changes, an occurrence which can only be accommodated by using a total systems approach.

The interrelation and interdependence of water and waste water and the competition and conflict between various statutory authorities have intensified with the growth of metropolitan areas. The variety of uses for water in metropolitan areas are constantly increasing, particularly for recreational purposes and for aesthetic enhancement. Also, people living in urban areas have an appreciation of aquatic life as part of their natural surroundings. Therefore, hydrological surveys of urban areas should be updated frequently and regularly.

Physical planning has always taken place in an atmosphere of tension between the satis- faction of present and future needs. Evidence of continued geometric growth of urban populations, urban land development, industrial and mining pursuits, water abstraction and pollution burdens, strongly suggests that total time dor developing urban water resources programmes and projects must be substantially reduced compared with the total development time that could be allowed in the past.

is the result of increasing demands of man himself. Modern man increasingly demands more water, more energy and more consumer goods. The results are more wastes of all kinds and increasing degradation of the environment. If the quality of life is to be protected and enhanced it is necessary to appreciate social and behavioural adjustment in order to ensure that static natural resources are used judiciously.

1-3.2 Current activities

Some research and development accomplished and under way in the nations represented by the Sub-Group is cited or implied in Parts II and III of this report. have been limited to the analysis of effects on a single component of the hydrological cycle, such as the effect on flood peaks or on low flow, or may be relevant only for a single geographical setting. In general, the available information is of severely limited application to other areas, partially as a result of the web of complexities imposed when open land becomes urbanized, but mostly because of investigative commitments well below levels that would be consistent with the economic and environmental importance of urban concentrations. To re- iterate, there is a general scarcity of data and information everywhere that can be used to relate changes in urban development with changes in the hydrological regime and vice versa. Although some data and information is available in every country and has been used to develop estimates of the effects of urbanization on the hydrological cycle, the data and research studies have been predominantly very fragmented.

piled. The catalogue would include descriptions of laboratory and field studies; instrumentation; methods of processing and analysing information from experiments; development of models of urban water systems and urban planning; analysis of water quantity and quality processes; observations of climatic modifications. This would be a difficult and large task, and probably should be undertaken by an international organization. However, a catalogue is justified considering the importance of problems connected with the hydrological consequences of urbanization, the evolution of which will continue to be rapid in all countries in the future, and recognizing the complexity of research to be undertaken and the length of time necessary for results to be obtained for guidance in the control of these consequences. A broad summary of problems and effects among nations, noted in Section 1-3.1, strongly suggested that there might be a substantial global return from greater international co-operation in research and development. The logical way to initiate a new co-operative effort would be through the proposed catalogue, because this information is urgently required.

In the absence of a comprehensive catalogue, the major research and development needs identified in Section 1-3.3 must be considered as reflecting a sample of international professional opinion rather than a complete global view. However, it is very significant that over thirty nations associate their major needs with a very small number of items.

Last but not least, it should be recognized that the extensive urbanization phenomenon

In most cases, studies

A catalogue of relevant current research around the world is needed and should be com-

30

Research m d deveLopmmt

I- 3.3 Inquiry on research needs

The Sub-Group identified 13 research topics on which, in the opinion of its members, more information is required to establish the effects of urbanization on the hydrological cycle. These topics are listed below in the approximate order of their importance or priority as defined by the Sub-Group.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Changes in urban runoff Measurement of discharge in sewers Experimental cat chment ar ea s Limnology of shallow lakes Mathematical models of river and lake pollution Water demand forecasting Soil-moisture and groundwater Thermal pollution Direct disposal o£ wastes to groundwater Application of isotope techniques and remote sensing Effects of industrial sludges on natural purification of rivers Air pollution- water quality relationships Microscale climatic factors

On behalf of the Sub-Group, the Secretariat of the IHD/Unesco sent a questionnaire on these research needs to all national committees for the IHD. The questionnaire posed three main questions I

a.

b. c.

Respondents to the questionnaire are identified in Annex I.

What are the major subjects needing serious research and development attention in your country and what is their approximate order of importance or priority? Why does your list for the preceding question differ from that of the Sub-Group? Can you specify some of the more important aspects of information needs within the individual subjects you have listed?

Table 4. Summary of responses to questionnaire

Percentage of response Topic is among Topic Approximate

has overall a Among Among Among Among priority

Topic highest priorities Topic description No. in research top 3 top 4 top 5 top 6 topic

priority topics topics topics topics questionnaire

(%I (%) (%I (% I (%I 1 2

3 4 5

6 7 8 9

10

11

12

13 14

Changes in urban runoff 86 71

46 18 Measurement of discharge in sewers Experimental catchment areas 75 43 Limnology of shallow lakes 46 7

61 14 Mathematical models of river and lake pollution Water demand forecasting 68 36 Soil moisture grpundwater 79 25

Direct disposal of wastes to groundwater Application of isotopes techniques and remote sensing Effects of industrial sludges

54 7 Air pollution - water quality relationships Microscale climatic factors 54 4 Topics not in questionnaire 14 4

Thermal pollution 43 7 68 25

61 4

on natural purification of rivers 68 21

75 79 79

28 28

x, 61 18 28

14 2 5

46 46 39 54 7 14

36 43

7 7

28

64 36

39

54 61 18

50

18

32 39 39

11 14 21

4 7 7 7 11 14

1

10

2 9

7

4 3

13

5

8

6

11

12 14

Research and devezopment

Table 4 gives a summary of the replies to the questionnaire. Nearly all of the respondents indicated or implied that the topics in the questionnaire completely covered their own list of priorities. More than half of the respondents agreed with ten of the thirteen Sub- Group topics. Several respondents suggested that the number of topics should be reduced further to those of most widespread interest and concern, to facilitate the organization of any new arrangements for international co-operation, discussed in Section 1-3.5. Because of differences in size of the urban populations of the responding nations, it is almost impossible to evaluate completely objectively the professional views offered. Therefore, in preparing Table 4, responsec’ were considered to be of equal value.

1-3.4 _Maior research and development needs

The preceding summary of replies to the questionnaire indicates six priority topics (descriptions have been modified where two or more respondents recommended a specific clarification, and the six topics are not in order of priority - obviously each nation would select its own priorities in accordance with its needs):

T1 Changes in surface runoff caused by urbanization, amount and quality (including sedi-

T2 Research on quantity and quality of runoff in terms of precipitation occurrences in

T3 Soil moisture and groundwater, quantity and quality relationships and effects; T4 Water demand forecasting, including technical, economical, social and political asp-

T5 Water quality effects related to gxoundwater arising from direct disposal of wastes

T6 Effects of waste water and sludge on the natural purification capacity of receiving

Explanations follow of the purposes of and needs for the above six topics; following the

ment), for storm water sewerage and urban streams;

experimental catchment areas ;

ects, and quality of source considerations;

and to indirect pollution from disposal of solid waste materials;

waters and their aquatic life, taking into account the processes involved.

discussion on each topic, the identification numbers of the related ‘Recommendations for international action’, from Section 1-3.6, are given in parenthesis.

T1 Surface runoff chmges. The objectives are to determine the amount and distribution of precipitation, evaporation, runoff and water quality, including sediment, within and discharged from urban systems, in flat regions and areas with steep slopes. This should enable the development of much improved models, needed for the design of urban storm water systems, both in terms of quantity and quality. Information, currently available, does not permit adequate consideration of improved techniques and requirements for urban areas, such as detention storage and quality control. (R3, R7, R8, R9 and R11)

mental catchments and to achieve major savings through wider use of existing data, it is necessary to improve, standardize and co-ordinate the collection of data and rep- orting and dissemination of results on an international basis. It is noted that experimental catchments are suited to the study of changes resulting from urbanization as described in T1. Obviously, data collected should be of comparable precision and should be usable in similar analyses for the development of valid models. Moreover, emphasis should be placed on facilitating the exchange of data among areas with similar conditions. (RI, R7, R8, RlO and Rll)

ing and controlling environmental changes brought about by urbanization. include base flow, effects from agriculture, structuxal considerations, and erosion. Included should be studies of the effect of urbanization on soil moisture-groundwater relationships, soil temperature, soil chemistry and infiltration. (R3, R7 , R10 and

T2 Experimental catchments. In order to make more effective use of data from experi-

T3 Soil moisture and groundwater. This research is particularly important in understand- These changes

R1 1) T4 Water demand forecasting. Because urban complexes are rapidly increasing in popula-

tion it is imperative that future demands be reliably determined so they can be related to alternative potential water resource plans. Also, as environmental considerations become more important, it may be possible to-reduce the need for additional sources of supply through more reliable forecasting. It should be emphasized that the focus here is on the social system (water resources) rather than on physical system (hydrology). (R5, R6, R7, R10 and R U )

32

Research and devzzopment

T5 Groundwater quality. It is recognized that the concentration of wastes in urban complexes in increasing both on a per capita basis and because of rapid increases in urban populations:. It is necessary from a public health point of yiew to know and predict the affects on water quality. It is further noted that research is needed both on disposal of liquid wastes in relation to groundwater and on the indirect effects of leaching of solia wastes on the surface. (R2, RlO and R11)

Water quality standards will be determined on a nation by nation basis. Depending on these standards the impact of waste water and sludge will vary. taking into account the use of the recipient water.

T6 Waste water and sludge effects.

Research is needed to determine how much treatment is necessary, (R7, R9, R10 and Rll)

Several respondents to the questionnaire mted that topics T1 and T2 are closely inter- related, that changes in runoff can best be documented by observing the responses of instru- mented catchments. Interest was not restricted to flooding and water quality considerations. Several respondents from countries with limited sources of water supply, expressed a particular interest in reclaiming urban runoff to augment supplies. Storm water sewerage here includes both storm sewer discharges and combined sewer overflows.

Land subsidence and land slides, related to topic T3, are subjects of serious concern in a number of countries.

Interest was expressed in the character of water demands, topic T4, by type of use, such as dense residential, light residential, kind of industry, etc. (An Expert Group meeting was held from 10 to 12 May 1972 in Budapest, Hungary, on the forecasting of future demands for water. The 17 working papers prepared by the participants of the meeting are available from the U.N. Secretariat).

and sludge. Although the questionnaire mentioned only sludge, several respondents added waste water to the topic description. Further, there was a persistent call for the application of available knowledge on domestic waste water and sludge, to studies of industrial effluents.

The point was made that the accent on limnology (topic 4, of the original listing) was too narrow and that an ecological base would be better, particularly if the subject could be expanded to encompass all types of water surface waters.

The Sub-Group recommended that emphasis be given to the inclusion of urban water matters as a part of urban planning and to the need for keeping this objective in mind when designing research and development studies (see Recommendation R7 of Section 3.6).

At the Warsaw Workshop it was agreed that before each nation draws up its priorities, an effort should be made to quantify the benefits of urban hydrological research, in terms of improvement of the quality of life of the people. Each nation should also quantify the adverse consequences of not proceeding with this research. In addition, each major research topic (T1 to T6 inclusive) should also be evaluated in terms of its potential influence for improving the quality of life. This type of information is essential for proper planning for . the decision-maker (see Recommendations R5 and R6 of Section 3.6).

In some countries, mining wastes would be included with topic T6, industrial waste water

1-3.5 International co-operation

The frequency with which some problems are encountered in urban areal: throughout the world suggests that there is considerable scope for international co-operation, for example in technology and exchange of information and experience,

The value of international co-operation, as exemplified by this report, indicates the necessity to continue co-operation beyond the IHD by a variety of means specially designed for this purpose. Consequently the Sub-Group considered the following as general areas in which co-operation would be most effective.

(Russell and Landsberg, 1971).

(a) More case studies should be made by both developing and developed countries and

(b) Attention should be drawn to current research, including that being done in repres- made available for exchange.

entative m d experimental basins where urban areas are Yncluded; and efforts made to ensure that the results so far obtained are disseminated for international use by means of seminars and exchange of research workers.

(c) The success of the Warsaw Workshop as a means of intensive study of the effects of urbanization on the hydrological cycle leads the Sub-Group to make a strong recommendation to use this method of international co-operation where practicable in the future.

33


R1

R2

R3

R4

R5

R6

(d) Multi-national research programmes should be promoted to improve the quality of data being collected and to find ways of reducing the damage done to the hydrological cycle in urban areas.

and results between researchers and users. (e) Greater efforts should be made to ensure the effective transfer of research needs

The Director-General of Unesco submitted to the Unesco General Conference a report on an International Hydrological Programme proposed for launching in 1975. The following phrases from that report bear repeating here:

ever, a growing interest in this topic. This is timely, because of the greatly increased urbanization foreseen in all couhtries. A well recognized, but not well understood effect, is the change in the quantity and timing of runoff resulting from changes in land surface infiltration and roughness characteristics. Conditions are affected by changes in stream channel geometry, particularly during flooding.

subsurface disposal of industrial waste, and waste water return; also the results of the flushing action of flood storms are important.

being generated by research among hydrologists through publications and seminars. Evaluation a d interpretation of urbanization effects would also appear to be an area for technical ass- istance. Encouragement of detailed pilot studies by countries of a limited number of typical. urbanizing areas in order to identify changes , by means of representative and experimental basins or areas. International exchange of results would be a useful activity, provided the studies are well designed and executed, ' (Co-ordinating Council, IHD, 1972) .

Among the activities of the proposed IHP would be the 'exchange of information on hydrological research and progress of hydrology'. It is qratifying to note that one of the three relatively long-period research themes identified was the ' effects of human activities on the water cycle'. Section 3 of the Council report annex, on the 'Effects of man's activities on hydrological factors', includes references to the 'effects of urbanization'. The Sub-Group urges that urban aspects be given a higher priority in the IHP than appears to be designated. It is important to note that the solutions to urban problems frequently differ from those for river basin development and often require a somewhat different expertise and approach.

An international conference is to be convened jointly by the WMO and Unesco from 2 to 14 September 1974. The aims of the conference are to review the major results of the IHD and to Prepare a draft work plan of the IHP for the period 1975-1980.

1-3.6 Recommendations for international action

The Warsaw Workshop discussed a number of suggestions for projects suitable for inclusion in the long-term or short-term phase of IHP. The Sub-Group, taking into account these suggestions, makes the following recommendations (the relations of the recommendations to the topics T1 to T6 inclusive - Section 1-3.4 - are indicated by topic identification numbers in paren- theses at the end of each recommendation; however, no priority is implied by this list, which clearly does not cover all possible topics in urban hydrology).

'Effects of urbanization on hydrology have not been adequately studied. There is, how-

'Quality changes are extremely significant as the result of municipal and industrial use,

'Efforts need to be made by international action to widely disseminate new information

Catchment Studies Report. Prepare a ' state-of-the-art' report on research executed in urban catchment areas , which would include instrumentation, data acquired, analysis performed and applications. (TS) Solid Wastes Report. Prepare a 'state-of-the-art' report on the effect of solid waste disposal on water quality, which would include protection of groundwater and management of leachates. (T5) Mathematical Models Report. Prepare a ' state-of-the-art' report on mathematical models applied to urban catchment areas and dealing with, for instance, rainfall- runoff relationships and water balances, both with respect to water quantity and quality. (T1 and T3) Remote Sensing Report. Prepare a ' state-of-the-art' report on applications of remote- sensing techniques to urban planning in connection with hydrology. Socio-Economic Report. Prepare a ' state-of-the-art' report on the known social and economic importance and economic relationship of urban hydrology. Economic Justification Workshop. Organize a workshop to explore a further report (beyond R5) on identification and evaluation of important relationships between econ-

34

R7

R8

R9

Rlû

R1l

The


omics and urban hydrology and to provide guidance and justification for management decision-making. Planning Models Workshop. Organize a workshop on the impact of urbanization on regional total water management planning, in relation to comprehensive urban-oriented models, which will facilitate national and regional physical planning. (T1, TS, T3, T4 and T6) Experience Exchange Workshop. change of findings and experiences of industrialized nations to emerging industrialized nations. (T1 and TS) International Basins. Emphasize International co-operation, such as in the Rhine Basin, in developing a methodology of evaluation of the effects of urbanization on water regimes and water quality at the scale of an international basin and of regions of similar characteristics. (T1 and T6) Information Manuals. Develop criteria for achieving uniformity of observations and data collection, and produce a manual on methods of data collection and utilization with regard to urban areas. (T1 through T6) Research Catalogue. world, which would include short descriptions of: laboratory and field studies; instrumentation; methods of processing atid analysing information from experiments; development of models on urban water-systems and urban planning; analysis of water- quantity and quality processes; observations of climatic modifications; etc. (T1 through T6) Workshop recognized the necessity of publishing all exchanged information in con-

Explore, by a workshop, ways of facilitating the ex-

Compile a catalogue of relevant current research around the

densed written form.

with the economic and environmental importance of urban areas around the world.

in Section 1-3.4 cover essential hydrological topics. Table 5 has been produced from which the following conclusions may be drawn.

The Workshop urged Unesco to give serious attention to these recommendations in keeping

However, to illustrate how these recommendations as well as the research needs presented

The recommendations Rl-Rll are concentrated on organizational and methodological aspects , thus indicating those activity areas where international co-operation is most desirable. The research areas T1-T6 concern activities which are best carried out on national or regional bases, adapted to the prevailing hydrological conditions. Different hydrological topics are covered, although giving special emphasis to water- quality oriented research.

35

Research and deveZopment

Table 5. Extent to which hydrological topics are covered by research projects and recommendations.

Organiz- ational aspects aspects

Methodological Phenomenological aspects

Research Projects d

C 5;. z 07 a o

r d & C h @ o -4 4J .ri a id

and

Recommendations 9 rl U C

ci -4 C 4J

ai

ci 45

Research Projects (Section 1-3.4) - T1. Changes in surface runoff X x x X

T2. Experimental runoff catchments X

T3. Soil moisture and groundwater X x X X T4. Water demand forecasting X X X

T5. Groundwater quality X X T6. Waste water and sludge effects x x

x x x

Subtotals : 0 1 1 2 1 1 6 3 2 1 1

Recommendations (Section 1-3.6) - R1 Catchment studies report R2 Solid wastes report R3 Mathematical models report R4 Remote sensing report R5 Socio-Economic report R6 Economic justification workshop R7 Planning models workshop R8 Experience exchange workshop R9 International basins R10 Information manual R11 Research catalogue

X X X

X X X X

X x x x x x x X

X X X X

X x x

Subtotals: 5 3 2 4 .3 1 3 1 0 o o

Totals : 5 4 3 6 4 2 9 4 2 1 1

36

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Kubo, T. 1967. Discussion of Cillie, et al., in Advances in Water pOlZUtiOn research. Proc. IIIrd Int. Ass. on Water Pollution Control Conf. Munich, 1966. Water Pollution Control Federation, Washington, D.C. 23-27.

Kurzweil, H. A. 1968. The pollution of runoff from urban housing estates. Gesmdheits- Ingenieur, 85 (6) . Landsberg, H. E. 1970. Climates and urban planninglin Urban Climates, Proc. mo Symp., Brussels, Technical note 108, WMO-No. 254. T.P. 141, 372.

Lindh, GunnB. 1972. Urkanization: a hydrological headache. AMBIO, 1, 192.

Lvovich, A. I. 1964. Rol zemledelcheskikh polei oroshenia v okhrane vodnykh resursov ot zagriaznenia stochnymi vodami (The role of the agricultural fields affected by irrigation in the conservation of water resources from the pollution by sewage water) , Ochistka i ispolzovanie stochnykh vod i promyshlennykh vybrosov, Kiev.

Lvovich, A. I. 1974. Mirovoi vodnyi balang. World water balance, gudrometeomzgatr , Leningrad.

Mann, R. E. 1966. Descx4ptive micrometeoro~ogy. Academic Press, New York and London. Mathur, S. P. and Stewart, R. Eds. 1971. Proc. Conf. on beneficial uses of thermal discharges. Office of Recovery, recycling and re-use, New York State Dept. of Environmental Conservation , Albany, N. Y. 227pp.

Meadows, D. H. , Meadows , D. L. , Randers, J- and Behrens , W. W. 1972. The limits to growth. Universe Books , New York, 205pp. Montgomery, Austin, H. Jnr., and Merklein, Helmut. 1972. Protection of the Rhine river

Hyd. publ. 85.

against pollution. JnZ. Amer. Water Works ASS., 64 (2) 108-113. I

Mozhaev, E. A., Osintseva, V. P., Yurasova, O. I., Lin'kov, Yu. V. and Litrinov, N. N. 1972. Detergents in water hygiene and sanitary protection of water reservoirs. Vestn. Akad. Med. NUL& SSSR, 27 (1) , 42-47 (English summary) . Muller, W. J. 1971. The contribution of rainfall runoff to the impurity of waters. GWF das Gas und Wasserfach. ZZZ(1). Negulescu, M. G. and Rabinovici, Iacov. 1964. Discharge of rain water from urban sewers into streams. Hidrotehnica Gospodarirea Apelor Meteorologia, 9 (4) . Neiburger , Morris o 1969. Artificial modification of clouds and precipitation. Technical notes 105, WMO-No. 249. T.P. 137, 33pp.

Orlob, Gerald, T. 1972. Mathematical modelling of estuarial systems. Proc. Int. Symp. on Modelling Techniques in water reservoir systems. Ottawa. I , 78-128. Parkhurst, John, D. earch. Proc.IIIrd Int. Ass. on water pollution Control Conf. , Munich, 1966. Water Pollution

1967. Discussion of Cillie, et az., in Advcmces in water poiiiiution res-

39

References

development. Technical Report Series No. 297 , Geneva. 37. World Health Organization. 1967. Treatment and disposal of wastes. WHO Technical Report Series. No. 367, Geneva. 7-8.

World Health Organization. 1968. Water pollution control in developing countries. Technical Report Series No. 404, Geneva. 6. world Health Organization. 1971. Automatic water quality monitoring in Europe. PPOC. , Speciality Conf. , Cracow. World Health Organization. 1973. Re-use of effluents: methods of waste water treatment and health safeguards. Technical Report Series, Geneva.

World Meteorological organization. 1970. Urban climates. Proc. WMO Symp. on urban climates and buiZding cZkmatoZogy. Brussels. Technical note 108, WMO-No. 254. T.P. 141, 390pp.

World Meteorological Organization. Selected papers, special environment reports 2, WMO-No. 312. 151pp.

Zuidema, F. C. 1974. Transformation of the hydrological regime of marsh-ridden areas by land reclamation and forecasting its. influence on the hydrometeorological conditions of the environment, in Proc. Minsk IHD-IASH Symp. on the Hy&oZogg of Marsh-ridden Areas, 1972. Zuylen, G. F. A. van. 1971. StadskZZmaat. Adademiedagen deel 22. Roy. Dutch Academy of Science, Amsterdam.

Zuylen, G. F. A. van. 1973. Stadsklimaten, in PhysicaZ Geography, Oosthoeks uitgeversmaats- chap-i j , Utrecht.

1971. MeteoroZogy as reZated to the h m m environment.

40

Part II Case studies of

hydrological effects of urbanization

CONTENTS

11-1 Federal RepilbliC of Germany 45

11-1.1 Introduction 11-1.2 Urbanization indices 11-1.3 Character of precipitation 11-1.4 Micro-scale climatic effects 11-1.5 Urban water management facilities and their effects 11-1.6

11-1.7 Water supply effects 11-1.8 Flooding effects 11-1.9 Water pollution 11-1-10 Effects of mining activities 11-1.11 Other water utilization 11-1-12 Legislation and water management 11-1-13 Conclusions 11-1.14 References

Projected effect of community-scale urban water conservation measures

11-2 The Netherlands 69

11-2.1 Introduction 11-2.2 Some passages from the second report on physical

11-2.3 urbanization indices 11-2.4 Character of precipitation 11-2.5 Hydrological effects resulting from water management

sys tems 11-2.6 Water supply effects 11-2.7 Flooding effects 11-2.8 Pollution effects 11-2.9 Micro-scale climatic effects 11-2.10 Effects of mining activities 11-2-11 Effects of other water body uses 11-2.12 Water balance inventories 11-2.13 Hydrological research in relation to national and

regional planning 11-2.14 References

planning in the Netherlands (1966)

11-3 Sweden

11-3.1 11-3.2 11-3.3

11-3.4 11-3.5 11-3.6 11-3.7 11-3.8 11-3.9

95 Urbanization indices Character of precipitation Hydrological effects resulting from water management systems Water supply effects Pollution effects Micro-scale climatic effects Additional industrial water effects Water balance inventories References

11-4 United States of America 113

11-4.1 Introduction 11-4.2 Urbanization indices 11-4.3 Character of precipitation 11-4.4 Micro-scale climatic effects 11-4.5 Major effects resulting from urban water resources

facilities

conservation measures 11-4.6 Projected effects of community-scale urban water

11-4.7 Water supply effects 11-4.8 Flooding effects 11-4.9 Pollution effects 11-4.10 Effects of mining activities 11-4.11 Effects of other Water body uses 11-4-12 Water balance inventories 11-4.13 References

11-5 Union of Soviet Socialist Republics

11-5.1 Urbanization indices 11-5.2 Water resources and water balance of the USSR 11-5.3 Climate of towns 11-5.4 Runoff from urban areas 11-5.5 Water quality 11-5.6 Pollution and self-purification of water in rivers,

11-5.7 References lakes and reservoirs

137

1 Hydrological effects of urbanization in the Federal Republic of Germany

bY

Herbert Massing

and Members of the State Institute for Hydrology and Water Protection Northrhine

Westphalia Krefeld

Hydrological effects of urbanization (Studies and reports in hydrology, 18) Paris, The Unesco Press, I974

Introduction

11-1.1 INTRODUCTION

Central Europe has a long tradition of change from rural settlements to town communities. The Middle Ages saw towns grow alongside rural settlements and the numerous royal and sovereign households as centres of population; subsequent growth of trade and commerce brought wealth and increased status.

further development of towns. By the end of the century, rapid industrial growth had led to extremely large and densely populated urban centres. Most of these grew around either existing centres of trade, at the sites of capitals of German states and principalities, or in the regions of existing mineral resources. Today there ar.e 24 industrial conurbations and 68 urban centres scattered throughout the Federal Republic, and these are characterized by, among other things, intensive industrial activity, high energy consumption, and a growth of service industries.

In past centuries, urbanization had already produced problems, and though many were of a local nature, catastrophic epidemics occurred due to contamination of drinking water by human waste. More recent industrialization in the conurbatiomhas resulted in a misuse of' natural resources, leading to permanent disturbance of natural systems. These effects spread beyond the urban centres to the surrounding transitional and rural regions, particularly in respect of the water cycle and air pollution. Increasingly, areas of lower population density have become affected as the demand for energy, minerals and transportation grows.

ization on the water cycle were taken, including the establishment of the great water association, the Emschergenossenschaft in 1904, and the introduction of the Prussian Water Law in 1913. This law set up government organizations to manage water resources, and led to further water associations, the Ruhrtalsperrenverein, the Ruhrverband, and the Lippeverband, being established. All these had important water management tasks in the Ruhrgebiet which was the most densely populated and heavily industrialized region of Germany. Modern legislative requirements are met by the Federal Water Management Law of 1957, and by supplementary Water Laws of the German States.

In the first half of the 19th century, the beginnings of industrialization led to the

Early this century the first legislative measures against the damaging effects of urban-

11-1.2 URBANIZATION INDICES

11-1.2.1 Population

The Federal Republic of Germany (FRG) currently (1970) has a total population of approximately 61 million people, which is expected to rise by some 10% to 68 million by the year 2000; this actual population growth will, however, depend in part on many unknown factors.

inhabitants, and 39% live in cities with 50 O00 or, more inhabitants (see Table 6). This percentage is expected to increase only slightly to more than 40% in the year 2000, as urbanization in the FRG has already reached an advanced stage (see Table 6). In urban centres the population density is greater than 1000 inhabitants per square kilometre, but in rural areas, the density is less than 100 per square kilometre (Statistisches Bundesamt, 1971).

cities with more than 100 O00 inhabitants, while 20% of the people will be living in cities with more than 500 O00 inhabitants in the year 2000. Similarly the population of those cities with more than one million inhabitants will increase from the present 8% to at least 9% of the total population by the year 2000.

These 61 million people live in 23 500 communities, of which 1610 have more than 5000

The population is shifting to larger cities; already one third of the people live in

11-1.2.2 Land occupancy

The total area of the FRG is approximately 249 O00 sq km (96 O00 sq mi). Settlements with a population exceeding 50 O00 people cover about 3.8% of the total area. Because of the present high population density in the FRG, rapid growth of these towns is not expected. It may be assumed that such settlements will cover slightly more than 5% of the total land area in the year 2000.

The average density of population in the FRG is now 245 persons per sq km (635 person per sq mi) , (see Table 7).

46

Urbanization indices

However, Table 7 also shows that the density of settlements varies within the FRG. Thus, for example, cities with more than 50 O00 inhabitants cover more than 9% of the state of North Rhine-Westphalia, and this percentage is expected to rise above 10% in the future.

11-1.2.3 Climatic - topographic distribution of population The FRG lies within the northern Atlantic temperate zone and does not experience sufficient variations in climate to significantly influence urbanization.

Table 6. Distribution of population in the Federal Republic (1970 and 2000)

Population as percent of Population Cumulative 1970 total population of

(millions) (millions)

Number of communities Population range for range , population 61 million

For Range Cumulative

In the year 1970

5 O00 - 10 O00 10 O00 - 20 O00 20 O00 - 50 O00 50 O00 - 100 O00 100 O00 - 200 O00 200 O00 - soo O00 500 O00 - 1 O00 O00 O00 O00 - or more

876 413 206 56 31 17 a 3*

6.1 5.6 6.4 4.3 4.2 4.9 5.3 5.2

48.8 34.7 29.3 22.9

15.4 10.5 5.2

18.6

10.0 9.2 10.5 7.1 6.9 8.1 8.7 8.6 ,

69.1 59.1 49.9 39.4 32.3 25.4 17.3 8.6

In the year 2000

5 O00 - 50 O00 1400 23 53.7 33 .a 79 .O 50 O00 - 100 O00 64 5.2 30.7 7.7 45.2 100 O00 - 500 O00 62 12.1 25.5 17.8 37.5 500 000 - 1 O00 O00 10 7.2 13.4 10.6 19.7

1 O00 O00 - or more 4 6.2 6.2 9.1 9.1

(* Berlin, Hamburg and Munich)

Table 7- Population distribution - cities with more than 50 O00 inhabitants Per cent of

Population Areas Population density Numbers total (Inhabitants of inhabitants per sq km) cities of the State (millions) (!-al2)

State Name

Schleswig-Holstein 2 557 15 676 163 4 27.2% Nieder sachsen 7 100 47 407 150 12 24.2% Hamburg 1 817 753 2 413 1 100 %

Bremen 7 56 40 3 i a72 2 100 %

Nordrhein-Westfalen 17 130 34 044 503 49 53 %

Hessen 5 422 21 110 257 9 30.2% Rheinland-Pfalz 3 671 19 834 185 8 23 %

Baden-Wurttemberg 8 910 35 750 249 14 24.6% Bayern 10 569 70 440 150 13 25.8% Saarland 1 127 2 567 439 1 11.6% Western Berlin 2 134 480 4 446 1 100 %

FRG 61 193 248 464 246 114 38.7%

47

Character of precipitation

The morphology of Germany has had far greater influence on town development and population density, and most towns are located in flat lands.

11-1.2.4 Development of urbanization indices

The indices of urbanization in Germany have changed considerably over the centuries. For example, the foundation of medieval towns (1000-1400) was based on trade, transportation and the nzed for security. In most cases they were located at junctions of old trade routes (Nurnberg, Augsburg) , or at the coast in places that were favourable for trade (Hanseatic towns - Bremen, Hamburg, Lubeck, around 1400). ty required the foundation of towns, from which the Princes governed their lands. Here, culture, trading by merchants, and the presence of the state government were the primary indices of urbanization.

Industrialization in the 19th century started a new city structure. The presence of coal in the Ruhr valley, combined with the inexpensive waterway o€ the Rhine river, presented a good economic location for efficient steel production. This led to a notable change of structure of the area which previously had been agricultural and forest land. The population moved from East to West, leading to a thinning out in the agricultural areas and a concentration of population in the industrial valley of the Ruhr. Because there was no regional planning that considered all interests, the individual towns in the Ruhr valley kept growing until they formed an urban conurbation (Dortmund-Bochum-Essen-Duisburg).

steel-producing industrial developments. This is because of changes in methods of transportation, a recognition of the importance of regional planning, as well as the introduction of other sources of energy including soil, water, and natural gas.

During the last few decades, more..importance has been attached to regional planning, and the industrial area in the Baden-Wurttemberg region, Stuttgart-Karlsruhe-Mannheim has developed accordingly.

own individual history.

During the course of several centuries, decentralization of the power of the sovereign-

Coal is no longer the deciding factor in the FRG in determining sites for heavy and/or

Thus, the origin of each of the agglomerations of population shown in Figure 4 has its

11-1.3 CHARACTER OF PRECIPITATION

11-1.3.1 Precipitation statistics

The FRG is located in the temperate zone. In the northwestern part of the country a marine climate is predominant, while towards the east this is gradually replaced by a more continental climate. The main wind direction is west-north-west, and this produces some 27% of the annual weather conditions (Burghartz, 1962). This factor influences many planning decisions in the FRG; for example, western suburbs of cities are normally preferred for residence areas because of the fresh air (RÖssert, 1969) - south - the distribution of temperature and precipitation over the FRG is very variable. For example, the average temperatures measured from 1881 - 1930 were:

Because of the variable morphology - plains in the north and mountains towards the

Frost days Summer days 6 ooc 25OC

Kiel (north) Karlsruhe (centre) Munich (south) Zugspitze (south)

78 75 105 313

5 41 30 O

The average rainfall in the FRG is 803 millimetres per year, compared with the world average of 883 millimetres per year. The driest region is near Mainz with 500 millimetres per year, and the wettest is in the Alps with more than 2000 millimetres. Mittelgebirge (highlands) - Sauerland, Harz, Black Forest - the precipitation reaches 1200 millimetres per year. (Figure 5).

In the German

Table 8 gives the average monthly precipitation, and shows that the seasonal influence

48

Figure 4. Major areas of population concentration

49

Figure 5. Mean annual precipitation (millimetres), years 1891-1930.

50

Micro-sea& cZirnutic effects

on precipitation during the year is similar throughout Germany. July and August are the wettest months, while November - February are the driest. As would be expected, there are less variations near the sea in the north than farther south.

11-1.3.2 Intensity of .rainfall -.-

The intensity of rainfall varies from one region to another, and generally follows the topography. Maximum readings of rainfall intensity include the following:

25 May 1920 in Bannwaldsee 126 millimetres within 8 minutes

14 April 1902 in Berlin 143 millimetres within one day,

in 1950 in Duisburg 170 millimetres within 2 hours.

Thunderstorms occur most frequently in the 'KÖlner Bucht' - the plains of the Lower Rhine.

During recent years, an increasing number of studies have been made of the effect of urban conurbations on the development of heavy rain routes. Thus, for example, the influence of the towns of Ludwigshafen-Mannheim, creates a cumulative rain route which passes on towards the northeast and diminishes towards the Odenwald. Bergland', the frequency and magnitude of this phenomenon is reduced as the air descends , and increases again after Mannheim-Ludwigshafen.

Away from the edge of the 'Pfälzer

Table 8. Average monthly precipitation (mm) (Cbservation period 1891-1930)

Month Total Place Per

I II III IV V VI VI1 VI11 IX X XI XII Year

Karlsruhe 50 44 53 59 57 72 77 78 75 65 60 66 756 Kiel 55 43 46 46 45 55 74 84 64 67 58 64 701 Munchen 51 38 50 77 93 117 128 102 89 57 47 55 904 Zuspitze 65 62 76 109 131 178 192 174 135 87 63 78 1350

I_-----_

11-1.4 MICRO-SCALE CLIMATIC EFFECTS

At present insufficient measurements have been madedto enable the effect of urbanization on the local climate to be determined. The main effects in towns in the FRG do, however, appear to be an increase in temperature and its consequences, and air pollution. It has been shown that temperature in big cities in Germany is l0C higher than in the surrounding countryside, and also that the extent of daily or yearly variations in temperature is lower in the cities. This change has led both to the increased development of fog, and in Bremen and Hamburg, to increases in local rainfall. Because prevailing winds are from the northwest, zones of drier climate develop to the southeast of these cities. It is also known that over the period 1950-1953, the sunshine recorded in Munich was significantly less than in the suburb of Riem, situated only 3 kilometres to the east.

11-1.5 URBAN WATER MANAGEMENT FACILITIES AND THEIR EFFECTS

11-1.5.1 Coverage of the water demand

The FRG is not poor in water resources, and the national water balance shows that resources will be adequate to cover water requirements for a long time to come. Water resources include annual yields of approximately 16 O00 million m3 of groundwater and 30 O00 million m3 of surface water, a total of 46 O00 million m3/annum. This can be compared to a present water requirement of 15 O00 million m3/annum which will increase to 27 O00 million m3 by

51

Urban water management faciZities and their effects

the year 2000. These requirements do not include those of publicly-owned electric power plants nor the recirculated water requirements of industry, Bundesminister des Innern (1972).

develop in the future, the cause is either that.the natural distribution of the water resources is locally inadequate (possibly temporary) or that the water resources no longer satisfy quality requirements. on a regional level. Two possible forms of management used in the FRG are:

Where regional problems in meeting water requirements already exist or are likely to

These problems can be solved by management of water resources

(i) water transfer from one catchment area to another (ii) regulating reservoirs

Problems due to inadequate water resources are arising in almost all of the metropolitan areas of the FRG shown on Figure 4, including the Bremen area, the Ruhr industrial district, the Rhine-Maine area, the Rhine-Neckar area of Stuttgart-Karlsruhe-Mannheim and the NÜrnberg-Fürth-Erlangen area. All these regions either have adequate water as a result of specific measures of water resource management, or plans have been made for an adequate supply of water in the future. For example, river management initiated at the turn of this century has supplied additional water to the North-rhine-Westfalen industrial complex (the Ruhr district) from a system of reservoirs located in the neighbouring Sauerland mountains. The required water flows from these reservoirs via the River Ruhr to the metropolitan area and is used primarily to ensure the supply of potable water. The discharge of water from this reservoir system is controlled so that the River Ruhr has a constant flow rate of 20 m3/sec in the Ruhr District. water supply its effluent load is kept down so that the resulting cost for processing the potable water is very low. The very large quantities of effluent produced in the metropolitan area are discharged into the Emscher River which runs to the north of the Ruhr. In order to prevent any additional effluent load on the Rhine due to the great quantities of waste water carried by the Emscher, a large-scale treatment plant has been built just upstream of the confluence of the Emscher and the Rhine. When the last phase of this plant has been built, it will be capable of treating 20 m3/sec.

this area has an adequate supply of water from the Weser River, its quality is extremely poor due to a high degree of contamination and to salinity; thus the cost of processing would be high. To reduce this processing cost and to improve the quality of the potable water, part of the water supply is obtained from reservoirs in the Harz mountains via a pipeline system 250 km long.

The transfer of major quantities of water in the form of a 'moving wave' (Ruhr District) or pipeline system (Bremen) will cause a corresponding effluent movement in the area being supplied. These increased quantities of effluent cause an additional load for the natural receiving waters. Thus, the conurbation of Central Wurttemberg - especially the Stuttgart area - is supplied primarily from the Danube lowlands and from Lake Constance, with a total of 5.5 m3/sec of potable water, via a long-distance pipeline system. potable water will have increased to 12.8 m3/sec (Bundesminister des Innern, 1971). The constantly increasing amount of effluent discharged into the Neckar River will create an urgent need for improvement of its low water flow rate. Even if all potential effluent treatment measures are exploited, the river's flow rate will need to be increased by 20 m3/ sec in the near future. The construction of several reservoirs (with a total capacity of 200 million m3) in the upper reaches of the Neckar River is being considered for this purpose.

Water transfer from one catchment to another is accomplished by a variety of techniques in the FRG, depending on the type of exploitation in the area being supplied. Whereas the Stuttgart and Bremen conurbations are supplied with potable water from remote watersheds via pipeline systems, a supply of industrial water or an input of water to improve the low flow rate of a river cannot be accomplished via a pipeline system because this would be too expensive in view of the quantities of water to be moved. Thus, it is intended to use the projected Main-Danube canal to move 15 m3/sec from the Danube to the Regnitz-Pegnitz-Main watershed, ie to the Nurnberg-Furth-Erlangen conurbation, in order to increase the low flow rate of these rivers. At the same time this water management measure is intended to provide new impetus to the industrial and trade development of this area.

Because the Ruhr water is used primarily for a potable

A different type of water supply system is used in the Bremen metropolitan area. While

By 1990 this influx of

52

Projected impact of community scale urban olater conservation measures

11-1.5.2 'Sealing' the surface

The area occupied by housing, industry and transport in the FRG is continually increasing. Thus, in 1970 as much as 10% of the total territory of the FRG was built-up, 50% more than in 1938. Until 1.980 an annual loss in the order of 45 O00 hectares of agricultural and forestry area for construction purposes is likely. This continual increase in the use of open areas for construction purposes causes a reduction of the pervious area in the affected regions. As a result of this artificial 'sealing' of the surface, precipitation will run off more quickly on the surface, and canalisation of natural stream courses wil1,accelerate this effect. Especially where separate foul and storm sewers are used, surface runoff is moved to the nearest water course via the shortest route possible. As a result of this development, flood waves in the rivers will be more frequent and will be steeper, while low flows will reduce and last longer. Depending on local conditions, severe lowering of the groundwater table may occur, so that public water supply systems which obtain potable and industrial water from these groundwater resources are forced to satisfy their water requirements from other sources.

Contamination of groundwater by effluent draining from unsafe sewage systems occurs in almost all urban and industrial districts of the FRG. Groundwater used for water supply must be protected against such harmful effects to safeguard the public water supply; the Water Acts afford a legal tool for this purpose.

11-1.6 PROJECTED IMPACT OF COMMUNITY-SCALE URBAN WATER CONSERVATION MEASURES

The German towns in the coastal area of the North Sea can be supplied with local alluvial groundwater, which is sufficiently recharged by precipitation to prevent drawdown problems. There are no problems of saline intrusion into the groundwater reservoirs.

Desalination of seawater is not yet used in Germany, and those coastal islands which have insufficient natural freshwater are supplied with extra water via pipelines from the mainland.

water using sprinkling. This type of effluent disposal has declined in use during recent years for health reasons, and it has not been practised where the groundwater is used for any purpose requiring drinking water quality.

ment Law requires water protection areas to be defined and established. This became necessary because industrial, housing, and roads are claiming more and more land. The definition and establishment of water protection areas is supervised by the water authorities of the states, and each area is subdivided into 3 zones, each zone depending on the degree of danger to the water supply.

Difficulties in protecting water supplies in urban conurbations against pollution will lead in the future to the closing down of smaller water treatment plants and the creation of larger ones giving better protection; however, water transportation over longer distances will be the price paid for such changes.

In some parts of the FRG, pretreated effluent has been removed by percolation to ground-

To protect the groundwater reservoirs of the FRG against pollution, the Water Manage-

11-1.7 WATER SUPPLY EFFECTS

3 The mean annual precipitation for the FRG is approximately 200 O00 million m . After deduc- tion of all losses, the remaining resource is 16 O00 million m3 of groundwater and 30 O00 million m3 of surface water, ie a total of 46 O00 million m3 which can be used; not poor in water resources.

zation during the cycling of river water, potable and industrial water, and wastewater. Table reflects the water requirements in the FRG, (Batelle-Institut e.V., 1972).

arately because engineering developments, particularly in coaling techniques, are difficult to predict.

the FRG is

The useful quantity of water available can be increased as a result of multiple utili-

The cooling water requirement of electric power plants for a public supply is given sep-

53

Water ;upnZy effects

Table 9. Water requirements in the FRG, in 1000-million m3

User 1969 1975 1980 1985 2000

Indu s try 10.7 12.2 13.3 14.7 22.1

Public supply 3.1 3.5 3.9 4.2 5.3

Agriculture 0.7 0.6 0.5 0.5 0.5

Sub-To tal 14.5 16.3 17.7 19.4 27.9

Electric power plants 12.5 14 .O 14.2 14.5 16.1

Total 27 .O 30.3 31.9 33.9 44.0

According to Table 9 , the water requirement of industry has the greatest growth rate, some 2.3% per annum on average. ment will have doubled, rising from about 11 O00 million m3 in 1969 to 22 O00 million m3 by the year 2000. As a proportion of the total water requirement, the industrial share will rise from 39.6% in 1969 to 50.3% in the year 2000. The largest user of industrial water is the chemical industry, and its share of the total water requirement rose from 28.8% in 1959 to 35.8% in 1969; estimates suggest that it will be 54.9% by the year 2000.

sources, one-third being from groundwater and spring water while two-thirds was from surface water. this percentage does however represent one quarter of the total public supply.

Subdividing the industrial water requirement according to use shows that the greatest increase in demand will be for cooling water, rising from 7 800 million m3 in 1969 to 16 700 million rr3 in the year 2000. The expected rise in the cooling water requirement of public electric power plants is from 12 400 million m3 in 1969 to 15 900 million m3 in the year 2000. Thus, the greatest use of water by industry and in public electric power plants is for cooling purposes.

power plants. The specific cooling water use for non-recirculating cooling systems is 150 litres/kWh, and 80 litres/kWh for recirculating cooling systems. The cooling water required by a recirculating cooling system to produce one kilowatt hour is therefore slightly more than half that required by a non-recirculating system. However, the capital cost of recirculating cooling systems is considerably greater than that of non-recirculating systems. In 1969 a total of 12 000 million m3 of water was used for non-recirculating systems, compared with 4 400 million m3 for recirculating systems. in 1969 was produced with recirculating systems, and this percentage is expected to rise by 50% by the year 2000 because of the limited water resources available for cooling purposes.

Consequently, by the year 2000 the industrial water require-

In 1969, 93% of the industrial water requirement was met from privately financed

The remaining 7% was provided by public water supplies;

Data or predictions for different types of cooling systems are available for public

Approximately 40% of the power generated

The water required for irrigation in agriculture will not change significantly. Domestic requirements from the public water supply are expected to rise from 2 600

million m3 in 1969 to 4 700 million m3 in the year 2000. steadily increasing demands for personal comfort by the population. In terms of consumption per inhabitant, the requirement is expected to rise from 118 litres per inhabitant per day in 1969 to a level of 204 litres per inhabitant per day in the year 2000.

and 40% from surface water resources. Because most of the high-quality groundwater resources are already being used for water supply, groundwater resources of a lower quality together with surface water resources must be developed to meet the continually increasing water requirement. Thus, in Northrhine-Westphalia, the region with the greatest population density, already about two-thirds of the water requirements are met by surface water, and only one- third from groundwater.

ed from the same sources in the year 2000 as today, some 14 O00 million m3 of water would be required from groundwater sources.

This increase is due in part to

Today, about 60% of the water requirements in the FRG is met from groundwater resources

On the assumption that the water supply for domestic and industrial use was to be obtain-

This would mean that the annual groundwater recharge of

54

I

Urbanization of the 5chwippe Valley 1900 ? .\./---í+’ -._-., .----/ r -. \ ___ _ _ .___- L,

Figure 6. Urbanization in the Schwippe Valley (after Bundesminicter des Innern, 1971).

55

FZooding effects

16 O00 million m3 would be almost depleted. 6 500 million m3 of surface water must more than double to 14 O00 million m3 by the year 2000.

The increase in effluent from the present 16 O00 million m3 to 28 O00 million m3 in the year 2000 presents severe difficulties for further abstraction from surface water resources; these difficulties will be very costly to overcome. Even today, the continually increasing pollution presents water treatment plants with major processing problems to overcome. A large variety of harmful substances contained in the raw water must be eliminated by costly treatment techniques. In the FRG these include the removal of suspended solids and colloids as well as certain dissolved solids. Filtration techniques are available and their effectiveness can be improved by flocculation techniques. In addition, oxidation and adsorption techniques are used to remove dissolved substances. As a rule, microorganisms are destroyed by chlorine or ozone. On the Ruhr River, in the Rhineland-Westphalian industrial district, a slow filtration technique is used to treat a potable water supply. Along the Rhine River the potable water supply is obtained from water which has seeped through the river banks, and subsequently treated by an activated charcoal and ozone process.

very high, so some conurbations in the FRG are supplied with high-quality water via long- distance pipeline systems. In this case the cost for the construction and maintenance of the pipeline systems will be high, but the cost of treating the raw water will be low. Thus, consideration of cost-effectiveness of different systems may in part determine the type of potable water supply in some conurbations within the FRG. For example the potable water supply for the city of Stuttgart is obtained from Lake Constance via a 300 km long pipeline.

groundwater from, for example, abandoned gravel pits, improperly arranged garbage dumps, and and intensive application of agricultural fertilizers. In addition, the danger caused by the drainage of hazardous liquids as a result of improper storage or accidents has become very great. To protect the catchment area of water supply facilities against hazards to the water resource, water protection areas may be established under the Water Act. However, not all the 15 O00 water works in the FRG are located in water protection areas. In future, problems arising from the protection of water supplies, especially in the conurbation, will result in the smaller water works being abandoned and larger water supply systems (which are more easily protected) being created, even if this means that a long-distance supply must be accepted. Sometimes the public facilities also supply both trade and smaller industrial establishments with water.

Consequently, the present abstraction of about

Treatment costs for improving the often inadequate quality of raw water are sometimes

Continually increasing water pollution affects not only the surface water but even the

11-1.8 FLOODING EFFECTS

In the FRG the surface of the earth is becoming increasingly covered over by urbanization. Therefore, not only is the rate of permeability being decreased, but the storm runoff from the surface is also changing. To date, scientific research has given little information on the extent of the change in runoff. The example given below dealing with the Schwippe River near BÖblingen/Sindelfingen, shows that as urbanization increases the flood peaks increase at a faster rate than the growth of impervious area. Therefore, the cost of a reliable drainage system will also increase more quickly than the growth of impervious area.

flat basin of some 50 sq km within the Schwippe catchment area. Thirty years ago there was only 4 sq km of urban area and this was sparsely developed. The developed area is now 12 sq km and will be 20 sq km in 1985; at the same time the developed portions are becoming densely populated (see Figure 6). According to surveys and observations over many years, a runoff coefficient of 0.15 is suitable when an area like this is undeveloped, ie 15% of the precipitation runs off the surface.

is heavy rainfall, the runoff per sq km of newly developed area will not be 1.5 - 2 m3/sec but 6 - 8 m3 per second. Therefore, the flood peak runoff of the Schwippe River has increased two-fold in recent years.

Further development will again increase flood runoff and in addition the floods will occur more frequently and runoff will be more rapid (see Figure 7).

The towns of BÖblingen and Sindelfingen and the community of Maichingen constitute a

When the development is dense, however, the runoff coefficient is 0.6. Thus when there

56

Figure 7. Flood hydrographs of the Schwippe Valley (after Bundesminister des Innern, 1971)

57

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58

Water poZZution

The increased frequency and intensity of floods necessitate flood protection measures, traditionally canalization and the construction of levees. In addition, during the last decades, more flood retarding works such as dams and flood storage basins, have been built. There are 34 large dans in the FRG (each with a volume of more than 8 million m3); twenty of them are used, among other purposes, for protection against floods. Innumerable flood storage basins in the lower reaches of the rivers serve for recreation and fishing as well as for flood protection. A particular flood protection system will be chosen largely on economic grounds.

plain have been built upon. Subsequently levees have been built to protect the towns against flooding.

The intensive growth of urbanization, especially during the last 100 years, has necessi- tated considerable improvement of the dike system, along, for example, the lower Rhine. It has been shown that these measures aggravate the flood problem in the valley by reducing the

Many towns in Germany have developed in river valleys, where parts of the natural flood

. available storage. /-

For these reasons, under the new law regarding water management in the FRG, the flood plain areas have been designated. Those areas are not to be built on and must remain largely unchanged. Physical changes on major rivers are to be carried out only after extensive experiments, mainly with models, have been made to investigate their effects. Under the new water management law, such changes will be approved only after a public enquiry.

account the need to protect urban areas. There are no official regulations concerning the degree of safety (offered by flood protection measures) in the FRG.

populated areas such as the lower Rhine. Due to the expansion of urban areas, and in particular industrial development, the need for protection has increased considerably during the last 100 years. Extensive modifications to old dikes had to be undertaken in respect of both profiles and height. For example, in the lower Rhine the design height of the dikes is based on a flood peak with a return period of 1000 years, plus an additional allowance for other influences such as wind, waves, and river diversions. Along the lower Rhine there are 350 km of dikes which are maintained and defended against floods by independent corporations under the supervision of the state.

The design frequency of flood protection works (dikes, storage basins, etc) takes into

There is a long tradition of dike construction, especially in endangered and densely

11-1.9 WATER POLLUTION

3 The wastewater generated in the FRG in 1969 amounted to 45.63 million m per day, an annual wastewater volume of about 16 O00 million m3 (Bundesminister des Innern, 1972a). A level of 28 O00 million m3 is expected by the year 2000 (Bundesminister des Innern, 1972b). At present about 20% of the surface runoff is from wastewater and it is expected that after 30 years about one-third of the natural water in rivers will be exploited, and that the greatest part of it will be returned to the rivers in the form of treated wastewater (Bundesminister des Innern, 1971).

The daily amount of wastewater generated, 45.63 million m3, does not inclùde cooling water discharged by public electric power plants, which amounted to about 34 million m3 per day in 1969, nor does it include recirculated water used in industry and power generation which amounted to 52.8 million m3 of water per day in 1969 (Bundesminister des Innern,l972a).

the FRG increased almost 48% between 1957 and 1969, (Bundesminister des Innern, 1972a). Dur- ing this period the pollution loads from fully biologically processed effluent (BOD5 reduction more than 75%) have more than quadrupled, those from partially biologically processed effluent (BOD5 reduction less than 75%) have more than doubled, and those from untreated effluent have doubled; pollution from mechanically treated effluent has remained approximately the same. (Bundesminister des Innern, 1972a).

erable funds to greatly accelerate improvements to and new construction of, effluent treatment plants. crease even faster in future to reduce water pollution. Thus, the Federal Government's environmental programme provides for 90% of the population to be connected to public sewerage systems by 1985, and that all treatment plants shall have a fully biological or equivalent process (Table LO). At present costs this will require annual investments of 1 100 million

Surveys show that the treated and untreated wastewater load carried by water courses in

Because of this increasing water pollution in the FRG, the government has spent consid-

However, investment for the construction of sewage treatment plants must in-

59

Water poZZution

Deutsche Marks for sewage treatment plants and 2 200 million Deutsche Marks for sewerage. The introduction of large quantities of effluent into surface water bodies results in

continuously increasing pollution. Thus, more than half of the surface water resources in the FRG are more than moderately polluted. Especially difficult loads are carried in areas of industrial concentration such as the lower Rhine, the Rhine-Main area, the Ludwigshafen- Mannheim metropolitan area, and the Stuttgart conurbation. Moreover, increasing water pollution is also observed where major cities are connected to rivers having low flows (such as Kassel on the Fulda River). A review of water pollution in the FRG is provided by Plate 1.

Increasing pollution of surface water constantly creates new problems where water supplies are obtained either directly from rivers or after filtration through the river banks. This is because the great variety of harmful substances carried by the raw water is continually increasing; hence water works have to employ increasingly advanced and sophisticated treatment processes to remove these harmful substances from the raw water. Sometimes this is very costly as, for example, for water works abstracting water from the Rhine River to supply the metropolitan areas of Cologne and Dusseldorf,

Hazards to the groundwater from abandoned gravel pits, poorly operated garbage dumps, and intensive application of fertilizer in agriculture are continually increasing. Moreover, the danger from drainage of hazardous liquids as a result of inadequate storage or accidents has become very severe. To protect areas located within the catchment area of water resources against hazards, water protection areas are established as required under the V?ater Act.

In addition to domestic and industrial sewage, environmental chemicals such as biocides, detergents and fertilizers, and toxic substances (toxides) have a very adverse effect on the natural self-purification capacity of surface waters. For example, it was found in 1967 that the natural self-purification capability of the lower Rhine River had been reduced by 30% as a result of toxides (Bundesminister des Tnnern, 1971). .

the 17.48 million m3/day of water drained via public sewerage in 1969, 49.8% was domestic sewage and sewage from small trade establishments, 36.9% consisted of industrial sewage, (Bundesminister des Innern, 1972a) and 13.3% was groundwater or stream water. Of this daily quantity of effluent, 37.9% was treated by a fully biological process, 9.5% by a partial biological process, and 28.4% by a mechanical process, while 24.2% was drained without any treatment at all. The treatment of effluent generated via the public sewer system increasingly creates problems. Both domestic and industrial loads must be considered and their degree of treatment determined with greater accuracy.

million m3 per day. cooling water. All this effluent, and 5.9% of other industrial effluent, was discharged into the rivers without treatment. Only 15.1% of industrial effluent was discharged into the rivers after treatment; however, the types and degree of this treatment are unknown. (Bundesminister des Innern, 1972a). Industry is faced with especially difficult problems in the construction of treatment works as industrial wastewater has a frequently changing composition, especially in the chemical and metal-proce’ssing industries.

The increasing application of fertilizer in agriculture results in more and more plant fertilizers (especially the nitrogen and phosphorus compounds) being leached from the soil and discharged into the rivers where they cause an increased growth of plant and animal organisms. The final result of this process is the accelerated eutrophication of the recipient water bodies.

The FRG is among the nations with the greatest application of mineral fertilizers. For example, a survey covering the period 1956-1970 showed that 69 kg of nitrogen and 60 kg of phosphorus were used per hectare of agricultural area (fields, meadows). (Bundesminister des Innern, 1972a).

in eutrophication of water masses. It has been estimated that a third of the phosphate input originates from leached fertilizer, a third is from human phosphorus metabolism, and the remaining third is from detergents. The high phosphate input originating from human metabolism (1/3) and from the use of detergents (1/3) by man must be taken into consideration, especially where settlements are located close to waters. Thus, in 1940, Lake Constance was entirely clean and was free of phosphorus;

Increasing water pollution affects not only the surface water but also the groundwater.

In the FRG wastewater is drained via either public or company-owned sewer systems. Of

In 1969, effluent discharge from the company-owned industrial sewer systems was 28.14 Of thisp15.7% was predominately saline mine water, while 63.3% was

This large input of phosphate is considered to be the primary cause of the acceleration

in 1964 the content was 50 mg of phosphorus per m3.

60

Plate 1. Degree of the pollution of surface waters in the Federal Republic of Germany in 1967.

61

Effects of mining activities

Requirements for cooling water in the FRG are continually increasing. Thus, industry used 24.74 million m3 of water per day for production purposes and for private power generation in 1969. The daily cooling water requirement of public power plants was about 34 million m3 per day in 1969, some 12 O00 million m3 of water per annum (Bundesminister des Innern 1972a). It is expected that by the year 2000 the public power plants will have a cooling water requirement of 15 500 million m3 (Batelle-Institut e.V. , 1972).

In 1969 non-recirculating cooling systems accounted for about 12 O00 million m3 of water, and recirculating cooling systems which provide only 40% of the electric power generation for only 4 400 million m3 (Batelle-Institut e.V. , 1972) . It is probable that this percentage will rise steeply in the future as a result of the limited water resources available and limit the use of cooling water in non-recirculating systems by 1980. Thus, it is expected that the percentage of cooling water used in recirculating systems will increase to 90% by the year 2000 (Batelle-institut e.V., 1972).

The discharge of large quantities of cooling water into rivers creates problems because of the resulting increase in temperature, particularly at low flows. Consequently, temperature standards are being established for all lengths of river which are very affected by cooling water. These temperature standards are one of the criteria used for selecting sites for thermal power plants.

Today, general practice in the FRG is to permit a maximum increase of only 3OC over the natural temperature of a surface water body; a maximum of 28OC is accepted at points where cooling water discharges into water bodies. Trout-carrying waters should not have a maximum temperature exceeding 20OC (Bundesminister des Innern, 1971). Because the capacity of water bodies to receive cooling water is limited, alternative ways of cooling water must be developed in the future.

er pollution. In separate foul and storm sewer systems the storm water is frequently led as quickly as possible to the closest water course, while the foul sewage is normally passed to a treatment plant. Today, storm runoff pollution during the first 15 to 20 minutes of rainfall corresponds to that of foul sewage. In future the practice in the FRG will be to pass storm water through settling basins before discharge into the water courses.

large storms is too great to be accommodated economically in sewers and treatment plants. consequently, flow in excess of five to fifteen times dry-weather flow is passed directly into the nearest water course via storm overflows. Again, in future, settling basins will be used before diluted wastewater is discharged in order to reduce pollution in water courses.

The design principles of sewer systems used in the FRG frequently cause additional wat-

The quantity of foul and storm sewage passed through a combined sewer system during

11-1-10 EFFECTS OF MINING ACTIVITIES

11-1.10.1 Coal mining

In the FRG coal mining has a long history. The coal is extracted not by opencast mining but in deep mines in the districts of the Ruhr, the Sa&, Aachen and Lower-Saxony. trated urban and industrial settlements with a high energy consumption have followed the mining operation.

demand for primary energy (Buch, 1972) and about 40% of the demand for power generation (Frewer, 1971). More than 240 O00 people are employed in coal mining.

Coal mining produces many water problems, usually including the large volumes of water that have to be pumped from the pit to the surface and then into the rivers to keep the seams and tunnels dry. The coal/water ratio in the Ruhr district has increased from 1:4 in the past century to about 1:1.3 at present. above the seams, from brine, and from thermal springs, and usually has a heavy uiire&i load (chlorides, sulphates, etc.) together with suspended solids. (Kaufmann, 1963). The content varies considerably, depending on the structure and the minerals of the seam. water is usually not possible, and some 11% of the salt load in the Rhine originates in the Ruhr mining district (Bundesminister des Innern, 1971).

washing the coal.

Concen-

In the year 1970 about 111 million tonnes of coal were mined,providing about 29% of the

The water cornes from groundwater, from ground

Re-use of the

A coal mining plant produces a number of kinds of sewage, notably the water used for This is treated mechanically by sedimentation in large settling tanks

62

Other water uti Ziza-tion

or chemically by flocculation in order to remove fine grained coal, clay and loam. In the densely populated and highly industrialized mining districts the deposition of the mud produces great difficulties.

satisfactorily by special treatment facilities using extraction processes, followed by treatment in biological plants.

Secondary industries such as coking plants produce a distinct sewage, which is treated

11-1.10.2 Lignite mining

In the FRG lignite is of great importance, and in 1970 some 108 million tonnes were dug from opencast mines. Of this total, 70% was used for power generation and 30% was used for the production of briquettes and other solid fuels (Buch, 1972). Lignite accounts for 9.1% of the primary energy production in the FRG, taking third place behind mineral oil (53%) and coal (29%) (Buch, 1972). The Lower Rhine opencast lignite mining area is the most important electric power generating centre in Europe as it is very close to the urban and industrial conurbations of the Ruhr, the Rhine axis and Aachen.

Opencast mining causes severe water problems of its own:

- lowering the groundwater table 300 m to drain the opencast mines and the lignite seams; this has widespread influence over about 1000 km2;

- the discharge of large quantities of drainage water (40-50 m3/s) into the river Erft, the artificial KÒlner Randkanal and the river Rhine;

- changes in soil water balance where groundwater levels are lowered; - effects on the water supply for drinking and industrial purpo.?es in the mining district and the very densely populated surroundings (KÖln, Dusseldorf , Aachen , etc) ; and

(See 111-2). - the use of the resulting depressions for recreation, fish and wildlife, etc.

These problems are solved by comprehensive planning of water management, building dev- opment in urban, transitional and rural areas, and reclamation or landscaping of derelict land for recreation purposes including national parks.

11-1.10.3 Potassium and rock-salt production

The FRG is rich in rock-salt, which has been extracted since about the year 2000 B.C. In 1970 the production of rock-salt reached 2.25 million tonnes, and potassium chlorate about 21 million tonnes. (ßundesminister des Innern, 1971). The..latter is mined in the lower Rhine (Wesel) and in the Hannover district (Celle, Wolfenbuttel, Helmstedt).

potassium industry into rivers as a saline solution, (Bundesminister des Innern, 1971). New methods of re-using the magnesium-salt to decrease the salt load of the rivers are being investigated.

About 1.6 million tonnes of salt per year (as NaC1 equivalent) are discharged by the

In the manufacture of raw potassium some 70-80% is left as residue of which:

- about 4.9 million tonnes/year are deposited on dumps; - about 5.0 million tonnes/year are returned to the pits in a solid state; and - about 4.1 million tonnes/year are pumped as a solution into underlying porous strata.

11-1.11 OTHER WATER UTILIZATION

11-1-11.1 Recreation

The need for leisure planning constantly increases as working hours decrease, particularly for the urban population. look increasingly for activities like fishing, boating, camping, bathing, swimming and water skiing.

Besides areas of water constructed or prepared specifically for recreation, as for example bathing lakes in former borrow pits, new or existing reservoirs for different purposes are often suitable for recreation without much additional expense. For example, the

Water based recreation is desired by many people in the FRG, who

63

Other water utilization

artificial Lake Bigge serves a recreational purpose as well as providing drinking water and river regulation and may be used for sailing,electric-propelled pleasure boats and other kinds of sport that do not pollute the water. The Bigge Lake Co. Ltd. which is a public company, builds sporting facilities for the public's use. In the state of Bavaria, a general ban on construction on many lake shores has been issued to keep the lakes clean and beau- ti£ul. regarded as vital to people seeking recreation on walking or bicycle tours. There are about one thousand wildlife and forest reserves of various sizes in the FRG, many of which are linked to water.

it with water and also providing its closest recreation area. The 'Ruhr-Recreation Scheme' which ws-s created 4û years ago, and which designated urban free zones, is becoming increasingly important as urbanization is extended. Landscaping of these zones uses the Ruhr River to a considerable extent as it offers open air swimming pools and the artificial Lake Baldeney .

tion, water supply, wastewater discharge, fishing, recreation, etc. The compatability of theCe interests is exceptionally difficult; nevertheless, the recreation requirements are increasingly considered, even on this much used river. Despite the importance of navigation, an active sporting boat business supported by the government exists.

In Munsterland the concept of a 'park landscape' linked to natural areas of water are

The Ruhr River flows through the largest industrial. area of Western Germany supplying

Many different demands are made on the water of the Rhine River: international naviga-

11-1.11.2 Fishing

(a) Coastal fishing

While the catch of deep sea and herring fishing of the FRG for 1970 show a continued decline compared with previous years, an increased catch of 11 100 tonnes (6.7%) has been recorded for inshore and coastal fishing.

Catches were (Statistisches Bundesamt, 1971) - 1969 - 1970

Deep sea fishing (tonnes) 444.822 405.489 Herring fishing (tonnes) 21.995 8.485 Inshore and coastal fishing (tonnes) i66.419 177.436 (more than 50% of the catch was cod).

The coastal fishery is along the German shores of the Baltic and German seas. The following number of fishinq boats have been in operation, (Statisticches Bundesamt, 1971):

Baltic Sea German Sea

1965 810 779 1971 738 996

Most of the catch has been herring, cod, shrimps and crayfish.

(b) Inland fishing

Both lake and river fisheries as well as fish pond management in the FRG receive subsidies from the states. These subsidies are used for fish stocking, extension of fish breeding plants, preparation of ponds, and for compensation of damage to the fishery. Damage was caused particularly by regulation and/or raising the limit of the rivers. ofl the weather and therefore vary from year to year and from area to area; fish were caught in Lake Constafice in 1970, and the delivery of fresh water fish to the fish market of Kiel was 334 tonnes. The FRG's total production of carp for eating reached about 3000 tonnes in 1970, scarcely half of the requirements. Trout rearings were also inadequate to meet the needs of the market, and 4 400 tonnes of trout were imported in 1970, (Bundesminister fur Ernahrung, i969 , 1970 , 1971) .

In parts of the FRG, for example North Rhine-Westphalia, professional £ishery has practically died out because of heavy pollution of the waters. professional fishermen in North Rhine-Westphalia, but by 1969 only 13 remained. During this

Catches depend 176 tonnes of

In 1950 there were still 75

64

Other water utilization

period the number of anglers increased. from 13 O00 to 15 000, undoubtedly an effect of increasing urbanization.

not directly edible because their taste is affected by mineral oils and other chemical matter.

(c)

In the Rhine a considerable number of fish still exist but the fish that are caught are

Regulation of waters suitable for a fishery

As late as the 1930's practically no value was set on the suitability of regulated waters for fishing. Today, planners and users increasingly recognize the value of a clean environment and of keeping waters suitable for fishing after regulation.

Fish ladders are constructed at dams, and when channel modifications are planned, fishery requirements for minimum water depths, sunshine effects, spawning and protection areas are taken into account. Streamflow velocities of 0.6 to 0.8 metres per second are suggested as desirable for fish life.

Fishery experts in the state governments of the FRG, (Wiesner, 19711, ensure that fishery requirements are considered when waters are to be regulated.

11-1.11.3 Navigation

After the railway, inland navigation accounts for the largest transportation of goods. 240 million tonnes were transported in 1970, nearly half by foreign vessels. At present 5410 freighters, 980 tug boats and 518 passenger boats are registered in the FRG, (Statistisches Bundesamt, 1971). The water ways available for navigation are: 4035 laa of navigable rivers, 1803 km of canals and 125 km of navigable lakes. Traffic rates are increasing by some 3.5% annually, and consolidation of the network of water ways is planned, (Bundesminister fÜr Verkehr, 1971).

below Duisburg, it is used by an average of 600 boats and a maximum of 900 boats, daily. At high water levels, navigation is stopped to protect the embankments from the higher waves that would otherwise be generated.

ing water, however, the occurrence of fog has increased.

caused by freighters have almost disappeared. This is because sailors are not usually accompanied by their families any longer.

The bilge waters found in all ships are collected by bilge oil extraction boats. At present there are seven such boats on the Rhine, and these belong to the bilge water extraction corporation founded in 1965 as a public corporation with statutory powers. The old oil which constitutes about half the bilge 'water' is recovered and sold and this revenue covers about half of the operating costs; way. Additional measures are needed to control completely the occurrence of oils and grease from ships.

The freedom of navigation and trade on the Rhine today is still regulated by the Bill of Mannheim dated 1831, and amended in 1868. It is an internationally acknowledged agreement, and can be regarded as something like a precursor of the EEC in the sphere of navigation.

The most important and most frequented water way is the Rhine;

Because of the increase in water temperature of the Rhine due to the discharge of cool- conversely the number of days when navigation is hindered by ice has decreased;

The danger of water pollution through cleaning of tankers still exists though problems

at present about 5000 tonnes/year are regained in this

11-1.11.4 Waste disposal management

Nearly all wastes contain water-soluble matter which may harm the ground and surface waters. The removal of the large number of residues in the FRG is a considerable problem for water management. The total quantity of residues in 1970 was about 260 million tonnes, or about 350 million m3, which included: 3 Million tonnes Million m

Domestic garbage and similar waste 13 - 22 76 - 114 Sewage sludge

(92.5 - 96% moisture content) about 18 18 Special garbage 2 2

65

Legislation and water management

At present about 200 kq of domestic garbage and trash per head accumulate annually, and while a large increase in weight is not expected, the volume will increase. The problem of disposing of sewage sludge will also increase considerably, and the same trend may be predicted for most of the other residuals.

At present composting, incineration and dumping of residues are the essential methods of waste disposal. Composting is used mainly for domestic garbage, though also for sewage sludge. or the possibility of using the compost developed. At present the waste from about 2% of the population of the FRG is processed for compost.

resulting slags and ashes still have to be tipped, and the effect on water supplies may be as bad as for unburned residues. Further, not all residues can be burned, and at present only 20% of the population's garbage is incinerated.

al. Even controlled dumping leads to considerable difficulties for water management, because nearly all wastes have to be considered either as matter dangerous to water, or to contain such material. Hence the dumping of water and water utilization are normally mutually exclusive and attempts must be made to coordinate these activities. In North Rhine-Westphalia maps are being produced to show where wastes may be dumped, taking into account sources of water supply.

Major problems are produced by some special wastes; the recently discovered problems of arsenic and cyanide sludge disposal in industrialized areas, led to greater supervision and the instigation of new legislation. To prevent unknown disposal in prohibited areas, the transport of all dangerous wastes must be authorized. Communities are instructed to

i use suitably sited common depots for wastes, and to use every possible protection measure and control. Poisonous wastes must be neutralized and decontaminated before being transported or deposited. In addition the production processes are checked to determine whether the amount of wastes can be reduced, or whether the waste can be converted into a harmless form.

Application of this method largely depends upon the composition of the garbage and/

The main advantage of incineration of residues is a reduction in volume. However, the

Because of these difficulties dumping is the most commonly used method of waste dispos-

11-1-12 LEGISLATION AND WATER MANAGEMENT

11-1.12.1 Organizational measures

Water legislation in the FRG is based on the Federal Water Act and the Water Act of every 'Land' (State) of the FRG. The Federal Water Act, the 'Wasserhaushaltsgesetz' (Water Man- agement Act), was enacted in 1957 as a general law, giving the principles of water management. In the following years, the complementary Water Acts of the 'Lander' were put into effect, setting out the purpose of the water authorities and the way in which thex were to be set up. The Water Law covers all aspects of and changes produced on natural and artificial rivers and lakes, and is based on the principle that all water uses require permission from the water authority.

Urban water measures such as water supply (especially drinking water) and sewage disposal (especially of domestic origin) are run on a local basis and regulations are enforced by the municipal authorities. The water authority gives permission for the abstraction of a given quantity of water from rivers and aquifers at a given place, and for the disposal of given quantities of treated sewage of known quality into rivers and lakes.

ages. Their traditional duties of flood protection, irrigation, drainage, maintenance of rivers, etc, are often supplemented or even superseded by responsibility for water supply and sewage disposal. The legal basis is the 1937 Water Association Act founded on special water acts which existed in the first decades of this century. The great water associations of the Ruhr area, the Ruhrverband and the Emschergenossenschaft and others, are noted for their efforts in the field of sewage treatment and river basin management.

To improve water management, statutory water associations have existed since the middle

11-1.12.2 Water management plans

The Federal Water Act requires the water authorities of the 'Lander' to set up water management plans for river basins or defined areas of special economic importance. To enhance these plans the Federal Government issued a decree in 1966 with detailed working principles

66

Condusions

and rules. The water management plan consists of four parts:

the region of the plan, with its political, natural and socio-economic situation; the water resources , with its usable part, its origin and its quality; the water demand, with respect to water supply, water control (sewage), flow regulation and flood protection, agriculture, hydro-power and shipping; and the water balance both at present and over the next 30 years, and its relation to water management

The water management plan is neither detailed nor specific and it is not a technical basis for the installation of water facilities. It is, however, the basis of all water management activities within the catchment area of the plan and for all future major water plans to meet different specific water requirements.

The water management plan has to be revised every five to ten years to account for changes in local conditions and in technological advances.

Ultimately the enforcing of the water management plan by decree is the responsibility of the Minister. Thus the plan is given legislative teeth, and every public authority within the catchment area has to take the plan into account in its activities.

11-1.12 -3 Water control

On the basis of the water plans the water authorities manage the water resources by measures which include supervision of water bodies and control of water use. To control the quantity of water extracted from the ground more than 100 O00 observation wells have been drilled. The height of the water surface in the well is measured periodically to map the groundwater levels (isohypes). Discharge in streamflows are gauged, and sometimes telemetered to a central control.

With respect to water quality control a range of measures are taken and a number of facilities are installed. Physical, chemical and biological methods are used to document exactly the quality of natural waters and effluents. Monitoring stations on the main or most important rivers and at the outlets of sewage conduits are monitored continuously for quality - some parameters automatically, others by hand - and the samples are taken for analysis and documentation. Ships and cars used as mobile laboratories are permanently in operation, and for some purposes, the results of on site analyses are telemetered to a central control.

11-1.13 CONCLUSIONS

Human settlement in urban areas accompanied by industrialization is increasing in extent and concentration. The urban activities including housing, transport, services, industry, energy consumption and recreation are the main source of the damage to the environment.

have to be applied, particularly with reference to the management of water bodies.

disciplinary courses on the ecological processes and the economic background; and through the mass media, to assist in political decision making.

These measures have augmented knowledge and the public conscience has been sharpened. The appearance of the 'Burgerinitiativen' (Initiative groups of citizens) all over the country and in all environmental fields make it clear that the recovery and conservation of water, air, and landscape have become a vital public concern.

These are the areas where the conservation and regeneration of environmental resources

Basically it is a question of public education: at schoo1,through intensive and inter-

67

References

11-1-14 REFERENCES

Batelle-Institut e.V. 1972. Wasserbedarfsentwicklung in Industrie, Haushalten, Gewerbe, Bffentlichen Einrichtungen und Landwirtschaft - Prognose des Wasserbedarfs in der Bundes- republik Deutschland bis zum Jahre 2000 Herausgeber: Bundesminister des Innern, Bonn.

Bretschneider, H. 1971. Taschenbuch der Wasserwirtschaft, 5. Auflage, Verlag WASSER UND BODEN Axel Lindow u.Co, Hamburg.

Brix, J., Heyd, H. und Gerlach, E. 1963. Die Wasserversorgung, 6. Auflage, Verlag R. Oldenbourg, Munchen und Wien.

Buch, Alfred. 1972. Die Entwicklung des Energiebedarfs und seine Deckung, Gluckauf, Jg.108, Nr.19.

Bundesminister des Innern. 1971. Umweltplanung - Materialien zum Umweitprogramm der Bundesregierung 1971. Drucksache des Deutschen Bundestages, VI/27iOI Bonn.

Bundesminister des Innern. 1972a. Bericht der Bundesrepublik Deutschland uber die Umweit des Menschen, Eigenverlag, Bonn.

Bundesminister des Innern. 1972b. Abwasser - Anfall, Behandlung und Beseitigung in Gemeinden und Industrie-betrieben in der Bundesrepublik Deutschland 'Umweltschutz' Heft 18 Eigenverlag , Bonn. Bundesminister fcr Ern&rung, Landwirtschaft und Forsten Jahresbericht Über die deutsche Fischwirtschaft 1968-69, 1969-70, 1970-71, Verlag Gebr. Mann, Berlin.

Bundesminister fur Verkehr . 1971. Jahresbericht fur die Binnenschiffahrt 1970. Eigenver- lag, Bonn.

Burghartz, F.-J. 1962. Westfalen, Verlag C.H.Beck, Munchen und Berlin.

Flohn, H. 1954. Witterung und Klima in Mitteleuropa, 2. Auflage Verlag S. Hirzel, Stuttgart.

Frewer, H. 1Y71 Energieverbund zwischen nuklearen und konventionellen kraftwerken, Atomwirt- schaft, Juli.

Harnisch. 1967. Die Grubenwasserwirtschaft des Ruhrbergbaues aus der Sicht der Pumpgemein- schaft, Gikkauf , 7 Dezember . Kaufmann, Bernd: genossenschaftlicher Grundlage im rheinisch-westfalischen Industrieyebiet und die Wasser- wirtschaft des Steinkohlenbergbaus, Dissertation, Techn.Bochschule Clausthal.

Koenig, I3.W. I Rincke, G. and Imhoff , K.R. 1971. Water Re-Use in the Ruhr Jlalley with Particular Reference to 1959 Drought Period, Proceedings 5th. 1nt.Water Pollution Research Con., 1970, Peryamon Press, London.

Kukuk, P. 1955. Geologie, Fineralogie und Lagerstattenlehre , 2. Auflage, Verlag Springer, Berlin-Göttingen-Heidelberg . Kukuk, P. Geologie des Niederrheinisch-Westf alischen Steinkohlenyebietes.

Meinck, F. , Stoof, €1. und Kohlschutter, H. 1968. Industrie-Abwasser, 4. Auflage, Gustav Fischer Verlag,Stuttgart.

2ossert, E. 1969. Grundlagen der Wasserwirtschaft und Gewasserkunde, Verlag H.Oldenbourg, Pfunchen und Wien.

Statistisches Bundesamt. 1971. Statistisches Jahrbuch fur die Bundesrepublik deutschland 1971 , Verlag W.Kohlhammer , Stuttgart und Mainz.

Wiesner, ?.R. 1971. Wegweiser fur den Fischerei- und Gewasserschutz, Verlag Lambert Muller , Munchen.

Wasse;haushaltsgesetz und Wassergesetz fur das Land Nordrhein-

1963. Wasser und Kohle - Wassezversorgung und Abwasserbeseitigung auf

..

68

2 Hydrological effects of urbanization in the Netherlands

F. C. Zuidema

Ijsselmeerpolders Development Authority, Le lys t ad

Hydrological effects of urbanization (Studies and reports in hydrology, 18) Paris, The Unesco Press, 1974

Introduction

11-2.1 INTRODUCTION

Among the densely populated countries of Western Europe, the Netherlands occupy a special place because it is one of the smallest it has a very high population density.

important water interests exist in the fields of economy, trade, traffic, transport, nature and recreation, in addition to domestic and industrial demands. It is clear that all these interests should be examined in relation to future urban development of the country.

pects of urban areas are consiaereü, based on the Second Report on physical planning in the Netherlands (Dutch Government, 1966). A Third Report is now in preparation for publication in 1975/1976. cussed in 1973/1974 in several orientation notes. On December, 28, 1973, the Government produced the 'orientation note on physical planning' (Dutch Government , 1974) to parliament , which can be considered as part of the Third Report. and solve spatially conflicting claims, to remove social problems caused by the physical structure and to improve the quality of living conditions. Recent developments in physical Planning need to consider first the methods used, and secondly, the question of whether the objectives and the framework of the physical structure must be changed. New social, economic and physical constraints lead to a confrontation between various aims , for example , between environmental protection and economic growth. the physical planning policy will be:

The geographic situation in the deltaic area of the rivers Rhine and Meuse means that

Before considering the hydrological effects of urbanization in detail , some general as-

Before this is published, however, a number of ideas and questions will be dis-

Its main aims are generally to prevent

In relation to urbanization the objectives of

- a better distribution of population, employment and of welfare facilities over the - a concentration of the buildings in the urban zones (deconcentrated into centres with country.

more accent on concentration than was proposed in the Second Report on physical planning) ; development of new towns, where necessary. - the development of regional urban structures with a variety of living conditions, (environmental differentiation) .

- a greater integration of living and working areas to reduce travel except where industries would cause a nuisance.

- an increase in the number of people living in city centres. - the promotion of public transport and the provision of reasonable traffic communications - the conservation of the central areas between urban zones, between regional urban areas - the fight against nuisance by air, water and soil pollution and by noise. It is emphasized that the physical planning policy alone will not be able to achieve these

by highways , especially between centres of economic activity.

and inside these regional urban areas (i.e. buffer-zones).

aims; the policy must be translated into the criteria and procedures needed to speed up its implementation before too much inadequate development occurs.

and water supply (for domestic and industrial use), and electric power, particularly with respect to the shortage of cooling water.

The orientation notes will also consider developments in water management, water demands

11-2.2 SOME PASSAGES FROM THE SECOND REPORT ON PHYSICAL PLANNING IN THE NETHERLANDS (1966)

11-2.2.1 Some bases for the development of residential areas

Physical planning takes place against a background of tension between the present and the future. on the one hand, attention to the needs and trends of the present, and, on the other hand, sufficient flexibility to enable unknown changes in the future to be possible.

are formulated, and it emerges in almost any discussion on the subject. One person sets out the requirements on the basis of the housing needs of the present generations, while another stresses the importance of development continuing along sound lines in the long-term.

has a very adverse effect on the well-being of current generations, while it is an obvious responsibility of Government to act with regard to the future. which may not lead to the same result, can be fairly reconciled is open to discussion.

The measures whichthe Government must take to achieve a harmonious development require,

This polarity is very apparent when the requirements to be fulfilled by residential areas

Both viewpoints are logical: taking care of the future without taking care of the present

Whether the two viewpoints,

70

The trend of the urbanization process

11-2.2.2 Conclusion

Good design of urban areas depends on close adherence to those requirements which man consid- ers his residential environment should fulfill. These requirements vary a great deal, and future residential environments will,therefore, also have to vary considerably. At present greater attention is needed to the provision of one-family houses in the suburbs, where the advantages of town life can be combined with those of the quiet residential atmosphere outside of a city.

Because of the justified continuation of urbanization , a certain degree of concentration is unavoidable and the large numbers (110 000) of new dwellings* that are required in new residential areas every year, constitutes a compelling factor in this respect. Duririg continued concentration, however, the emphasis should be placed on good development of residential centres around the urban areas. In this way it will be possible to provide the inhabitants with good services and in the long-term, adequate communications, public transport and an attractive residential environment, where the experience of living 'out of town' can still be enjoyed. This style of urbanization is also attractive from an economic point of view and is preferred to substantial decentralization because many costs tend to be lower. In addition demands made on space are minimized while still fulfilling the present needs.

11-2.3 THE TREND OF THE URBANIZATION PROCESS

11-2.3.1 Character of the process

Although urbanization results from a very complicated social process, it usually takes place in a certain order. At firstthis order produces a hierarchic structure of centres, and in the longer term as a growth of the centres in a characteristic ratio of number and size.

In the original, largely agrarian society of the Netherlands, the structure of centres was simple; a close network of villages within a walking distance of only a few kilometres, a large number of small service producing centres,** and only a few large cities. The present structure of centres in the north of the country still clearly illustratesthis pattern.

be better situated than others and consequently they expanded a little faster. Facilities not required daily were concentrated there and transport facilities improved further, leading to the formation of a regional service centre of greater size and complexity than the other centres,

For example, although originally the expansion of industry and services and the accompanying migration to the cities, strengthened the regional centres, increased mobility and the widespread availability of power and modern cornunications has meant that more places can now be developed into centres of employment than was possible when industrialization began.

The effect of changes in housing needs on the pattern of the centres is not so clear; commuting by villagers to work in the city does not strengthen their structure. However, if the suburbs are absorbed into the city, then viewed nationally, the existing structure would be strengthened.

Another very important aspect of the present situation is the acceleration of the urbanization process; expansion which once took centuries can now take place in a period pf ten . years.

Even today the pattern demonstrates the origins of the pattern. Some places appeared to

The same process also takes place today, although partly influenced by social requirements.

11-2.3.2 Population concentrations

Figure 8 gives the possible distribution of the major concentrations of population in the country in about the year 2000. This projection is based mainly on demographic and economic predictions, though an effort has been made to strengthen the existing structure. In this way the future urban structure discussed in section 11-2.3.1 is most likely to be compatible with future development needs.

* 1972 and near future: 150 O00 dwellings. ** Since 1966 the growth of these small centres around the cities has been very fast, and has

had an adverse effect on the landscape.

71

1 rnln inhabitants and over

1/2-1 rnln inhabitants

125 000-250 O00 inhabitants


30 000-65 O00 inhabitants indicated on the map.

15 000-30 O00 inhabitants 0 10 000-1 5 O00 inhabitants

O II

1/4-1/2 rnln inhabitants

another 2400 nuclei have not been

Figure 8. Likely distribution of the major concentrations of population in the year 2000.

72

, -



0 30 000-65 O00 inhabitants

O 15 000-30 O00 inhabitants o 10 000-15 O00 inhabitants A. 1/2-1 rnln inhabitants

1/4-1/2 rnln inhabitants

Figure 9. Distribution of the major concentrations of population throughout the Netherlands in 1960.

73

- - urban zones city regions within the urban zones

t o w n s outside the urban zones

. . *:: park areas

#: central open space

,,,~ ..,..,,, ,,,, adjacent similar areas in Belgium and Rhine-Ruhr area

Cchaal 1 : 2.5OO.OOi 9 ~__ d 10 .o*

74

Figure 10. Urbanization pattern of the Netherlands in relation to neighbouring countries.

75

Figure 11. Map of the Netherlands with Provinces.

16

The urban picture of the Netherlands

For sake of comparison, the distribution of major concentrations of population in 1960 is given in Figure 9 using the same symbols.

11-2.4 THE URBAN PICTURE OF THE NETHERLANDS

In the region along the North Sea, development is underway which increasingly involves the Netherlands in the growth of an extensive complex of cities, industrial areas and ports in and around the Rhine-Meuse-Scheldt Delta. The principal conurbations are the Randstad, the Rhine/ Ruhr and the agglomerations in Belgium/North France (Figure 10). Partly because of these trends, urbanization in the Netherlands has to date been concentrated in an area south o5 the Alkmaar-Arnhem region (Figure 11). Because of demographic and economic requirements an initial general survey of the physical planning needs of the Netherlands has been made. Allowance has been made for the Government's proposed policy for population distribution, which includes a target figure of 3 million persons for the north. Together with the account given in section II-2.3.2 of possible future distribution of the population, the survey will provide the starting point for the future urban pattern of the Netherlands.

11-2.4.1 Deconcentration into centres

In principal there are three possible patterns for future urbanization: increasingly widespread concentration; deconcentration into centres and widespread deconcentration*. All three have their advocates both in the Netherlands and elsewhere; in the Netherlands deconcentration into centres has been chosen.

It was argued that future population density would not permit widespread deconcentration: extensive redistribution is already giving rise to difficulties and would also remove future recreational space. Increasing and widespread concentration on the other hand is incompatible with present trends and housing needs, and should not, therefore, be considered.

Hence, only the second choice - deconcentration into centres - remained and this is discussed below. In general though, the pattern envisaged maximised the possibilities for housing, working, recreation, transport, etc., while not restricting future physical planning of the country more than is absolutely necessary. Both these aspects are essential in the present state of social development: well-being requires freedom i.e. a range of possibilities to chose from, and present rapid changes (both social and technical) demonstrate the need to maintain the greatest possible flexibility.

11-2.4.2 Future overall structure

The change in overall structure of the future development patterns for the Netherlands proposed by the Government is indicated in Figure 12 and 13 . When discussing this structure it is impossible to pass over the rural areas as figures and show that highly and less urbanized areas alternate. This is most evident in the south-west of the country, where urbanization is greatest. On the basis of present trends, four large urban zones are indicated:

1. The north wing (Alkmaar, Ijmond, Haarlem, Amsterdam, Zaan region, Gooi region, Utrecht,

2. The south wing (Leiden, The Hague, Delft, Schiedam, Vlaardingen, Rotterdam, Dordrecht). 3. The string of towns in the province of Brabant (Bergen op Zoom, Roosendaal, Breda,

Amersfoort, Utrechtse Heuvelrug, Veluwezoom, Arnhem, Ni jmegen) .

Tilburg, Waalwi jk, 's-Hertogenbosch, Oss, Eindhoven, Helmond) , with to the west a continuation on the islands of Zuid-Beveland and Walcheren (Goes, Middelburg, Flushing) .

4. South and Central Limburg (Maastricht, Heerlen, Kerkrade, Sittard, Geleen, Roermond, Venlo), forming part of the Belgian-Dutch-German urban area (Luik, Aken) .

Between these four zones thereis a large, little urbanized and largely agrarian area. The significance of such an area can be illustrated by the contents of the report 'The West of the Country', in considering the way in which the structure of urbanization in the Netherlands can be organized to ensure an attractive residential and work environment. At the time this led to a recommendation that the central area of the Randstad be protected against intensive

* Forms of urbanization such as development on a strip, star or concentric pattern have not been taken into account.

77

2 5 0 - 5 0 0 inhabitants/sq. krn.

500-1 O00 inhabitants/sq. krn.

1 000-2 O00 inhabitants/sq. km.

urban areas

Figure 12. Density of the urban areas in 1960.

- O 20 40 krn

78

500-1 O00 inhabitants/sq. km. 0 urban areas 1 000-2 O00 inhabitants/sq. km.

2000 inhabitants/sq. km. and over - O 20 40 km

Figure 13. Predicted density of the urban areas for the year 2000.

79


urbanization. The Government adopted this recornmendation and sought the co-operation of the pïovincial administrative bodies to ensure its implementation.

The four urban zones are not compact, and largely comprise a city region which has been extended to incorporate a large number of green areas, which have been so blended with the urban sphere that they must be regarded as belonging to the sub-urban area. Examples are the natural country areas in the Gooi region and along the Utrechtse Heuvelrug, as well as the so- called buffer zones, which were introduced in the report 'The West of the Country'. They refer to the separation of adjoining areas at those points where there is a risk of their growing together. It is, in fact, considexed advantageous for urban zones to consist of independent towns, agglomerations and cities, particularly from the point of view o€ its inhabit- -ants and the cultural-historical aspect. The separation by physical planning, of towns to form separate geographical units, can make an important contribution to the preservation of awareness of the culture and history of a town.

year 2000 are based on the boundaries indicated in Figures 12 and 13. Table 11 shows, for example, that the density of the string of towns in the provinces of North-Brabant about the year 2000 will have become higher than the density of the north wing now.

The data given in Table 11 of the density of the urban areas for today and for about the

Table 11. Numbers of inhabitants and population density in various parts of the Hetherlands in 1965 and 2000.

Inhabitants Density/ (mi 1 lions ) sq. km

Urban Zone around

1965 2000 1965

North wing 3.2 4.8 900 1200 South wing 2.6 3.7 1500 2200

' String of towns province of North-Brabant 1.3 2.4 500 1000

District of Twente O. 4 0.6 500 900 Central Groningen/northern part of province of Drenthe O. 4 0.8 400 700

South and Central Limburg O. 6 1.0 1200 1900

(Source: Second Report on Physical Planning in the Netherlands (1966) )

11-2.5 UE3ANIZATION INDICES

11-2.5.1 Population

Population growth is expected to continue in the coming decades, although as Table 12 shows, the prediction for the year 2000 is considerably lower than that of some years ago.

Table 12. Total national population in millions of inhabitants. (Source: Central Bureau of Statistics)

Year in which 1965 2000 estimate was made

12.5 12.8 15.8 20.7 (1965) 14.4 17.9 (1970)

17.1 (1971) 16.0 (1973)

80


The nuTbers in Table 13 were also obtained from the Central Bureau of Statistics and for the year 2000 give the land occupancy and density for 20 million inhabitants.

Table 13. Number of communities (1965) and concentrations of population (2000)

Inhabitants rations of Population , n^^^

20 O00 or more 10 7 - 30 O00 or more 88 50 O00 or more 37 - 65 O00 or m r e 56 100 OCO or more 14 -

- -

125 OCO or more 250 O00 or mre 500 O00 or more

4 3

34 18 7 (The Hague,

Utrecht , Eindhoven , Arnhem, mente , Amsterdam, Rotterdam)

1 O00 O00 or more - 2 (Amsterdam, Rotterdam)

Figures 12 and 13 show the distribution of the concentrations of population throughout the Netherlands in 1960 and around the year 2000. consist of towns, agglomerations (several towns together) , city regions (with one or two towns or an agglomeration or a combination of both as centre) or urban zones.

These concentrations of population can

11-2.5.2 Land OCCUPXICY

The total area of the Netherlands is about 33 400 sq km if open inland water is included. In 1965 about 631% of the total area of the Netherlands was built-up, and by the year

2000 this will probably increase to between 12% and 15% (including industrial areas). This comparatively large airea means the disruption of built-up areas is of great significance.

million people by the turn of the century. this figure would be about 480, for 18 million it would be about 540.

In 1965 the population density was 375 inhabitants per sq km. For a population of 16

11-2.5.3 Climatic and topographical distributions

There are no important climatic and topographical differences between the urban areas.

11-2- 6 CHARACTER OF PRECIPITATION


The annual average precipitation in the Netherlands over the period 1931-1960 is 742 mm. The regions with the highest precipitation (>785 mm) are: a. the northern part of the province of Friesland (Figure 11); b. the area west of the Pleistocene chain of hills called Hondsrug (Drenthe) ; c. the Pleistocene hiìly region of the Veluwe (Gelderland); d. the hills above 200 m altitude in the extreme southeast of the country; e. small areas in the neighbourhood of Amsterdam and Rotterdam. The highest average values are at Vaals (South Limburg) (863 mm) and at Apeldoorn (Veluwe)

The regions with the lowest amounts of precipitation (<7OO mm) are: f. the area east of the former Lauwerszee;

(846 mm) .

81

Hydrological effects resulting from water management systems

g. the areas west and east of the northern part of the Ijssel lake; h. parts of the province of Zeeland; i.

The lowest average amount is to be found at Roermond (Central Limhurg) (656 mm) . These data are taken from K.N.M.I. (1968a and 1972). Various studies have been made of the frequency distributions of rainfall, (K.N.M.I.,

1. Frequency distributions of the total rainfall amounts in periods of k consecutive days, for k = 1, 2, 3, 5, 7, lo, 15, 30, 60, 90, 180, 360, 540, 720, 1080, 1800. These distributions were derived from measurements at 24 stations in the Netherlands with long period of observations.

2. Frequency distributions of the amounts of precipitation in periods of 5 to 660 minutes; these distributions were derived only from measurements at De Bilt.

the area of the eastern part of the province of North-Branant and North and Central Limburg.

1956-1965 and 1968a).

11-2.7 HYDROLOGICAL EFFECTS RESULTING FROM WATER MANAGEMENT SYSTEMS

There are many examples of the hydrological effects resulting from water management techniques. Some arbitrarily chosen examples are given in the following sections.

11-2.7.1 Sea water penetration inland (Sni jdelaar, 1970)

The second largest source of saline intrusion, after the aine, are open esturies and open rivers. Because of the difference in density between salt and fresh water, seawater enters as a saline wedge along the river bottom beneath the fresh water. Mixture of the fresh and saline waters takes place through turbulence produced by currents, tides, ships propellers and irregularities in the channel profiles. The extent of saline intrusion at low water tide is determined mainly by the volume, rate of river flow and water depth. Experiments have shown that the salt gradient is inversely proportional to the third power of depth. Thus, in the Rotterdamsche Waterweg, a waterway which has been deepened considerably over the last 10 to 15 years, the chloride-ion content at low river flows does not diminish to an acceptable value for many kilometers inland. Saline intrusion at high tide reaches approximately 10 lcm further up river, and, as a result, various river abstractions along this waterway had to be abandoned.

outlets to the sea, and to shorten the coastline; this was called the Delta Plan. This plan serves other objectives as well, such as safeguarding the low-lying polder land, producing fresh water reservoirs and assisting land development.

As both the Nieuwe Waterweg and the Nieuwe Maas remain openly connected to the sea, a decrease in saline intrusion is obtained by raising the bottom of the two waterways, thereby producing a steeper salt gradient which shortens the distance over which instrusion takes place.

A third source of salt is formed by the locks situated on the coast a short distance inland, which separate the salt water from the fresh. Again the difference in density causes large quantities of salt to penetrate the fresh water behind the locks each time a ship passes through them. In fact, when the outer gates are opened the fresh water in the lock chamber is displaced by sea water, and a second exchange occurs when the inner gates are opened. This form of salt intrusion was recognized many years ago by Henric Stevin, who suggested means of reducing the quantities entering. Today, salt intrusion is reduced by special sluice const- ructions , by pumping out the incoming sea water, and by the use of air bubble screens.

11-2.7.2 Dividing the functions o5 the waterways (Snijdelaar, 1970)

To reduce the magnitude of the intrusion, it was decided to reduce the number of river

It will be obvious that shipping interest, particularly those at the large, increasingly deeper and readily accessible ports which have good communications channels inland, conflict with those of water management, as harbour developments promote saline intrusion of inland waters. It is vital therefore that works designed to serve water management or shipping take full account of each other, and provide safeguards for all the interests.

The main effort must therefore be to reduce saline intrusion, but whatever measures are taken it wilì not be possible to eliminate it completely. In consequence, it is best to separate water coursss into those for carrying good quality water and those for shipping purposes.

82

HydroZogicaZ effects resulting from water management systems

This principal of division of functions cannot be applied in the low-lying part of the Netherlands because the situation there has in the past required watercourses to fulfill simultaneously functions that are usually mutually conflicting. Normally, they are used for a combination of shipping, draining off excess and frequently polluted water and for carrying good quality water, and only a division into salt water near the sea and fresh water inland will be effective. While this division must be strictly enforced, the construction of new works should be based on the principle of complete division.

11-2.7.3 Integration of two main water supply systems

The water management structure of the Netherlands is based around the Rhine and Meuse with their branches to the reservoirs in the southwest and to the open Rotterdamsche Waterweg, ahd the Ijssel, which removes approximately 10% of the Rhine's total discharge, and the Ijsselmeer. These two main components of the water management system must provide the future water resources of the Netherlands.

To provide the necessary flexibility in the system, integration of its two principal components is very necessary. By this means the distribution of available water to the various supply areas can be revised, should their future water requirements change from those predicted.

Integration also provides security of water supply for economically important areas, which need no longer rely on supplies from a single source; this security must be included in all future plans.

11-2.7.4 The effects of canalizing rivers

The canalization and regulation of the rivers Rhine and Meuse considerably improves their nav- igability. However, because many bends in the rivers were removed, the area of the flood plain on which water can be stored during high river levels in winter, was reduced. Further, maintenance of the flood plain, river straightening and bed improvements lead to higher river levels than before at certain places, and this results in more seepage into the polders along the river-dikes. Thus, for example, in a polder near the Rhine, 10-15% more seepage can be expected.

11-2.7.5 Gravel extraction in the Meuse flood plain

Around Roermond (centre of Limburg) gravel is being extracted from the flood plain of the river Meuse. Thus the storage capacity is not only increased but also used more frequently because.. the reduced levels of the plain are reached at lower water levels than before. Thus gravel extraction has produced greater attenuation of the flood wave than before.

11-2.7.6 Influence of deep-drained urban areas in polders on saline seepage

Urbanization in Dutch polders often leads to a lower open water level and hence to a lower groundwater level (incidentally, about 75% of the Netherlands lies below sea level). Lowering of the water level causes a larger saline seepage not only from the sea, but also upwards from deep groundwater to the existing polders. This damages the grass yield, the water supplies for cattle and the domestic water supply, as well as vegetables and flowers spray irrigated in the summer. To reduce saline seepage the inundation of uneconomic polders is under consideration, particularly as the resulting lakes could be used for recreation.

11-2.7.7 Influence of the reclamation works in the Ijsselmeer on deep groundwater flow

The new polders in the I jsselmeer substantially reduce groundwater levels in the surrounding area. The lakes of Eastern Flevoland prevent dehydration of the bordering lands which are highly susceptible to drought. It is expected that the future Markerwaard will increase saline seepage from the North Sea to the old deep polders in the province of Noord-Holland (Figure U), and fresh water will be injected to minimize the damage to veget&les and other crops.

83

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84

Water supply impact

11-2.8 WATER SUPPLY IMPACT

11-2.8.1 Urban public abstractions and independent indus trial water abstractions

Increasing population, industrialization and water consumption in the Netherlands and neighbouring countries have resulted in an increasing water demand and a deterioration in the quality of the sources of water.

able that the relative quantities obtained from groundwater and from suface water váry considerably in the provinces. In the low-lying western part of the Netherlands nearly no fresh water is available, while in the eastern part and in the hilly regions of the Veluwe, adequate groundwater is present.

The demand for water will increase in the future, and to meet this future demand a master plan has recently (19,721 been prepared as part of the Third Report on Physical Planning in the Netherlands,

In 1967 water abstractions in the Netherlands were as shown in Table 14, and it is not-

In the master plan, demands for water in the year 2000 are estimated as shown in Table 15.

Table 15. Water demands for the year 2000, based on a population of 17.1 million people.

Water Demand Miilion m3

Domes tic 1250 (1) Trade and Public Services 250 (1) Indus try 2150 (2) (3)

Leakage losses and flushing water 300 (1) Agriculture 100 (1) (4)

Total 4050

(1) total public supply abstractions : i900 million m3 (2) public supply abstractions: 1150 million m3 , self-supplied industrial water

(3) excluding cooling water from surface water,expected cooling water demand from

(4) this figure represents only the water suppl by public water companies.

abstractions 1000 mi ilion m3.

surface water for electric power plants 57 x lo9 m3/year, industry 13.109 m3/year.

remaining agricultural demands 3300 x 10 6 3 m /yearIin a dry summer. to reduce saline instrusion 10800 x lo6 m3/year )

3 Table 15 shows that, for a population of 17.1 million persons, some 4000 million m of drinking water will be used by domestic, trade and agriculture in the year 2000. Factors affecting domestic consumption were considered to be population increase, development of new sanitary equipment, smaller sized families and a change in attitude towards water use. Cal- culations of industrial water demands were based on the estimated increase of industrial production, and took a water re-use factor into account. A check calculation, based on the amount of the land area to be occupied by industry (with the assumption that industrial water demands per unit area will remain about the same), gave the same result.

ready been urbanized, the differences in water use by households in urban and rural areas is insignificant.

will be about 3000 million rn3 by the year 2000, of which 2500 million m3 will be highly purified water (drinking water quality), and 500 million m3 will be partially purified water (only usable in industrial processes).

supply; thus the master plan contains several projects for artificially recharging the dunes and the hilly Veluwe area, and for supply from surface water reservoirs.

of 4000 million m3 per year, to give flexibility ana a better choice of alternatives.

The report on future water demands also concluded that because the Netherlands has al-

The footnotes of Table 15 show that the total water supply from public water companies

Tables 14 and 15 show that future water demands will surpass the available groundvrater

The water supply measures planned will have a capacity greater than the estimated demand A

85

FZooding effects

possible solution to the water supply problem is given in Figure30 in part III.

11-2.8.2 Present and expected public and industrial water supply problems

Considering the contents of the previous paragraph and accepting the present limitations of their validity, the following future trends are expected:

1.

2.

3.

4

Because of the size of installations required it is not expected that industries will in future abstract new and large quantities of surface water, except for cooling purposes; instead industries are likely to call increasingly on the urban public supply * Special drinking water reservoirs will be sited where the salinity of the surface water is likely to remain low. Some reservoirs are already in operation; two near Rotterdam (Biesbosch and Beerenplaat) and smaller ones near Andijk and near Terneuzen. Bigger reservoirs are planned in the Ijsselmeer (500 million m3) and in the Grevelingen (southwest Netherlands). By filling the reservoirs to the highest possible stage when the inflow of good quality water is plentiful, drinking water requirements can probably be met. However, because of the present poor water quality of the Rhine, the required quality of drinking water cannot always be obtained; only a combination of storage in special reservoirs and a reduction in the salt load of the Rhine will ensure the quality of drinking water at all times. For many years, surface water from the river Rhine has been infiltrated into the dunes along the North Sea coast. In future this area will be too small for the required storage and purification, and preliminary plans have therefore been made for the infiltration of water from the Rhine into the hilly regions of the Veluwe. Research and experiments on the desalination of sea water for use as drinking water are under way. The flash evaporation method is used at Rotterdam, at Terneuzen (southwest Netherlands) and on the island of Texel in the Waddensea. The reverse osmosis method is still at the experimental phase, and while the electrodialysis method is being used by a brewery, some problems with the membranes, which are very sensative to solid loads, still remain.

All these points clearly demonstrate that both water demands and economic considerations play a major part in the development of new techniques and in decisions on the application of alternative solutions.


Three main differences can be identified between runoff from an urban area and from an arei with fewer paved surfaces:

1.

2.

3.

runoff in an urban area will have higher peak flows due to the large paved surface and the relatively low storage capacity. the more stringent requirements for drainage from e.g. groundwater levels, during and after house building, compared with those for agricultural land, will give higher discharges. the higher discharges can interfere with runoff from other paved and unpaved areas, and with the discharge of domestic and industrial waste water in separate or combined sewer systems.

Research on items 1 and 2 is taking place in several urban areas (see section.11-2.14, Water balance inventories).

At

a. 1972).

b.

C.

present the following criteria are used in areas of development (Blok and Dorfmeijer,

Stormsewer size is based on a discharge of 90 litres/sec/ha, using a minimum storm duration of 15 minutes, a storage of 7 or 8 mm is used for combined sewers and about 3 mm for a separate storm system. These criteria give an estimated design frequency of one in one year failure. Combined sewer systems should not overflow more than 5 times per year (previously 7 to 10 times). By accepting an average of 5 overflows yearly the storage of the system can be reduced by 7 or 8 mm. Sewer water will be drained off into special storage basins (90% of urban development) and/or into existing open waterways which have been enlarged (10% of urban development) Storage basins reduce urban runoff to a value which is acceptable to Existing waterways

86

Pollution effects

d.

within the rural area. It is advantageous for the size of the storage basins to be modified as the residential sector grows; otherwise the larger waterways required for the ultimate development would be needed when development starts. The required storage in existing open waterways is based on a design frequency of one in ten years exceedence, which in the Netherlands represents a rainfall of 40 mm in 180 minutes, combined with a one in one year discharge from the surrounding rural areas. This criterion is applied for the summer as well as for the winter, though it is noted that winter runoff from rural areas is twice the runoff in summer for the frequency quoted. In addition to the above criteria the storage basin design is based on:- - a storage on paved surfaces of 3 mm; - a storage in a combined sewer system of 7 or 8 mm; - an excess capacity at the sewer pumping station of 0.8 mm/hour to ensure that the - a minimum waterdepth of 1 metre; - that one third of the total open water storage is available after 24 hours. The size of a storage basin will be about 1.5 times larger for a separate sewer system compared with a combined sewer system. Generally, an open water area of 2-4% of the total urban area will be sufficient for surface water storage. While the design frequency for a pumping station in a polder is one failure per year, the pumping station for a sewer system must’cope with four times the discharge of waste water. ,

sewer system can be emptied with 10 hours;

Finally, in the north of the country considerable subsidence of the soil, due to the removal of natural gas, has been observed; on the island of Ameland subsidence was 280 mm and in the city of Groningen some 500 mm. Subsidence of this extent can lead to flooding.

11-2-10 POLLUTION EFFECTS

It is generally expected that urbanization, industrialization and mining wiil lead to a continually greater pollution of water and air if no preventative action is taken; only general trends in pollution effects are given in this section.

has been collected to record changes and to indicate when action should be taken. Unfortun- ately, it is difficult to derive firm conclusions from the results of these studies, as they are diverse and mostly short term. There are, however, some data on the rivers Rhine and Meuse over a series of many years (Kooien, 1973). Organic, inorganic and thermal aspects of pollution have produced some important legal considerations which were accepted by the Govern- ment in 1970.

For decades in the Netherlands, many investigations have taken place and much information

11-2.10.1 Organic, inorganic and thermal aspects

Annual changes in weather conditions influence the extent of pollution; thus fluctuations in river flow greatly influence the water quality of the rivers Rhine and Meuse, which constitute the majority of the surface waters in the Netherlands. This water is used as a source of drinking water, in agricultural areas (both for water supply and for flushing out saline intrusion) , for fisheries, as industrial and cooling water, etc. The big lakes, which are fed by the above two great rivers, and are, therefore, generally polluted, have problems of algal growth, which depends on meteorological conditions. could suffer from algal blooms, the causative nutrients originating from the rivers Rhine and Meuse, due to heavy pollution from countries upstream. Local discharges of waste water or effluents from purification plants add further to the nutrient content.

Recent studies have led to the concentration of new purification plants, catering for several urban areas, into one large plant, near surface water with a good self-purification capacity. as on the need to protect smaller areas of water where even a discharge of a purified effluent might be too much. this policy. €or requirements in the year 2000. Obviously the policy of concentration of plant requires the whole agglomeration to be viewed as the main issue, rather than individual local interests.

Nearly every area of surface water in the Netherlands

This policy is based on financial, economical and technical considerations as well

Town and Country Planning and ease of enlarging the plant encourage In the case of an urban area near Arnhem, the treatment works have been designed (20% more capacity than needed at present), but the sewerage is sufficient to meet 1980,

87

Micro-scale climatic effects

Considerable increases in the production of poultry, pork and beef have led to problems in the discharge of waste water, the pollution of the soil by manure, and leaching of minerals through the soil to the surface water. found in the eastern and southern parts of the Netherlands where only small streams exist.

Welmelsfelder (19722 describes some water management aspects of cooling water supply from which the following passage has been taken:

'Because of the abundance of large, open waters, cooling for electric power plants with surface water was and is still the normal practice in the Netherlands, due to possibilities, to economical considerations and to landscape protection. Future electrical energy demands due to the increasing population and the increasing use per capita, however, require many more, large power plants. The capacity of the plants will be much more than that of those already existing (for example: 10-fold). In spite of the apparent abundance of surface water, the provision of those plants with cooling water will be a real big problem because of a multi- tude of other, already existing functions of rivers and lakes, and because of the negative effects of too much rising temperature on the water quality and the aquatic life. The quantities required for cooling purposes are so large that possible sites offering the required cooling water with a minimum of conflict with other water management functions must be given priority. The availability of cooling water might, in this case, be a factor which over-rides other factors such as landscape aspects, recreation areas, residential areas, distances to consumer areas, high-voltage transmission lines, attainableness for heavy transport, etc. Painstaking analyses in time and space, especially of the hydrological aspects of the available surface water, are required in order to evaluate the possibilities of site.'

'Besides the water management aspects, attention must be paid to the biological aspects of cool-ing water (Anon., 1971). Investigations in the field and in the laboratory have been undertaken to ensure the safety of these aspects to the maximum extent possible. The Inter- national Commission for Protection of the Rhine against Pollution proposed to limit the rise in temperature of the river water, due to discharges of calories, to 3 degrees Celsius. For supplemental electricity requirements, building of cooling towers is an alternative. Also generating electricity at places where no river water is used for cooling, for example alongside the greater lakes, is a possibility. The Dutch Board of Ministers adopted these rules.'

The greatest concentrations of these industries are

11-2.10.2 Pollution from urban sewer systems

In the past most new sewer systems in towns and villages take both storm water and waste water. At present there is a growing view that the frequency of combined system overflows should be reduced to 5 or 6 times per year; further, the need to purify storm water in a separate system is under discussion. It is expected that oil and other pollutants, such as detergents, will adversely influence the quality of open waterways.

has been measured. This is probably caused by detergents used in the cleaning of cars on the streets. basins or pumping storm water into the foul sewer for treatment at night at the purification plant.

It is well known that storm water overflows frequently carry a considerable quantity of sludge; by making a number of assumptions the BOD of storm water has been roughly computed, (Eggink and Hulshof , 1968) .)

11-2.10.3 Disposal of solid waste from livestock

At farms most organic matter is cycled in'a closed loop, whereas in urban areas which contain a number of livestock markets this circle is not closed, and sludge treatment is necessary. At present, the surplus sludge is normally drained and dumped with domestic disposals; in future both are likely to be burned.

In the new town of Lelystad a rather high, variable phosphorus content in the storm sewer

Possible methods of improving water quality include the installation of settling


It is well known that the micro-climate of urban areas differs from that of the country. Four physical mechanisms contribute to the effect, (Munn, 1966).

The natural radiation balance is disturbed by changes in the properties of the underlying surface.

1. Vegetation is replaced by large areas o€ concrete and brick.

88

Micro-scaZe cZimatic effects

2. Buiit-up areas are obstacles to the wind, changing the natural flow and turbulence of of air.

3. The water vapour balance in a city is upset by the change from moist to dry surfaces. 4. The city emits heat, water vapour and pollution to the atmosphere. In addition, traf-

fic is a source of local turbulence. In the Netherlands the Institute for Meteorology and Oceanography of the University of

(Royal Netherlands Meteorological Utrecht and the Physical Geographical Laboratory of the University of Amsterdam are investig- ating the urban climate in co-operation with the K.N.M.I. Institute). The first made a survey of the climate of the city of Utrecht, particularly with respect to the distribution of temperature and , in co-operation with the Netherlands Laboratory for Air and Space (NCR) , studied the effect of high buildings on the wind; the results will be published in the near future. The second institute is studying the climate of Amsterdam in relation to its surroundings and. a summary of the results obtained to date are given below, (Zuylen, 1971 and 1973).

this topic, as discussed in the climatological literature, including Munn, 1966; Alissow, To enable these data to be evaluated it is first necessary to summarize general opinion on

and Rubinstein, 1956; Geiger, 1961 and Katzer, 1956; Zuylen, 1971 and 1973. Drosdow A.

B.

C.

D.

The Air Temperature. This climatic element has higher values for urban areas than for country. The difference for the annual average temperature varies between 0.5 and 2 degrees centigrade, (Alissow, Drosdow and Rubinstein, 1956) due to the following factors : 1. A much smaller latent heat flux because the rain falling on the paved area quickly

runs off to the sewer system and snow is removed from the streets by snow shovels. Accordingly the precipitation hardly gives rise to evaporation.

and the structures of the urban surface differ. The heat capacity and the thermal conductivity of urban materials generally exceed those of a natural surface and the daytime heat storage is therefore greater than in the case of pasture. Moreover, in an urban area there is a layer several metres thick with radiation absorbing surfaces, of which several are perpendicular to the sun's rays. At night, the stored daytime heat is released from buildings and pavements, resulting in higher air temperatures than occur in the country.

human metabolism). In Vienna the artificial heat supply per annum is one-sixth to one-quarter that provided by direct solar radiation, and in Berlin the ratio is one-third , (Kratzer , 1956) .

4. The pall of dust and carbon dioxide over a city influences not only the incoming solar radiation (especially the ultraviolet rays) by increasing flux divergence, but also reduces the outgoing longwave radiation. In Boston solar radiation in the city averaged 15% less in the suburbs, and in Toronto, Canada the solar radiation averaged 3% higher on Sundays than on weekdays. In winter the ultraviolet radiation in the centre of Leicester, England amounts to 70% of that on the outskirts, (Geiger, 1961). This characteristic warmth of a city is called the urban heat island, the size and intensity of which changes from day to day. It is a maximum at night and as for most climatological elements there is evidence of a weekly cycle.

2. The physical properties (such as albedo, specific heat and thermal conductivity)

3. The energy generated by combustion processes (house heating, factories, cars and

The Water Vapour Content of the Air. The urban water vapour pressure is generally lower than that of the country because the precipitation is quickly removed as storm water. Because the air temperature is normally higher, it can be understood that the relative humidity will be lower; for American cities it has been found that the difference is 8% in summer, _while in winter this is reduced to 2% , (Zuylen, 1971) , because of the emission of water vapour by combustion processes. Cloudiness and Precipitation. Of thè factors affecting cloudiness and precipitation, two factors in particular differ between urban and rural areas. First, in the urban atmosphere, there is an abudance of condensation and freezing nuclei. Second, the city heat island induces a convection cell which stimulates rising air currents. Several investigators have found a weekly cycle that is thougkto be related to human activities. For instance, for Paris, (Zuylen, 1971 and 1973) , and for Rochdale, England, (Alissow, Drosdow and Rubinstein, 1956), there is convincing evidence that the amount of precipitation during working days exceeds that of weekends. The Wind. Because of the relatively high aerodynamic roughness, the mean wind velicity

89

Micro-sea le e Zirnatie effects

in the city is lower than in the country. in the city was 0.9 mysec, less than at a nearby rural station. periods of calm weather the city heat island may induce a country breeze, which in turn creates upward currents over the city itself.

In MOSCOW, the annual average run of wind Moreover, during

The urban-country weather relations for Amsterdam have been studied by comparing a rural and a city observatiron station, (Zuylen, 1971 and 1973). The rural conditions are indicated by the station Oude Wetering, 20 km outside Amsterdam, towards The Hague. Here the climate is not complicated by local orographic features because the xestern part of the Netherlands consists of the alluvial plain of the Rhine. Data on the temperature and the moisture content of the air in the city are taken from the observation station in the Hortus Botanicus in the centre of Amsterdam, while precipitation is measured by recording gauges in a westerly suburb (Sloterplas) I in the centre (Hortus Botanicus) and the east side of the city (pumping station, Zeeburg) .

A. The air temperature (at 2.2 m above ground level). The monthly average daytime temperature in the city is 0.3 to 0.5OC higher than that at Oude Wetering; at the maximum temperature the difference is 0.1 to 0.3OC and at the minimum temperature 0.8 to 1.5OC higher. The energy generated by human activities in 1970 is estimated to be 16 x 1015 calories, including energy from:

power stations combustion of natural gas 4158 Combustion of fuel oil and coal 3500 road traffic 2210 incineration of refuse 67 3

Total 15365 >: 10l2 cal.

4824 x loL2 cal. 11

II

I,

II

The area of Amsterdam is 4240 ha; together with factory, dock and store sites, the artificial energy producing area is estimated to be about 5500 ha. Thus the energ generated is equivalent to a heat flux Öf 0.05 langley/min. For the year 1970 the solar radiation, at the meteorological station de Bilt, averaged 0.16 langley/min, and at den Helder(a port in the extreme northwestern part of the Netherlands), 0.18 langley/min, for December 1970 these values were 0.030 and 0.033 langley/min respectively. It can be concluded, therefore, that in winter the energy

. generated by human activities exceeds the solar energy in Amsterdam. The ratio between the artificial heat supply and the solar radiation per annum is one-third, the same value as Kratzer (1956) calculated for Berlin.

The water vapour content of the air is represented by observations at 14.00 M.E.T. Unlike the general trend the relative humidity of Amsterdam is similar to that in Oude Wetering, and is, in fact, slightly higher in spring and autumn. This may be due to the relatively large area (2000 ha) of open water (harbours, canals) in Amsterdam.

No weekly cycle in the precipitation data of Amsterdam-West has been found. Comparing precipitation data from the central observation station (Hortus Botanicus) with those from stations to the west and east of the city shows a greater precipitation distributed fairly evenly over the year. Two maxima in the daily precipitation pattern are also observed, one in the afternoon and one during the night. The maximum in the afternoon is most marked at inland observation stations, because atmospheric stability is then minimal. At stations near the coast a nightly maximum is also observed, especially in summer, due to showers originating above the sea during the night. It appears that at Amsterdam both effects are emphasised by the urban conditions.

Wind data are recorded by a cup anemometer installed LO metres above the roof of the building of the Geographical Institute. It is intended to compare the data with those recorded at Schiphol Airport about 5 La out of Amsterdam.

3 (1 langley = 1 cal/cm )

B. The water vapour content of the air.

C. Cloudiness and precipitation.

D. The wind.

90


11-2-12 EFFECTS OF MINING ACTIVITIES

TWO effects of mining activities have already been mentioned in preceeding sections: - subsidence of the soil surface as a result of the exploitation of natural gas; this may aff-

- gravel exploitation in the flood plains of the river Meuse, which lead to an attenuation of ect the height of dams.

flood waves.

11-2-13 EFFECTS OF OTHER WATER-BODY USES

1. The effect of water front development and water traffic in the esturaries near Rotterdam

2. The recreational requirements for water are: clear, without odour and without taste; more- on saline intrusion is discussed in section 2.7.

over for swimming, bacteriological reliability is required. Due to the difference in water quality of new and future lakes in the Delta-area (Zealand, South-Holland) provisions for recreation have been carefully distinguished.

11-2.14 WATER BALANCE INVENTORIES

Progress on special studies is as follows:

11-2.14.1 Studies of a working group on urban runoff

Aided by a computer, about 6600 storms that occurred at de Bilt (Royal Netherlands Meteorol- ogical Institute near Utrecht) over a period of 12 years were transformed to a series of storms, the dry period between which was less than 20 hours. Based on a sewer storage of 4, 5, 6, 7 and 8 mm, the frequency, duration and quantity of overflows can now be computed as a function of time.

In 1973, a Working Group on runoff coefficients of urban areas in the Netherlands published a preliminary report, from which the following conclusions have been derived: - the quantity of runoff during overflows from a sewer system in a flat area can be predicted reasonably accurately; in sloping areas this prediction is still impossible.

- on the basis of available data the effects of discharges at several points into open waterways can generally be computed.

- storage basins can be reliably designed. - there is a need for further research on: a. the runoff coefficients of the various kinds of paved surfaces; b. the surface storage of streets; c. the influence of the lag on the inflow hydrograph and the outflow hydrograph, for flat as

d. precipitation data from several observation stations, for periods greater than 12 years. well as sloping areas;

11-2.14.2 Research on urban hydrology in the new town of Lelystad

To overcome the limitations of empirical methods, research on urban hydrology is taking place in the new town of Lelystad in one of the Ijsselmeerpolders. The project is co-operative between the Ijsselmeerpolders Development Authority at Lelystad and the Agricultural University of Vageningen. To' determine the inflow and outflow criteria for storm sewers and subsurface drainage systems in urban areas, a number of research areas of different types have been selected, varying in size from 0.7 to 4.0 ha. The existence of separate sewer systems for surface water from paved areas, for subsurface runoff, and for domestic and industrial waste water, provides an opportunity for extensive investigations.

To date four reseach catchments have been equipped with instruments: 1. a residential area of 2.0 ha area with a paved area of 44%; 2. a car park of 1.0 ha area; 3. a shopping centre of 3.0 ha area with special attention to the runoff from small and

4. two flat roofs of 250 and 350 sq m. In these areas precipitation, the discharge in both storm sewers and subsurface drainage,

large flat roofs;

and groundwater level are measured either continuously and/or at intervals between 13 and 27

91

IiydrologicaZ research in re Zation to national and regionai! planning

seconds depending on changes in the variables; soil moisture is measured periodically by neut- ron probe.

level gauges. A more detailed investigation with more than 500 rainstorms confirmed these results (Berg, 19731. Attention will be paid to changes in this correlation when short time intervals with the rainstorms are considered. By eliminating the storage of the storm sewer system and using data from the residential area, the inlet hydrograph for the area has been computed to give information about the time lag between rainfall and inflow.

Further research should lead to the development of design criteria for storm sewers in catchments with different percentages of paved areas.

Analysis of rainfall data from 115 storms showed a high correlation between three ground

11-2 - 15 HYDROLOGICAL RESEARCH IN RELATION TO NATIONAL AND REGIONAL PLANNING

In section 11-2.1 it was mentioned that several orientation notes will treat various aspects of the physical planning of the Netherlands: further that in hydrology and water management considerable efforts and research will be necessary. Recently the solution of the problems of water distribution, total water management planning and even physical planning is being approached by means of modelling techniques. In this section three examples are described briefly.

11-2.15.1 A national water management model (Oudshoorn and Rutgerc, 1973; Rijkswaterstaat,l973)

The government note "The Water Management of the Netherlands" (1969) gives a rough estimate of the available quantity of water in a fictive dry year and the total water demand in the year 2000. To obtain optimum regulation and distribution of water over the country, more detailed calculations have to be done for a number of successive years, both in respect of the required water quality and quantity. From a comparison of demand and supply the expected timing, location and magnitude of water deficiencies can be found. When these figures are known, measures can be taken to prevent the occurrence of the estimated deficiencies, and these considerations are the basis of a national water management model.

In outline the model is a network of branches and junction points. At each junction point the water balance of demand and supply will be computed for a series of different flow conditions. In this way the effects of many climatic conditions which influence the quantity and quality of the sources can be related to the demands for domestic, industrial and agricultural water. In addition the influence of man's activities on the supply from each junction point can be found.

Because of the extent and complexity of the computation a mathematical model must be used.

At present the model is under construction.

11-2.15.2 A regional water management m o s (Colenbrander and van de Nes, 1974)

In 1970 a long term multidisciplinary research programme was set up in the province Gelderland to study the integrated approach to the solution of hydrological and economical problems related to various kinds of land use and various management techniques for water resources. The aims of the study are to find a scientific basis for an optimum management of the present surface water and groundwater in the province Gelderland, with respect both to quantity and quality. the greatest social benefits, and it is clear that social-economic studies have an important place in this research programme. The water management aspects of most interest are: drinking and process water for domestic use, industry and agriculture; water control (especially the control of the water level) in rural and urban areas; nature conservation and landscape; outdoor recreation (including angling); transport and purification of waste products and shipping.

Sub-models are divided into economic or demand models and hydrological or supply models. Quantitative aspects of the management of groundwater and surface water can be modelled by considering the interactions between meteorology, cropping, unsaturated and saturated groundwater and open water. In the qualitative approach BOD and the oxygen content are the main factors. Relations between these two components and discharge, flow velocity and water depth forms a link between quantitative and qualitative water management.

Thus, all aspects of water management will be optimized to reach the procedure giving

The main model 1s an optimization package to integrate all aspects of water management.

92

References

11-2.15.3 fi regional urban planning model

'Midden Randstad' is the open rural area within the broad urban arc formed by Utrecht, Amsterdam and Haarlem to the northwest and by Leiden, The Hague, Rotterdam and 'Dordrecht to the southwest.

Realizing that the urban sprawl resulting from population growth must not erode the whole area of the 'Midden Randstad' the future structure for growth in both the urban and rural areas must be planned comprehensively, with policies for greater growth in the western, very densely populated part of the country relative to other parts.

would enhance the urban environment of the Randstad in terms of its quality and variety of form, while simultaneously safeguarding the open character of the 'Midden Randstad'.

which includes the rural 'Midden Randstad' and the urban arc, in tandem with another model for the 'Midden Randstad' area only. For both models the potential surfaces analysis should be applied, though at different scales. This method is essentially a systematic scoring technique, in which for each area of land a quantitative value is given to a particular factor (including hydrological factors). Because modelling techniques are based on computer application, a geographical zoning system should be defined; data therefore have to be expressed in standard quantitative forms.

One of the principle factors which will infludence the recommended strategy deals with environmental issues and to a lesser extent hydrological and/or water resources issues. They will include adequate utilities for ground and surface water drainage, avoiding harmful pollution, balancing the growing water demands and possible water supplies and facilities to conserve the natural environment.

to the following recommendation: the results of hydrological surveys and studies should be incorporated at the beginning of regional planning. This can be done by formulating absolute constraints for use in the activity-allocation models (for instance, of the Lowry-type) and by measuring the hydrological factors which are important for any kind of existing or future land use. This may result in a more balanced regional development of land use in accordance with the objectives of the entire community.

TO tackle this problem, a study started in 1971 to identify a development strategy which

The methodology of the study has been based on an activity-allocation model for an area,

This modelling approach, which is in the first operational phase of its development, leads

11-2-16 REFERENCES

Alissow, B. P., Drosdow, O. A. and Rubinstein, E. A. 1956 Lehbuch der KZimatozogie (Trans- lated from Russian). V. E. B. Deutscher Verlag der Wissenschaften. Berlin.

Anon., 1971 Electrical energy needs and environmental problems, now and in the future. Serie Toekomstbeeld der Techniek nr. 7.

Berg, J. A. van den, 1973 Measurements of precipitation in an urban catchment area. Flevo- bericht nr. 88, Lelystad.

Colenbrander, H. J. and van de Nes, Th. J. 1974 Watermanagement in the past, at present and in the future. H20, vol. 7, nr. 1. Dutch Government, 1966 Second Report on Physical Planning in the Netherlands.

Eggink, H. J. and Hulshof, J. E. 1968 The quantity of B.O.D. discharge with storm water. H20, vol. 1, nr. 8. Geiger, R. 1961 Das KLima der bodennahen Luftschicht. Braunschweig. (English translation, The climate near the ground. - Harvard Univ. Press. Cambridge, Massachusetts). K.N.M.I., 1956-1965 Frequentiec van k-daagse neerslagsommen op nederlandse stations. 24 delen. + delen 25A en 25B: Verklaring en toelichting. De Bilt, K.N.M.I.

K.N.M.I., 1968a Climatological data of Netherlands stations, Normals for the standard period 1931-1960. De Bilt, K.N.M.I., Staatsuitgeverij, 's Gravenhage.

K.N.M.I., 196813 Detailanalyse van pluviograwaen. A. Frequentieverdelingen van de hoeveel- heden neerslag in tijdvakken van 5-660 minuten, De Bilt.

K.N.M.I. , 1972 KZimaatutZas vun NederZand. 's Gravenhage, Staatsuitgeverij .

De Bilt, K.N.M.I.

93

References

Koolen, J. L. 1973 The water quality of the river Meuse in the Netherlands. Hzo, Vol. 6, nr. 6.

Kratzer, P. A. 1956 Das Stadtklima. Wissenschaft (Braunschweig) 90.

Made, J. W. van der 1966 Flood prevention by enlargement of flood wave subsidence. Publ. nr. 72 Symp Garda, 1.A.S.H. Munn, R. E. 1966 Descriptive rnicrorneteoro2ogy. Academic press. New York and London.

Oudshoorn, H. M. and Rutgers, F. 1973 The regulation of the use and the course of water. Contribution to a Symposium 'Wutermunagernent into service of industry and environment'. R.I.D. 1972 Statistical data and information on future trends, based on regional plans for the future water supply, Government Institute for Water Supply.

Snijdelaar, M. 1970 The watermanagement of the Netherlands. P2anning und development in the NetherZands (quarterly) . Timmermann, H. 1963 The influence of topography and orography on the precipitation patterns in the Netherlands. Mededelingen en Verhadelingen K.N.M.I., Staatsuitgeverij, s'Gravenhage.

Rijkswaterstaat, 1973 Watermanagement model, realization of the model, note WH-73-11.

Wemelsfelder, P. J. 1972 Watermanagement aspects of cooling water supply (Dutch with Eng- lish Summary). Serie Toekomstbeeld der Techniek nr. 12: Electricity in our future energy supply ; possibilities and consequences.

Zuylen, G. F. A. van, 1971 Stadsklimaat ("City climate"). Akademiedagen deel 22. Roy. Dutch Academy of Science, Amsterdam.

Zuylen, G. F. A. van, 1973 Stadsklimaten (Urban climates). Chapter 6 of Physical Geography, Oosthoeks uitgeversmaatschappij , Utrecht.

94

3 Hydrological effects of urbanization in Sweden

Gunnar Lindh

Division of Hydraulics, Institute of Technology, University of Lund, Sweden.

Hydrological effects of iirbonizution (Studies and reports in hydrology, 18) Paris, The Unesco Press, 1974



11-3.1.1 Population

In the near future, the whole of Sweden will be demographically divided into about 250 co- operating communes or municipal blocks. None of them now has less than 600 inhabitants. These blocks will be the smallest administrative areas for planning purposes in Sweden. Table 16 gives the population of the municipal blocks by size of group. As a first approximation, it was assumed that actual increases of population for periods of five years until 1980 or 2000 would be the same as for the period 1965-1970. However, this trend would give values that would be too high when summarizing the population for the whole of Sweden. The population values have thereEore been reduced. The biggest reduction has been made for the largest areas, a technique that is consistent with the expected decline in the population increasas in these areas. The figures for 1980 and 2000 are estj-mates. The distribution of population in different groups is also given in Table 14 for the years 1970 and 2000, cf., (Hansson & Svensson, 1.972).

Table 16. Numbers of municipal blocks and their populations foi- the years 1965, 1970, 1980 and 2000 (Öberg, 1972)

1965 1970

Number of Population urban Population Per

Cent

Population Numbei- of

size class localities local it ie s urban

-- > 1 O00 O00 1" 1 265 O00 1 1 328 O00 17 500 O00 - 999 O00 lb 616 O00 1 676 O00 8 100 O00 - 499 O00 7 1 015 O00 9 1 311 000 16 50 O00 - 99 000 18 1 225 O00 17 1 162 O00 14

o - 49 000 217 3 662 O00 216 3 616 O00 45

Totals 244 7 773 O00 244 8 093 O00 100

-~

1980 2000 --

Number of Per Cent

Population Number of

size class localities localities

> 1 O00 O00 1 1 450 O00 1 1 690 O00 18 500 O00 - 999 O00 1 770 O00 2 1 540 O00 16 100 O00 - 499 O00 11 1 725 O00 13 1 870 O00 20 50 O00 - 99 000 23 1 430 O00 22 1 340 O00 14

o - 49 O00 208 3 225 O00 206 3 060 000 32

urban Population urban Population

Totals 244 8 600 O00 244 ' 9 500 O00 100

a: Stockholm b: Gothenburg, Malmö (2000)

96


11-3.1.2 Land occupancy

Table 17. Land occupancy in 1970

Population size class Land occupancy area (ha)

> 50 O00 2 415 000 > 100 m o 2 079 300 > 500 O00 101 920a > 1 O00 O00 18 450b

a. Stockholm, Gothenburg and Malmö suburbs not included b. Stockholm suburbs not included

It is difficult to give reliable density data. Because of the new demographic divisions, the population density is rather low except for the two largest classes, where the population density is about 160 persons per ha. It may be of interest to note that urbanization in Sweden is of rather modest proportions when judged from a European point of view (Swedish Govt. 1970). According to this official report, metropolitan problems do not exist in Sweden and thus problems arising from this cause are avoided. However true this statement may be, there is nevertheless a growing problem of urbanization in the Maimo- Copenhagen region where consequences of the human influence on the water cycle may be important in the near future. The population of this region is now about 2 700 O00 but it is expected to increase to about 4 O00 O00 by the year 2000.

11-3.1.3 Climatic-topographic distribution of population

O Because Sweden extends nearly 1600 km through 14 of latitude, there are considerable changes in climate from one end to the other. There is a continuous succession from a maritime to a continental climate, within both of which are some important local anomalies. However, neglecting details in climatic variations, Sweden can be divided into two parts: a southern part with a humid temperate climate and a northern part characterized by a humid and cold climate. Today (1970) about 70% of Sweden's population are to be found in the southern climatic region and the remainder in the northern part. It is very difficult to estimate the probable values of the percentage distribution of persons living in these two areas for 1980 and 2000.



The mean annual precipitation in Sweden ranges from about 300 mm to about 2 O00 mm according to observations made during 1931-1960, (Swedish Meteorological and Hydrological Insti- tute, 1969). A mean value for the whole of Sweden is approximately 700 mm. The lowest value (300 mm) is observed at Abisko in the Swedish Alps in the northern part of Sweden, whereas one of the highest values has been found in the southern part of Sweden. These observations may be considered as anomalies because they do not reflect the general pattern of precipitation. In general, low values (400 to 500 mm) are encountered along the coasts including the two large islands Gotland and Öland; Swedish Alps, especially along the west side of the Alps. The largest value, about 2000 mm has been calculated from runoEf ïneasurements in the Sarek region in the North.

while the high values occur in the

The mean annual precipitation that occurs in the largest cities in Sweden is:

Stockholm - 555 mm Gothenburg - 670 mm Malmö - 550 ~IIEI

These three cities are situated on the coasts.

97

iiydro Zogica 1 effects resu Z ting from water management s y s terns

11-3.2.2 Intensity of rainfall

Rainfall intensities have been measured in Stockholm on the east coast (1907-1946) and in Gothenburg on the west coast (1926-1935). From these observations, diagrams have been prepared showing specific intensity (litres/sec/ha) as a function of duration of rainfall (O to 60 minutes) with frequency as a parameter (0.5 to 100 years) , (Höganäs, 1969). From these diagrams the values in Table 13 have been found.

Table 18. Intensity of rainfall in Stockholm (SI on the east coast and in Gothenburgh (G) on the west coast

Approximate maximum average rainfall in millimetres per hour

Average return period 5 min 30 min 60 min

S G S G S G

2 year 60 80 25 30 15 ia 5 year 80 95 35 40 20 25 25 year 130 - 58 - 35 -

86 - 52 - 100 year - -

The figures given above are very approximate. Moreover , recent work on urban runoff (see below) has suggested that much more careful analyses should be made of maximum average rainfall depth-duration-frequency relationships. Such an analysis is planned to be carried out in a co-operative effort by the National Swedish Environment Protection Board and the Swedish Meteorological and Hydrological Institute.

11-3.3 HYDROLOGICAL EFFECTS RESULTING FROM WATER MANAGEMENT SYSTEMS

II-3.3.1 Urban storm runoff

As in many other countries, there is a recent interest in urban runoff problems, one of the most important hydrological consequences of urbanization. This problem may be divided into three, one purely hydrological which involves the central problem, another about the collection of urban storm water (combined or separate systems) and finally one concerning the treatment of the wastewater.

icipal sewage treatment. Of this sum about 500 million Skr are intended to be used for conduit installations. The total length of sewage conduits in Swedish cities is approximately 35 O00 km. Of this total 21% are combined foul and storm drains, 55% are foul sewers only and 24% are storm drains (Jansson, 1971a). According to the predominating current opinion, the separate system will be preferred. However, the rearrangement of the existing system will cost approximately 10 O00 million Skr (about 2 O00 million US dollars) to which must be added the cost of reconstruction in all streets and city quarters. The cost for this work for Stockholm alone has been estimated at 1 200 million Skr.

engineering formulas for calculating thequantity of urban storm runoff have shown poor correlation with available observations (Lindh and De Mare, 1972).

lems (Nilsson, 1972; Cawood et al., 1971), but this presupposes sufficient knowledge about the solution of the hydrological processes involved. Members of the Swedish IHD Committee approach this problem by means of a mathematical model technique taking into account the transport and storage mechanism occurring in the soil and adjacent regions (precipitation, infiltration, interflow, percolation, etc.). However, while awaiting the solution of these problems an interim answer is needed to guide engineering techniques. cause the sewage treatment plants are to incorporate chemical treatment and there is an urgent need to be able to estimate the volumes of wastewater that have to he dealt with.

It,is interesting to note that about 1300 million Skr are invested in a plan for mun-

Returning to the central hydrological problem, there remains much to do. Existing

The use of computer techniques may offer a means of solving urban storm runoff prob-

This is mainly be-

98

?i c, fi 3 o U

99

HydroZogicaZ effects resuZting from water management systems

Studies of the hydrological problem of urban runoff are planned or are in progress, (Nilsson, 1972; Cawood et al., 1971; Lindh et al., 1972). Research work on the latter was inspired by Professor Yevjevich.

Apart from the question of engineering computation of pipe size and the type of system preferred, some questions of a hydrological character have attracted interest. One important question is associated with the problem of conduit lealcaae. Some observations (Jansson , 1971b) indicate that due to leakage through the conduit walls and joints, the volume of sewage water received at the sewage treatment plants is much higher than the water distributed from the water works, a ratio of something like 2:l to 7.5:l. Of course, this causes problems at the treatment plants as the efficiency of the treatment process is reduced, especially the activated sludge process.

The reverse situation is also encountered where leakage occurs from the conduit to the surrounding soil. conveying wastewater in the Stockholm region have shown that mineralized nitrogen was present in appreciable quantities (Fleetwood, 1969). One conclusion was that small communities which for economic reasons are forced to use groundwater sources situated nearby should be warned about the risks of the possible contamination of their source by leaking sewers.

used on the chemical content of the urban storm runoff water. It has been shown that the greatest quantity of pollutants in urban storm runoff will probably occur during the spring and the summer (SÖderlund, 1972). It has also been found that there is a strong correlation between suspended solids and flow and it was established that a high rainfall intensity is accompanied by high concentrations of pollutants.

Finally, it should be mentioned that some small process plants intended for treatment of urban storm runoff alone have been put into operatiofi (Liedberg, 1971).

11-3.3.2 Effects of lowering groundwater tables

About 47% of the water requirements of urban areas in Sweden is supplied by groundwater. About 38% of this amount comes from artificially infiltrated surface water. In many urban areas the withdrawal of groundwater together with the lowering of the groundwater table caused by building development, has given rise to building damage associated with the settlement of foundations (NÖrdstrom, 1970a; Stega, 1971). Severe destructive effects have been observed in Stockholm where clay consolidation occurs in the clay areas which are widespread in certain parts of Stockholm. geological surveys be made in order to avoid settlement from this cause.

water conditions exist and can be compared with the groundwater situation encountered in developing built-up areas. ties are not expected in the foreseeable future. ing four reference areas in Stockholm selected to form a so-called groundwater cross (Gustafsson and Nilsson, 1970). Such a cross also exists in Gothenburg and another is planned for Maimo. continues to be a serious problem. Swedish cities (National Swedish Board of Urban Planning, 1972).

The second part of the urban runoff problem deals with conveyance.

Observations made in connection with the construction of a big tunnel for

The third part of the problem is the treatment process. Special interest is now foc-

It has been recommended that careful geological and hydro-

Furthermore, it has been proposed to establish reference areas wher'e natural ground-

Such reference areas have to be located where building activi- This idea has been realized by establish-

However, the subsidence through the lowering of the groundwater table Settlements of a 0.5-1.0 meter have been observed in

11-3.3.3 Exploitation of sand beneath the groundwater table

There is a growing demand for sand and gravel in Sweden. Eskers have been exploited extensively, and to the problems which nowadays are encountered by an extractor must be added ail increased reaction from those involved in the protection of our natural resources. It is interesting to note that exploiting the sea floor for sand and gravel may be a more favourable alternative than that of a gravel pit on land. The sand from the sea can generally be obtained at a much lower price there have been some attempts to extract sand beneath the groundwater table. It goes without saying that an insufficient knowledge of the harmful consequences of such exploitation may result in extremely dangerous situations. ential problems are connected with the influence of the exploitations on hydraulic ,

Whilst waiting the results of exploiting marine deposits

According to Swedish scientists, the consequ-

HydroZogicaZ effects resulting from water management systems

geological and topographic conditions (Gustafsson et al, 1970). Among other problems there could be the risk of pollution in a groundwater lake intended for recreation, bathing, fishing, etc. There are in this case many additional problems related to water circulation, biological activity and the choice of suitable material to be used for the shore.

11-3.3.4 A special groundwater problem illustration

A special groundwater problem that has occured in Stockholm is worth mentioning because it illustrates the influence of urbanization on hydrological processes. When the subway was built in Stockholm large quantities of water were pumped in order to drain the construction works. This pumping contributed considerably to the settlement problem mentioned earlier. However, a large volume of water is constantly withdrawn from groundwater and is used for air conditioning installations and power stations in Stockholm. At least 8 O00 m3 daily are used during maximum cooling demand. During the 1960s the temperature of the groundwater rose 1 to 1.5OC in cities and at present the temperature is about 10.5 to ll°C. A large increase in temperature has occurred near the infiltration plant which explains the fact that the groundwater sources nowadays have an increased temperature. The water which is discharged to the infiltration wells after being heated during its passage through the cooling plants flows beneath the cellar floors to the groundwater sources without being appreciably cooled. In this way the cellars will have too high a temperature. One important consequence of this is that one of the groundwater consumers could not use water when its temperature exceeded f12OC. The result is that the groundwater temperature has to be continuously controlled (Nordstrom, 1970b).

11-3.3.5 A reclamation problem

The handling of solid wastes is a serious problem in Sweden as in many other countries. In the Malmö area, in the south west of Sweden, there is a plan for extensive reclamation by moving the shoreline outwards by filling with solid wastes, suitably pretreated. The land area created in this way will be about 1000 hectares of which 600 hectares will be used for an extension of the harbour area and 400 hectares will be used for recreation. The filling of the area is planned to be completed in 4 stages by the year 2000. However, many questions have been raised about this enterprise. The most serious one is associated with the possible risk of pollution from the solid wastes. Will there be any leakage through the sea defence dikes. This problem is comparable with the contamination risk at a site for solid waste disposal on land. Another important question is whether the ground beneath the fill is sufficiently waterproof to prevent filtration. Infiltration of polluted water would endanger the so-called Alnarp stream which flows below the surface in the immediate vicinity of the proposed land fill area, and is one of the most important sources of groundwater for south western Sweden.

11-3.3.6 Thermal effects of heated effluents in Lake Mälaren

Some interesting features have been observed at a power plant situated at one of Sweden's largest lakes; Lake Mälaren. A 200 MW capacity power station belonging to the National Power Ad- ministration and also the 300 MW combined district heating and power station of the Aroskraft Corporation is situated at Vasteras Bay. The cooling water discharges from these two stations are 14.5 m3/sec with a temperature increase of 8 $0 9OC and 5 to 6 m3/sec with a temperature increase of 8 to 9OC respectively. The bays at Vasteräs nave a combined surface area of about 50 km2 and a volume of about 3 3 5 ~ 1 0 ~ m3- There is a very limited renewal of water in the bays and this is mainly due to wind influence (Ehlin, 1970; Carlsson, 1970). Temperature conditions in the Västeräs bays have been observed continuously.

water discharged into a water bay during winter is cooled quickly and sinks. If the lake is sufficiently large, the effect on the ice will be limited to a small open area caused by melting. But if the volume of the lake or bay is relatively small, as also is the renewal, a very different situation may be expected. The Västeräs bays are good examples of this situation. In 1970, when other parts of Lake Mälaren were covered by ice, the Vasteras bays were largely ice-free. significant heat discharge was occurring, the heat content was 3.3 x losi4 cal. 1969 it was 4.8 x 1014cal and in March 1970, it was 6.5 x 1014cal.

A specially interesting situation arose in the winter of 1969-1970. Generally, cooling

Observations of the heat content showed th t in 1968, when no In March

101

Water suppiiy effects

The consequences of this extensive ice melting are not wholly understood. As far as is known at present, one positive consequence seems to be that the earlier melting of ice in the nearby bays had an advantageous effect on the oxygen balance due to the reduced period of ice cover. A negative effect is the fact that the lake cannot be used for skiing or ice-skating.

According to some preliminary plans it is intended to locate a nuclear power plant not far from Stockholm with a thermal effect of 1550 MW. The cooling water needed is estimated at 30 m3/sec and the water will be heated to approximately 10°C. that the plans are only preliminary. Some preliminary studies have been made on the expected effects O€ this plant on the environment. Of special interest here is a study made on the effect of temperature distribution from cooling water discharge.

ice cover, even at some distance from the proposed discharge points, because deeply injected cooling water will be conveyed to the surface by circulation (Sprinchorn and Ehlin, 1971).

It should be emphasized

Preliminary calculations indicated that the cooling water may cause weakening of the


11-3.4.1 Urban public supply withdrawals

An estimate of the net annual precipitation shows that per capita this amounts to about 27 O00 m3 and of this quantity about 3% will be consumed. age will rise to 5% in the year 2000 and that industry will use 80% of the total amount (Royal Ministry of Foreign Affairs/Royal University of Agriculture, 1971).

With the aid of statistical data concerning Swedish municipal water works (Swedish Central Bureau of Statistics/National Swedish Environment Protection Board, 1969), it has been possible to render an account of the use of groundwater and surface sources respectively in urban areas (19681, Table 19. The data, which are as complete as possible, are arranged according to cdunties ipdicated by letters. The figures in the col-mns of the table representing groundwater and kurface water supply show that about 47% of the requirements of urban areas is derived from groundwater whereas about 53% is obtained from surface water. However, the individual figures for each county indicate that there is a great variation in the relation between groundwater use and surface water use. The use of groundwater in Swedish cities is increasing (Winquist, 1968).

of groundwater in Sweden. The groundwater abstraction capacity of a Swedish esker may rang'e from approximately 10 abstraction capacity is less. From Table 19 it can be seen that the water requirements for domestic and industrial use amount to about 62% and 20% respectively of the total annual abstraction. The column entitled 'remaining' and 'losses' includes all abstraction for general public use (street cleaning, fountains, etc.). (Table 19 is on Page 99.)

follows.

It is expected that this percent-

Although the superficial deposits are generally thin they are extensively used as a source

m3 per second to some 100 1i3 per second. In sedimentary rocks the

According to Sweden's national report (Jansson, 1971a) the future water use will be as

Table 20. Future water use

3 Use iñ million m /year

Year Indus try Urban areas

Pulp and paper Total Total

End of 1960's 3 200 4 O00 870

2 O00 2000 6 700

The quantities given in Tables 19 and 20 do not take into account the fact that water may be re-used several times along a water course. Furthermore, the water use in urban areas in

I02

Water suppZy effects

the year 2000 is based on the assumption that the population in Sweden will have increased from 8 to 10 million. Moreover, it is expected that of the 10 million people 90% will live in urban areas compared with the present 80%.

The figures also include an allowance for an assumed increase in water usage, per person.

11-3.4.2 Independent industrial water abstractions

In Sweden, large industries use surface water drawn almost exclusively from their own supplies. The largest water user is the pulp and paper industry: the next largest are the mining and metal industries. Industrial water usage has been approximately doubled in the past ten years.

The water requirement for cooling use in Sweden is small at present. Only one experimental nuclear power plant (65 MW) is in use. In 1973 a nuclear power plant (760 MW) will be in operation and this plant will later be expanded to 3000 MW. In 1974 another nuclear plant will be developed (1000 MW). In 1980 it is supposed that 75 O00 MW will have been installed. Of hydrological interest are the thermal pollution effects of this activity. problem has already been discussed in Section 3.3.6. It is generally estimated that a power plant of 3000 MW uses about 150 m3/sec of cooling water and that the need for cooling water is proportional to the size of the nuclear plant. Most likely, nuclear power stations in addition to those already agreed upon will be located on the coasts where water is readily available. Exceptionally, some may be located in the vicinity of lakes.

and the planning of their location is an important part of the preliminary work of a national physical plan. It is difficult to predict the volume of abstraction but it seems likely that by the year 2000 the rate of abstraction will be about 2000 m3/sec. water discharge will be contributed by ten plants along the coasts of Southern Sweden. This quantity corresponds approximately to four times the discharge of the Göta River, the largest Swedish river and will almost certainly cause local hydrodynamic effects on the water circulation. Abstraction of water from groundwater sources is likely to be extremely small.

This type of

The problems of locating a nuclear power plant close to an urban area have been studied

This volume of cooling

11-3.4.3 Present and anticipated public and industrial water supply problems

If the mean water supply per capita in Sweden is calculated, taking into account the estimated increase of population until the year 2000, the future sources appear to be sufficient to meet the demand. However, the practicalities of organising the supply are more difficult since the natural occurrence of water does not coincide with the distribution of the population. As already mentioned, the total annual precipitation is estimated to be 27 O00 m3 per capita of which about 3% is uged for water supply. The normal minimum demand averages 5 500 m3 The uneven distribution of population is such that about 80% of the population lives in the southern part of the country. In this area the annual mean runoff, 300 mm, is the equivalent of 7 O00 m3 per capita, which is much lower than the national average of 27 000 m3 per capita.

the rest of the country and because sources are scattered it is difficult to make efficient use of them. Resort has been made to regional distribution to meet requirements (Swedish Government Official Report, 1965-8). In order to guarantee a sufficiently large water supply for the metropolitan Malmö-Lund-Helsingborg in the south west of Sweden, water will be transferred from the River Lagan through an 80 km tunnel from Lake Bolmen. The water will be distributed to five cities through three mains with a total length of about 300 km. This project will be completed by 1978 or 1979. During the planning of this work calculations were made to study the possibilities of supplying water to the Hamburg area of north Germany. The so- called Bolmen project has been extensively debated, and a strong public resistance to this project has been expressed, including the opinion that the groundwater resources have not been thoroughly surveyed. Sweden appear to be sufficient to maintain supplies at least until the year 2020.

method has been studied by a special group (Swedish Board for Technical Development, 1970). It has been found that a ditional water may be produced through a distillation process at a cost of about 0.70 Skr/m

per capita per year.

The southern part of Sweden must be considered as a region short of water compared with

According to preliminary calculations the resources for southern

An alternative for the future would be to supplement supplies by desalination. This

9 ’ ( = 14 cents/m3).

103

Po Z Zution effects

11-3.5 POLLUTION EFFECTS

11-3.5.1 Organic, inorganic and thermal aspects

The present total discharge of oxygen-consuming organic substances for 6he whole of Sweden is estimated at 670 000 tonnes BOD7 per year (Andersson, 1972). Of this quantity, about 270 000 tonnes will be discharged to inland waters and about 400 O00 tonnes to coastal waters. Forest industries are responsible for about 83% of the total discharge and urban areas for about 14%. Most of the coastal discharge comes from forest industries whereas the disposal of organic pollution in inland waters comes from urban sources.

Total phosphorus discharge has been estimated at 13 O00 tonnes per year for the whole of Sweden. Of this quantity 59%, or 7 700 tonnes per year is discharged to inland waters and, 41% or 5 200 tonnes per year, to coastal waters. Calculations show that about 58% of the total discharge originates from urban areas, about 30% comes €rom industry and the remaining 12% from forest and arable land. Urban areas are responsible for about 71% of the discharge into inland waters and industry and urban areas account for 51% and 46%, respectively , of the discharge to coastal waters.

whole of Sweden and of this sum 77 O00 tonnes or 83% is discharged to inland waters and the remaining 16 000 tonnes or 17% to coastal waters. The leaching of nitrogen from agricultural and forestry areas is assumed to contribute 65% of the total nitrogen discharge. Urban areas are responsible for about 27% and industry for about 8%. The discharge from urban areas into coastal waters amounts to about 48% of the total nitrogen discharge.

11-3.5.2 Pollution from urban sewer systems

The disposal of total nitrogen has been estimated at 93 O00 tonnes per year for the

Storm water overflow and urban storm runoff are considered potentially harmful to the environment under Swedish law. The legislation requires individual authorization before the construction of new sewerage works and the extension of existing ones. The discharge of wastewater from urban areas is mainly effected by combined or separate systems.

In Sweden, there is a total of about 8 O00 km of combined conduits and they constitute about 21% of the total conduit system. Storm sewers comprise 24% and sanitary sewers about 5S% of total conduit length.

When a combined system is used a hydraulic surcharge may result from snow melt and intensive rainfall occurrences. During severe overloads water is discharged by means of overflow weirs to stream courses. The quantity which added in this way to the water courses is estimated at 3 to 5% of the total pollution from an area with a combined system. This implies (Ulmgren, 1971) that pollution by overflow constitutes 30 to 50% of the total discharge of pollutants which is discharged annually from a treatment plant after combined biological and chemical treatment (which means a 90% reduction of BOD as well as phosphorus). The instantaneous quantity of pollutants from the overflow may in many instances be much higher than the discharge of pollutants from the sewage treatment plants despite the fact that, +e discharged water is diluted by storm runoff water.

culated according to certain rules. These stipihlate that biological and chemical treatment processes shall not bb loaded in excess of 2 Qdim. Greater quantities are rejected through overflows. It has been shown that with a load of 4 @im, for instance, much better treatment will be effected if the biological and the chemical stages are each loaded with 2 Qdim rather than to dispose of 2 Qdim and only treat the remaining 2 Qdim biologically and chemically. Separate, small treatment plants for urban storm runoff treatment have been built in some cities in Sweden.

aining in the effluent from biologically treated sewage, derived from an urban area of comparable population density. The authors found that urban storm water contained a higher proportion of suspended material and bacteria but smaller amounts of BOD, phosphorus and nitrogen than in the treated water. Thus, if the standard of treatment of effluent is improved then the relative importance o€ storm runof€ pollutants will increase.

worthy of note. They paid particular attention to the pollution effect of snow in urban

In Sweden, the dimensioning hydraulic load, Qdirnr at a waste treatment station is cal-

A comparative study was made of the pollutants in urban storm water with those rem-

In this connection another pollution problem observed by SÖderlund and Lehtinen 1970b is

I04

Po ZZution èffects

areas, In Stockholm, for example, where the mean annual precipitation is about 555 mm of which an equivalent of 120 mm is from snow, about 850 O00 m3 of snow is deposited in the Lake Malaren every year. The authors found that the percentage of suspended matter was considerable. The conclusion drawn was that there may be a stabilizing mechanism involved in the dispersal system of sand and water. Such a mechanism may indicate that an adsorption of bitumen, oil products and light hydrocarbons occurs. One consequence is that a considerable quantity of sand will enter the treatment process along with the oil products. These products should have been separated off in the grit chamber. Another consequence of the stabilization mechanism is that sand, with its attached oil and bitumen products, etc., will be carried to stream courses without treatment.

To Compensate for the negative effects of the discharges mentioned, great efforts axe made to provide municipal sewage plants with facilities for biological and chemical treatment. The present annual investment in treatment plants alone amounts to 230-300 million Swedish Crowns (equal to about 45-60 million US dollars). in 1970 about 20% of the urban population was not served by any sewage treatment while some 30% were connected to plants with only sludge separation. About 50% were connected to plants providing more advanced treatment. In 1975 the sewage from almost the entire urban population will be discharged to treatment plants according to present plans. One half of the population will be served by sewers connected to chemical, or combined chemical and biological treatment works, and more than 30% by sewers connected to biological treatment worlts, cf., (Royal Ministry of Foreign Affairs/Royai University of Agriculture, 1971) .

11-3.5.3 Disposal of solid wastes

Detailed information about the quantity of total municipal wastewater solids in Sweden is not available. It is generally assumed that conventional treatment, on average, will result in 90 g (dry weight) per day per person. By 1975, because of an extended programme of treatment for the whole country this quantity may be increased to about 120 g per day per person. The sludge is processed by drying, settlement in lagoons, spray-irrigation on farmland or incineration.

Sweden does not dispose of sewage sludge by dumping it at sea. Incineration is the principal method of waste disposal employed for large city areas. About 20% is incinerated at present but this proportion is increasing. However, it must be mentioned that open bum- ing is not considered to be an acceptable method of disposal and the large new solid waste incineration plants represent considerable progress from the point of view of air protection. About 80% of the solid wastes is deposited on land and the number of these sites is estimated to be 1 O00 (Von Heidenstram, 1972) -

The deposition of solid wastes on land has attracted much interest during the last few years on account of the possibility that these wastes might contaminate surface and groundwater.

The general increase in weight of domestic wastes amounts to 3 to 4% annually (Swedish Government Official Rept., 1969:18). However, it is likely that this will be reduced to 2 or 3% during the 1980's. The part assignable to trade and industry is assumed to increase by 2 to 3% yearly.

Table 21. Composition of domestic wastes

Mean values, % Components

The whole country Stockholm 1967

Paper 40.0 - 65.0 63.0

Garbage 8.0 - 20.0 Glass. 10.0 - 20.0

8.0

9.0

Metals 4.0 - %.O 5 .O

Pl as tics 1.5 - 5.0 1.5

I05

Pollution effects

A Swedish study has shown that water draining from a dumping site of solid wastes may be ten times more polluted than municipal waste (Gustafsson, 1969:3). One dumping site alone has been observed to have as great an oxygen-consuming load as an urban area of some one thousand inhabitants. Substantial amounts of pollution may be created by dumps containing process slurries, oil products, scrapped vehicles, deceased animals, etc. The same opinion is expressed by Swedish scientists (Brink et aii., 1971). A study of a dumping site for solid wastes in the vicinity of Uppsala showed that the leaching water from the dump was equal in many respects to municipal wastewater.

11-3.5.4 Air pollution problems

Air pollution problems have received considerable attention during the last decade in Sweden and Swedish research workers have made a case study for the United Nations conference on the human environment (Royal Ministry of Foreign Affairs/Royal Ministry of Agricul- ture, 1971). As early as the beginning of the 1 9 5 0 ' ~ ~ measurements of the acidity of precipitation were made in Sweden. Repeated studies have revealed that there has been a general increase in acidity in southern Scandinavia, the increment corresponding to an average of a few per cent annually since the beginning of the 1950's.

dioxide emission from both Swedish and non-Swedish sources. The transport of airborne pollution is of course a fact of importance since the sulphur remains in the air for 2 to 4 days. In this time it may be transported more than 1000 km before being deposited on the ground.

deposition of sulphuric acid which has originated far from the place of deposition. Meas- urements made in recent years have shown that the half-life of sulphur dioxide may vary upwards from less, than one hour depending on local conditions (Rodhe, 1969-70; 1970; Munn and Rodhe, 1971; Eriksson, 1971). Before analyzing in detail the problems associated with pollution by sulphur it may be informative to look, at the costs of &age caused to materials by air pollution. According to Sweden's national report (Royal Ministry of Foreign Affairs/Royal University of Agriculture , 1971) : 'It is assumed that annual expenditure on anti-corrosion protection , galvanization and nickel plating has doubled in urban areas between 1961 and 1968; it is estimated that in 1968 this amounted to around Skr 780 million. Together with the sum of Skr 210 million which this expenditure is assumed to be in sparsely populated areas (no change since 1961) , the total annual expenditure on anti-corrosion painting, galvanization and nickel plating is estimated to have been about Skr 1000 million in 1968. At the same time, it is estimated that the cost attributable to corrosion of motor vehicles in urban areas amounts to about Skr 325 million per year, a third of which figure, i.e. about Skr 110 million, is assumed to be due to the action of sulphur dioxide. To sum up, calculations indicate that pollution is the reason why the cost due to corrsion in Sweden is about Skr 500 million per year higher than it was ten years ago . . . . . '

ity (pH) of lakes and rivers in recent years (Eriksson, 1969; Dickson, 1970; Oden & Ahl, 1970; Oden, 1968).

the last decade. The decrease is different from lake to lake due to the fact that vegetation and type of soil within the area and also the size of the lakes differ. Recent studies have shown that the small lakes have been particularly affected. It should be noted that there-may be factors other than acidification of precipitation - such as increased water pollution, change of forestry methods and a decrease in the agricultural use of lime and other fertilizers with an alkaline effect contributing to the lowering of pH values.

It has been found that the change in acidification of Swedish lakes has been between 0.2-0.5 pH units over five years and the question now arises as to what degree of deterioration of lakes and rivers can be accepted before the damage is of a catastrophic nature. This will happen whe pH values fa11 to between 4.5 and 5.0. This situation already exists in some lakes in Sweden and southern Norway where it means a catastrophy for fish life. is established that, in some rivers in Norway, fishes of the salmon type have ceased to breed but very few studies have been made to verify the biologi'cal effects of sulphur pollution in particular.

of one-half of Sweden's rivers may become critical from a biological point of view. One

The primary cause of the increased acidity of precipitation is the increase in sulphur

Consequently harmful effects on surface water or on a catchment may be caused by the

A series of investigations have been undertaken in Sweden to study changes in the acid-

These studies show that the pH-values in lake water in South Sweden have fallen during

It

Extrapolation of trends already obtained indicates that within 50 years the situation

I06

Micro-scale dimatic effects

way of compensating for the present acidification would be to spread some 250 000 tons of lime every year over Swedish lakes at a cost of about 25 million Skr. Nobody involved in environmental protection would recommend such an action.

itself depends on the basic structure of the soil and on the natural circulation of the chemical constituents in the normaL geochemical and biochemical cycle. Loess soils in central Europe are resistant because they are effectively buffered. In northern and western parts of Europe soils are mostly acidic, (podsols) and have a low content of certain plant nutrients which make them susceptible to additional effects to which they are sensitive. The effect depends on a number of interacting factors and may result in the leaching of the nutrients. If the nutrient balance is changed this will probably influence the vegetation.

This short description of the sulphur and sulphur dioxide pollution is intended to stress the fact that this type of pollution is considered as one of the most serious effects of urbanization on hydrological processes.

The extent to 97hich sulphur will affect the biological system in the soil and the soil

11-3.5.5 Oil pollution problems.

Oil pollution problems are mainly caused by accidents occurring either on land or at sea. Some serious accidents have occurred on land but little is known about the effect of oil pollution on the soil (HÖrnsten, - ) . Pollution problems at sea seem to increase at the same rate as the consumption of oil (more than 3 m3 per person per year in Sweden) transport of oil by ship. discharged from vessels which have run aground or been involved in a collision is not contained there is, as a rule, a grave risk of severe damage being caused to the marine ecosystem. Of special interest to Sweden is the consequences of oil spills in the Baltic and in the four big lakes. To increase traffic safety at sea, compulsory pilotage has been introduced for vessels carrying a load of more than 2000 tonnes of crude oil while they pass through Lake Mälaren and the Stockholm Archipelago.

by pumping. This method is considered safe from an ecological point of view. Another method which is very much used is to emulsify the oil, but it is quite apparent that opinions on the harmfulness of this method are very divergent (Ganning , 1970; Engdahl , 1971) .

the Baltic and the North Sea came into force in 1967; nevertheless the discharge of oil along the coasts has increased.

and the When oil

There are several methods of rendering oil at sea harmless. One is to remove the oil

The revised International Convention €or the prevention of spillage of oil at sea in


According to Munn (1966) there are essentially four mechanisms which contribute to the climate of a city, the natural climate of which is to a great extent modified by man. The radiation is disturbed by the fact that natural vegetation is replaced by concrete and steel. How- ever, in certain parts of the city, gardens and park areas may influence the climate in a way quite different from that of the paved areas. Built-up areas obstruct the wind flow which may result in lower mean velocities but may produce more pronounced turbulence. The water balance is influenced by the alteration from humid to dry surfaces. The city emits heat, water vapour and pollution to the atmosphere. However , the precise mechanisms by which different physical factors influence the local climate in a city have yet to be demon- s tr at ed .

A characteristic feature of the city climate which makes it different from rural surroundings is the so-called 'heat islands' (Lindqvist, 1970; HÖgstrÖm, 1972). The temperature in the city is generally higher than in the surrounding rural areas and highest in the centre of the city where the 'heat island' feature is most distinct at night time during clear weather and light wind. The temperature distribution in the city also causes a wind circulation similar to that which characterizes a sea and land breeze. This produces a pulsating wind towards the city centre. The air rises in the central part of the city and then flows outwards, sinks and perhaps returns again. This process involves an increase of air pollutants. Because of the structure of a city which is built up of irregularly shaped and situated buildings a very pronounced turbulence is created.

tation. There are, however, some research results from other parts of the world which indicate that the precipitation may be doubled in cities compared with rural land. The reason

In Sweden, no research work has been'done about the effects of urbanization on precipi-

107

Additional industria2 water effects

for this may be attributed to the characteristic temperature distribution in the city and the role played by industrial pollutants not necessarily created in the city. Pollutants may form condensation kernels which facilitate precipitation. The observed higher precipitation in the city gives rise to another problem - an increased runoff caused by reduced infiltration.

occurrence is higher in the city than in rural surroundings. This may be true if the air pollution effect is disregarded, but it seems reasonable to assume that fog may occur when the relative humidity is less than 100%. The reason for this is probably that the small particles appearing in the fog are hydroscopic with the additional property of attracting sulphur dioxide from the air. Like many other city phenomena fog occurrence has not been exhaus- tively studied. As pointed out by a Swedish scientist, no concise methods exist by which the character of the fog may be determined or even if fog exists at all (Andersson, 1968).

From a hydrological point of view the most pronounced feature of the city is the increased runoff that appears as a consequence of impervious areas. This problem has already been discussed in Section II- 3.3.

of view, of chang.i.ng the cverall negative effects created by the city. emphasized that the details of the influence of urbanization on the micro climate are not very well understood. also been observed for hilly rural areas. Nevertheless, the most important factor influencing the climate of a city seems to be the air pollution but even the extent of this influence could be considerably modified by the reduction of the emissions, the incorporation of large green areas and the use of heating plants remote from the city.

Lindqvist (1970) has expressed the opinion that there is no reason to believe that log

HÖgstrÖm (1972) asks if there is any chance, from meteorological and hydrological points Again, it should be

Lindqvist pointed out that detectable differences in temperature have

11-3.7 ADDITIONAL INDUSTRIAL WATER EFFECTS

Sweden is estimated to have about 100 O00 lakes, of which 90 O00 have a surface area less than 1 km2. recreation and fishing, and it is obviously vital that they must be protected against severe pollution. Increased urbanization since the 1930's has resulted in these inland waters being used as recipients for watez with an increasing nutrient content (OCDE, 1970; Willen, 1972).

est since 1964/65 when about 100 sampling stations were established. The special interest in Lake Mälaren arises from the fact that, as a result of an approximately twenty-fold increase in population in its catchment over the past hundred years, the water quality has deteriorated considerably, especially during the last few decades. Water samples for chemical and biological analyses were collected six times during the first few years but since 1967 the number of sampling stations has been greatly reduced. It has been established that Lake Mälaren has the highest nutrient load among Swedish lakes, 800 tonnes of phosphorous being added annually corresponding to 7 kg per hectare of lake surface. The nitrogen load is estimated at 90 kg per hectare which means a total of 10 O00 tonnes. Municipal discharges are mostly responsible for this pollution.

The importance of preserving Lake Mälaren can be appreciated from the fact that the lake is very important as a source of water supply. About 1.3 million derive their drinking water from this lake and it is expected that abstraction will increase to six times its present amount over the next 30 to 40 years.

Four of the lakes because of their size play an important role in navigation,

One of the largest lakes in Sweden, Lake Mhlaren, has attracted much scientific inter-

Lake Vanern should also be mentioned since it is Sweden's largest lake, with a surface , area of 5 600 km2. About 700 O00 people live within the Vänern catchment and some 400 O00

of these people live in urban areas. This oligotrophic lake receives about 1500 tonnes of phosphorous annual.ly or approximately 3 kg per hectare. The wastes discharged from timber, pulp and paper industries have increased the organic content during this century from 4 to 5 times its previous value.

Lake Trummen has been the subject of a special investigation which is important since it is an attempt to restore to its former condition a lake which has been very extensively destroyed by wastewater. The upper Layer of the sediment deposit containing the mineral nutrients was dredged away, and part of the vegetation was also removed. As part of this project a cost-benefit analysis has been made, and it found that the cost of restoring the lake corresponds to an annual fee of about 10 Skr over 50 years for the 15000 persons who live in

108

Water balance inventories

the vicinity of the lake (Ripl, 1970). The pollution of the Baltic, one of the world’s largest lakes with about 20 million

people living near its coastsl is a problem not only to Sweden. The lake surface is 360 000 km2, with a mean depth of 60 m, a maximum depth of 459 m and a water volume of 22 O00 km3. Swedish investigations have found that the oxygen content of the bottom waters has dropped gradually during this century. At the beginning of the century the oxygen content of the bottom water in the deepest part of the lake was about 4 mg per litre. hydrogen sulphide occurred in the whole deep water body with the result that the deep areas could no longer sustain higher forms of life. levels in the bottom waters have increased by a factor of three from 1954 to 1970.

(Swedish Environment Protection Board, 1971) and it is estimated that 1 200 O00 tonnes of oxidizable organic material, calculated in terns of the 5 day BOD value, is discharged to the Baltic annually. Moreover, the yearly addition of phosphorous amounts to about 14 O00 tonnes. Metallic pollutants from industries are being disposed of at an increasing rate. Dumping of radioactive wastes has occurred but is now under control. Very little is known about damage to biological conditions by war material, but dumped war material is marked on sea charts.

As mentioned earlier, the pollution of the Baltic is the concern of several countries. It seems to be well established that a continuing increase of nutrient supply to the Baltic will create an evil circle of eutrophication processes with alternating accumulation of nutrients in the deep water and fertilization of the surface water. Consciousness of the very severe problems involved and the need for common action has, among other actions, resulted in conferences on the Baltic between the USSR and Sweden in 1971 and 1973.

vestigations and the team work between scientists of different disciplines in studying the Byfjord is particularly worthy of note. ally renouned for the stochastic analysis which was carried out (Cederwall, 1971).

In 1968,

Some studies indicate that the phosphorous

A series of investigations on the pollution problems of the Baltic are now proceeding

The condition of Swedish rivers and coastal waters are also the subject of several in-

The investigation of the Göta River is intemation-


Only one experimental study is being conducted in Sweden on the human influence on the water balance in urban areas. This investigation is being carried out at the city of Lund in south- e m Sweden. changes in the water balance (Lindh and Falk, 1972). of it will be used in the near future as a dwelling house area. ed aims at characterizing the pre-urban state by observation of precipitation, runoff, infil- tratior. etc. ematical model which can be used to describe the original state. The intention is to observe what happens from a hydrological point of view during the period the area is developed.

A study is also being carried out (Gottschalk and de Mare, 1970; Gottschalk, 1971) on the effect of urbanization on the water balance encountered in the construction of an airport. ween a catchment which will be used for the airport and an adjacent catchment which will be unaffected and therefore suitable as a control. As the airport construction has already started there may be insufficient time for a thorough study of the pre-urban state. Never- theless the study is considered as being of value.

representative Verkah basin where the Stanford watershed model will be used to study problems (Nilsson , 1969) .

In a part of the urban area not yet developed, there are current studies on The area is about 3 km2 and two-thirds

The investigation just start-

The investigation has progressed sufficiently for the construction of a math-

The area chosen for the investigation isselected so as to allow for a comparison bet-

Another investigation of the effect of impending mbanization has been started in the

11-3.9 REFERENCES

Andersson, B. 1972. The distribution of wastewater load in Sweden. Institute of 4eehnoZogy, BuZZetin Se&es A 80. Zi!, Lund.

Andersson,T. 1968. Fog climate in the Stockholm region. Meteorological Institute - Univer- sity of UppsaZa. Report Alo. 9, Uppsala. Brink, N. AgrieuZture, Report No. 8, Uppsala.

Gustafsson, A. and Wiklund, U. 1971. Report from a amping site. Institute Of

I09

References

Carlsson, B. 1970. Thermal effects of heated effluents in Lake Mälaren. Nordic conference on HydroZogJ, Stockholm, I, Lund. Cawood, P.B.; Thunvik, R. and Nilsson, L. Y. 1971. Hydrological modelling. An approach to digital simulation. Swedish Nationa2 Sdence Research CounciZ, Report 2Vo. Cedemall, K. 1971. The Göta River. A hydrological analysis of transport and mixing processes , C"naZmers Institute of Technology, avision of hydraulics, Report No. 63, Gothenburg. Dickson, W. 1970. pH-conditions in Zakes in the western part of Sweden in November - December 2970. Report from the National Swedish Environmental Protection Board.

Ehlin, U. 1970. Hydrological effects of warm water effluents. Swedish MeteoroZogicaZ and HydroZogicaZ Institute, Stockholm. Engdahl, R. 1971. Defence of the coasts against oil pollution. Forskning och Framsteg, No 1, Stockholm.

Eriksson, E. 1969. SuZphur dioxide and the acidification of the precipitation - facts and SpecuZations. Report from a IVL-conference in Stockholm. Eriksson, E. 1971. The fate of SO mmentaZ change, MIT Press , Cambridge , Mass. . Fleetwood, A. 1969. The influence of urbanization on groundwater. Vatten , J. Water management and Res. , Stockholm. Ganning, B. 1970. The Baltic - the oil - the decontamination. Forskning och Framsteg, NO. 8, Stockholm.

7.

and NO in the atmosphere, in Power generation and envir- 2

Gottschalk, L. and de Mare, L. 1970. Effects of urbanization on water balance. Nordic Conf- erence on Hydro Zogy, Stockho Zm, Lund. Gottschalk, L. 1971. On the effects of urbanization on surface runoff. 7th Nordic Symposim on Water Research, Jyväskylä, Finland. Gustafsson, Y. 1969:3. Sanitary land fills and damage on groundwater. Vatten, J. water management, Stockholm.

Gustafsson, Y.; Eriksson, K.G. and HÖrnsten, A. 1970. An ad hoc-group for gravez expzoiting beneath the growlhater ZeveZ. Report to the National Swedish Environment Protection Board. Gustafsson, Y. and Nilsson, L.Y. 1970. A "groundwater cross" across Stockholm. Byggmästaren, No 6, Stockholm.

HÖganäs AB. 1969. The HÖganäs sewage technique handbook, Lund. Sweden.

Hansson, G and Svensson, L. 1972. The distribution of the population according to size of urban regions 1965 - 2000. Ministry of Labour and Housing, Grup, Stockholm. HÖrnsten, A. ( ). Groundwater damage caused by oil leakage. Report from the National Swedish Environment Protection Board.

HÖgstrÖm, U. 1972. Urbanization and weather - an interaction - good or evil? Naturvetenskap, Stockholm. Jansson , L.E. 1971a. Distribdtion lines. 7th Nordic Symposium on Water Research, Jyväskylä, Finland.

JanSSOn, L.E. 1971b. Conduit system. 7th Nordic Symposim on Water Research. Jyväskylä,

SVenSk

. Finland.

Liedberg, A. 1971. Urban storm runoff. 7th Nordic Symposim on urban storm runoff. Jyväskylä, Finland. Lindh,'~. and Andersson, H. 1972. Extraction of unconsolidated sediments from the Sea bottom.

Lindh, G. and De Mare, L. 1972. Urban runoff. A survey of the literature. Institute of TechnoZogy ¡%vision of HydrauZics BdZetin Series A No 9, Lund.

A report to the Swedish Board of Technical Development, Lund.

1 IO

Re ferences

Lindh, G. and Falk, J. 1972. Yärpinge - a study of the effect of urbanization on water balance. Vannet i Norden, 2, Stockholm. Lindh, G.; Falk, J. and Niemczynowics, J. 1972. Runoff from a small experimental area. Nordic Conference on HydroZogy, Sandef j ord , Norge. Lindqvist, S. 1970. Climatological studies of built-up areas. Doctoral Thesis, Gleerup, Lund.

Munn, R. 1966. Descriptive micrometeorology New York.

Munn, R.E. and Kodhe, H. 1971. On the meteorological interpretation of the chemical composition of monthly precipitation samples. TeZZus, 23, 1-13. National Swedish Board of Urban Planning. 1972. Report from a meeting concerning lowering of the groundwater table in urban areas, Stockholm.

Nilscon, L.Y. 1969. The verkaa basin. IHD Report, No. 5, Stockholm. Nilsson, L.Y. 1972. Hydrological aspects on urban storm sunoff. Conference on urban runoff, Royal Institute of Technology, Stockholm,

NoxdstrÖm, A. 1970. Groundwater control in cities. Nordic Conference on Hydrology 2970, z, Lund.

NordstrÖm, A. 1970. Discussion on a paper. Nordic Conference on HydroZogy, StockhoZm 2970, 3, Lund.

Öberg, S. 1972. Municipal block statistics. Ministry of Labour and Housing Stockholm.

OCDE. 1970. Eutrophication in large lakes and impoundments. Uppsala Symposium. Paris. Oden, S. 1968. The acidification of air and precipitation and its consequences on the National Environment. NationaZ Sdence Research Coun&-ill of Sweden. EcoZogy Committee BUZZ. 2. Oden, S. and Ahl, T. 1970. The acidification of Scandinavian lakes and rivers. Ymer, Yearbook.

Ripl, W. 1970. Probleme der Zeerestaurierung. Wasser, Luft und BetKeb, 22, Mainz. Rodhe, H. 1969-1970. Measurements of sulphur in the free atmosphere over Sweden.

Rodhe, H. 1970. On the residence time of antropogenic sulphur in the atmosphere. TeZZuS, 22, 137-139.

Royal Ministry for Foreign Affairs/Royai Ministry of Agriculture. across national boundaries. The impact on the environment of sulphur in air and precipitation. Sweden's case study for the United Nations conference on the humm environment, Stockholm.

Royal Ministry of Foreign Affairs/Royal University of Agriculture. 1971. Sweden's national report to the United Nations Conference on the human environment, Stockholm.

SÖderlund, G. and Lehtinen, H. 1970a. Pollutants from urban storm water runoff. Vatten, J. water management, Stockholm. SÖderlund, G. and Lehtinen, H. 1970b. Will dumping of snow in a lake give rise to a pollution problem? Vatten, J. water management, Stockholm. SÖderlund, G. and Lehtinen, H. 1971. The nature of stom runoff. 7th Nordic SympOSiwII on Water Research, Jyväskylä, Finland. SÖderlund, G. 1972. Pollutants in storm runoff. Conference on urban runoff. Royal Institute of Technology, Stockholm.

Sprinchorn, G. and Ehlin, U. 1971. Hydrological conditions in Lilla Vartan and adjacent water regions. Swedish MeteoroZogicaZ and HydroZogicaZ Institute, Stockholm. Lltega. 1971. Groundwater problems in urban districts. National Swedish BuiZding Research, Sumaxies, Stockholm.

1971. Air pollution

1 1 1

Re ferences

Swedish Central Bureau of StatisticsfNational Swedish Environment Pxotection Board 1969. Statistical data for municipal water work, Stockholm.

Swedish Board for Technical Development 1970. DesaZ$r@$on of sea Water. A technical and economical study with application to the water supply for Scania, Stockholm.

Swedish Environment Protection Board. 1971. The Baltic Current Swedish Research, Stockholm.

Swedish Government Official Report 1965: 8. Water supply for Skane and Halland, Stockholm.

Swedish Government Of ficial Report 1969 : 18. Towards a cleaner society, Stockholm.

Swedish Government. 1970. The role of urbanization in Sweden, Stockholm. Official Reports 1370: 14 (SOU) . Swedish Meteorological and Hydrological Institute (SMHI) 1969. Monthly and yearly summary of weather and water supply in Sweüen. Yearbook 51, part 1, Stockholm.

Ulmgren, L, 1971. Influence of urban storm runoff on the wastewater treatment process. 7th Nord;c Syrnposiwn on water research, Jyvaskyla, Finland. von Heidenstram, O. 1972. Waste disposal - methods and development. kîodern Kenri, NO. 4, Stockholm.

Willen, T. 1972. The gradual destruction of Sweden's lakes. Adio, 2, (2) Stockholm. Winqvist, G. 1968. Artificial infiltration. Grom&ater. Wenner-Gren Center International Symposium Series, 11, Pergarnon Press.

4 Hydrological effects of urbanization in the United States of America

M. B. McPherson

American Society of Civil Engineers Marblehead, Mass., U.S.A.

Hydrological effects of urbanization (Studies and reports in Iiydrology, 18) Paris, The Unesco Press, 1974

Introduction

11-4.1 INTRODUCTION

The United States report prepared for the United Nations Conference on the Human Environment held in June, 1972, at Stockholm, Sweden, states that 'we are now aware of the extent to which our air and waters are polluted, our wildlife endangered by man and his works, our land scarred and being swallowed up by the demands of a burgeoning population, our mineral resources dissipated through profligate use, and the quality of life of vast numbers of people inexorably dimishing. The present challenge to the United States - and to every developed and developing nation - is to determine a more rational way of using resources so that economic growth and social progress can continue without jeopardizing the health, safety and well-being of people or endangering the Nation's security. . . . . . Only when confronted, in recent years, by gross pollution and threats of irreversible environmental damage have we begun to accept fully the fact that the wastes heedlessly generated by a growing, urbanized, high-production, high-consumption society exceed nature's capacity for self-renewal. ..... A new ethic has emerged which repudiates the mistakes of the past and demands the restora- tion and preservation of a safe, wholesome, aesthetically satisfying environment' , (Anon, 1971).

physical, biological , social, economic , and cultural conditions and natural beauty which relate to the habitat of man and other creatures', (Stevenson, 1970). In the US problems arise from water pollution, air pollution, long-term effects of human activity on climate, solid wastes disposal, noise, pesticiaes, radiation, and land-use, (Council on Environmental Quality, 1970).

water-based recreation , accommodation of waste heat from power generation , flood mitigation, groundwater recharge, disposal of liquid wastes, surface drainage, land-use, and a host of related factors are heavily influenced and/or constrained by regional and local climatic-ay- drogeological characteristics. Perennial and intermittent streams are characteristic of most of the eastern third of the US, whereas much of the rest of the country is arid with ephermeral streams; snowmelt being the basic water source for a number of metropolitan areas. Although most major eastern cities are on ocean bays, estuaries, principal rivers, or the Great Lakes, the stream beds in Los Angeles are dry most of the time and the only flow in Denver's streams during the long dry season is diverted water on its way downstream for the use of those who have riparian rights.

While the US has been predominantly an urban nation for over half a century, hydrological research has mainly served agricultural needs and river basin development. Hydrological research in support of comprehensive water resource development at the metropolitan level has been frustrated by the fact that the planning, implementation and operation of facilities and services are usually fragmented in both the central cities and in their metropolitan districts, (McPherson, 1970). 'The field of urban hydrology is almost devoid of modern research investment', (Ackermann, 1966). However, the Office of Water Resources Research (OWRR) has developed a broad programme of projected urban water resource research, (1971) based partly on national assessments by the American Society of Civil Engineers (ASCE), (1968; 1969) and has supported a number of projects involving hydrological studies. The US Geological Survey has initiated an urban water programme with an emphasis on urban hydrology, (Schneider, 1969).

Environment quality, in its broadest sense, has been defined as 'a measure of all the

Practices and possibilities for re-use, low-flow augmentation, water transportation,


In 1970, of a total US population of 203 million people, three-quarters were living in 'urban areas', defined as places with 2 500 or more occupants. (Bureau of the Census, 1971a).

The National Government uses as a measure of urban concentration what is termed the 'Standard Metropolitan Statistical Area' (SMSA). An SMSA has a cen'cral city with at least 50 O00 inhabitants; and includes the county in which the central city is located as well as adjacent counties judged to be metropolitan in character and economically and socially integrated with the county of the central city. In 1970, two-thirds of the US population resid- ed in SMSA's, The distribution of population by size of SMSA in 1970 is given in Table 22 (Bureau of the Census, 1970).

114


Tabie22. Metropolitan population in the USA

Number

for all 230 SMSA's within range

Population in millions Population range of SMSA's

For range cumulative

1 000 O00 500 O00 to 1 O00 O00 400 000 to 500 O00 300 O00 to 400 O00 200 O00 to 300 000 100 o m to 200 O00 50 O00 to 100 O00

31 34 8 23 47 68 19

77.86 23.67 3.51 7.99 11.93 9.78 1.57

77.86 101.53 105.04 113.03 124.96 134.74 136.31

Three quarters of the total SMSA population , or one-half the total national population, is in the size range of 500 O00 or more persons. in 65 SMSA'S.

in their suburbs; reached nationally , nearly all the resultant increase being in urban areas , (Advisory Commiss- ion Intergovernmental Relations , 1969) . By then , 90% of the population will be urban dwellers.

million square kilometres) are divided into four arbitrary metropolitan regions.

That is, half the nation's population is

By 1985, SMSA'S will hold 50% more people with practically all the growth taking place and by the end of the century the 300 million mark may be approached or

Table 23 shows the distribution of population in 1970, if the 48 contiguous States (7.85

Table 23. Population distribution in the USA

SMSA population Area of Region , Region - (states) milllon per cent of 48 states

North-east (Me. , N.H. , Vt. , Mass., Conn. , R.I. , N.Y. , Pa. , N. J.)

North Central (Oh. , Ind. , Mich. , Wisc., Ill. , Min. , Ia., Mo., N.D., S.D., Neb., Kan. 1

South-east and South Central (Del. , Md. , Va. , W.Va., Ky. , N.c., S.C., Ga., Fla., Tenn., Ala. , Miss. , Ark. , La. , Ok. , Tex., Dist. of Columbia)

West (Mon. , Wy., Col. , N.M. , Id. , Ut., Ariz., Wash., Or. , Nev., Cal.)

-

38.6

36.8

34.3

26.0

5.6

25.3

29.8

39.3

(The SMSA population in 1970 was 0.61 million in Hawaii and there were no SMSA's in Alaska).

The concentration of large metropolitan complexes in the North-east and North Central regions is partly explained by the presence of manufacturing industries. However, some time within the last few years the US economy moved beyond its industrial base to become the world's first fully-fledged 'service economy'. (Anon , 1971b) . Consequently service industries are displacing manufacturing as a prime economic motivating force , favouring greater

115


rates of population growth in the crescent covering roughly the South-east, South Central, and the South-west Pacific Coast portion of the West, where the more moderate climate affords a longer season of outdoor leisure and recreation. Despite these regional trends, projections for individual metropolitan and urbanized areas suggest that a major share of all national population growth will be in the largest urban areas. Projected data for separate areas indicate that 27 urbanized areas will raise their population by over 65 million during the remainder of this century and thereby be responsible for more than 60% of the net national increase. (Advisory Commission on Intergovernmental Relations, 1968).

has been one of steady decline. (Anon, 1970a). Land occupancy has shifted from a primarily rural dispersion to a concentrated urbanization of about 5% of the nation's land area. Den- sity of land use is better indicated by a 'major urbanized area' population concentration of 100 O00 or more) than by an SMSA. Land area projections for 'major urbanized areas' , based on historical growth and current trends, are given in Table 24 (Pickard, 1967).

In the US as a whole, the peak of ruralsettlementwas in 1920; and since then the trend

(area occupied by an urban

Table 24. Population growth in the USA

- Population Land Average Number

(millions) Year area density of (square kilometers) (persons/sq. km. areas

1920 34.6 14 000 2 470 70 1940 52.4 23 000 2 280 98 19 60 91.0 56 000 1 630 160 19 80 148.0 100 o m 1 480 19 4 2000 220.5 153 O00 1 440 223

The developing national urban land policy could significantly alter these projections. The added impacts of such growth on present and planned metropolitan water services of all kinds and on megalopolitan water supply and water quality control are viewed with grave concern.


The mean annual precipitation in the US ranges from over 5 O00 mm (200 in.) in some parts of Hawaii to less than 100 mm (4 in.) in some parts of the south-western States, (National Oceanic & Atmospheric Administration, 19681 . Variations between cities are generally less, ranging from about 1 730 mm (68 in.) in Mobile, Alabama to about 180 mm (7 in.) in Phoenix, Arizona. Mean annual precipitation for the three largest cities are: New York, New York, 1070 mm (42 in.); Chicago, Illinois, 840 mm (33 in.); and Los Angeles, California, 370 mm (14 in.). (Bureau of the Census, 1971b).

National maximum average rainfall depth-duration-frequency amounts have been mapped for mean recurrence intervals of one to a hundred years and for durations of a half an hour to a day. (ESSA-Weather Bureau, 1961-62.) Shorter duration rainfall can be determined by multi- plying the mapped half-hour amount for a selected return period by the following ratios: 5 min., 0.37; 10 min., 0.57; and 15 min., 0.72. Mountains in the Western States cause considerable local differences that are obscured in continental maps, and a series of detailed precipitation-frequency maps has been prepared, one set for each of eleven Western States.

span the range for most of the urban areas in the 48 contiguous States, the New Orleans rates being several times greater than those for Seattle:

Maximum average rainfall intensities for New Orleans , Louisiana, and Seattle , Washington,

I16

Micro-scale climatic effects

Table 25. Maximum average rainfall intensities in the USA

Average return

Approximate range of maximum average rainfall intensities in millimetres per hour

period 30 minutes 2 4 hours

2 year 10 to 80 2.0 to 5.0 5 year 20 to 100 2,5 to 8.0

100 year 40 to 150 8.0 to 15.0 25 year 30 to 130 3.3 to 12.5

High intensity rainfall in metropolitan areas is often from convective precipitation. The annual average incidence of thunderstorm days in New Orleans is near the national maximum whereas thunderstorms rarely occur in Seattle.

11-4.4 MICRO-SCAIL3 CLIMATIC EFFECTS

While the exact roles of heat discharges and thermal characteristics of superficial modifications in influencing the climate of metropolitan areas have not been defined, there are measurable and even rather large effects in terms of climatic parameter differences between urban concentrations and their environs , (Kneese, et al., 1970.)

environs are given in table 26 (Lowry, 1967.)

Table 26

Reported differences in climatic effects between a city and its suburban and non-urban

Climatic vari able Ratio: city to environs

Solar radiation on horizontal surf aces O. 85 Ultraviolet radiation, summer O. 95 Ultraviolet radiation, winter O. 70 Annual mean relative humidity O. 94 Annual mean wind speed O. 75 Speed of extreme wind gusts O. 85 Frequency of calms 1.15

Frequency of fog, summer 1.30 Frequency and amount of cloudiness 1. lo

Frequency of fog, winter 2.00 Annual precipitation 1. lo Days with less than 5 mm. (1/5 in.) of precipitation 1.10 - 'Both the advantages and the disadvantages of city climate testify to the fact that the city's climate is distinctly different from the countryside's. Every major aspect of climate is changed, if only slightly, by an urban complex' ..... Current meteorological research may make possible the ascertainment of 'the potential of extensive urbanization for causing large- scale changes of climate over entire continents .....'

'Climatic studies of four various-sized cities in the Midwest and two large eastern cities have shown apparent urban-produced precipitation increases ranging from 5 to 16 per cent in annual precipitation and rain days, with 7 to 22 per cent increases in summer thunderstorm days. Substantially greater increases in precipitation, thunderstorms, and hailfalls, 31 to 246 per cent, have occurred in the past 25 years in an area downwind from a major steel mill complex in the Chicago area .....I, (Changnon, 1969).

117

Effects of community scaZe urban water conservation measures

The cumulative effects of urbanization on a drainage basin can either diminish or increase the natural low flows of streams , depending upon local conditions. Evidence indicates that the principal effect of urban development on surface water is to increase the amount of direct runoff, (Waananen, 1969). This increased volume of direct runoff , (Leopold, 1968) can reduce low flows because less precipitation is available for soil moisture replenishment and groundwater storage. Base flows of streams can be raised by wastewater originating as imported water, (Spieker, 1969) or be diminished as a consequence of recharge being prevented by imperviousness or by surf ace water diversions.

Some land subsidences appear to have been caused or intensified by lowering of groundwater levels. Evapotranspiration can be reduced by the introduction of impervious surfaces and increased by irrigation. Yields of aquifers may be increased by leakage of water from water distribution systems, (Howe, 1971) or be decreased by seepage of groundwater into sewers, (American Public Works Association, 1970). Some irrigation water as well as seepage from cesspools and septic tanks can contribute locally to groundwater recharge. Numerous case histories on the effect of urbanization on overall groundwater recharge have shown instances of increases, of decreases, and of no change, depending on local factors, (Task Committee on Effects of Urbanization, etc. , 1972).

Because of protracted delays in resolving conflicts of interest, the time necessary to implement water resource projects has been of the order of 20 to 25 years, particularly for the larger projects , including certain large urban water supply works , whereas the construction requires only 1 to 5 years for smaller projects and 5 to 15 years for larger projects , (Hall, 1970). If the geometric increase in demand for urban water resources is to be met more rapid means of resolving conflicts of interest must be found.

11-4.6 EFFECTS OF COMMUNITY SCALE URBAN WATER CONSERVATION MEASURES

Stream regulation structures, for the amelioration of droughts, and protection against floods and seawater intrusion, can have pronounced beneficial effects on local urban water supplies.

Groundwater recharge from the sea, by seawater intruding into aquifers previously filled with fresh water, is almost always the inadvertent result of an attempt by man to improve some other aspect of the environment, (Task Committee, 1969) for example the adoption of ocean disposal of treatment plant effluent from coastal areas which draw heavily on local groundwater supplies , (Franke & McClymonds , 1972; Anon , 1972a) . To reverse the effects of seawater intrusion is difficult and expensive, (Bruington, 1972).

No surface water supply works can be designed for the 'ultimate' projected drought,consequently a risk of failure of supply must be accepted. In these circumstances the use of water would be inflexibly controlled by the limits of the supply. In the absence of adequate or timely releases of compensation water, the constriction of impounding reservoirs can reduce downstream flows below pre-existing levels, to the detriment of downstream users. The most severe drought on record in the North-eastern US occurred in the 1 9 6 0 ' ~ ~ and competition for available supplies was at times intense, (Feldman, 1971; Russell et al. , 1970; Hogarty,1971). On the other hand, the incorporation of water-supply storage in most of the recent multi- purpose projects developed by the National Government has provided drought relief in numerous instances.

charge, (van der Leeden, 1971) various forms of re-use, (Haney, 1969; Water Resources Research, 1973) desalination, (Brice,l969; Anon,1972b) and weather modification, (Lumb, Linsley,l971; Kahan,1972).

tions of mountainous areas in California, (Williams,l971). However , a national assessment found that information available on the possibilities of increasing water supply during droughts was too limited to reach firm conclusions on the value of this technique (Lackner, 1971).

As the cost of importing water from distant sources of the conventional type increases, desalination of seawater in coastal towns and cities, (Montanari & Brennan, 1972) may become economically more attractive, particularly as research efforts are committed to reducing unit processing costs. in 1971, their combined capacity was less than 14 m3/sec, (Owen, 1971). Desalination must stili be regarded as a long-range alternative, (Anon, 1972~).

Methods for enhancement of water yields exist. These include artificial groundwater re-

Weather modification has been used to develop supplementary water supplies in large sec-

However, although there were more than 600 desalination plants in the world

118

kjor effects resulting from urban uater resource faciZities

Smog , sometimes aggravated by temperature inversions , and air pollution , tends to occur and concentrate predominantly in metropolitan areas. The sources are almost entirely the products of combustion of fossil fuels. The total mount of such pollutants emitted each year in the US is estimated to be 164 million metric tons, about half of which comes from automobiles , (Newell , 1971) . 11-4.5 PVLSOR EFFECTS mSULTING FROM URl3KN WATER F?ESOURCE FACILITIES

Large capital investments have been made in water management structures and related facilities for urban populations. For example , the replacement value of public water works exceeds the combined total national capital investment in iron , steel, food and kindred products , is more than twice the investment in gas utilities, and is considerably more than the investment in railroads , (Gustafson , 1968). Replacement values of public wastewater works and public storm drainage works are, respectively, about 80% and 50% of that of water works , (American Society of Civil Engineers , 1968).

The concentration of large numbers of people in urban areas is characterized by water demands which exceed the amounts that can be obtained from the vicinity of the urban areas. The hydrology of urban water supply is therefore frequently sub-regional rather than local in extent. About 1 out of 8 persons having access to public water supplies in the North American continent take water from a system which has its source 120 kilometres, or more, away, (Howson, 1957). The longer the distance the larger the capacity of the transport system, (Linaweaver & Scott Clark, 1964). Thus, the larger a metropolitan area the greater the hydrological region affected. In the U.S., almost all the larqer cities draw their water from surface sources, (Advisory Committee on Intergovernmental Relations, 1966). The poor quality of local sources has sometimes resulted in the need or desire to use more remote sources. They are also being used to supplement supplies. The hydrological region affected by an urban centre thus tends to expand as its population increases, giving rise to conflict between competing interests.

Water Project of which a 1 100 kilometre long aqueduct which is nearing completion will bring a total of 167 m3/sec. of additional water to the State, Gianelli & Jansen, 1972).

Water-borne carriage of wastes in public systems of wastewater sewers, a creation of urbanization, is practised extensively in the US, with septic tanks and cesspools for individual buildings giving way to community sewerage as local land occupancy becomes sufficiently intensive. In general, most of the water distributed from public supplies eventually enters public waste water sewer systems (except the portion, often significant, used for irrigation of lawns , and that used for air conditioning). The hydrological territory affected by water pollution from an urban centre tends to grow as its population and land occupancy become larger, but the sub-region affected may differ appreciably from that required for water supply. There may be partial or even no overlap.

faces (except combined sewers, which in addition convey waste water on a perennial basis). Surface water drainage is more of an amenity than a protector of health and safety. Intang- ible damages from flooding, such as inconvenience and nuisance, are much more extensive than for stream flooding and generally recur more frequently.

All the basic engineering methods of in-stream flood regulation are applicable to flood mitigation works within local urban catchments, but generally on a smaller scale: acceleration of flood flows by canalization through threatened reaches with consequent reduction in stages; isolation of floodable land by means of embankments, such as levees and flood walls; and the reduction of flood peaks by storage, located either upstream from threatened reaches or where they can be fed by diverted flows. Similarly, possibilities also exist for social- economic-administrative-legal controls to mitigate the damage, such as flood-plain zoning , flood-proofing of structures, flood insurance and related schemes.

ed natural channels or special channels excavated for the collection of storm water from drainage conduit outlets.

major cities are located on large streams or bodies of water, where they are vulnerable.

The most ambitious transportation scheme undertaken in the US is the California State

(Miller & Miller, 1968;

The function of underground drainage conduits is to remove storm water from urban sur-

In addition, nearly all major cities such as in Milwaukee, (Prawdzik, 1970) use improv-

New suburbs have sometimes aggravated flooding and caused damage to major cities. Most

I I9

Mujor effects resuZting from urban wuder resource faciZities

A common form of indirect re-use is the downstream withdrawal of streamflow which contains diluted upstream effluents. Probably 3 out of 5 Americans served by public water supplies re-use water from sources that have already been used at least once for the conveyance of domes tic and industrial wastewater, (Wolman , 1965) . The practice of successive withdrawals is obviously most feasible from the waters of perennial streams. The more intimate coupling of direct recycling, artificial recharge of aquifers, and reclamation for supplementary industrial and agricultural supplies, are the only feasible alternatives of fresh water re-use in arid metropolitan areas where water courses have dry beds throughout most of the year, and in places where groundwater is the predominant supply.

claimed from wastewater to serve as a supplementary source mainly for irrigation and industry, (Murray, 1968). While 85% of the non-recoverable water abstracted in the US has been consumed in the seventeen relatively arid Western States, (Murray, 1969) mostly for irrigation, it is estimated that in this region municipal effluents cannot supply more than a few per cent of the irrigation demand, (Eastman, 1967). Further, reclamation is complicated by the fact that the natural dissolved mineral content of water tends to increase in concentration with each successive re-use unless means for its removal are employed before it is re-used.

(American Institute of Chemical Engineers, 1967) and the practice is expected to grow because of the combined effects of increased competition for sources and higher standards required by water pollution control regulations, (Rey, 1971). Re-use of water within the same industrial plant ' recirculation' constitutes the 'most important brake on industrial demands' because of growing water costs and the expense of waste treatment for 'once-through' use, (Stewart and Metzger, 1971).

Where they are more fully utilized they are often artificially recharged with surplus surface water through basins, (Task Group, 1963) or injection wells, (Task Group, 1967). In such areas, augmentation by introduction of reclaimed wastewater is sometimes advocated, (Cleary & Warner, 1970; Owen, 1968; Peters et al., 1968; Parkhurst, 1970) I

precedents exist. There is currently concern over the need for more reliable water treatment as the relative quality of source water diminishes, (Wolf, 1971; Long & Bell, 1972; Anon, 1972d). The Denver Water Board has embarked on 'a three-stage study programme for development of the treatment and water-quality-monitoring techniques that are necessary for the construction and operation of a full-scale potable reuse plant by the year 1985', (Linstedt et al, 1971.

of operation and management. The response to this increased complexity may be the widespread introduction of automation of the affected works, (McPherson, 1971).

The economic incentives for adapting and using reclaimea waste water on a large scale are lacking at present. A national assessment expressed the optimistic view that this practice will concomitantly respond to the growth of population and industry, (Gavis, 1971). In the meantime the re-use techniques are regarded as means of providing extensive auxiliary supplies, which initially eliminate, but eventually only delay, the extension of existing supply facilities.

groundwater supplies. water supplies, the need to incorporate recharge facilities will quite likely accentuate as demands increase, (Schneider and Spieker , 1969) .

and wastewater problems found that, while technically feasible, water re-use on a household basis is not generally practicable at present because of the high costs of operating and maintenance and new requirements that would be imposed on occupiers, (Bailey & Wallman, 1971). The only scheme that had costs approaching an acceptable level was the use of washing water for re-use in flushing toilets. This practice would save a third to a half of the household water and wastewater volumes, and would carry no overall cost penalty for the occupants. The market incentive for such domestic conservation schemes clearly appears to be missing, How- ever, a number of water works are actively encouraging householders to reduce their water usage as a means of conserving supplies.

Less than 4% of the total national abstraction of water for municipal use has been re-

Direct recycling of large amounts of industrial process water is extensively practised,

Groundwater resources, in general, are very incompletely developed, (Geraghty, 1967) .

The direct recycling of municipal wastewater is being regarded with caution, although

Re-use closes the urban water cycle more tightly and thereby increases the complexities

As water demands grow, recharge will be more extensively practiced in areas served by Where present surface water supplies are extended by developing ground-

About 80% of piped public water returns as wastewater. An evaluation of domestic water

120

Water supply effects


The national abstraction of water is collectively expected to quadruple, with a doubling of the consumptive portion, by the year 2020, (Water Resources Council, 1968). Because this projected abstraction for all fresh water uses would appxoximate two-thirds of the average annual natural runoff from the mainland of US, it appears quite safe to predict that water resource conservation will be practiced much more extensively by 'chat time. Present total fresh water uses are already equivalent to about one-fifth of the total natural runoff.

The eastern US receives two-thirds of the nation's rainfall and the larger western portion the remaining third, and the limited undeveloped, uncontaminated water resources of the arid West are almost exhausted, (Wolman, 1963).

and the amount of municipal use is expected to double by the end of the century and to treble by the year 2020, (Water Resources Council, 1965):

About 10% of the total national water abstractions in 1965 was for municipal supplies,

Table 27. Current and future water requirements in the USA

Municipal water requirements, m 3 /sec Year

1965 1980 2000 2020

1 040 1 470 2 230 3 260

However, these estimates may be too high because recent population growth has been somewhat less than had been predicted. Projected increases reflect growth expected in both population and economic activity. The amount of national municipal water 'consumed' irrigation, distribution system leakage, etc.) is expected to rise from the present level of about one- fifth to about one third between 1980 and 2020.

Of the municipal abstraction, surface water predominates, with only a third of the total coming from groundwater sources. A third of the total serves industrial and commercial uses, (Murray, 1968; Murray & Reeves, 1972).

Some 15% of all municipal water distribution systems are privately owned and operated, although they serve mostly small and medium-sized communities, (Water Resources Council, 1968) . There are more than 300 O00 private water-using industrial plants, (Anon, 1971a).

in Table 28.

Table 28. Industrial water demand in the USA

The abstraction growth by independent industrial concerns on a national basis are given

National total Per cent self su plied industrial withdrawn 3? Type of withdrawal

Other than for thermo- electric power - from groundwater from fresh surface

from saline sources sources

300

1 300 400

59

71 72

Thermo-electric power - from groundwater 50 (not known) from fresh surface

sources 4000 ( II 1 from saline sources 1 600 ( II 1

121

Flood<ng effects

Approximately 90% of the nation's industrial supply is obtained independently: the remainder is taken from municipal systems. Cooling water for thermo-electric power is virtually all self-supplied, (Water Resources Council , 1965) .

From these facts it is clear that water management in cities is divided between public agencies and private interests. Projections of metropolitan industrial withärawals are not available; however, as the total industrial use on a national scale is predicted to be more than five times the present amounts by the year 2000, (Water Resources Council, 1965) the metropolitan portion will increase substantially. Of course, the ratio of withdrawal to use will decrease as recirculation practices intensify.

Regional management is also fragmented. For example , some 400 separately-managed water agencies serve 16 million people in the metropolitan region around New York City, (Zobler et d., 1969) . and poses problems for public health surveillance , particularly in many of the smaller systems , (Johnson, 1970). About 80% of the country's population is served by some 23 O00 water systems, (Anon , 1970b) .

Ohio, Michigan, New Jersey and Florida contained 50% of the national population and 60% of the total national SMSA population. These nine most populous States not only had 60% of the total national SMSA population but of groundwater abstracted; water from surface sources; population served by public supplies; industrial and commercial service; and water consumed, (Murray, 1968) . As for the nation as a whole, about 33% of the public supply for the nine States is from groundwater sources and about 33% of the public supplies is used by industrial and commercial services. This suggests a geographical imbalance in the effect of both population and water supply. However, there are significant variations among the nine States. For example, Florida obtains 90% of its public supply from groundwater whereas Pennsylvania obtains 90% of its public supply from surface water sources, and California is supplied about equally from both types of sources,

In the future,problems of water quality are expected to dominate those of quantity, at the national level, and the need for better waste treatment and additional storage will become greater in the East than in the West, (Wolman & Bonem, 1971). to transport water from remote sources via undersea aqueducts , (Armstrong , 1972).


A review of current studies conducted by a national questionnaire on the effect of urban development on flood discharges indicated that 'too few data have been collected to describe the effect of urban and suburban development on flood runoff . . . . . It was recognized that, in general, the volume of flood runoff is increased by the increase in impervious roofs, streets, and parking areas which are a part of urban development ..... It was agreed that the acceleration and concentration of flood waters by runoff from impervious areas, and by the construction of storm sewers , gutters , catch basins , and channel improvements contributed most to the increased flows experienced in urban areas . . . . . , (Task Force, 1969). Dis- claimers or qualifications of further generalization were stipulated because of the restricting effect of various encroachments, such as loss of natural storage by flood-plain development , and the wide variety of drainage and flood mitigation patterns commonly encountered.

Examination of data and of the results of various studies indicates that the most dramatic hydrological effect of urban development, and the one that has received the most attention, is that on peak flows in streams and storm drains. 'Changes in timing and time distribution of direct runoff from urban areas are a distinct and striking reflection of the influence of urban development. These result from: reduction in opportunity for infiltration , evaporation and transpiration; increase in degree of imperviousness ; and modification of surf ace-drainage patterns , including the associated development of storm-drainage facilities. Lag time (or time of concentration) is reduced as an area becomes urbanized, and the stormflow often is concentrated in sharper , shorter , higher peaks than those for natural runoff. ' Comparative studies of urban and rural drainage basins indicate that as the magnitude of flood peaks increase, the ratio of urban peak rate to rural peak rate declines, the effect of urbanization being more pronounced for the more frequent occurrences , (Waananeo, 1969).

Few local goverments adequately control development of flood plains, steep slopes, or land above aquifer recharge areas , (Anon , 1971a) .

The national plethora of systems defies comprehensive metropolitan management

In the last decade , the nine States, California, New York, Pennsylvania, Illinois , Texas ,

dhey also share approximately 60% of the national total

It may become feasible

I22

Po Z Zution affects

At least 5% of the nation's territory is in flood-prone areas, (US Congress, 1966). Probably about 15% of all urbanized areas is within natural flood plains and more than 50% is drained by underground conduit systems. Urban expansion has continually intruded on flood plains, and consequent flooding has resulted in extensive property damage, economic loss and some loss of life. Property damage due to the flooding of drainage systensis perhaps as great as that in flood plains. Improved flood-plain management is necessary if the quality of the urban environment is to be improved, (Goddard, 1971).

III. Additional details on flooding effects in the US are given later in chapter 1 of Part

11-4.9 POLLUTION EFFECTS

Wide recognition of the deteriorating quality of natural waters and large scale efforts to control waste discharges in the US, date essentially from the end of World War II, (Kneese & Bower , 1968) . cal management is now widely recognized and advocated in the United States. However, it is of such recent origin that no precise definition of the term has been established and widely accepted, principally because the jurisdiction in which the responsibility for management fall is exceedingly fragmented, ' (McGaugley, 1968). The most recent philosophy of public objectives relates to the nature of water as a resource, with an emphasis on its capability for meeting a variety of social objectives. Such orientation moves away from an almost exclusive emphasis on control of quality-depreciating agents as an end in itself. There has been a definite shift from 'pollution control' to 'quality of the environment' as the objective of national policy, (National Academy of Engineering, 1970). The Federal Water Pollution Control Act Amendments of 1972 set forth a national goal of 'zero' pollution.

may be divided approximately as follows: industrial or trade wastes, 33%; municipal wastes , 33% ; agriculture , 20% ; water management practices , construction, navigation and recreation, 6%; mining, 5%; and other urban wastes and power generation about 2%, (US Congress , 1971). The division of pollution among these sources varies widely with location. The same assessment of the prevalence of pollution found that about 30% of US stream lengths are polluted. The incidence of polluted streams is correlated with major urban centres, as the above estimate implies. Subsurface water pollution has not been overlooked, (US Environmental Protec- tion Agency, 1972).

More than 67% of the nation's population is served by public systems of wastewater sewerage: about 46% of these people are served by systems with treatment plants that are over1oa.d- ed or in need of major upgrading and 7% reside in communities with no treatment facilities, (Federal Water Quality Administration, 1970). However, 80% of the total SMSA population is served by wastewater sewerage. Although about 55% of the volume of wastewater that is processed by municipal plants comes from homes and commercial establishments and the remainder is from industries, (Council of State Governments, 1970) the latter is only a small part of the total urban industrial load. 'Industries discharge the largest volume and most toxic of pollutants . . . . . Major water-using industries are believed to discharge, on the average, about three times the amount of settleable and suspended solids and oxygen demanding organic materials as is discharged by all of the sewered persons in the United States ..... The volume of industrial wastes is growing several times as fast as that of sanitary sewage .....' The fact that potential water supply sources are evaluated with regard to quality as well as quantity means that the choice of source ultimately can be dictated by quality considerations, and thus quality, rather than quantity alone, can determine the location of the affect that the source has on the hydrological balance of a sub-region.

are the nation's 'raw' sources for drinking-water supplies. The most demanding requirements are for the transformation of raw water into drinking water in purification plants and the subsequent delivery of safe water to users. Standards for stream quality have tended to emphasize dissolved oxygen level and micro-organism content. The operation of water purification is little affected by dissolved oxygen levels in raw water, and micro-organisms can be rendered harmless as is evidenced by the essentially unblemished public health record of water treatment and distribution over the past several decades. cals , including heavy metals and exotic organic compounds in raw waters , unc.ertainties about

'The concept that management of the quality of water is quite as important as its physi-

Using broad, collective, subjective indices, the estimated pollution causes of US streams

The surface and groundwater , which are the focus of water pollution abatement activities ,

Rising amounts of toxic chemi-

123

Po Z. Zution B ffects

their instantaneous and cumulative hazards to health, and resultant doubts about treatment and standards, are sources of considerable concern to management. It is now widely accepted that water purification should be carried out meticulously, (Graeser, 1970).

About 20% of the nation's population (or 30% of those served by community wastewater sewerage) is provided with combined systems of sewerage, (Sullivan, 1968) and of the fourteen largest cities, ten have combined systems in whole or in part, (Picpherson, 1967). The first definitive identification of the pollution problem from combined sewer overflows on a national scale appeared in 1964, (US Public Health Service, 1964). Where dry weather flow receives secondary treatment, it has been estimated that, during storms, overflows from combined sewers represent on average a load equivalent to about 33% of the treatment plant effluent load, which is about 25% of the total load discharged to water courses, (Guarino & liadziul, 1971). The average annual BOD load from combined sewer overflows is estimated to be roughly 550 kilograms per hectare served, not including additional loads arising from failures of treatment plants or flows bypassing the works during storms, (Rosenkranz & Condon, 1972).

'Requirements for control of pollution from combined sewer overflows are rapidly becoming more stringent. Control of pollution caused by urban storm water discharges is on the horizon,' (Cywin & Rosenkranz, 1971). Documentation of the potential problems of pollution arising from storm drainage (rainwater sewers) started in 1964, (Weibel et al., 1964). A disproportionate amount of street surface pollution is associated with fine dust and dirt particles, and it is significant that concentrations of heavy metals and toxic material are much higher in urban runoff than in domestic sewage. Preliminary findings indicate that polychlorobiphenol concentrations in storm water range between 0.4 and 2 parts per million; BOD ranges between 1/2 and 17 kilograms per kerb kilometre; COD ranges between 4 and 110 kilograms per kerb kilometre; and mercury and lead have been found to range between 0.0055 and 0.085, and between 0.034 and O. 522 kilograms per kerb kilometre, respectively. (Tetraethyl lead is currently an additive in most US petrol).

Very few sewered catchments have been gauged, and these nearly all at outfalls, consequently very little is known about rainf all-runof f-quality processes. Much more investigation must be undertaken.

and ice conditions, results in concentrations of leachates in the soil locally, (Syracuse University, 1971; Edison Water Quality Laboratory, 1971) .

In 1966, the amount of pesticide used in the mainland US amounted to almost one third of a million metric tons of active ingredients. Half this was used by farmers and the remainder by government, industry and homeowners, (Economic Research Service, 1970). Pesticides and herbicides which have been diffused or concentrated throughout the land, air and water pose direct and indirect threats to the health of urban dwellers and the survival of numerous animal species, (Pimental, 1971). One of the first documented studies of pesticides from agricultural land was reported in 1966, (Weibel et az., 1966).

ing a major problem, (Anon, 1971~). The quantities 05 sludge are increasing but potential sitesfor disposal on land are becoming scaxcer as land is required for development, and sea disposal is challenged as a suspected cause of environmental degradation.

treatment, average approximately 90 metzic tons dry weight per day per million persons served. However, slutk~eis often transported as a slurry to disposal sites. Costs of transportation and handling can be lowered by reducing the volumes of slurry by concentration technique. Assuming the maximum concentration that can be hydraulically transported, the minimum slurry load is about 360 metric tons per day, per million persons served. However, normal practice, which reflects reliability of operation as well as cost-attractiveness, results in a slurry of about 900 metric tons per day per million persons served. The magnitude of the sludge disposal problem can be appreciated by noting that this tonnage is in the neighbourhood of half the weight of solid wastes per million persons per day. In contrast to solid waste, wastewater sludge disposal has to cope with very high water and organic content. Consequently, the feasible avenues of disposal generally differ from, and often are more restricted than, those for solid wastes.

daily sludge production in slurry form by barge, to an area about 320 kilometres from Chicago, (Anon, 1972e). The expected increases in sludge from the Chicago area will be disposed of in strip or opencast, mines and farmland reclamation.

The scattering of salt on streets and highways, to facilitate movement of traffic in snow

The disposal of the solid residue from wastewater treatment, (Burd, 1968) is fast becom-

The total amount of municipal wastewater solids, most of which are removed by conventional

Since mid-1971, most of the Chicago metropolitan area has disposed of about half of its

124

PoLZution effects

Several major coastal cities dispose of sewage sludge by barge to the sea. Almost 4 million cubic metres of sludge slurry from the New York metropolitan area are disposed of annually in the New York Bight of the Atlantic Ocean, (Ketchum, 1970; Anon, 1971d).

in surface water drawn for domestic use usually exhibit large seasonal variations (largely by entry of suspended sediments) which can range from small amounts not requiring treatment for removal to concentrations well above those of normal wastewater. Consequently, the seri- ousness of the sludge disposal problem varies among different sections and localities, (Anon, 1969 and 1970). ment plants is 25 metric tons of slurry per million persons served, (Karasauskas, L969).

The disposal on land of effluents from wastewater treatment plant, as an alternative to conventional disposal by water, is receiving greater attention as concern for the control of the quality of surface water grows, (Lewicke, 1972; Evans, 1970).

to mingle with surface water and groundwater. leaching of surface water on its way through deposits of solid wastes is largely dependent upon the character of the immediate geological environment, (Schneider, 1970) but groundwater can be protected by modifying landfill sites, ( Coe, 1970; Zanoni, 1972; Hughes & Cartwright, 1972).

Table 29.

ïn contrast to the relatively constant quantity of solids in wastewater systems, solids

On average, the amount of sludge produced annually from all US water treat-

Wherever solid wastes are deposited on land, there will be opportunities for effluents The extent of pollution of groundwater by the

The estimated sources of total solid wastes produced in the US in 1969 are given in

Table 29. Sources of solid/waste in the USA

Source of waste Million metric tons

Residential, commercial and institutional 230 Industrial LOO Mineral 1 500 Agricultural 2 100

Concentrations of mineral and agricultural wastes are spread widely over the land and are usually isolated from centres of population, although some deleterious effects on urban resi- dents are suspected, and have been documented in isolated instances. The bulk of the other wastes are disposed of in, or near, urban areas and represent an ever-present threat to public health. The space available for the land disposal of municipal solid waste is fast disappear- ing. The integrated management of urban residuals in air and water and on the land is regarded as a necessity for environmental protection in the future, (Council on Environmental Quality, 1970).

land erosion, (Office of Water Resources Research, 1971). Damage is inflicted where soil is eroded, where it is washed downstream, where remains suspended and when it comes to rest.

which is already affected by sediment, but also with controlling the massive amounts of soil being washed into waterways each year', (Powell et aZ, 1970) . There are three broad categories of land disturbance which require to be controlled: erosion of 'natural' or geological character; erosion resulting from agricultural, forestry and mining activities; and erosion associated with suburban development. 'Evidence being made available by current research suggests that sediment yields in areas undergoing suburban development can be as much as 5 to M O times greater than in rural areas.' An estimated 170 O00 hectares of land per year are taken over by urban expansion, (Anon, 1971a).

ity are described quantitatively in Table 30 , (Guy, 1970).

Urbanization and associated human activities have accelerated geological processes of

'Efforts to control sediment pollution must be concerned not only with treatment of water

The sequential effects of various land-uses on relative sediment yield and channel stabil-

125

Pollution effects

Table 30- Sediment yield and channel stability related to land usage

Land use Sediment yield Channel stability

Natural forest or LOW Relatively stable with grass land some bank erosion.

Heavily grazed areas Low to moderate Somewhat less stable

Cropping Moderate to heavy Some aggradation and

Abandonment of land Low to moderate Incre as ed s tabi 1 i ty . Urban construction Ver y heavy Rapid aggradation and

Stabilization Moderate Degradation and severe

Stable urban Low to moderate Relatively stable.

than the preceding,

increased bank erosion.

from cropping

some bank erosion.

bank erosion.

Sediment yields when urban development has stabilized tend to approach precettlement

Sediment from erosion impairs water quality, reduces the volume of water available for levels, (Wolman, 1972) as noted above.

supplies , and damages recreational waters both quantitatively and qualitatively , for example , by accelerating eutrophication. The effectiveness of mosquito control works can be seriously reduced by erosion deposition occurrences. hibited by suspended sediments , resulting in a reduced waste assimilation capacity of water bodies and other deleterious effects, (Task Committee, 1971). The 'importance of sediments as pollutants is increasing, particularly in view of the ability of soil to absorb pesticides and other organics including oily substances and to release these materials in the water resource. Indeed this facility of sediments to receive chemicals from the solution phase, when properly understood, may be subject to manipulation and made to serve effectively to trap and immobilize harmful wastes moving in our environment' , (Office of Water Resources Research, 1971).

main channel deposits can aggravate main stream flooding; bank flooding occurs can cause considerable damage over and above that of inundation; structural integrity of works, such as culverts and bridge piers, can be impaired or destroyed; buildings can be badly damaged or destroyed, and channel flooding can be aggravated by land slides induced by heavy rains, (Rantz, 1970; Guy, 1971; Guy & Earl Jones, 1972).

The removal of deposits of sediment from thoroughfares and other public areas adds to the cost of their maintenance, and the turbidity from mineral and other sediments can make water treatment more difficult.

and the cost of uncontrolled sediment movement is large.

generation has been noted in Section 11-4.6. sumption in the US persists, the present amount will be doubled in about fourteen years. generation of electricity accounts for less than 25% of all US energy consumption, (Ehrlich & Holdren, 1971). Waste heat from the generation of electric power is emerging as one of the most serious sources of water pollution, accounting at present for 80% of all the heat entering the nation's waters, and as generating capacity doubles every decade the heated discharges will also increase, (Council on Environmental Quality, 1970). The total quantity of waste heat discharged in cooling water will more than double from the year 1967 to the year 1980, (Levin et al., 1972). The trend towards larger , nuclear plants, which discharge one and a half times as much heat in water per unit of power as fossil-fuel plants, poses an increased threat to aquatic systems. Among alternatives to the use of water bodies as heat sinks is the use of cooling towers, particularly for nuclear plants. These towers are commonly deployed in Europe but little used in the US, much to the ire of conservationists,

The biological viability of aquatic biota is in-

The problem of eroded sediment can be expressed in terms of public safety: sediment deposited on and in property when over-

Few beneficial effects, if any, can be claimed for erosion in the urban environment,

The significant amount of water abstracted in metropolitan areas for cooling in power- If the present growth rate of total energy con-

The

(Anon,

I26


1971e). Dissipation of residual heat is regarded as a serious problem for future generating plants, (Brown, 1970; Dallaire, 1970; Hauser, 1971) . Considerable attention is being given to the environmental problems Of plant siting, (Committee on Power Plant Siting, 1971) but the root source of these and related problems is considered to be the absence of a national energy policy, (Anon., 1972f).

National energy and water policies will be shaped by overall growth policy. The National Government in 1971 was attempting to determine a national growth policy, (Advisory Commission on Intergovernmental Relations, 1972) and in 1972 it was asserted that 'the time has come for the United States to adopt a deliberate population policy', (Commission on Population Growth and the American Future, 1972). Because most land use decisions are made by private interests and governmental control over land use is fragmented at the local level, better land use planning, at all levels of government, is advocated as a part of overall national policy, (Dreyfus, 1972). Regional bodies with authority to plan and control those facets of land use such as pollution abatement, that transcend local boundaries, (Citizen's Advisory Council on Environ- mental Quality, 1972) are also required.

11-4.10 EFFECTS OF MINING ACTIVITIES

A relatively small number of urban areas are affected by mining activities, and the affected regions exist in only a few part of the US.

Mine drainage constitutes one of the most significant sources of water pollution in the Appalachian region of the central East, in the Ohio River Basin States, and in certain other areas. In Appalachia alone, where an estimated 75% of the coal mine pollution occurs, about 17 O00 kilometres of stream courses have qualities below desirable levels caused by acid mine drainage. Other regions are polluted by drainage. Other regions are polluted by drainage from other types of mining, such as phosphates, sand and gravel, clay, iron, gold, copper, and aluminium, (Council on Environmental Quality, 1970).

and pumping of brine deposits. Some effects of oil development are discussed in Section II- 4. lo.

As stated in 11-4.8 the pollution of streams due to mining is estimated to be 5% of the burden considered in a nationwide context. The local effect varies widely, being small in urban areas but the main contributor in some areas.

To gain perspective of this problem it is worth noting that while the mineral industry withdraws 25% of its water in metropolitan areas, the amount withdrawn by and for the manufacturing industry in similar areas is fifty times as large,

Other adverse effects on quality caused by mining include siltation from scarred lands

(Tucker et al., 1972).

11-4.11 I EFFECTS OF OTHER WATER-BODY USES

Although three quarters of the US population is located in urban areas, only one quarter of public recreation facilities are located there, (Rickert & Spieker, 1971). The incorporation of artificial recreational-aesthetic lakes in some suburban extensions and in new communities, usually as part of private land development is a trend that modifies this distribution to a modest extent, (Rickert & Spieker, 1971).

Lakes, and these waters are among the most valuable of the nation's recreational resources. The discussion of pollution effects in Section 11-4.8 avoided the important question of estuarine-coastal pollution.

are increasing, using larger vessels which need deeper channels. Mining and oil drilling in coastal waters grows daily. Industrial and residential developments compete to fill wetlands for building sites. Airport and highway construction follows and further affects growth patterns in the coastal zone, As a result, natural coastal waters are being nibbled away. In addition to the adverse effects caused by physical alterations of submerged and adjacent lands, pollution of estuaries and ocean dumping of wastes pose further problems. In polluted waters, vast numbers of fish and shellfish are affected as well as numerous birds, reptiles, and other wildlife that are a part of this food chain. Since over 90 per cent of US fishery yields come from coastal waters, the dependence of the commercial fisheries industry upon a stable estuarine system is obvious. ..... The mineral and chemical resources of the sea that will

The majority of people reside in proximity to estuaries, coastal waters and the Great

'Competition for the use of the limited coastal zone is intense. Shipping activities

127

Water balance inventories

be of practical interest to from sea water or recovered .....II (Anon, 1971a). The vide direction for improved

Half the world's ocean

man over the next half centuty are those that can be extracted from the seabed of the Continental Shelf and oceanic rises. Federal Coastal Zone Management Act of 1972 is intended to pro- planning. cargo weight is oil, (UNESCO, 1970). It is estimated that more

than 4 million metric tons of oils is dumped or spilled into the oceans each year. This probably is discharged into coastal waters, the zone where almost all of the oceans' biological productivity occurs and the incidence has risen as oil production has grown by a factor of ten over the past thirty years, (Murphy, 1971). In the US, serious incidents of estuarine- coastal oil pollution from tanker spills have occurred near large metropolitan areas, and ruptured off-shore oil wells have resulted in extensive urbanized portions of coastal shores being defiled. (Navigable waters of the US are polluted by an estimated 10 O00 spills of oil and other hazardous mat rjals annually, and of the approximately one thousand reported oil spills exceeding 12.4 m (100 bbl) that have occurred annually in recent years, most have come from ships, although about 30% involved pipelines, oil terminals, and bulk storage facilities on shore, (Council on Environmental Quality, 1970).

Preliminary estimates indicate that some 44 million metric tons of wastes from the US civilian sector were disposed of at sea in 1968, including:- dredging spoils, industrial wastes, domestic refuse I sewage sludge, construction and demolition debris, and miscellaneous items such as airplane parts.

South-east Florida, (Stewart e-¿ al., 1971) dispose of effluents from wastewater treatment plants of E-shore through pipelines, (Anon, 1961) .

national debate on appropriate disposal methods in 1971 , (Dallaire, 1971) .

Over 301 of the nation's 100 O00 lakes are showing signs of cultural eutrophication, and the danger of accelerated eutrophication continues to grow as stresses on natural water resources increase, (Hasler & Ingersoll, 1968). Of the urban contributions to eutrophication, wastewater effluents from public systems are believed to be the largest in terms of relative production of nutrients per unit of area, (Weibel, 1969). The recreational capacity of lakes is threatened simultaneously by rising demands from urban dwellers for recreational waters, particularly on the Great Lakes where there are many urban concentrations.

The use of the waterfront for all activities is restricted when the quality of the water is poor. Periodic dredging of navigation channels in ports aggravates pollution by increasing water turbidity, (Manga, 1971) and when open-water disposal of dredging spoil, (Cable, 1969) is practised the survival of certain organisms in the disposal areas can be threatened, (Flemer , 1968) . for example, to irrigate parks and green belts, golf courses and landscape areas adjoining highways I (Coe & Laverty, 1972) .

5 -

A number of large coastal metropolitan centres including Los Angeles, (Rawn, 1960) and

Concern over the effects of ocean disposal of waste materials erupted into an intense

Natural and artificial lakes serve as inadvertent sinks for stream-borne contaminants.

Reclaimed water may be used, where there is a scarcity of water, to improve amenities,


There are in excess of eighty thousand units of local government in the US. About 25% of all the metropolitan areas containing the largest populations include four thousand special districts and public authorities I of which about 65% provide water-related services, greatly outnumbering the major municipal water agencies in their midst, (Bureau of the Census, 1968). A continuing ambivalent on thewpart of the National Government on its role in metropolitan areas is helping to proliferate the number of special districts, (Advisory Commission on Intergovernmental Relations , 1972) . Water balance surveys are complicated and often frustrated by fragmented management.

and conflict between multiple authorities have intensified with the growth of metropolitan areas. The variety of uses for water in metropolitan areas is continually increasing, particularly for recreational purposes. Consequently, there is a need for hydrological surveys of urban areas to be brought up to date.

lysis, has been initiated, (Water Resources Engineers, Inc., 1970). This is on a metropolitan scale and covers all aspects of urban water resources. in addition applied follow-up field

The interrelationship and interdependence of water and wastewater, and the competition

The design of a comprehensive simulation model for an engineering-economics systems ana-

128

References

work is being undertaken. In application, the most formidable complication is the amount of data needed for proper systems accounting. This applies to quantities in the water balance and to quality parameters of the components.

and is experiencing continuous urban growth toward its eastern extremity as the distribution of population density of the metropolitan region tends to level out, (Chinitz, 1965) is an instance of a nearly 'closed' hydrological system covering about 3 600 sq km. sulted in it becoming the subject of extensive water-budget studies, (Franke & McClymonds, 1972; Cohen et ai!., 1968).

mental and resource study of the San Francisco Bay area in 1970. In 1971, studies of six other metropolitan areas Connecticut Valley (Hartford, Conn) ; Denver, Colorado; Pittsburgh, Pennsylvania; Seattle, Washington; Tucson-Phoenix, Arizona; and the Washington, DC, -Baltimore, Maryland area were started, (Walling & Murray, 1972). The aim of these studies is to help in the achievement of a balance between the needs for huge amounts of resources and the avoidance of environmental degradation 'by understanding large-scale natural forces and the response of our environment to man's activities. ' In all these areas a considerable amount of resource data had already been obtained by the Geological Survey, and part of the task is to integrate that information on a regional scale, applying 'basic surveys and research in topography, geology and hydrology more directly to the problems of intensive land use and urban expansion than has been done in traditional surveys.' Among the products in the field of water resources will be maps to show:- service areas of water distribution agencies; water-quality data of major streams; effect of land-use on water qality; groundwater recharge areas; sewerage systems; suitability for septic tanks systems; landfill sites both existing and potential; flood-hazard areas; basins, (Hack, 1971).

undertaken over the next few years in response to the emerging needs of metropolitan-area management and will supplement more specialized long-range field work.

ter quality balance is being developed, (Koch, 1972). ref-

erences which include several specific to water resources, (Berlin, 1971). Interest in pollution detection by remote sensing is growing rapidly, (Anon, 1971f; Scherz, 1971). An- other instance of the use of remote sensing is to quantify impervious urban surfaces, (Root & Miller, 1972).

Long Island, which contains at its western end a large part of New York City,

This has re-

The Geological Survey of the US Department of the Interior began a three-year environ-

and the sediment yield of drainage

These examples represent forerunners of the type of comprehensive studies that will be

A hydrological balance has been achieved for metropolitan San Antonio, Texas,and a wa-

A recent bibliograph on the use of aerial photographs and remote sensing, cites

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Office of Water Resources Research. 1971. A national urban water resources research program. us Dept of the Interior, GPO, Washington, DC. Office of Water Resources Research. 1971. 2970 Annual Report. US Dept of the Interior, GPO , Washington, DC.

Owen, Langdon. 1968. Groundwater management and reclaimed water. J. AWWA, 60 (2) p 135. men, Langdon W. 1971. An argument for water-resource management. J. AWWA, 63 (12). Parkhurst, John D. 1970. Wastewater reuse - a supplemental supply. J. Sanitaqi Engng. Z V . BcE Proc., 96, No. SA 3, Paper 7318, p 663. Peters, John H. and Rose, John L. 1968. Water conservation by reclamation and recharge. J. Smitarg Engng. ZV. ASCE Proc., 94, No SA4, Paper 6065, P 639.

1972.

1970. Po2icies for solid

Climatic At2a of the Us. Environ-

Pickard, Jerome P. 1967. Dimensions of metropoZitanism, Urban Land Institute, Research Monograph 14 , Washington, DC 48-53.

Pimental, David. 1971. EcoZogicaZ effects of pestieides on non-target species. Office of Science and Technology, Executive Office of the President, GPO, Washington, E.

Powell, M. D., Winter, W. C. and Bodwitch, W. P. and sediment control. Nat. Ass. of Counties Res. Found., Xashington, DC p 6-3.

Prawdzik, Ted B. 1970. Environmental and technical factors for open drainage channels in Milwaukee. ASCE Urban Water Resources Research Program. Tech. Memorandum 22, ASCE, New York, NY. (NTIS Id. No. PB 191 710)

Rantz, S. E. 1970. Urban sprawl, m d f2ooding in Southern California. US Geol. Survey, Circ. 601-B, GPO, Washington, DC.

Rawn, A. M., Bowerman, E. R. and Brooks, Norman H. 1960. Diffusers for disposal of sewage in sea water. J. Sanitary Engng. Z V . , ASCE Proe., 86 (SA21 Paper 2424.

Rey, George, Lacy, William J. and Cywin, Allen. 1971. industrial water reuse: future pollution solution. EnvironrnentaZ Science and TechnoZogy, 5 (9) 760-765. Rickert, David A. and Spieker, Andrew M. 1971. ReaZ-estate lakes, US Geol. Survey, Circ. 601-G. GPO, Washington, DC.

Root, R. R. and Miller, L. D. 1972. Identifica-t;ion of urban watershed units using remote mUztiSpectYa2 Sensing. Colorado State University , Ft. Collins, Environmental Resource Center Completion Rept. No. 29. (NTIS Id. No. PB 209 639).

Rosenkranz, William A. and Condon, Francis, J. 1972. Technology improvements related to storm and combined sewer pollution control. ASCE National Meeting, Atlanta, Georgia.

omu unity action guidebook for soi2 erosion

134

References

Russell, Clifford S,Arey, David G. and Kates, Robert W. 1970. Drought cmd Water Supply. Implications of the Massachusetts experience for municipal planning. Resources for the Future, Inc. the Johns Hopkins Press , Baltimore , Maryland. Scherz, James P. 1971. Monitoring water pollution by remote sensing. J. Sumeying and igapping ZV., ASCE Proc., 97 (SU 2) Paper 8550. Schneider, William J. 1969. The US Geological Survey urban water program, in Effects of watershed changes in StremfZow. (Ed. W. L. Moore and C. W. Morgan) Univ. of Texas Press, Austin.

Schneider, W. J. and Spieker, Andrew M. 1969. Water for the cities - the outlook. US Geol. Survey, Circular 601-A, GPO, Washington, DC.

Schneider, William J. 1970. Hydraulic implications of solid-waste disposal. us Geological Survey, Circular 601-F , GPO , Washington , DC.

Spieker, A. M. 1969. Urbanization and the water balances, in Proc. symp. u?'l Water Balance in North Amer5cu, Banff, Alberta. Amer. Water Resources Ass. , Proceedings Series No 7 p 185.

Stevenson, Albert H. 1970. Human ecology considerations in water quality management, in Is water quality enhancement feasib Ze? Stewart, Robert H. and Metzger, Ivan. 1971. Industrial water forecasts. J. AWA, 63 (3) p 156.

Sullivan, Richard H. 1968. Inventory of combined sewer facilities Civil Engng. ASCE, 38 (11) 52-53.

Syracuse University. 1971. Street salting - urban water quality workshop. Proceedings , State University College of Forestry, Syracuse , NY - Task Committee. 1969. Saltwater intrusion in the United States. J. Hydyau. L%v. ASCE Proc, 95, No HY5, Paper No 6788 p 1668. Task Committee. 1971. Influences of sedimentation on water quality: an inventory of research needs. J. Hydraulics Z V . ASCE Proc., 97, No. HY8, Paper 8325. Task Committee on effects of urbanization on low flow; total runoff infiltration, and groundwater recharge. 1972. Prelim. Rept. to 'Nat. Meeting, Atlanta, Georgia. Meeting Preprint 1620, ASCE, New York, NY.

Task Force. 1969. Effect of urban development on flood dischaxges - current knowledge and future needs. J. Hydraulics EU., ASCE Proc., 95, No. HY1, Paper 6355, p 290, 292. Task Group. 1963. Design and operation of recharge basins. J. AWWA, 55 (6) 697-709. Task Group. 1967. Artificial groundwater recharge. J. AWWA, 59 (1) 103-113. Tucker, L. S. , Miilan, Jaime and Burt, Wilford W. 1972. ?detropolitan industrial Water use. ASCE Urban Water Resources Research Program, Tech. Memorandum No 16 , ASCE, New York, IUY. (NTIS Id. No. PB 212 578).

Specialty Conf. Proc., ASCE , New York p 66.

US Congress , House of Representatives, Task Force on Federal Flood Control Policy 1966. A -unified nationaZ program for managing flood losses. House Document No. 465. 89th Congress, 2nd Session, GPO, Washington, DC p 12.

US Congress, House of Representatives. 1971. The cost of clean Water. Vols I & II, House Doc. No. 92-23, GPO, Washington, DC.

UNESCO. 1970. UNESCO, Paris.

US Environmental Protection Agency. 1972. Subsurface water pollution , a selected annotated bibliography. Parts 1-111. Office of Water Programs, Washington, DC. (NTIS Id. No. PB 211 340-2).

US Geological Survey. 1971. Program design, 2.971 - San Frandsco Bay region environment and rasources planning study., Washington, DC. (NTIS Id. No. PB 206 826).

impacts of man on the biosphere , in Use and Conservation of the Biosphere,

135

References

US Public Health Service. sewer systems - a prel'hrhry apprdsal. van der Leeden, Frits. 1971. Groundwater - a selected bibliography. The Maple Press, for Water Information Center , Port Washington, NY. Waananen, Arri O. SihwUnfZm (Ed. W. L. Moore and C. W. Morgan) Univ. Texas Press, Austin.

Walling, F. B. and Murray C. R. 1972. Federal research in potable - water technology (Geological Survey) J. AWWA, 64 (10).

1964. Pollution effects of stormwater and overflaws from combined Publ. No. 1246, GPO, Washington, DC.

1969. Urban effects on water yield, in Effects of watershed changes on

Water Resources Council. 1968. The nations water resources. @O, Washington, p 4-1.

Water Resources Engineers , Inc. 1970. Systems analysis for urban water management, rept. for Office of Water Resources Research, US Rept of the Interior. (NTIS Id. No. PB 197 677).

Water Resources Research. 1973. Water Reuse: a bibliography. 2 vols. US Dept. of the Interior, Washington, DC (Vol I, NTIS Id. No. PB 221 998; Vol II, NTIS Id. No. PB 221 999.

Weibel, S. R., Anderson, R. J. and Woodward R. L. 1964. Urban land runoff as a factor in stream pollution. J. WPCF, 36, (7).

Weibel, S. R. 1969. urban drainage as a factor in eutrophication, in Eutrophication: causes consequences, correctiues. Nat. Acad. of Sciences, Washington , DC. Williams, Merlin C. 1971. Status of weather modification in watershed management. J. Irri- gation and Drainage %V. ASCE Proc., 97, No IK 4, Paper 8608, p 599. Wolf, Harold W. 1971. Biological problems with reused wastewater. J. AWWA, 63 (3) p 182. Wolman, Abel. 1965. The metabolism of cities. Sei. Amer, 223 (9) , p 182. Wollman, Nathaniel, and Bonem, Gilbert W. 1971. The out2ook for water - quality, quantity and national growth. Mary land.

Resources for the Future Inc. The Johns Hopkins Press, Baltimore,

Wolman, Abel. 1963. Status of water resources use, control, and planning in the United States. J. AWA, 55 (910) 1255, 1258. Wolman, Gordon M. 1972. The nation's rivers. J. WCF, 44 (5).

Zanoni, A. E. 1972. Groundwater pollution and sanitary landfills - a critical review. Gpoundwater, 20 (1) . Zobler, c. et al. 1969. Benefits from integrated water management in urban meas - the case of the New York metropolitan region. (NTIS Id. No. PB 184 019).

Barnard College, Columbia University, New York, NY.

136

5 Hydrological effects of urbanization in the Union of Soviet Socialist Republics

V. V. Kuprianov

State Hydrological Institute Leningrad

Hydrological effects of urbanization (Studies and reports in hydrology, IS) Paris, The Unesco Press, 1974


II. 5.1 URBANIZATION INDICES

11.5.1.1 On 15 January 1970, the urban population of the USSR was 136 million persons, ie 56% of the total population.

In 2000 the population of the USSR is expected to be 330-340 million persons including an urban population of 240-250 million (72-75%). In 2070, the total population is expected to be 500-550 million, with an urban population of 450 million (90-92'9).

11.5.1.2 The distribution of population in towns of various sizes (Anon, 1971) is given in Table 31 based on the census for 15 January 1970.

Table 31. Urban population in the USSR

Number Total Population of

towns population, mi Ilions

> 1 O00 O00 500 O00 - 1 000 O00 400 O00 - 500 O00 300 000 - 400 O00 200 O00 - 300 O00 100 O00 - 200 o00 50 O00 - 100 O00

9 24 12 23 39 114 i a9

19.10 18.20 5.29 8.08 9.30 15.53 13.00

II.5.1.3 The distribution of urban population in republics and economic regions of the USSR on 15 January 1972 is given in Table 32.

Table 32. Distribution of urban population in the USSR

Republic & regions Population, millions

Per cent of urban dwellers of total population

FGFSR North-Wes t Central Volgo-Vy ats ky

80.98 8.90 19.70 4.40

62 73 71 53

Ts entralno-Che mozemny 3.20 40

North-Caucasus 7.10 50 Urals 10.40 69 Wes t-Siberia 7.40 61 Eas t-Siberia 4.60 62 Far East 4.10 71

Ukranian SSR 25.90 55

Usbek SSR 4.30 37 Kazakh SSR 6.50 50

Azerbaijan SSR 2.60 50 Lithuanian SSR 1.60 50 Moldavian SSR 1.10 32 Latvian SSR 1.50 62

Povolzh je 10.50 57

Byelorussion SSR 3.90 43

Georgian SSR 2.20 48

Kirghiz SSR 1.10 37 Tadjik SSR 1.50 59 Armenian SSR 1.50 59 Turkmen SSR 1.00 4a Estonian SSR 0.90 65

138

139

Water resources and water buZance of the USSR

11-5.1.4 In 1967 the area covered by towns of the USSR was 7.7 million ha, ie, 0.35% of the USSR territory [Kudryavtsev, 1971) .

11-5.2 WATER RESOURCES AND WATER BALANCE OF THE USSR

11-5.2.1 Precipitation

Precipitation over the USSR varies greatly in different areas. In the semi-deserts of Central Asia the annual precipitation sometimes does not exceed 100 mm while in the Caucasus it may reach 4 O00 mm.

Figure 14 illustrates the average annual precipitation for a long-term period.

11-5.2.2 Runoff

There is a greater degree of variation in runoff values compared with variations in precipitation.

Annual runoff ranges from a few parts of a millimetre in deserts to more than 1 500 mm in the Pamir and the Caucasus.

Figure 15 illustrates average annual river runoff of the USSR in mm.

11-5.2.3 Evaporation

The long-term average evaporation over the USSR, computed by the difference between the determined norms of precipitation and runoff, is given in Table 34. The values obtained include evaporation from land and from the surface of lakes and reservoirs. In the calculation an allowance was made for that part of the precipitation that went to groundwater store.

11-5.2.4 Water resources and water balance of the Soviet Union

Because of the great variety of physiography that exists in the different regions of USSR, precipitation, river runof£ and evaporation in time and over territory, vary considerably. However, because the mean annual water balance components for large areas for long-term periods are reasonably stable, it is possible to establish general laws describing their distribution over the study area.

The total water resources of the rivers of the Soviet Union Table 33 eq al 4 714 km per year, a volume which is drained from the USSR territory of 22 272 O00 km . On average, 198 thousand m3/year per km2 falls on the USSR. The lesser total river runoff is an indication of the average water resources of the USSR recovered yearly. It does not include long- term water storage in lakes , swamps , glaciers , high-mountain ice-fields and also sub-channel and deep underground waters that are not drained by rivers.

3 11

A water balance of sea basins is shown in Table 34.

I40

w O

Ici W O c 5 !4

141

142

Water resources and water balance of the USSR

Table 33. Water resources of USSR rivers

Water resources

Per cent of thousand m3 Area

km3 thousand km2 Republic

national total per km2

Russian Federation 17 075.0 4 003.00 91.3 234 Ukranian SSR 601 .O 49.90 1.1 83 Moldavian SSR 33.7 O. 81 0.1 21 Byelorussian SSR 207.6 36.40 0.8 175 Estonian SSR 45.1 11.70 O. 3 259 Latvian SSR 63.7 17.10 0.4 268

, Lithuanian SSR 65.2 15.30 O. 4 234 Georgian SSR 69.7 53.60 1.2 769 Azerbaijan SSR 86.6 8.71 0.2 131 Armenian SSR 29.8 6.50 0.1 2 18 Kazakh SSR 2 715.0 64.80 1.5 24 Uzbek SSR 449.6 11.10 O. 3 27 Kirghiz SSR 198.5 52.80 1.2 274 Tadjik SSR 143.1 51.20 1.2 35 8 Turkmen SSR 488.1 1 .o0 0.1 2

Total USSR 22 272.0 4 384.00 100 .o 19 8

Table 34. Water balance of the Soviet Union in terms of sea basins

Water balance elements, km3 Runoff

cient

Area, Sea basin coeffi- thousand km2 Precipita- Runoff Evapora- ti on tion

White & Barents seas 1 192 8 46 408 438 0.48 Baltic Sea 661 506 171 335 0.34 Black & Azov seas 1 347 889 159 7 30 0.18

Kara Sea 6 579 3 640 1 324 2 316 O. 36 Laptev Sea, East

Caspian Sea 2 927 1 440 300 1 140 0.21

Siberian Sea and Chuckchee Sea 5 048 2 135 1038 1097 0.49

Bering Sea, Sea of Okhotsk and Sea of Japan 3 269 2 126 890 1 236 0.42

Endorheic areas of Kazakhstan and Cen tual As i a 2 420 72 3 125 59 8 0.17

Total runoff losses by evaporation, infiltration and unreturned water withdrawal in arid regions of the USSR - 150 -

Total for the USSR 22 013 11 694 4 358 7 482 O. 36

I43

Climate of towns

11-5.2.5 Water Use

The use of water in towns (municipal needs) averaged 170 litres/day per capita in 1968. jected per capita water use is expected to be 400 to 500 litres/day. half of the water for municipal needs is obtained from subsurface water, but in the future this will rise to @-go%.

Pro- At present, more than

Table 35. Mean daily delivery and water use per capita for some towns (Dekhtyavev, 1968; Markizov, 1969; Novikov, 1971; Panov, 1969)

Towns Mean daily water

delivery, thousand m3

Water use per capita, litre/day

Mos cow Leningrad Sverdlovsk Kiev Kharkov Dniepropetrovsk Odessa LVOV

5494 39 40 4 80 69 7 358 2 50 324 115

438 374 185 3 70 189 226 2 39 159

Table 36. Water use for national economy (Anon, 1970a)

km3/year Waters users

Delivered Unreturned

Domes ti c us age 6 2 Industry 27 2 Cooling water for electrical generation 30 1 Irrigation 120 90

Fishery 8 1 Agricultural water supply 7 6

The Data given in Table 36 are approximate and will be changed as the inventory of water use is improved and more precise methods for the estimation of unreturned losses are developed.

11-5.3 CLIMATE OF TOWNS

The climate of towns differs greatly from the climate of surrounding areas, due to the following :

(a) air pollution in cities; (b) change of the earth's surface by building; and (c) change of heat characteristics of the earth's surface.

Data on mean changes of meteorological elements caused by urbanization extracted from WMO information were cited earlier. ZISSR with respect to the order of possible changes.

mese data may also be applied to the towns o£ the Naturally, averaged data cannot

I44

Runoff from urban areas

characterize the climate of a particular town although they can give indication of possible changes. Actual values of such changes can be established only by direct observations under particular conditions.

The climate of towns is studied intensively in the USSR. Network observations and special microclimatic investigations provide data for the study of urban effects on radiation balance , air temperature , cloudiness, precipitation , etc. Results of fundamental investigations of the climate of some towns, (eg, MOSCOW, Leningrad, Riga, etc) have been published.

solar radiation. The coefficient of air transparency in towns is 3 to 5% less than that of the surrounding area. For a clear sky, the daily income of direct solar radiation in towns is 10% smaller in summer and 15 to 30% smaller in winter than in the surrounding areas. The reduction of total radiation for an overcast sky is approximately the same.

The radiation balance of the underlying surface in towns is higher due to smaller values of albedo.

The effect of urbanization on precipitation and evaporation is of great interest hydrologically .

On average, precipitation is 10% greater in cities than in the environs (Dmitriev & Bessonov, 1969; Temrikova, 1962). Of course, the increase of precipitation may vary greatly according to specific conditions of a city. It is known that in the centre of Bremen precipitation was 16% greater (using a 15 year average) than in the port 1.5 kilometres away from the centre. In Moscow during 1910-1962, precipitation was 11% greater than in the neighbouring localities. A considerable increase in precipitation is observed in Stockholm, Hong Kong, Munich, Prague, Vienna and other cities. The number of rainy days, mainly those with light rains, is also greater in cities, being 10% greater in the summer and 20% greater in the winter.

a first approximation, it might be assumed that the difference in evapotranspiration from urban and rural areas lies within the limits of observational accuracy. Evaporation in cities potentially might be higher due to the greater amount of heat and larger area of evaporation surface.

In big towns a considerable amount of dust in the atmosphere substantially reduces direct

Evaporation data from urban areas are rather limited and contradictory. Apparently, as

However, there is less moisture in towns due to greater runoff coefficients.

11-5.4 RUNOFF FROM URBAN AREAS

Runoff in urban areas differs markedly both quantitatively and qualitatively from runoff in natural watersheds. Changes have been observed in the volumes of annual maximum and minimum runoff, and volume of runoff, as well as in the relations between surface and subsurface components of hydrographs.

Natural water r5gime and water quality may be disturbed in large areas and water bodies beyond the boundaries of urban areas. Modern towns , where intensive transformation of water balance elements is observed, occupy areas of dozens and sometimes thousands of sq km. Be- side climatic factors, there are a number of other factors influencing the water balance of urban territories. For instance: -

(a) income of water influencing water exchange from beyond the boundaries of the local

(b) large areas of impervious surface due to buildings, asphalted streets, various watershed (to satisfy municipal and industrial needs) ;

industrial structures , etc. , preventing infiltration and causing large values of runoff coefficients;

and subsurface basins in the given watershed or beyond its boundaries. (c) drainage and sewerage systems which discharge surface water into water bodies

Annual runoff from urbanized territories may be greater by lo%, or more, than that from rural areas. This is explained by the greater amounts of precipitation and higher runoff coefficients. Maximum discharges of normal rainfall floods may be several times greater than in natural watersheds. Absolute flood values, aside from considerations of amount and intensity of precipitation, depend on the extent of areas of impervious surface and on the hydraulic capacity and the condition of the sewerage system.

145

Water quality

11-5.5 WATER QU?iLITY

The influence of urbanization on natural water quality mainly depends on the Eollowing factors :

(a) release of wastewater from industrial enterprises situated within urban areas; (b) release of municipal wastewater; (c) contamination of precipitation water; (d) pollution of surface runoff from urban areas.

The release of industrial wastewater should be considered separately since this problem is not regarded as the direct consequence of urbanization.

Apart from industry , urbanization leads to pollution of the environment, which is closely connected with the number of inhabitants and the size of an urban area. In cities the volume of sewage water may range from several dozens to hundreds of thousands of m3 per day. Depending on the water content of the city river, sewage water can constitute a considerable portion of its natural runoff.

The release of sewage water may influence considerably the biochemical qualities of the natural water in an urban area. The sharpest increase is observed in the content of dissolved and suspended organic substances, biogenic elements and dissolved gasses. The extent of bichromatic oxidation of water , which characterizes the total content of dissolved organic matter subject to oxidation, may become four times greater. Approximately the same rise is observed in the biochemical need for oxygen. The content of nitrogen and phosphates increases 3 to 10 times.

oxygen content is reduced to 30-70% of saturation near sites of sewage water discharge.

which are widely used in domestic washing. Such substances make water quality considerably worse and cause foam formation which seriously hinders the work of the sewage and water- supply systems.

As to the gas content, marked changes are observed in the amount of dissolved oxygen.

One of the specific types of water pollution is that produced by synthetic substances

11-5.5.1 The influence of surface runoff from urban areas on water quality

Until recently, due attention was not paid to this pollution problem and watex discharging from streets into storm water drains was regarded as relatively clean. Special investigations (Lvovich, 1964) showed that this water contained a substantial amount of organic and mineral substances, washed out of the atmosphere and from the surface of urban areas.

Due to ail- pollution , precipitation falling on urban areas contains rather complicated solutions of salts, acids and organic matter, and also includes a variety of suspended particles.

1964) , precipitation falling on a sq km of the earth's surface over a year brings 5 to 15 tons of dissolved matter in rural areas and 20 to 30 tons in urban areas.

surface of urban areas is equivalent to 8-15% of the corresponding vaLues of pollution of municipal sewage water which form at the same place.

According to computations in the USSR, on the basis of observational data (Lvovich,

The total amount of pollutants discharged into water bodies and water courses from the

11-5.6 POLLUTION AND SELF-PURIFICATION OF WATER IN RIWñS , LAKES AND RESERVOIRS

The influence of urbanization on water quality also depends on the type of natural water body receiving the sewage water and on the conditions of its self-purification.

At present, when making plans for water management and water quality control it is essential to take into account not only the possibilities of improving sewage water purification but the self-purification which takes place in water bodies as well. This will provide on the one hand a better outline for the development of productive forces within individual countries and regions, and on the other hand permit a more rational use of water resources.

tion of natural water bodies. In this case it is important to study not only the rate of It is essential to make a detailed field investigation of pollution and self-purifica-

146

Re ferences

pollution of the water body as a whole, but to investigate in detail the zones of pollution in reservoirs , and to evaluate the conditions of self-purification within these zones. Using field investigation data in hydrological and hydrodynamical computations , it is possible to develop general and specific recommendations to improve water quality and to regulate water use.

lem of man's influence on the hydrological environment, especially on surface water quality, are observational studies of water pollution , and the development and improvement of general theoretical models of pollution and self-purification processes. These models should be regarded as a basis for the improvement of existing computation methods and for the development of new ones.

Application of the techniques of hydrological investigations and a detailed study of individual factors depend on the hydro-meteorological regime and location of the water body under study.

water pollution consequences and inadequacies of sewage and purification works, as well as for the development of mthods for computation of self-purification and for verification of exis ting techniques.

In the USSR, the most popular and well-developed methods of computation of wastewater dilution in rivers, lakes and reservoirs are based on the general differential-equation of turbulent diffusion. Design methods have been developed for steady and unsteady diffusion. Detailed methods have been developed for the dilution of polluting admixtures in rivers, characterized by both high and low rates of mixing. Special methods have been developed for lakes and reservoirs to take into account the pollutant storage at the discharge site, its transference and diffusion. It is planned to study the possible effect of wind-wave turbulence on dilution. Supplementary design considerations make it possible to analyse the de- composition of destructable substances and settlement of suspended pullutants , and to obtain characteristics of recurring water pollution due to the disturbance of polluted sediments caused by hydrodynamical effects.

for the practical estimation of pollution and self-purification in rivers, lakes and reservoirs (Anon, 1970b). This publication presents an analysis of the following problems:

Awng the most important tasks of a programme of international co-operation on the prob-

Actual results obtained may be used for economic planning, for timely prediction of

In the USSR, the State Hydrological Institute has developed and published recommendations

(1) classification of water bodies with respect to conditions of wastewater dilution; (2) recommendations on how to select a method for estimating dilution for different

(3) selection of the initial hydrological values and hydraulic elements necessary for

(4) description of detailed and simplified methods for estimation of wastewater dilu-

ways of discharging wastewater;

the estimation of dilution in rivers, lakes and reservoirs;

tion in rivers , lakes and reservoirs.

11-5.7 REFERENCES

Anon , 1970a. ' Gidroenergetica i kompleksnoye ispolzovanie vodnykh resursov SSSR' (Hydro- energetics and complex usage of water resources in the USSR) . Moscow , 'Energia'. Anon , 1970b. Prakticheskie rekomendatsii PO raschetu razbavleria stochnykh vod v rekakh , ozerakh i vodokhranilishchakh (Practical recommendations for the computation of dilution of sewage water in rivers, lakes and reservoirs) , Hydrometeorological Publishing House , Leningrad. mon , 1971. Chislennost , razmeshchenie , vozrastnaya structura , unrovon obrasovania , matsio- ralny sos tav , yazyki i is tochniki srodstv sushchestvovania naselenia SSR podanaym Vsesoyuxnoy perepisi nesslenia 19709. (Size settling, age structure , standard of education, national bodies , languages and means of subsistence of the USSR population according to the ALL-Union Census of 1970) . Moscow , Statistics. Dekhtyarev A. P. 1964. cities) , Moscow, 1968. and keep clean the reservoirs of the capital) , Goredskoe khoz-vo Moskvy, No.5;

Voprosy vodosnabzhenia krupnykh gorodov (Problems of water supply of Basaev I.A. Berech i solerzhat v chistots vodoemy stolitsy (Conserve

147

References

Kudryavtsev A. O. 19 71. Ratsionalneye Ispolzovanie territoriy pri planirovke i zastroyke gorodov SSSR.

Lvovich A. I. 1964. Rol zemledelcheskikh polei oroshenia v okhrane vodnykh resursov ot zagriaznenia stochnymi vodami (The role of agricultural fields affected by irrigation in the conversation of water resources from the pollution by sewage water. In: Ochistka i ispolzovanie stochnykh vod i promyshlennykh vybrosov. Kiev.

Makizov V.I. 1969, Sovershenstvovaniya proektirovania i stroitelstva golovnykh voùoprovo- dnykh i kanalizatsyonnykh soorushenyi MoskVy, Moscow, p. 19. Improvement of projects and construction of main water pipe-lines and sewerage structures in Moscow.

Novikov M. G. O merakh dalneyshego ulutshenia vodesnabzhenya Leningrad, dcrklad nautshno- teknitsheskey konferentsii LNIIAKKH, sb. deklaüov, Leningrad, 1971, pp. 57-60. On arrangements of further improvement of water supply in Leningrad.

Panov P. G. Blagoustroystvo naselennykh mest, Sverdlovsk, 1969, p. 140. (Improvement of populated areas) . Temnikova H. S. 1962 Klimat Rigi i Rishskoga vzmoria (The climatte of Riga and its sea-shore). Hydrometeorological Publishing House, Leningrad,

(National exploitation of land while planning and building towns in the USSR). Moscow, p.8.

148

Part III Illustrative special topic studies

111-1

111-2

111-3

111-4

111-5

CONTENTS

111-6

Urban runoff

111-1.1 111-1.2 111-1.3 111-1.4 111-1.5 111-1.6 111-1-7 111-1.8 111-1.9

Introduction Land-use changes Morphological changes in drainage Changes in flood characteristics Flood mitigation versus the amenities of drainage Some management possibilities Research status and needs Other,developments and considerations Ref er ences

Effect of lignite mining on the urban water cycle in the Federal Republic of Germany

111-2.1 Introduction 111-2.2 The lower Rhine open mining area 111-2.3 Mining of lignite, its use and some problems 111-2.4 Water management in opencast lignite mining areas 111-2.5 Conclusion 111-2.6 References

Effects of industrial waste water and sludge on the self- purification of rivers in the Federal Republic of Germany

111-3.1 Introduction 111-3.2 Biological self-purification 111-3.3 Study of natural self-purification and its interference

111-3.4 Practical effects on natural self-purification in the

111-3.5 Potential measures for prevention or reduction of inter-

111-3.6 References

effects

River Rhine

ference with self-purification

Some aspects of ‘solid waste disposal in the Federal German Republic

Waste water dilution in rivers, lakes and reservoirs

111-5.1 Introduction 111-5.2 Types of water masses with respect to sewage dilution

111-5.3 Selection of method to compute dilution for rivers and

111-5.4 Selection of initial hydrological values and hydraulic

conditions

reservoirs for different ways of discharging waste water

elements necessary for calculation of dilution in rivers, lakes and reservoirs

111-5.5 References

Synthetic detergents and water quality in the United Kingdom

111-6.1 111-6.2 111-6.3 111-6 -4 111-6.5 111-6.6 111-6.7

Introduction Detergent concentration at sewage works Detergent concentrations in rivers Eutrophication and effects of phosphates on water quality Boron in sewage effluents and rivers Enzymes in washing powders Other constituants

153

177

193

211

219

229

111-6.8 References

111-7 Effect of opencast mining on the water balance of an area

111-7.1 Introduction 111-7.2 Kursk Magnetic Anomaly territory 111-7.3 Conclusions 111-7.4 References

111-8 Water management in the Netherlands and the effects of urbanization, with particular respect to runoff, in polder areas

245

251 111-8.1 Introduction 111-8.2 Changing aspects of water management 111-8.3 Climate 111-8.4 Drainage and drainage requirements 111-8.5 Hydrological effects of the rain storms on the

111-8.6 Summary 111-8.7 References

1st and 3rd August 1972

1 Urban runoff

M. B. McPherson

American Society of Civil Engineers Marblehead, Massachusetts

U.S.A.


Introduction

III. 1.1 INTRODUCTION

This chapter deals with some of the principal aspects of surface runoff in urban areas of the United States of America (USA) . The reader is referred to the companion report, Chapter 6, Part II, for supplementary information related to the subject.

Flow in urban drainage conduits is principally by gravity. As in natural drainage basins, smaller sewer branches unite with larger branches, and so on, until a main sewer is reached. The smallest catchment area, in the order of a fraction of a hectare in size, is the tributary to a street inlet. For most smaller tributary areas in the upper reaches of an urban drainage system, the time required to reach peak runoff after the beginning of a storm is a matter of only a very few minutes. Hence, high-intensity, short-duration con- vectional rainfall is normally the main type of precipitation contribution to the largest runoff rates found in the majority of US metropolitan areas. However, pollution loads are also a function of land-management practices and antecedent precipitation, and maximum loads might not coincide with maximum runoff. Further, because all pollution loads are of concern, the effect of cyclonic storms cannot be ignored.

Rainfall interception by vegetation seldom has an important effect on the magnitude of urban runoff. Most soil infiltration-capacity curves approach a steady, minimum rate after one or two hours and the capacity of vegetation cover may be several times as great as for a bare soil. Antecedent precipitation can affect soil infiltration capacity but very few quantitative data are available for evaluating this factor.

Some of the precipitation which reaches roofs, pavements and other impervious surfaces is trapped in the many shallow depressions of varying size and depth present on practically all urban surfaces. There have been no field measurements of depression storage because of the obvious difficulties in obtaining meaningful data.

"he residual or excess precipitation remaining after infiltration and depression storage have been removed is available for detention, the storage effect of overland flow in transit. Overland flow refers to unsteady state surface runoff across a sloping-plane surface, which occurs over extensive portions of an urban area in conjunction with storm occurrences. ûver- land flow from the land is usually collected in street gutters or ditches which in turn are drained by street inlets. Additional storage effects occur in the gutters or ditches. Con- siderable research attention has been accorded to the development of inlet hydrographs but progress has been handicapped by a scarcity of suitable field data.

Flow from the surface enters underground systems of conduits at street inlets. The volume of üetention in a conduit can effect a reduction in the peak rate of flow of an input hydrograph in the same basic way as any detention storage attenuates an inflow hydrograph, and storage routing can be applied to estimate conduit system hydrographs when estimated inlet hydrographs are used. Advances in conduit routing capability are outpacing reliable data for monitoring the suitability of techniques developed. This is not to say that the advances have not been significant but only to emphasize a disadvantage that is encountered univers ally .

A simplified description of the major components of the urban storm water disposal physical subsystem is shown schematically in Figure 17 (American Society of Civil Engineers, 1969a). In a given instance, either or both of the two components indicated by dashed lines might be absent.

Whereas there is a continuum between the subsystems of water supply, water use and waste water reclamation, storm water has long been regarded as a nuisance and its subsystem has seldom been deliberately connected to the other urban water subsystems.

Historically , urban settlements have been drained by underground systems of sewers that were intentionally designed to remove storm water as rapidly as possible from occupied areas. Substantial departures from that tradition are required by the new national priorities of enhancement of urban environments , conservation of water resources and reduction in water pol lution.

is intimately related to the acknowledged urgency of aesthetic enhancement , expansion of recreational opportunities and extraction , the availability of waterfronts for public uses. Runoff is a carrier of wastes, either in the course of conversion from water supply to water- borne sewage or in flushing urban ground surface. Thus, public health considerations can transcend or temper economic considerations. In addition , comprehensive approaches for

Increasingly the greatest public concern will be on the quality of water. This concern

154

f A

-b

-b --i

z

155

LancZ-use changes

managing water pollution problems require that other water uses , planning, and sound development, also be considered (Advisory Committee on Inter-governmental Relations 1962) . I.or example, utilization of the 'blue-green' development concept, which employs ponds with open space for storm water detention and recreation, can enhance the value of urban property and decrease the depreciation rates of property , thereby increasing long-term local government revenues (Jones 1967). On the other hand, Jones also points out that peak drainage runoff rates can be reduced by proper land-development design. The guiding principle is to reduce the liabilities and increase the assets of urban runoff (Thomas & Schneider 1970).

ulation served by public waste water collection systems) is served by combined systems of sewerage (Sullivan, 1968). Overflows from combined sewers are thought to comprise a significant source of stream pollution (US Public Health Service, 1964). Combined sewers have the dual functions of removing ephemerally occurring storm water from urban surfaces and conveying waste water on a perennial basis. Conduit size is governed by storm drainage requirements since the capacity requirements for waste water are comparatively small. For all but the relatively few days a year that storm runoff occurs, the continuously flowing waste water is intercepted near the combined sewer outfall by means of a regulating device which diverts it to the treatment plant via an 'interceptor' sewer. Most storm flows are much too great to be accommodated by interceptors, and almost all the waste water burden is discharged through the outfall to the water course when rain storms are heavy and prolonged. At the same time, sludge and debris that have been stranded in combined sewers during relatively low rates of flow in preceding dry-weather periods are scoured from the laterals and trunk sewers of combined systems and are transported by the augmented flows and eventually discharged to a water course. It is estimated that, in consequence, as much as 5% of the annual flow of sewage, and 20 to 30% of the annual volume of solids, are discharged to water courses from combined systems (American Society of Civil Engineers, 196913).

that from combined sewer overflows. The US Environmental Protection Agency advised in 1971 that requirements for control of pollution from combined sewer overflows were rapidly becoming more stringent and that control of pollution caused by urban storm water discharges was on the horizon (Cywin et al, 1971). More recently, the US Council on Environmental Qua- lity (1971) has noted that the contribution of pollution from runoff sources is even greater than had been suspected, from both urban and non-urban sources. When abatement of pollution from storm water conveyed by separate systems of storm drains is attempted, the difficulties to be overcome may be more severe. 'ibis is because all such storm water must be passed through new and special treatment facilities, there being no interceptor sewers in separate storm water systems to divert small storm flows to perennially operated waste water treatment plants as in combined systems.

There is widespread intexest in multi-purpose drainage facilities that exploit opportunities for water-based recreation, provide more effective protection of buildings from flooding, and allow for the use and re-use of storm water for water supply. All these requirements need storage facilities and special treatment plants, together with some kind of control system able to manage the sudden and brief impact of storm water. The scale of the problem is almost overwhelming: most of the larger metropolises have well over a hundred catchment areas and cumulative drain lengths of several thousand kilometres in length. The difficulties to be overcome were compounded by the 1972 Amendments to the Federal Water Pol- lution Control Act which established a national goal of zero-pollution.

For historical reasons, about 20% of the nation's population (or, about 60% of the pop-

Pollution from storm sewer discharges (Weibal et al, 1964) may be almost as severe as

111-1.2 LAND-USE CHANGES

Much of the land occupied by metropolitan areas has been drastically altered by urbanization, particularly in large central cities. For example, the distribution of land use in the City of San Francisco is estimated by the City's Department of Public Works (1971a) as follows:

Res i den tia 1 Streets

C1 as s i f i cati on Percentage of

Total Area of City

30 25

156

Land-use chánges

public (about half recreational) 23 Vacant 8 Comercial 5 Indus trial 5 utility 3 Ins ti tutional 1

Distribution of land use between a city centre and its contiguous metropolitan area can differ apreciably. For example, the proportion of land occupied by residences is commonly higher in the suburbs. Furthermore, there is considerable variation in land use from one metropolis to another. Contributing to this variability are dissimilarities in growth rates. Ranges in land use among seven of the largest US metropolises are given by Abrams (1956) follows :

as

Land Use Minimum Portion

Maximum Portion

1/2 1/3

Residential u 3 Roads and Streets 1 /6 Open Space and Recreation 1/20 1 /4 Commercial, Industrial, Institutional and Mass Transportation 1/8 3/10

Urban expansion absorbs an estimated 170,000-hectares of land each year in the US (Dept of State, 1971). Metropolitan suburbs will be particularly hard-pressed to expand all public facilities in the face of a doubling in residential construction expected for this decade (Anon, 1969a). Nationally, suburban populations of metropolitan areas had surpassed those of the surrounded central cities by 1970, and this sprawling trend is expected to continue. Of considerable importance to urban runoff management is the usual rapid decline in population density with distance from the densest centres. For example, in 1960 the urban population around the City of St. Louis was one-fifth larger than that of the City but distributed over four times as much land area (Advisory Commission on Inter-governmental Relations, 1969).

Buildings, streets and other urban land cover inhibit the access of precipitation to the soil. The presence of extensive impervious surfaces is thought to be the main reason why the total volume of direct storm runoff from urban areas is generally greater than for comparable non-urban catchments (Task Force 1969). For example, greatly increased volumes of direct runoff associated with urbanization growth have been documented for some streams in Long Island, New York (Franke and McClymnds, 1972). Although an indirect indication, evidence has been given of a correlation between the degree of imperviousness and the post-urban enlargement of stream channels for a number of small watersheds in the Philadelphia metropolitan area (Hammer, 1972).

The Soil Conservation Service (1971) gives estimates of imperviousness ranges for typical urban development as €allows:

Land Use % Imperviousness

Low density residential Medium density residential High density residential Business -conmerci al Light industrial Heavy industrial

20- 30 25-35 30-40 40-90 45-65 50-70

Another estimate of imperviousness for typical urban development has been made (by Stankowski (1972)) :

157

kforpho logica l changes in drainage

Land Use

Single -f amily res i denti al Multiple-family residential Commercia 1 Indus trial Public and quasi-public

% Imperviousness Low Intermediate 9 - 12 25 60 70 80 90 40 70 50 60

40 80 100 90 75

Thus, it is not uncommon to find individual central city catchments that are almost entirely covered by impervious surfaces and outlying suburban catchments with as little as 10% impervious cover. It follows that the effect of imperviousness on direct storm runoff volume can vary over a considerable range from one urban catchment to another.

characteristics are closely related to population density. For the State of New Jersey, Stankowski (1972) finds that urban and suburban land-use

111-1.3 MORPHOLOGICAL CHANGES IN DRAINAGE 2

Figure 18 indicates the diminution of tributary channels over a 53-year period in a 68-km section of Maryland of the Rock Creek watershed, now a heavily populated suburban area adjacent to Washington, DC. In 1913 this section was rural, with many small tributaries fed by springs and seepages, most of which were covered over as storm sewers were installed. Of the 103 km of natural flowing stream channels that existed in 1913, only 42% could be found above ground in this section in 1966.

surprising to find that the total lengths of underground drainage conduits dwarf those of open water courses in major cities. of Milwaukee as at the beginning of 1970 were given by Prawdzik (1970) as follows:

There are over 300 O00 km of storm and combined sewers in the US; it is therefore not

For example, total lengths in the 246 km2 of the City

Lake front length - 13 km River lengths - 60 km Combined sewers - 885 km Storm sewers - 1 320 km

(In addition, there were 1 105 km of sanitary sewers).

Further examples of the density of underground conduit drainage in some major cities Ratios of total sewer length in km to City area square kilometres are given in Table 37.

range only between 8 and 18, except for Los Angeles which makes much more extensive use of open channel drainage than the other cities cited. Also shown in Table37 are ratios of total sewer length in km to the 0.6-power of the city area in km2 , ranging between 81 and 136, except for the low value of 20 for Los Angeles. The corresponding ratio would be only about 2 for river and stream channels (Leopold et al, 1964) tending to support the notion that subsurface storm drainage systems mostly replace the smallest natural channels.

the natural streams passing through major urban areas, as implied by the examples in Table 37. sys tems replace mostly the smallest natural channels, because natural catchment boundaries tend to be preserved when subsurface drainage systems are provided.

A survey of combined sewer sizes in major cities revealed that an average of 70% of cumulative city system lengths are 60 cm or smaller, and that this ratio increases for smaller cities (Hallmark et aZ, 1967). Because their design capacity criteria are very similar, it seems safe to conclude that an average of at least 70% of total system lengths of both combined and storm sewers are 60 cm or less in size. The typical design capacity (American Society of Civil Engineers, 1969~) of a 60 cm storm or combined sewer is not much more than about 0.3 m3/sec, indicating that the bulk of storm drainage systems convey very modest rates of flow, again confirming that because the majority of catchments are of small size and therefore collect mostly storm sheetflow , they replace mainly fringe tributary natural channels.

The catchment sizes of sewered drainage areas are generally much smaller than those of

The small median sizes further substantiate the contention that underground drainage

I CHEVY CHASE /-

Figure 18.

w m \

2 5

z U

LL LL O Z 3 E

Z n a f I z ì2 -z a

-I J

[L

Reduction of tributary channels due to urbanization.

RAI N F A L L 7 I I I I I I I I I I

I I I l I I l I I I I I I I I I I I l I

\ \

\ \ \

TIME FROM BEGINNING OF RAINFALL, MINUTES

I

Figure 19. Hyetograph and hydrograph of storm on 4 August 1965 for 19 hectare Northwood drainage area, (after Tucker, 1968).

I59

TABLE 37

DENSITY OF UNDERGROUND DRAINAGE CONDUITS IN SOME MAJOR CITIES

Total length of storm and/or

Area of city combined sewers L/A L/Ao;600. - City A, Km2 LI fi Km/Km2 Km/(Km )

a Bos ton, Mass. Chicago, 111.~ Detroit,

Mich.a Los Angeles,

Cal .b Milwaukee,

Wis. .New York,

N.Y.d Philadelphia,

Pa.e Saint Louis,

MO.^ San Francisco,

Cal. a WashingtDn,

D.C.a

124 580

360

1 191

246

829

337

160

114

15 8

2 190 5 786

4 656

1 389

2 205

6 650

4 023

1 796

1 400

2 816

17.6 10.0

13.0

1.2

9 .o

8 .O

12 .o

11.2

12.3

17.8

121 12 7

136

20

81

118

12 2

85

82

135

a: Hallmark, Dasel E. , and John G. Henrickson, Jr. , Study of approximate lengths and sizes of combined sewers in major metropolitan centers , ASCE Combined Sewer Separation Project, Technical Memorandum No. 4, ASCE, N.Y. , N.Y. , May 1, 1967. (NTIS Id. No. PB 185 999).

b: Bauer, W. J., Economics of urban drainage design, Journal Hydraulics Division , ASCE Proc., Vol. 88, No. HY6, Paper 3321, November, 1962.

c: Prawdzik, T. B., Environmental and technical factors for open drainage channels in Milwaukee, ASCE Urban Water Resources Research Program, Technical 14emorandum No. 12 , ASCE, N.Y. , N.Y., February, 1970. (NTIS Id. No. PB 1.91 710).

d: (Unpublished notes of ASCE Combined Sewer Separation Project, November 15, 1967).

e: Radziul., J. V. , C. F. Guarino and W. L. Greene, Combined sewer considerations by - Philadelphia, Journal Sanitary Engineering Division , ASCE Proc. , Vol. 96 , No. SA1, Paper 7050, February, 1970.

i 60

Changes in f Zood churueteristics

Table 38. Storm water drainage-catchment area-size distributions for some major cities,(Tucker, 1969a).

Total Area Largest Average Median

of area , area , are a, of City, Number drain age drainage dr ainagd

City Km catchments hectares hectares he ctares 2

San Francisco , Cal. 114 42 1 750 227 77

Washington, D.C.

Milwaukee, Wisc.

158

2 46

93 2 500 152

465 740 39

26

10

Houston, Texas. 1 150 1 283 1 030 26 2

111-1.4 CHANGES IN FLOOD CHARACTERISTICS

Although the majority of storm drainage conduits have small hydraulic design capacity and usually serve only small tributary areas, because they are so numerous, they are responsible, together with the larger catchments, for draining most of the metropolitan surface areas. For example, from 70% to 90% of the total areas of Milwaukee, Washington, San Francis0 and Philadelphia are drained by sewered catchments , compared with only about 30% of Houston (Tucker 1969). Because very few flow gaugings have been made at conduit outfalls over hydrologically significant pexiods, there are few, if any, trustworthy generalizations that can be made about sewered catchment flooding. useful data has been secured from stream gauges on catchments that have undergone varying degrees of urbanization. Examination of data and of the results of various studies has indicated that the most dramatic hydrological impact of urban development is that on peak flows, where the basin lag time (or time of concentration) 'is reduced as an area becomes urbanized, and the stormflow often is concentrated in sharper, shorter, higher peaks than those for natural runoff,' (Waananen 1969).

graph shown was obtained at the outfall sewer exit of a 19-hectare drainage area using a Parshall flume. Response time is so short for such a small but typical catchment that an observation interval no longer than one minute is required to obtain sufficiently detailed data. Rapid response and 'Lhe serious difficulties of making flow measurements within underground sewer systems, which was found by Wenzel (1966) to present severe obstacles in the acquisition of basic data.

Over a period of two dec des the portion covered by impervious surfaces grew from 17% to 31% in an urbanized 356 km catchment located in the metropolitan area of Atlanta, Georgia. Analysis of rainfall and runoff records for the period implies that storm runoff volume has increased in dry months, base flow has decreased in wet months, and peak runoff from summer storms has increased significantly (Wallace 1971). The latter implication was based on observed changes over time in unit hydrograph characteristics and further sub- stantiates earlier observations by Riley and Dhruva Narayana in 1969.

than the natural minor rills that formed the definite watercourses and the ephemeral channels in the original catchment areas that they mostly replace. In addition, nearly all major cities use improved natural channels or excavated special channels for collection of storm water from drainage conduit outlets, such as in Milwaukee (Prawdzik 1970). They also expedite the collection and traversing speeds of surface runoff. Because dramatic increases in peak runoff have been documented for some partially and even lightly sewered catchments, it appears likely that the increased peaks could be caused by the acceleration of flow afforded by the lower frictional resistance of streets and conduits, although the role of changed aggregate channel lengths is clearly uncertain.

Comparative studies of urban and rural drainage basins indicate that as the relative magnitude of flood peaks increases, the ratio of urban peak rate to rural peak rate declines ,

The very rapid response of a sewered catchment is illustrated in Figure 19. The hydro-

4

Man-made underground conduits and street gutters have much lower frictional resistance

161

FZoocl mitigation versus the amenities of drainage

the effect of urbanization being more pronounced €or the more frequent occurrences (Waananen, 1969) . Apparently, grossly overburdened surface and underground collection systems revert towards the carrying capacity of the natural systems they replace.

111.1.5 FLOOD MITIGATION VERSUS THE AMENITIES OF DRAINAGE

Most large metropolitan areas originated as urban centres on or near streams, lakes, estuaries or seacoasts because of an early dependence by commerce on water transport. Intrusion of urban development on natural flood plains has resulted in damage to occupying structures and sometimes loss of life. However, as argued in previous sections, the bulk of urban development is located on land that was originally subjected to sheet-flow runoff collected locally in minor channels. Subterranean systems of conduits facilitate human occupancy by draining sheet-flow runoff from the land surface. That is, fluvial drainage areas contributing to urban flood-plain inundation are often of gigantic size compared with individual underground conduit catchment areas which rarely exceed 2 600-hectares in extent. underground drainage systems are more of a convenience of amenity than a preserver of public safety. Structural means for mitigating flood-plain inundation are designed to provide a much higher level of protection than that for storm drainage systems because of the much greater threat to human life and because of economic implications.

Urban drainage facilities are generally owned, operated and maintained by local governments, and designed and constructed by local governments and private land developers. Human life is seldom threatened by the flooding of these facilities. Because the principal local detrimental effects of flooding are damage to the below-ground sections of buildings and hindrance of traffic, the consequences of flooding range from assessable property destruction to annoying inconvenience. It follows that provision of complete protection from flooding can only rarely be justified. Instead, facilities are designed which will be overtaxed in- frequently. However, because of the marginal level of protection afforded, damage by storm drainage flooding is also of considerable magnitude , probably exceeding those in urban flood plains. In addition, intangible damages occur which are much more extensive than for stream flooding and generally recur more often; direct damage is usually much more widely dispersed throughout a community .

The safety of people and properties occupying flood-prone areas is the concern of every level of government and National , State, special district and local governments are involved in the development of an ever greater arsenal of remedial mitigational measures and policies. However, most stream flood-management is undertaken by national agencies. Protection against . 'upstream' floods experienced on creek and headwater areas is afforded primarily by the Soil Conservation Service, whereas the Corps of Engineers concentrates more on ' downstream' floods on mainstreams and major tributaries. A notable exception is the Tennessee Valley Authority, which has primary responsibility for both aspects in its region. 'A complete inventory of nationwide flood damage has never been undertaken. . .. . Current efforts to manage flood-plain use and development on a national basis are increasing' (Water Resources Council, 1968).

Goddard (1973) states that 60% of national average annual flood plain stream flooding damage occurs in urban areas. This level of damage is close to that for the estimated national average annual loss from the flooding of urban areas served by underground drainage (storm and combined sewer) systems (Poertner et al, 1966). Further, national investment for storm drainage conduit facilities appears to be more than four times as great as that for flood plain protection works benefitting urban areas. The dominance of storm drainage investment over stream protection costs is expected to continue. While the need for more stream protection will rise as greater urban sprawl leads to inevitable new encroachments on flood plains, the same urbanization is expected to require as much as a doubling in the extent of storm drainage systems by the end of this century.

compared with well over 50% of that territory being served by systems of underground drainage conduits. Thus, flood damage per unit of area is clearly greater in flood plains than in sewered sectors of metropolitan areas.

flooding of urban flood plains. On the other hand, increased receiving-stream stages can cause or induce flooding of underground drainage systems because of the intimate hydraulic linkage between them. Extensive programme? of integrated flood plain management are particularly crucial for metropolitan areas that have little topographical relief , such as greater

Thus I

Only 15% of metropolitan territory is within 100-year flood plains (Goddard, in press) ,

Increased volume of direct runoff from subsurface drainage conduits can clearly aggravate

162

Some management possibilities

aicago (Sheaffer et al, 1970). Some large cities such 4s Philadelphia, early on dedicated most of their flood plains to parks, or such as Los Angeles, developed extensive systems of major drainage channels in step with urban development, (Wood, 1970; Rantz, 1970). However, new suburbs have often aggravated flooding with subsequently induced damage in many major cities located on large streams or bodies of water because their low topological elevation makes them hydrologically subservient.

the tenacious inclination of people to occupy the flood plains of urban streams, but these require changes in the activities of occupants and are therefore socio-political in character. study of occupant motivation, hazard perception and attitude, and receptivity towards various forms of communication designed to discourage further encroachment, (James et al., 1971; James, 1972).

Discharges from conventional storm drainage facilities and flood-plain -intrusion by structures both tend to aggravate flooding, and thereby jointly tend to raise the risk of flood damage. Revising storm sewerage criteria, such as by including much more in-system storage, can be an effective adjunct to flood plain management. While there is universal agreement that planning and development of drainage systems and flood plain management programma should be co-ordinated and integrated, prospects for accommodation diminish in the fact of increasing concern over water quality in sewered areas and a contemporary neutrality or indifference on water quality matters by agencies dealing predominantly with flood plains. It is ironical that much of the flood plain flooding problem, as well as the land runoff water quality problem, could possibly be remedied more effectively on the land feeding urban water courses.

of main channel improvements for metropolitan areas, sharp differences of opinion arise, partly or perhaps principally because implementation of the two methods commonly falls within different authorities (McPherson 1971a) .

There are several non-structural means for mitigating flooding damages inevitable through

The tendenq of home-owners to remain on flood plains has been demonstrated in a pilot

While the principle of the use of local detention storage is often championed in lieu

111.1.6 SOME MANAGEMENT POSSIBILITIES

In the past, drainage conduits were deliberately designed to accelerate the movement of stom, water to receiving water bodies by gravity flow. Detention storage was seldom incorporated in systems because of the preoccupation with rapid removal of surface water. However, in- system storage is being provided in a number of new systems and is being added to some existing systems. Interest in in-system storage has come about because of broader attitudes to integrated facilities-planning. As noted earlier, there is widespread interest in multi- purpose drainage facilities that exploit opportunities to provide for water-based recreation, substantial increases in levels of flood protection for buildings at small extra cost, use and re-use of storm water for water supply by artificial groundwater recharge and related means, and reduced md/or controlled pollution burdens at outfalls. These all require the use of storage.

alternatives to the direct disposal of storm water runoff have been explored by Laursen et al, i968 .

land-use controls, such as designed ponding (Rice, 1971) and encouragement of land development site grading to increase flow distances over unpaved areas (Jones, 1971). The turf areas separating pavements have long been exploited to produce ponding of overland flow, with consequent savings in drain size and reduction of peak outflows, at airports (Hathaway, 19451, highway intersections (Forest and Avonson, 1959) and for shopping centres (Anon, 1960) I Recreational areas have also been utilized for temporary detention storage, (Daily, 1961).

as in the basements of homes. Hence, to justify the greater use of designed storage in place of undesirable storage depends on the relative protection from flooding afforded by different systems at corresponding differences in cost. That is, 'trade-offs' between advantages and disadvantages should be resolved by choosing among various mixes of flow-acceleration and storage components. Unfortunately , the contemporary absence of a satisfactory body of hydrological and economic field data on urban storm drainage system floods constitutes a monumental liability in the assessment of +ose floods and their associated damages.

Requirements for assessment of flood damage by storm drainage have b,een studied, and

Peak flows of storm drainage facilities can be reduced by a number of structural and

Damage by storm drainage is the consequence of storing water in the wrong places, such

163

Some management possibilities

The Council on Environmental Quality (1971) estimates that the cost of alleviating pollution from combined sewer overflow, other than by separation into independent storm and waste water systems, would be greater than the combined amunt required to eliminate existing deficiencies in waste water treatment facilities and to provide new treatment capacities to meet replacement and population growth needs between 1971 and 1974. Because twice as many people are served by separate storm sewer systems as by combined sewer systems, it is evident that the cost of alleviating pollution from storm water discharges would be even greater. Stated another way, the cost of alleviating pollution from combined sewer overflows and storm sewer discharges would be at least twice the replacement value of all such existing sewers.

The US Government has been involved for several years in the development of measures for countering pollution from combined sewer overflows (Field & Struzeski, 1972; Office of Research and Monitoring, 1972). The ultimate solution for the problem of pollution abatement from both urban storm sewer discharges and combined sewer overflows is the treatment of such flows before their release into receiving waters. Collecting, transporting and treating all discharges/ overflows at unattenuated flow rates would require gigantic sewers, pumping stations and treatment facilities - all of which would be used a very few hours in a year. Therefore, practically all schemes for system-wide discharge/overflow collection and treatment incorporate some form of auxiliary storage for the purpose of reducing sudden inflows, to scale down the size of collection and treatment facilities to reasonable and manageable proportions.

On the basis of limited information, it appeared to Urt: (1972) that complete collection of combined sewer storm water would require perhaps 300 m3 of storage per hectare of drainage area. of storage required can be reduced by taking advantage of the fact that, because of the areal and temporal variability of rainfall intensity, the proportion of main sewer capacity in use at a given time varies between sewers throughout a rain storm.

There are three basic approaches involved in the most advanced comprehensive attacks on the combined sewer overflow problem. The first utilizes exploitation of ambient storage in existing trunk sewers by manipulating add-on constrictions (movable dams or gates) in outfall sewers. The constrictions are placed in the vicinity of existing regulators, and all flows other than from rare rainfalls are released thereby at attentuated rates to existing interceptors and thence to existing treatment works. - That is, by raising the constrictions in those main sewers where the potential storage volume is under-used at a given time during a storm, and lowering the constrictions in advance of local inundating inrushes, the flows into the interceptors can be adjusted for more efficient use of the interceptors. This is reflected in a greater diversion of flows to the treatment plant by way of the interceptors and consequent reduced overflows to the receiving waters. This basic approach is exemplified at Minneapolis-St. Paul, (Anderson, 1970; Callery, 1971; Anon, 1971; Tucker, 1971; Anderson et al, 1972) Detroit, (Brown and Suhre, 1964; Detroit Metropolitan Water Services, 1970; Remus, 1970; gnon, 1970) , Seattle, (Gibbs and Alexander, 1969; Municipiality of Metropolitan Seattle, 1971; Gibbs et al, 1972a and b) and Cleveland (Pew et al, 1972).

A second basic approach incorporates new storage located at elevations well below all street sewers, in the form of tunnels or vaults, and new or auxiliary discharge/overflow treatment works. It may or may not have ancillary features such as pretreatment basins or pumped-storage power generation to offset the substantial energy requirements for eventual lifting of flood waters from underground storage to the ground surface. A bonus of this approach is that street trunk sewers would be converted into manifolds of diversion diffusers, with the result that their effective hydraulic capacity would be raised. is exemplified in the pioneering plan developed in Chicago (Pikarsky and Keifer, 1967; Anon, 1969b; Koelzer et aZ, 1969; City of Chicago et al, 1970; Pikarsky, 1971; University of Wisconsin, 1970; Flood Control Co-ordinating Committee , 1972) and in analogous plans under consideration elsewhere (Parthum, 19 70) .

The third basic approach is embodied in a plan proposed by the Department of Public Works for San Francis0 (1971b) which includes: a single, new combined flow treatment plant; a number of new detention reservoirs located immediately below the streets in the upstream portions of a majority of catchments; a number of new shore-line detention reservoirs; a deep cross-system storage and transmission tunnel; and achievement of a fully automatic operational control for the whole system.

of their complexity (McPherson, 197l-b) .

However, more recent estimates place storage requirements nearer 600 m3/ha. The amount

This basic approach

All three basic approaches incorporate plans for some degree of automatic control because Because combined sewer overflows occur very suddenly,

164

Research status and needs

any facilities provided for treatment of potential overflows must be put on-line almst in- stantaneously. This means that they would have to be activated immediately any storm water flow exceeds interceptor sewer capacity. Further, such plants might be idle most of the year. The effectiveness of overflow pollution abatement, using treatment facilities designed specifically for that purpose, will therefore require some form of automatic operational control. Remote supervision would quite likely not be responsive enough. The control logic required has yet to be developed and it is possible that different metropolitan sewer systems will require their own unique logic development.

Pollution treatment of water from separate systems of storm drains faces almost the same difficulties. In one sense, requirements are more exacting because &J. storm water must pass through new and special treatment facilities, there being no interceptor sewers in such systems to divert small storm occurrence flows to peremidly operated waste water treatment plants.

Storm water conduits may be incorporated in multiple-service tunnels as is the case in numerous existing utility tunnel systems in Europe, Asia and North America (Corey, 1972). Most utility tunnel concepts (American Public Works Assn., 1971) deal with structures located fairly close to the ground surface and include possibilities for limited incorporation of storm sewers (McPherson, 1972). Ac an adjunct or alternative, consideration could be given to much deeper locations, at least for main feeders and arteries, for power transportation, surface water and waste water, and for other services (Sarensen, 1971).

Lastly, possibilities exist in rainfall-deficient regions for deliberate capture of urban storm water to augment water supplies, provided the quality is suitable, a requirement that might be met by various managerial schemes (Angino et al, 1972). Manipulated recharge of groundwater supplies with swrplus surface water has been practised for many years in some regions (Task Group, 1963; Knapp, 1973).

111.1.7 RESEARCH STATUS AND NEEDS

'The field of urban hydrology is almost devoid of modern research investment,' said Ackermann in 1966. 'More research is needed to develop understanding of the whole storm water pollution problem. This research should cover the hydrology, the hydraulics, the treatment, the effects on receiving waters, and related factors ' (National Research Council, 1766) ' . . . . . too few data have been collected to describe the effect of urban and suburban .'svelopment on flood runoff,' (Task Force 1969). As a consequence, little is known about the rainfall- runoff process and still less about rainfall-runoff-quality, particularly for sewered catchments. ' ..... considering the huge relative investment in sewered systems and the almost complete absence of hydrologic data on sewered systems, it has been obvious for quite some time that this is the sector most woefully needing research attention,' (ASCE, 1969). Sui table data collected with properly co-ordinated instrumentation in networks representing a variety of climatic, topographical and land-use conditions are virtually non-existent. Further, while all metropolitan areas have subsurface systems of storm drainage, flooding of waterways is a serious problem in some metropolises but negligible or non-existent in others. Additionally, flood amelioration is preoccupied with rainfall-runoff whereas rainfall-runoff- quality processes are of more vital concern nationally.

proposed, together with a documentation of its justification, (American Society of Engineers , 1969) but progress in implementation has been painfully slow. In anticipation of the possible future availability of new data, considerations for modelling sewered urban catchment rainfall-runoff-quality processes were drawn up (Dawdy et al, 1968) and considerations for characterizing rainfall time and spatial distributions in future research were explored (Thomasell, 1968). In support of the latter, existing raingauge networks were surveyed by Tucker in 1969b and 1970a. The US Geological Survey is developing a programme of data collection and studies to serve national needs in urban hydrology (Sneider ,1969 ; Water Resources Division 1972). The Office of Water Resources Research has developed a broad programme of projected urban water resources research, (1972) including urban hydrology analyses.

the 'rational method, ' (American Society of Civil Engineers 1969) . The method yields only an estimated peak flow but none of the other attributes of a hydrograph and its many limitations have been reviewed elsewhere (McPherson, 1969).

A national programme for the acquisition of much needed sewered catchment data has been

The procedure used for design of storm sewers in the United States is almost exclusively

A full hydrograph is needed for the

165

Research status and needs

design of detention storage, for evaluation of pollutant burdens, Sor design of storm water pollution abatement facilities, for designing local pratection works , such as pumping stations for passing local drainage flows over levees and dikes, and as inputs for design of stream arid river development works. Also, quantification of the effects of urbanization on the hydrological regime is dependent in many cases upon the availability of sewer outlet hydrographs. Further, as urban water management problems become increasingly acute , the need Lfor multiple- use of water becomes more evident. In exchanging one use for another, for example by using storm water as a source of water supply, knowledge of the time-histories of flows and water qualities is essential for reliable design of transfer facilities.

over more than a very few seasons. Although rainfall-runoff had been measured, only a few of the catchments had rainfall-runoff-quality measurements made at outfalls and not insystem; data reliability was often suspect because of known instrument errors, lack of observations synchronization, and crude signal resolution (Tucker , 1969c) . Proportionally more rainfall- runoff data were available for partially sewered areas (Tucker, 1970b) but the amount was nevertheless pitifully small. Since then, field research sponsored by the Environmental Protection Agency (Field et al, 1972) and others has extended the data somewhat (Stall & Tierstriep, 1972). ments using flumes or weirs rather than stage-gauges for determining discharge.

numerical values to model component parameters. Reliability of judgment is improved when parameter values are based upon fits to observed events for the catchment being modelled, and is maximized when parameter values can be generalized for a number of catchments in terms of physical features such as degree of imperviousness, type of land use and channel density. The usual purpose of modelling is to project performance for future events, For urban catchments, this usually involves physical changes over time such as revised land use, new detention storage and modified land management practices. Independently from any consideration of catchment changes, recorded precipitation must be adapted in some way to represent expected future precipitation. Thus , projections of runoff-quality events inevitably require the application of some degree of judgment. The principal reason for testing or calibrating a mdel with observed data is to enhance confidence in its use, and this approach of going from the present to the future is employed in all water resource computations involving risk and uncertainty.

of infiltration, depression storage, etc from total rainfall to resolve the amount and pattern of rainfall excess, which is the input from which an equal volume of direct runoff is generated by models of one kind or another.

modelled for sewered and partially sewered catchments (Tucker, 1970). A project completed since then (Water Quality Office, 1971; Chen & Shubinski, 1972; Lager et al, 1971) has developed the only existing model that readily accommodates water quality parameters. The model was developed as an assessment technique for comparing alternative solutions by means of a comprehensive computer programme capable of 'representing urban storm water runoff phenomena, both quantity and quality, from the onset of precipitation on the basin, through collection, conveyance (both combined and separate systems) , storage, and treatment systems to points downstream from outfalls which are significantly affected by storm discharges, ' (Lager, 1969). An improved version of the model has been tested for a 1 500 ha San Francisco sewered catchment (Roesner et al, 1973). These and any other models purportedly developed for sewer application suf€er substantially from a severe shortage of data for their calibration, verification and, particularly, for their realistic application to ungauged catchments.

generalized unit hydrograph parameters (Eagleson, 1963; Espey 8, Winslow, 1968) in analysis of areawide storm sewer performance. for synthetic triangular unit hydrographs applicable to small non-urban catchments throughout the country (Soil Conservation Service, 1971) . Local synthetic triangular unit hydrograph parameters have been developed for the San Francisco Bay Region using observed data for non- urbanized catchments and empirical indications for urbanized catchments for which suitable data did not exist (Rentz, 1971). planning for the Denver metropolitan area, Colorado (Wright-McLaughlin Engineers , 1969 ;

By 1969, only a very few sewered catchments had been gauged and records seldom extended

However, not much new data has been acquired on completely sewered catch-

All hydrological models require some degree of subjective judgment in the assignment of

The inherent difficulty with any runoff model in the necessarily subjective separation

Nine projects were identified in 1970 where the urban rainfall-runoff process was being

In default of suitable data, some astute planners have applied necessarily weakly-founded

The Soil Conservation Service has developed parameters

A unit hydrograph has been defined for use in drainage

c

166

Other deveZopments and considerations

Clayco&, 1970) and again for estimating flows from local drainage in conjunction with river protection works (Hydrologic Engineering Centre, 19 70) .

A sewered catchment runoff generation technique developed in the United Kingdom has been tested using some US data (Stall & Terstriep 1972; Terstriep & Stall, 1971).

A dearth of historical runoff records on urban streams, compounded by the rapid changes that have taken place in urban watersheds, has thwarted effective use of existing simulation models for planning.

A mathematical watershed simulation model that operates with continuous, multi-seasonal hydrologic data was used in a study of the effects of rainfall data time-interval and raingauge density on simulated hydrographs compared with observed hydrographs for four sewered catchments (Crawford, 1971) but experimentation was severely hampered by the almost total absence of appropriate data.

the runoff volumes measured at the outlets of four sewered urban catchments (Miller & Viessmen, 1972) .

A recently developed model requires as computational input the ratio of direct runoff volume to the volume of rainfall subsequent to the beginning of direct runoff; and the associated duration of rainfall excess (Rao @-¿ al, 1972). For predictive application these two factors must be guessed where no runoff records are available or generalized in some way in the unique instances where some runoff data do exist.

flows in an interceptor sewer of a combined system (Harris, 1970) and was verified in part using unsteady flow laboratory test findings (Pinkayan, 1972).

An empirical total rainfall-total runoff relation has been developed that approximates

An elegant mathematical model has been developed for routing intercepted storm water

III. 1.8 OTHER DEVELOPMENTS AND CONSIDERATIONS

The office of Water Resources Research has prepared an extensive bibliography on urban water planning (Mangan and Swenion, 1972). Many major streams pass through several metropolitan areas with consequent complications for runoff analysis , a subject considered in detail at the International Symposium on Mathematical Models in Hydrology in Warsaw , July 19 71 , and earlier by Dawdy and Kalinin in 1970. areas and here also methods of analysis have progressed considerably in recent years, particularly with regard to water quality parameters (Orlob, 1972).

flood mitigation models related to planning for river management while Bowers et UZ (1972) have compiled an annotated catalogue of computer programmes which includes reference to some of the few programmes developed for urban runoff. Features of existing hydrological models for simulating rainfall-runoff of urban streams have been compared by Linsley (1971).

selected papers dealing with various aspects of urban storm water runoff, (The Franklin Institute Research Laboratories, 1969, 1970 & 1971; Office of Research and Monitoring, 1972a) and the US Geological Survey has compiled over 600 abstracts of selected papers on the subject of urban hydrology (Knapp & Glasby, 1973). tinues to accumulate (Office of Research & Monitoring, 1972b).

ships for estimating stream discharge and stage frequency for use in connection with flood- plain mapping in the Chicago metropolitan area. flood plain mapping study that was undertaken with simulation techniques (Hydrocomp Inter- national Inc., 1971).

A flood control and drainage background study has been undertaken by San Diego County, California, as a part of its comprehensive planning programme. An operational computer programme produces preliminary costs for channel improvements , based on the outputs from two other programmes which, for alternative land use distributions , calculate ' the outflow from each sub-basin for a flood with any pre-assigned recurrence interval' and compute 'the relation between water-surface elevation and flow rate' (Reimer & Franzini, 1971). Analyses yield information on the relationship between projected land use alternatives and degree of flooding, and the cost of attendant flood protection measures.

and design purposes are considered, where historical data is at issue, it appears that

Some streams are estuarine when they reach metropolitan

Ferguson and Loucks (1972) have reviewed a variety of streamflow, dissolved oxygen and

The Environmental Protection Agency has sponsored the compilation of 1 600 abstracts of

Information on drainage system contaminants con-

A study for the Northeastern Illinois Planning Commission developed simulation relation-

'The North Branch Chicago River was the first

When the difficulties encountered in modelling urban streamflows and stages for planning

-.-.

I67

Other developments and considerations

capability for real-time operation of urban stream control structures will take some time to develop, because flows and stages must be simulated simultaneously with the occurrence of precipitation events , including simulation of alternative operating tactics and incorporation of mostly yet-to-be-defined management operating strategies.

A monumental problem in the analysis/design of drainage systems is the choice of storms to be used. In the operating mode, any control system must not onLy respond almo5t instan- taneously to the actual occurrence of rainfall but must anticipate the probable character of subsequent time and spatial changes almost before they occur. A desirable adjunct would be an incipient storm-occurrence forecasting capability. As in design/analysis , separation of infiltration, depression storage etc from total rainfall to derive rainfall excess is necessarily highly subjective and limits the reliability of affected control-response components.

Despite.these reservations, the generation of a sewer hydrograph for a given storm is not all that difficult and can readily be processed using one model or another. Storm definitions used €or deriving river basin extremes such as 'reservoir design floods' and 'spillway design flaods are irrelevant because urban sewer systems are necessarily designed with a lesser level of protection, and are expected to be overtaxed much more frequently than major river structures whose failures could be catastrophic. From this standpoint, the mean frequencies of occurrence of flow peaks and volumes and quality constituent amounts is the issue, not the frequencies of the input rainfall, and were it possible to arrive at statistical series for discharge-quality independently of rainfall we could vastly simplify the design issue. More correctly , because of metropolitan socio-political considerations , the probability of recurrence of a given event magnitude being equalled or exceeded within the same year may be more important than a mean recurrence which requires a number of years for its average to apply (Thom, 1959).

Furthermore, because there are inherent non-linearities in most methods for processing inputs for linear models, and dynamic models are non-linear by definition, the statistics of the rainfall input array may differ appreciably from the statistics of some or all of the arrays for runoff-quality characteristics. That is, attempting to assign a mean frequency of probable recurrence to a 'design storm' is meaningless because of statistical non- homogeneity of rainfall, runoff and quality. A ~ S O , such an approach neglects the effect of prior storms on the runoff from a given storm (Linsley, 1970). Statistical definition of collective time and spatial variations of storm rainfall has thus far defied modem analysis.

rainfall time-patterns and areal distributions , there is an interim possibility that might be considered (Jens & McPherson 1964). A few metropolitan areas have reasonably dense raingauge networks that have been in operation for five years or more (Tucker, 1969). From the data available, the time-history of rainfall on a particular catchment could be interpolated and entered into a model from which runoff-quality arrays could be generated. Confidence levels for frequencies assigned to given events in the arrays would obviously not be very high, but the results could well be adequate for differentiating relative superiortiy among alternative designs.

given rainfall space-time distribution to the sizing and deployment of conduits and storage reservoirs adequate to accommodate runoff rates and volumes at the level of protection desired or elected, with an accounting and allowances for affected water quality control facilities, such as storm water treatment plants, and reclamation facilities, such as recharge spreading basins. This is a tall order. Because responsible metropolitan planning explores alternative futures on an areawide scale, storm sewer planning of the type needed requires coarser handling, otherwise information processing requirements will be overwhelming. On the other hand, storm sewer systems are designed a catchment at a time, so tile basic distinction between planning and design is greater extensiveness for the former and greater intensiveness for the latter. of rainfall-runoff-quality processes , even if still somewhat limited due to the complexity of hydrological systems and the resultant inherent empiricism of applied hydrology. modelling can never be perfect or complete: it is an analytical tool and hence is surely as much an art as a science. ' -. . . . a model system is merely a researcher's idea of how a physical system interacts and behaves, and in the case of watershed research, watershed models are usually extremely simplified mathematical descriptions of a complex physical situation. -. . . . until each internal sub-model of the overall model can be independently verified, the

While it is hoped that storm research ultimately will provide statistical insights to

To sum up, storm sewer design methods of the type needed would permit proceeding from a

Hopefully, field research on urban drainage will yield greatly improved understanding

Hydrological

I68

Other deve Zopments and considerations

model remains strictly a hypothesis with respect to its internal locations and transformations. . . . . . When using models and their results, researchers must be continually aware of what is fact and what is model output which is subject to the limitations and biases of the model's development' (Gbunck, 1971) . Simulation, by definition, is not replication.

The remainder of this section is devoted to developments in precipitation analysis. According to Tucker (19691, 15 of the largest metropolitan areas had a network of recording raingauges of between about 5 and 192 instruments, with records spanning periods of 2 to about 50 years. The most advanced network installed since is in San Francisco, where signals from about 30 raingauges and over a 100 water-level gauges are transmitted to a central data acquisition and recording station as part of a system cleveloped for the City (Dept of Public Works, 1971; Control System Industries , 1971; Anon, 1972) . Various metropolitan areas are using precipitation network data , particularly in the development of combined sewer overflow abatement schemes. At the same time, advances have been made in the analysis of small-area storms.

Thunder storm cells are the most frequent source of intense rainfall in the Midwest. Cells at ground level have a diameter of 5 to 10 kilometres, areas of 40 to 80 km2, and a residence time of 30 to 60 minutes (Stall & Huff 1971). Most of the rainfall occurs in two to four bursts from two or three contiguous cells during the first 10 minutes.

major field-laboratory programme complex on precipitation, is in progress in the St Louis metropolitan area. Instrumentation includes a network of 250 recording raingauges covering 10 O00 km2. far indicate that the storms presumed to be affected by the urban areas produce greater mean rainfall, are larger in areal extent, are longer lived, have a longer path length, and move more rapidly than their non-effect counterparts. Similar effects have been noted for some other US cities (Changnon, 1973).

of 10 minute interval rainfall depths (Raudkivi & Lawgun, 1972) and hourly rainfall for a three-station network, (Franz, 1971) building on earlier works (Grace & Eagelsun, 1967; Eagelson, 1967, Raudkivi & Lawgun, 1970).

been initiated on the use of rainfall data rather than runoff records for the derivation of peak flow frequencies, by routing runoff through hypothetical catchments from those storms of a given set considered likely to produce the larger peak flows (Leclerc & Schaake , 1972a). Further, the same authors have defined a conceptual framework for deriving peak flow frequencies regardless of the rainfall and routing models employed. In the infrequent instances where a runoff record spanning a number of years is available, the data are often statisti- cally distorted by a non-homogeneity resulting from catchment urbanization changes that have occurred over the period of record. possibilities exist for accommodating historical and projected changes in catchment response via the routing model used.

An urban-weather research programme, (Changnon et al, 1971; 1972) the world's first aimed at assessing the effect of a major urban-industrial

Results from analysis so

Techniques have been developed for the stochastic generation of a continuous long series

Lastly, in recognition of the limited urban drainage flow data available, research has

By using rainfall data for deriving flow frequencies,

I69

References

111-1.10 REFERENCES

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Knapp, G. L., and J. P. Glasby. 1973. Urban hydrology: a selected bibliography with abstracts, U.S. Geological Survey, Water Resources Investigation 3-72, 211 pp., 80, Washington, D.C.

Koelzer, Victor A., William J. Bauer and Frank E. Dealton. 1969. The Chicago area deep tunnel project - a use of the underground storage resource. J. WCF, 42, (4). Lager, John A. 1969. A simulation technique for assessing storm and combined sewer systems, in Combined Sewer Overflow Seminar Papers, FWPCA, U.S. Dept. of the Interior, Water Pollution Control Research Series, DAST 37, 11020-03/70, GPO, Washington, D.C., p. 151.

Proc. Xnt. Symp. on ModelZing Technfques in Water Resources System, Ottawa, Ontario,

Lager, John A., Robert P. Shubinski and Larry W. Russell. 1971. Development of simulation model for storm water management, J. WCF, 43, (12).

Laursen, E. M., W. J. Bauer, B. R. Hanke, M. M. Hufschmidt, L. D. James, J. W. Knapp, and P. H. McGauhey. 1968. Findings of the damage and storage Task Committee,Appendix C in Urban Flater Resources Research, ASCE, New York, N.Y. (NTIS Id. No. PB 184 318).

Leclerc, Guy, and John C. Schaake, Jr. 1972. Derivation of hydrologic frequency curves, Massachusetts Institute of Technology Water Resources and Hydrodynamics Laboratory, Report No. 142, Cambridge, 151 pp. (NTIS Id. No. PB 209 761).

Leclerc, Guy, and John C. Schaake, Jr. 1972. Derivation of hydrologic frequency curves from rainfall, a paper presented at the 53rd Annual Meeting of the American Geophysical Union, Washington, D.C.

Leopold, Luna B., M. Gordon Wolman and John P. Miller. 1964. FZuuZaZ Processes in Geomor- phology, W. H. Freeman and Co., San Francisco, California, p. 145. Linsley, Ray K. 1970. Discussion of Urban runoff by Road Research Laboratory method, Hydraulics L%v. ASCE Proc., 96, (HY4), Paper 7189, p. 1102. Linsley, Ray K. 1971. A critical review of currently available hydrologic models for analysis of urban storm water runoff, Hydrocomp International, Inc., Palo Alto, California, 83 pp., (NTIS Id. No. PB 204 815).

Mangan, George F., and Herbert A. Swenion, Eds. 1972. Urban Water planning, a bibliography, Water Resources Scientific Information Center, Office of Water Resources Research, U. S. Dept. of the Interior, WRSIC 72-215, GPO, Washington, D.C.

McPherson, M. B. 1969. Some notes on the rational method of storm drain design, ASCE Urban Water Resources Research Program, Technical Memorandum No. 6, ASCE, New York, N.Y., (NTIS Id. No. PE 184 701) - McPherson, M. B. 1971a. Management problems in metropolitan water resource operations , ASCE Urban Water Resources Research Program, Technical Memorandum No. 14, New York, N.Y. , p. 8. (NTIS Id. No. PB 206 087).

! 73

References

Mcpherson, M.B. 1971b. Feasibility of the metropolitan water intelligence system concept (integrated automatic operational control) , ASCE Urban Water Resources Research Program, Technical Memorandum No. 15, ASCE, New York, N.Y. (NTIS Id. No. PB 207 301).

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Miller, Clayton R., and Warren Viessman, Jr. 1972. Runoff volumes from small urban watersheds, Water Resources Res. 8, (2) . Municipality of Metropolitan Seattle. U.S. Environmental Protection Agency, Water Pollution Control Research Series, No. 11022 ELK, GPO, Washington, D.C.

National Research Council. 1966. waste managemnt and control, National Academy of Sciences, Publication 1400, GPO, Washington, D.C. p. 170.

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Office of Research and Monitoring. 197223. Water pozzution aspects of street surface conta- TriinantS, Environmental Protection Technology Series, EPA-R2-72-081, GPO, Washington, D.C. Office of Research and Monitoring. 1972. Projects of the munieipaii technology branch through June 29 72, U .S. Environmental Protection Agency, Environmental Protection Technology Series, EPA-R2-72-080, GPO, Washington, D. C.

Office of Water Resources Research. U.S. Dept. of the Interior, GPO, Washington, D.C.

Orlob, Gerald T. 1972. Mathematical modelling of estuarial systems, pp. 2, 78-128, Proc. Int. Symp. on IdodeZZing Techniques in Water Resources Systems, May 9-12, Ottawa, Ontario, Canada.

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1971. A nationa2 urban water resources research progrm,

Parthum, Charles A. 1970. Building for the future - the Boston deep tunnel plan, J. PCF,

Pew, K. A., R. L. Callery, A. Brandstetter and J. J, Anderson. 1972. The design and operation of a real-time data acquisition system and combined sewer controls in the City of Cleveland, Ohio, a paper presented at the WPCF Annual Conference, Atlanta, Georgia.

Pikarsky, Milton, and Clint J. Keifer. 1967. Underflow sewers for Chicago, CiwiZ Eng. ASCE, 37, (5) - Pikarsky, Milton. 1971. SiXe years of rock tunnelling in Chicago. J. Construction Div. ASCE Proc., 97, (COZ) , Paper 8504. Pinkayan, Subin. 1972. Routing storm water through a drainage system, J. HydrauZics Div., ASCE Proc., 98, (HY1) , Paper 8642.

42, (4).

Poertner, H. G., R. L. Anderson and K. W. Wolf. 1966. Urban drainage practices, pPOcedUreS, and needs, Amer. Public Works Ass. Special Report, Project 119, Chicago, Ill. p.3. Prawdzik, Ted B. 1970. Environmental and technical factors for open drainage channels in Milwaukee, ASCE Urban Water Resources Research Program, Technical Memrandum No. 12, ASCE, New York, N.Y. (NTIS Id. No. PB 191 710).

Rantz, s. E. 1970. Urban sprawl and flooding in Southern California, U.S. Geological Survey, Circular 601-B, GPO, Washington, D.C.

Rantz, S. E. 1971. Suggested criteria for hydrologic design of storm drainage facilities in the San Francisco Bay region, California, U.S. Geological Survey, Open File Report, Menlo Park, California.

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References

Rao, A. R., J. W. Delleur and B. S. P. $arma. ing basins, J. Hydraulics av. A$CE Proc., 98 (HY7) Paper 9024. Raudkivi, A. J., and N. Lawgun. 1970. Synthesis of urban rainfall, Water Resources Res. 6. (2).

Raudkivi, A. J., and N. Lawgun. 1972. Generation of serially correlated non-normally distributed rainfall durations, Water Resomces Res. 8, (2).

Reimer, Paul O., and Joseph B. Franzini. 1971. Urbanization's drainage consequences , J. Urbm Planning and Devel., ASCE Proc., 97 (UP21 Paper 8600. Remus, Gerald. 1970. Storm water retention can work . . . and prevent the heavily polluted 'First Flush' from overflowing to damage the receiving river, American City, 85, (10). Rice, Leonard. Reduction of urban peak flows by ponding, J. Irrigation and Drainage ZV. ASCE Proc., 97, (IR31 , Paper 8351.

1972. Conceptual hydrologic models for urbaniz-

1971.

Riley, J. Paul, and V. V. Dhruva Narayana. 1969. 'Modelling the runoff characteristics of an urban watershed by means of an analog computer'; E. F. Brater and Suresh Sangal, IEffects of urbanization on peak flows'; William H. Espey, Jr., David E. Winslow and Carl W. Morgan, 'Urban effects on the unit hydrographl; and Donald Vansickle, 'Experience with the evaluation of urban effects for drainage design' : all in Section 3, 'Urban Watersheds," pp. 183-254, Effects of Watershed Changes on Streamflaw, (Ed: W. L. Moore and C. W. Morgan), Univ of Texas, Austin.

Roesner, Larry A., David F. Kibler and John R. Monser. 1973. Use of storm drainage models in urban planning, Nat. Sym. on Watersheds in Transition, June 19-22, 1972, Colorado State University, Proceedings, American Water Resources Association, Urbana, Illinois, pp. 400-405. Schneider, William J. 1969. The U.S. Geological Survey urban water program, in Effects Of Watershed Changes on Stream Flow. (Ed: W. L. Moore and C. W. Morgan), Univ. of Texas, Austin.

Sheaffer, J. R.,.D. W. Ellis and A. M. Spieker. 1970. Flood-hazard mapping in Rd2WpoZitan Chicago, U.S. Geological Survey, Circular 601-C, GPO, Washington, D.C. Soil Conservation Service. 1971. Section 4, Hydrology, in SCS National EngGeering Handbook, U.S. Dept. of Agriculture, GPO, Washington, D.C., p. 15-11.

Sorensen, Kenneth E. 1971- Fourth dimension for urban development, J. Urban Planning and Devel. Z v . ASCE Proc., 97, (mi), Paper 8064. Stall, John B., and Floyd A. Huff. 1971. The structure of thunderstorm rainfall, ASCE Natio- nal Water Resources Engineering Meeting, January 11-15 , Phoenix, Arizona, Meeting Preprint 1330, ASCE, New York, N.Y.

Stall, John B., and Michael L. Terstriep. 1972. Storm sewer &sign - an evaluation of the &?L method, Environmental Protection Technology Series, EPA-R2-72-068, GPO , Washington, D. C.

Stankowski, Stephen J. 1972. Population density as an indirect indicator of urban and suburban land-surface modifications, U.S. Geological Survey Professional Paper 800-B , GPO, Washington, D.C.

Sullivan, Richard H. 1968. Inventory of combined sewer facilities, Civil Eng. 38. (li).

Task Force. 1969. Effect of urban development on flood discharges - current knowledge and future needs, J. Hydraulics ZV. ASCE Proc., 95 (HY1) Paper 6355. Task Group. 1963. Design and operation of recharge basins, J. AWWA, 55, (6).

Terstriep, M. L., and J. B. Stall. 1971. Urban runoff by Road Research Laboratory method, J. Hyhaulics ZV., ASCE Proc., 95, (HY6) 1969. Authors' closure to discussion, 97, (HY4) , Paper 8012.

Thom, H. C. S. 1959. A time interval distribution for excessive rainfall, J. Hydraulics XU., ASCE Proc., 85, (HY7), Paper 2083.

Thomasell, Albert, Jr. 1968. Considerations for characterizing the time and space distributions of metropolitan storm rainfall, Appendix B in U r b m Water Resources Research, ASCE, New York, N.Y.

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Tucker, L. S. 1969. Sewered drainage catchments in major cities, ASCE Urban Water Resources Research Program, Technical Memorandum No. 10, ASCE, New York, N.Y. (NTIS Id. No. PB 184 705).

Tucker, L. S. 1969. Raingauge networks in the largest cities, ASCE Urban Water Resources Research Program, Technical Memorandum No. 9, ASCE, New York, N.Y. (NTIS Id. No. PB 184 704).

Tucker, L.S. 1969. Availability of rainfall-runoff data for sewered drainage catchments , ASCE Urban Water Resources Research Program, Technical Memorandum No. 8, ASCE, New York, N.Y. (NTIS Id. No. PB 184 703).

Tucker, L. S. 1970a. Non-metropolitan dense raingauge networks , ASCE Urban Water Resources Research Program, Technical Memorandum No. 11, ASCE, New York, N.Y. (NTIS Id. No. PB 191 709).

Tucker, L. S. 1970b. Availability of rainfall-runoff data for partly sewered urban drainage catchments , ASCE Urban Water Resources Research Program, Technical Memorandum No. 13 , ASCE , New York, N.Y. (NTIS Id. No. PB 191 755).

Tucker, L. S. 1971. Control of combined sewer overflows in Minneapolis-St. Paul, Technical Report No. 3 , Metropolitan Water Intelligence System Project, Colorado State University. Ft. Col lins.

University of Wisconsin. 1970. Deep tunnels in hard rock, Proc. of An Engineering Institute, Milwaukee , Wisconsin , November 9-10, Water Pollution Control Research Series , U.S. Environmen- tal Protection Agency , GPO , Washington , D. C. Ure , James E. 1972. Reducing pollution from combined sewer overflows , APWA Reporter, 39, (5).

U.S. Public Health Service. combined sewer systems - a preiiintinary appraisal, Publication No. 1246 , GPO, Washington , D. C. Waananen, Arvi O. 1969. Urban effects on water yield, pp. 169-182, in Effects of Watershed Changes on Streamflow, edlted by W. L. Moore and C. W. Morgan , University of Texas Press , Austin.

Wallace, James R. 1971. The effects of land use change on the hydrology of an urban watershed, School of Civil Engineering, Report ERC-0871 , Georgia Institute of Technology , Atlanta, Georgia, 66 pp. (NTIS Id. No. PB 206 426).

Water Quality Office , Storm Water Management Modez, 1971. Water Pollution Control Research Series, in four volumes (GPO, Washington, D.C.) : Vol. I - "Final Report," 11024Do~7/71, 352 pp. Vol. II - "Verification and Testing," 11024WcO8/71, 172 pp. Vol. III - "User's Manual," 11024WC09/71, 359 pp. Vol. IV - "Program Listing," 11024WC10/71, 249 pp. Water Resources Council. 1968. !The Nation's Water resources, GPO, Washington, D.C. pp. 5-2-2

Water Resources Division. 1972. Projects related to WRD urban water program, FY72, U.S. Geological Survey , Washington , D. C.

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Wood, Walter J. 1970. Los Angeles county flood control system and the early 1969 storms, Civil Eng., 40 (i) . WrLgh-McLaughlin Engineers. 1969. Urban storm drainage criteria manual, Denver Regional Council of Governments , Denver , Colorado.

1964. Pollutional effects of storm water and overfhs from

Environmental Protection Agency ,

and 5-2-7.

176

2 Effects of lignite mining on the urban water cycle in the Federal Republic of Germany

Herbert Massing

and Members of the State Institute for Hydrology and Water Protection

Northrhine-Westphalia

Hydrological efeeefs of urbanizution (Studies and reports in hydrology, 18) Paris, T h e Unesco Press, 1974

Introduction

111-2.1 INTRODUCTION

Since the early days of industrialization in the last century a number of densely populated and highly industrialized urban concentrations have developed in the Lower Rhine and Ruhr regions : the Ruhr District (Duisburg-Dortmund) and the Rhine Axis (Bonn-Cologne-Dusseldorf- Duisburg). 70% of the steel industry and 50% of the primary chemical industry of the Federal Republic of Germany (FRG) have become settled in the Ruhr District with an average population of more than 1300 inhabitants per km2 (Frewer, 1972). Like all urban and industrial areas, they have a high energy demand.

The most important primary source of energy for the industrial centres of both the Rhine and Ruhr districts comes from the pit coal deposits in the Ruhr and Aachen regions, although the importance of the pit coal may be expected to become substantially reduced in the future because of high labour requirements, increasing mining depths and consequential costs.

primary sources of energy, notwithstanding future potential from scientific research. Al- ready, about 26% of the power supply of the FRG comes from the Lower Rhine lignite opencast mining area, the most important electricity generating centre in Europe. The power stations operated on low-cost lignite cover the base-load requirements (approximately 7000 hours a year) in a vast power supply grid system to supply the adjoining eastern and north-eastern areas (Rheinische Braunkohlenwerke AG, 1971).

opencast mines of the Lower Rhine area is influencing water management in ways which will be explained as follows.

On the other hand, present extraction methods make lignite one of the more important

However, the extensive and mechanized haulage of lignite from the shallow and deep

111-2.2 THE LOWER RHINE LIGNITE OPEN MINING AREA

111-2.2.1 Geological structure of the Lower Rhine Bay

The lignite of the Lower Rhine Bay was originally deposited in a basin formed in the Oligocene. Complicated rift and fracture systems subsequently produced a block-faulted area with a general plunge to the north-west (Figure20) whose differential subsidence and tilting commenced during sedimentation. Distinction is made, from east to west, between the Cologne- and Ville-fault blocks, the Erft basin and the Rur fault block, (Figure 21).

The lignite in the tectonicly elevated Cologne fault block has been eroded. In this area the Rhine terraces unconformably overlie the interbedded sand and clay of the Oligo- miocene while in the adjoining Ville area the lignite bed has been preserved with but little cover of Pliocene and Pleistocene. At the west side of this block the lignite plunges to greater depths due to the formation of a major fault and/or a number of step faults. the northern Ville area there is a fault scarp structure with strata inclinations up to 20 . In the north-west the Ville area inclines toward the Venlo Valley.

a depth of more than 500 metres. Above the bed are interbedded sands, gravels and clays of the Pliocene which are unconformably overlain by Pleistocene deposits. Westwards the individual series of strata rise and simultaneously reduce in thickness. To the south-west of the Erft basin, the Rur margin and Rovenich fault, provide a boundary to the Rur fault block area. Even though this fault block area is subdivided by some major fault zones the strata generally dip from the Eifel margin to the north-east and increase in thickness while at the same time the Rur fault block area reaches an increasingly low tectonic depth. In this area, too, the overlying beds are interbedded Pliocene sands, gravels and clays which in turn are covered unconformably Pleistocene deposits.

As may be seen from the longitudinal section through the Erft Basin (Figure22) the individual series of strata rise to the north and south while reducing in thickness so that the entire Erft Basin is looked upon geologically as a trough. Petrographically, silting increases to the north-west and there is a considerable increase in clay in the south- eastern direction.

In o

In major fracture zones west of the Ville area the lignite bed in the Erft basin reaches

I78

Fault \ O 10 20 km

Figure 20. Lignite distribution in the Lower Rhine Basin.

179

O Z (u

O

-e: u v)

- - 8 r: -

:O Y S

a, '2

u

a, e 't Lu 3 v)

.

d -4

rri Id m LI a, 3 2,

L

=I .- m

al

5 d

r\l

al

-4

li h

N c

i=

L

d

E o- Y

m-

U-

m-

N-

O

c, 4-( LI w al

5 (u

(u

al LI. 3' br -ri F

180

Mining of lignite, its use and some problems

III-2.2.2 Hydrological situation

The structure and the sequence C E groundwater layers are quite uniform in the Lower Rhine Bay can be discussed jointly.

main lignite bed and/or the principal lignite bed as shown in Table 39. The most important groundwater retaining horizons are the Reuver clay formation and the

Five groups of water bearing beds can be distinguished:

(1) Pleistocene above the Reuver clay formation and/or also above the clay formations in deeper levels where the Reuver clay is eroded. This aquifer with free groundwater table has been found in thicknesses up to 80 metres in the Erft Basin.

(2) Pliocene between the Reuver clay formation and the lower red clay. Its maximum thickness of 40 to 60 metres is likewise found in the Erft Basin; only in the marginal zones of the Erft Basin and the Rur fault block area has it a free table.

(3) Lower Pliocene and upper Miocene, between the lower red clay and the principal lignite bed group. Within the Erft Basin it has a thickness of up to 200 metres. This aquifer also has a unconfined groundwater table in its marginal zones only.

(4) The groundwater is confined except in minor marginal areas.

(5) Oligocene sands in the lignite group.

III-2.2.3 Lignite deposits

The lignite deposit in the Lower Rhine Bay, totalling about 55 x lo9 tonnes, is the largest genetically-closed lignite deposit found in Europe.

Lignite deposits: 9 Federal Republic of German 60 x 10 tonnes

Europe

World

9 2100 x 10 tonnes 9

155 x 10 tonnes

Lignite is mined in 28 countries of the world.

on top of them. In the past, extraction has been mainly from the shallow beds in the eastern part but shallow opencast mining will be superseded by deep opencast exploitation to 300 metres and deeper in the future. This will require the removal of an increased amount of overburden which will be reflected in the overburden-to-lignite ratio. This ratio, which is an important economic factor, increased from 0.75:l to 2:l during the years 1950 to 1970 and is expected to rise to about 2.5:l or even 3:l by 1980 (Leuschner, 1970).

As well as increases in the ratio of variation of the overburden to lignite there have been considerable increases in the amount of water to be lifted (up to 1.28 x lo9 m3 in 1969). Based on an exploitation of 91 million tonnes in 1969, this makes the water to lignite weight ratio about 14:l.

about 1900 kcal/kg.

Lignite deposits exist at different depths and with formations of different thicknesses

The lignite as excavated has a moisture content of up to 60%. Its calorific value is

111-2.3 MINING OF LIGNITE, ITS USE AND SOME PROBLEMS

111-2.3.1 History

Until the middle of the 19th century lignite was used primarily as domestic fuel and in agriculture as fertilizer except for minor production of mineral pigments and alums. The lignite bed or seam as a whole has a relatively thin overburden consisting of gravels and sands. Clay in the area west of Cologne in the Ville fault block, is also fully exposed in some locations. In these areas, lignite extraction was initially by tunnel working methods or in open pits. Accordingly the opencast lignite mines were small and very scattered due to the then existing ownerships; mostly they were agriculture-related operations. Only

181

Table 39. Synoptic table of the stratification in the brown coal district of the Rhineland

GEOLOGICAL FORMATION SERIES OF STRATA

AGE IN YEARS

TALTERRASSEN COVERED BY LOAM HOLOCENE 11 o00 110 O00 WUERM-GLACIAL NIEDERTERRASSEN ) 230 O00 RISS-GLACIAL UNTERE MITTELTERRASSE COVERED BY 2 470 O00 MINDEL-GLACIAL MITTL . -/OBERE MITTELTERRASSE~ LOESS

2 PLEISTOCENE GUENZ-GLACIAL JÜNGERE HAUTTERRASSE 1 800 O00 TEGELEN- INTERGLAC IAL TEGELEN-SCHICHTEN ( "TEGELENTON" )

01 ALTERE HAUPTTERRASSE 1 O00 000 OLDER "ALTESTE DILUVIALSCHOTTER~~ (J~LICHER SCHICHT. )

OBERER REUVERTON SANDMITTEL UNTERER REWERTON SANDE UND KIESE ZW I SC HENTON SANDE UND KIESE OBERER ROTTON

REUVER-SERIE

PLIOCENE

ROTTON-SERIE SANDE UND KIESE UNTERER ROTTON

12 O00 O00 HAUPTKIES-SERIE SANDE UND KIESE FLOZ SCHOPHOVEN

INDENER OBERFL~Z- FLÖZ KIRCHBERG

F ISCHBACH- SCHICHTEN FLÖZ FRIESHEIM RESPEKTIVELY GRUPPE ZWISCHENMITTEL

SANDE UND TONE

"NEURATHER SAND" MIOCENE FLOZ GARZWEILER

VILLE-SCHICHTEN FLöZ FRIMMERsDORF GRUPPE ZWI SCHENMITTEL

FLÖZ MORKEN SANDE, TONE UND BRAUNKOHLEN SANDE UND KIESE TONE UND BRAUNKOHLEN

H 23 O00 O00 SANDE E+

GRUPPE SANDE ffi UNTERFL~Z- TONE UND BRAUNKOHLEN E KÖLNER SCHICHTEN

OLIGOCENE

TONE UND BRAUNKOHLEN SANDE TONE UND BRAUNKOHLEN SANDE

GRAFENBERG- MARINE SANDE MIT SIDERITSANDSTEIN LINTFORTER SCHICHTEN RATINGER SCHICHTEN "RATINGER TON" VALLENDARER SCHICHTEN TONE, SANDE, SCHOTTER RATHEIMER SCHICHTEN MARINE SANDE 35 o00 O00

EOCENE 55 O00 O00 (SCHICHTLUCKE)

MARINE SANDE HUCK3i;LHOVENZR PALAECCENE RESPEKTIVELY

77 O00 O00 ANTWEILER SCHICHTEN TERR. QUARZSCHOTTER, TONE UND BRAUNKOHLEN PALAEOZOIC RESPEKTIVELY MESOZOIC

The.mining of lignite, its use and some problems

after the hriquetting press had been invented and railways had been constructed around the turn of the century was a wider field of use and sales created for lignite. Centralization of the smallest scale mines into a total of about 600 operations around 1885 then resulted in the first increases in exploitation capacity when average daily yields of 75 tonnes per mine were obtained.

The beginning of this century saw the introduction of mechanical lignite mining using excavators, especially as the suitability of lignite for use in the electricity generating field was recognized. The demand for lignite increased tremendously with continuing technical development of mining machinery and equipment (Raack, 1962).

111-2.3.2 Development of excavating machinery, conveying and deposition equipment

Until 1955,exploitation was substantially restricted to the Ville fault block area. The bed, which may be considered as a classic deposit with an overburden to lignitemtio of only 0.75:l (m3 0verburden:tonnes lignite) sets the standard for the design of the initial excavating equipment.

Mechanization and opencast lignite extraction was initiated by means of steam operated excavators. Developments were from single and double dischargers to swing excavators which could be used as upward and downward cutting units. Overburden transporter bridges made it possible to carry the overburden over the shortest distance possible, namely above the exposed lignite, to the dump. The introduction of crawler mounted equipment made the mining machinery free to operate independently from track routes. The development of the bucket wheel excavator finally led to continuous mining operation.

The Bucket Wheel Excavator:

The bucket ladder excavator then gave way to bucket wheel excavators, the development

The bucket wheel excavator can be used for a variety of applications depending on the of which was very rapid as dictated by new openings from 1955 onwards.

conditions prevailing in any one deposit. Thus, it can be operated in an upcutting or down- cutting mode relative to its base line. Separate removal of clay and sand beds in the lignite, and of inferior quality coal, unsuitable for use, can be performed. Several of these bucket wheel excavators having daily capacities of 100 O00 m3 (Leuschner, 1970) are in operation in the opencast mines of the Rhinich Lignite District.

use within the next few years. When extracting the lower level deposits in the Hambacher Forst between Cologne and Aachen it is possible that open pit mining units of 300 O00 m3 daily capacity will be utilized if present plans as shown in Table 2 come into fruition.

It is expected that excavators having daily ields of 200 O00 m3 (Figure 23) will be in

Deposition Equipment:

Simultaneously with the increase in capacity of the excavating machinery the size of the depositor (Figure 24)has had to be adapted to these mining units. Generally it consists of two main units - the deposition section and the receiving section. The connecting part is a belt conveyor. The depositor unit moves on crawlers over the dump face. Ln installations of this type high capacities are reached by continuing feed of overburden to the dump rather than by mechanical or design improvements. A prerequisite to this is, however, that the overburden absorbing capacity of the dump trench be as large as practicable. Over- burden is fed to the dump trench either by overburden trains or by belt conveyors. This ensures substantially continuous filling. Details of the depositor are given in Table 41.

Conveying Equipment: .

the overburden and the lignite were transported by means of trains. Wagons each having a capacity of 96 m3 were developed specifically for overburden handling. axle loads involved also required separate track systems with high-strength rails. The operational track assemblies must always be adapted to the unit of the loading excavator which changes its excavating range.

In the early days of lignite mining, i.e., when the opencast mines were still shallow,

Of course the high

I83

i 3 Figure 23. Bucket wheel excavator with a daily capacity of 200 O00 m

Table 40. Technical data of bucket wheel excavators with 3 200 000 m

Excavator No 255

Year of order 1952

Length of the bucket wheel arm m 69

Diameter of the bucket wheel m 16.0

3.6 Bucket volume m

Propulsive output of the

3

bucket wheel kW 1 050

Cutting height m 47

Depth of cut m - Total cutting width, max. m 57

Installed driving energy kW 7 500

Total working weight MP 5 700

Medium soil pressure kp/cm2 1.28

Daily capacity 1000 m3/d 109

259

1957

71

17.3

2.6

1 700

53

22

10 5

9 400

7 200

daily capacities of 100 O00 m3 to

262 284 Projected

1.62 1.40 1.48 1.50

112 112 112 200

1963 1969 1970

70.5 70.5 70.5

17.5 17.5 ca. 21

3.5 3.5 5 .O

1 710 1 290 2 500

52 50 50

25 18 18

107 98 98

10 400 8 800 14 O00

7 600 7 900 -

184

The mining of lignite, its use and some problems

3 Figure 24. Depositor with a daily capacity of 200 O00 m .

Table 41. Technical data of depositors with daily capacities of 100 O00 m3 to 200 O00 m3

Depositor No. 735

Year of order 1952

Length of the receiving arm m 77

Length of the deposition arm m 91

Deposition height m 34

Deposition depth m 53

Total deposition width m 87

Installed driving energy kW 2 980

Total working weight Mp 2 560

Medium soil pressure kp/ cm2 1-00

Daily capacity 1000 m3/d loo

737 7 44 7 50

1956 1957 1963

58 49 50

100 100 90

35 38 36

60 60 53

103 101 104

3 840 4 960 2 940

2 440 3 820 2 410

1.20 1.14 1.23

110 150 110

Projected

1971

79

110

40

67

127

7 O00 - 1.20

200

As the pits increased in depth it was no longer possible for trains to overcome the gradient, a problem solved by the provision of belt conveyors (belt width from 2 to 3 metres and speeds of 5.2 m/sec) to carry the overburden and/or coal to the dumping areas.

111-2.3.3 Output rates and use

As well as an increase in the lignite output rate from 60 x lo6 tonnes in 1950 to in excess of 91 x lo6 in 1969, there has been a transition from shallow to deep opencast operations reflected hy the large increase in the overburden handling rates from 45 x lo6 m3 in 1950 to approximately 185 x lo6 m3 in 1969. iod from 1950 to 1969 from an average of 0.75:l to more than 2:1, with some individual opencast mining fields already having an overburden to lignite ratio of over 3:l. Added to this is a considerable increase in the amounts of water to be lifted, as will be discussed later.

The absolute increase in exploitation rates should not be evaluated alone since at the same time there has been a concentration of several medium-scale opencast mining operations into fewer large-scale mines. came from 19 open

The overburden to lignite ratio increased during the per-

In 1950 the total output of 105 x lo6 m3

I85

Water management zn opencast lignite mining areas

pits, but only 6 opencast mining operations were left by 1969; these had produced a 2.7-fold increase with rates of 276 x lo6 m3 put of each opencast mining unit. In addition, the mean shift output increased from 25 to 60 tonnes/man during that same period.

for the generation of electricity while 64.6% went into the production of domestic fuel briquettes. This proportion has changed fundamentally owing to thetxemendous increase in the demand for electricity and the continually changing living habits as well as higher demands for comfort. went to the power stations and only 27.4% was processed into briquettes, a trend which is still continuing, being in line with efforts to reduce air pollution.

, making an average 8.4-fold increase in the total out-

Of the 60 x 106 tonnes/year of lignite extracted in 1950, approximately 29.4% was used

By 1969, 69.1% of the 91 x lo6 tonnes of lignite extracted during the year

111-2.3.4 Resettlement

The opening of new opencast mines often means the resettlement of individuals or entire communities, because to leave a community in the middle of a mining field would impair the mining operations to an unjustifiable extent for technical reasons, not to mention the very considerable embankments that would have to be provided. Where a community or village is situated at the outskirts of a mining field, however, mining can be arranged so as to spare it in exceptional and urgent cases.

In case of resettlement - after a comprehensive public planning procedure - a new community would be established with due attention to landscaping and urban planning aspects to provide for the social interests of those affected by the resettlement. About 20 communities have been resettled to date and a few more resettlements are likely to follow the opencast mining expansion in the north and west of the mining area (Dalldorf, 1970).

Many such resettlements are improved because they incorporate modern ideas on housing, agricultural commercial/industrial planning and traffic control.

Large size overburden dumps occurred only in the initial phase of large-scale opencast mining; in the present stage of opencast mining the overburden material is insufficient to fill up the excavations and their potential as reservoirs for water is being considered.

111-2.4 WATER MANAGEMENT IN OPENCAST LIGNITE MINING AREAS

111-2.4.1 Draining

Exploitation of the deposits in the Rhinish lignite area requires a lowering of the water level to 300 metres below ground level to permit the recovery of dry lignite, to avoid cracking of the mine base and to stabilize the mine embankments. It exerts a considerable influence on the hydrology of the area.

1.4 x lo9 m3 of water lifted represented an absolute maximum; during the last 10 years average change substantially during the next decade (Heitkamper , 1971) . has an effect far beyond the opencast mine. level in the top aquifer while lowering and/or releasing water in the lower aquifers affects an area of some 2000 km2.

The large volume of water involved is pumped from a large number of large diameter gravel pack wells extending at present to depths of about 180 metres on an average and 450 metres maximum. The total number of operative drain wells in all opencast mines is 1 120.

where the wells are constructed by flushing methods in the absence of well casings does the ,

operation become economic. This drilling method permits the sinking of wells in a minimum of time: the time for completion of such a well, depending on its depth, is 5-15 days inclusive of setting up the drilling equipment (Siemon, 1967).

The wells are fitted with screens. After many trials with different types of construc- tiori material it has been found that asbestos cement pipes are most suitable for both lining- and screens in well construction. These pipes, with internal diameters of 400 to 800 mm can be installed down to a depth of 350 metres. Apart from their cheapness, they have the

The total amount of water to be drained is of the order of 35 m3/sec. In 1966 the the volume of water pumped

some 1.2 x lo9 m3 per annum. This value is not expected to

The high permeability of the strata means that the lowering of the groundwater level About 1000 km2 are affected by lowering the

Because of the large number of wells necessary and their great depth, only in those cases

I86

Water management in opencast Zignite mining areas

advantage that excavation can be performed around the mining area and that they can be used again from a lower level.

the lowest open pit floor in continuous operation. The pump motors are rated for 1400 kW and designed to operate at a voltage of 6 kV. while working against static heads of up to 320 metres.

In spite of the gravel screens, the 800 metre diameter well pipes cannot prevent a certain amount of fine-grained sand being pumped with the water and since groundwater often has a high iron content, the pumps are subjected to considerable wear and tear; they also gradually get clogged up. TV cameras are used to find and examine damage inside the wells.

A small meshed network of about 6000 measuring points are available for groundwater observation. Measurements are taken in the observation wells at weekly, monthly or half-yearly intervals and comprehensive statistics thus obtained are fed into modern data processing machines to provide accurate knowledge of the groundwater conditions in the area surrounding the mines. The resultant information is used as a basis for preparing maps at regular intervals of isopiestic lines and lines of equal lowering of the groundwater table for planning the position of wells for pumping and to observe the influences of the drainage measures already taken. ,

ditions and their variations with time; this network is checked every other three months (Gruber, 1971a). .

water. However, the variation in iron and manganese content remained within normal limits for potable supply. General fears about the infiltration of salty water or that the extracted water would exhibit a rise in temperature due to the lowering of the groundwater have been without substance. Only in a few locations in the vicinity of faults within and at the outskirts of the mining area itself, was slightly mineralized or warm water observed from deep wells. Such phenomena are for the time being, therefore, theoretical scientific interest only in view of the small areas and minimal volumes involved (Lindner, 1963).

The groundwater lowering in the Rhinish lignite mining area represents a time-restricted influence on the groundwater balance. As soon as the water has been lowered to the desired level and groundwater reserves removed to achieve this, the removal rates will undergo a substantial reduction to the volume required to keep pace with replenishment only.

The submersible pumps which are used are capable of lowering the water table to below

Their capacity is 15 m3 of water per minute

A grid of 40 index measuring points has been derived for supervision of groundwater con-

The quality of the pumped water differs slightly from that of the upper layers of ground-

111-2.4.2 Discharging

3 The groundwater recovered during the draining, approximately 30 m /sec, is mainly discharged through pipelines to the Erft River and Kolner Randkanal except when used as replacement water (Heitkamper, 1971).

it touches the present mining area along its entire length. With a mean water flow of originally approximately 5 m3/sec, however, its capacity is inadequate to receive large quantities of water from the mining drainage. Extensive works were undertaken to increase the capacity of the Erft River which is now capable of discharging 30 m3/sec without any damage and of carrying off some 66% of the water drained from the mines. With this extra load the Erft River now carries an average of 25 m3/sec of water which corresponds to a mean flood water.

was built during 1955-57 at the time of changing over to large-scale opencast mines when it was realized that the capacity of the natural drain, the Erft-River, was not sufficient to receive the estimated amount of extracted water. A maximum of 24 m3/sec of water can be discharged by this channel at a mean velocity of flow of 2.3 m/sec. It passes through the Ville crest by a 6 km long tunnel then crosses the Middle and Lower Rhine terraces as an open channel and finally joins the Rhine River at Dormagen through an intake structure.

a pumping station. Randkanal to compensate for the influx from the opencast mines during flood seasons and thus prevent natural flood waters being increased even further by the additional water from the mines.

The Erft River seemed particularly suitable to accommodate drained groundwater because

The artificial Kolner Randkanal, by which some 33% of the drainage water is discharged,

The KÖlner Randkanal is in communication with the river system of the Erft River through A control system permits the entry of natural Erft-River water into the

187

Water management in opencast Lignite mining areas

111-2.4.3 Soil-water-situation

Subsoil conditions within the Erft River area are substantially determined by the relative position of the Erft River level. Accordingly, there are permanently flooded and water- logged soils present in the Erft River plain attributable for the most part to the Erft River flood waters. The predominant type of soil is gley with transitional formations of brown earth gley (Eskuche, 1962).

The predominant type of soil on the plains in the Erft River basin on both sides of the Erft River is loess which overlies the terrace sands and gravels and extends from south to north in increasing thickness to reach a thickness of up to 20 metres in the north. A highly developed agriculture demonstrates that this is one of the most fertile regions of Germany.

As a type, the loess soils of the Erft River area belong to the so-called 'parabrown earths' which are characterized by a relocation of clay substances from the top soil into the enrichment horizon of the bottom soil. This provides a barrier to infiltration of water but this is not a disadvantage from an ecological aspect. The water and the air condition is nicely balanced and any extra drying-out or wetting is not to be expected. Biological activity is good, too, as indicated by the presence of many earthworms deep in the subsoil.

adverse consequences to the agriculture of the Erft River area. In the loess areas the groundwater table was already so low before the lowering campaign that it had no impact on vegetation. Generally, there is no correlation between subsoil water conditions and agricultural utilization at a ground water table from 1.50-2.00 metres below the surface since plants in such cases are supplied from the adhesion waters present. It may be said, therefore, that the water supply of the plants will also be ensured in the absence of any subsoil water influx as has been conventional practice hitherto namely, to grow only one field crop each vegetational season. This is the reason why groundwater lowering is either of no importance to the growth of crops or even advantageous where damage due to excessive wet- ness, causing wet rot is thereby avoided.

Only in the valley plain of the Erft River where the plant roots reached the groundwater before the lowering campaign started could changes in vegetation be observed. Unti- lowering took effect, the Erft River plain used to be almost exclusively covered by wet, swampy meadows and pastures which produced unsatisfactory crops; afterwards, they were changed into profitable fertile meadows and pastures. However some damage could be attributed to groundwater lowering in valley plain areas with swampy soils where soil settling was observed and detrimental effects on poplar cultures were encountered due to water extrac tion.

The extensive lowering of the groundwater table has not resulted in any substantial

III-2.4.4 Influences on surface waters

Apart from the problem of large-scale groundwater lowering, the Erft River area also involves further water management problems including a number of measures to preserve existing drainage conditions, to provide flood protection and to eliminate wastewaters.

m3/sec and often resulted in inundations and heavy damage, it was not capable of draining the substantial quantities of water originating from the mines (Heitk'&per, 1971) . hensive extensions to the Erft River increased its drainage capacity for larger volumes of drain waters and at the same time provided increased safety against inundation.

Where the Erft River constituted an obstruction to lignite mining because it adjoined directly the opencast mines or even passed across exploitation fields, its bed was diverted several times. These diversions were necessary to make the opencast mining operations safe and/or to permit continuous extraction. (70 m3/sec) and the river bed dimensions determined accordingly.

advantages that introduction of large volumes of clean groundwater improves the water quality in the Erft River which is pretty much affected by wastewaters.

lower course was allocated Class II which means 'moderate pollution' class (Table 42) so that in this mining area the Erft River is today known for good fishing.

As a river with an average flow of 5 m3/sec which during flood seasons rises to 40-50

Compre-

All diversions were based on the flood water figures

Besides flood protection, these operations and subsequent precautions offer the further

The river has a plentiful and well-balanced biocoenosis of native species. Even its

188

Water management in opencast Lignite mining ureas

Table 42. Chemical and physical measurements

Erft at Neussr near its mouth into the Rhine

Measurements : May 1966 - May 1967 in intervals of 14 days Measurements : May 1967 - May 1968 in intervals of 14 days - - x = Average of 27 single measurements

G1 pH GU Wi Ca Mg Alk.1.W. Fe Kn UC03 C1 SO4 PO4 NO3 NH4 oz mn04 PSB T 1-1s OdU OdH mg/l mval mg/l mg/l mg/l mg/l mg/l w / l mg/l mg/l mg/i mg/l mg/? oc

:qLn 463 6.7 13.9 10.8 66 17 0.6 0.22 0.01 241 32 31 0.15 6.0 0.14 7.1 6.6 0.3 12.6

66/67 Max 529 8.2 15.7 12.3 76 32 2.0 4.83 0.73 275 43 49 0.8 11.8 1.52 9.6 25.9 9.0 19.7

X 502 7.5 14.6 11.7 70 21 1.0 1.0 0.29 255 36 40 0.4 7.8 0.47 8.2 10.8 3.4 16.5

Min 487 7.3 13.6 8.8 63 17 0.8 0.38 0.13 192 39 26 0.15 3.3 0.08 7.1 5.2 1.0 11.2

67/68 Max 549 8.2 15.4 12.7 74 30 1.5 4.81 0.04 178 46 67 0.82 15.5 1.79 9.4 30.7 16.4 22.1

R 523 7.7 14.5 11.6 69 21 1.2 1.54 0.28 253 43 39 0.46 7.7 0.95 7.9 11.8 3.4 17.3

The continuous flood waters of the river narrow the area of intense plant and animal population and biomass production to a small strip of maximum 1.5 metres width along the river banks.

The Erft River has almost homothermal water due to the predominant influence of the drainage water which is subject to very slight seasonal temperature variations only. This results in very interesting consequences with regard to the plant and animal life of the river; subtropic compsopogon hockeri from warm water aquaria.

groundwater due to the continual groundwater lowering and hence still only serve as drains for surface waters. This is the reason why the discharges in these brooks depend substantially on precipitation which is quite different in the various seasons (Diesel, 1963).

for instance it accounts for the presence and tremendous development of the tropic/ red algae which were presumably placed into the Erft River

The small brooks within the Erft River area are not often in communication with the

IIï-2.4.5 Water supply - Gärtner Scheme The lowering of the groundwater meant that a large number of water supply plants failed or, at the margins of the mining area, operated under more difficult conditions, but inadequate supplies are maintained because the mining authorities provided compensation.

This substitution of water supply is being accompanied by a considerable readjustment within the area either by a merger of several large-scale supply undertakings into a joint supply facility or by connection of small-scale and even minute supply systems to central- ized grids. which finally took care of water supply. Thus, in an effort to safeguard public water supply, one new water supply works was constructed, 13 waterworks were extended and about 8 others were replaced by connections to other systems (Heitkhper, 1971)

To permit an adequate volume of water to be extracted as the groundwater table is lowered, wells were sunk to levels of more than 300 metres below datum level. Simultaneously, it was necessary to construct new treatment plants because the water obtained from greater depths contains a higher percentage of iron and more carbon dioxide. are today being supplied from substitute water supply facilities.

Moreoverr the lignite mining company provided a number of its own installations

Some 240 O00 people

i 89

Water management in opencast Zignite mining areas

A major part of the water demand is met by mining drainage waters which have been avail-

The total delivery from mine draining installations is currently 155 million m3 per able at a mean rate of approximately 1.2 x lo9 m3 per annum for the last ten years.

annum which is subdivided as follows (Gärtner, 1968)

3 95 million m per annum = 62% for power stations 40 million m3 per annum = 25% for industrial needs 20 million m3 per annum = 13% for public water supply.

3 The present water requirements in the Erft River area are about 370 million m per annum and are covered by 708 installations, of which 107 plants belong to the public water supply. The current water demand is still below the average groundwater replenishment rate which is approximately 400 million m3 per annum in this area (Gärtner, 1972).

In view of the tendency towards increased demand, however, requirements may well exceed the groundwater recharge rate in the seventies. Nevertheless, such increased demands can be satisfied without difficulty from the tremendous volume of water drained from the lignite mines for another 30 years.

a considerable supply required in this area especially as the ever increasing demands are expected to grow as high as 600-700 million m3 per annum by the year 2000 and cannot be satisfied by the available resources (Heitkämper, 1971)

requirements from other sources, the water supply could possibly be provided by utilizing the remainder of the opencast mining area for water supply purposes. Intense feasibility studies for this project called ‘Gärtner Scheme’ after its initiator, are currently being made.

Termination of lignite mining will leave depressions totalling at least 3 x 10 m because of the removal of lignite. The space thus left over would gradually fill with water in the course of time (Gärtner, 1968).

waters from other streams into the depressions but since the introduction of Erft River water is expected to be feasible only during periods of higher river discharges and the average amount available annually only 15-30 million m3 , the filling process would take decades However, the volume of water required for a fast fill could be made available from the Rhine River which has a yearly discharge of approximately 70 x LO9 m3. be necessary to avoid substantial water pumping works and would have to pass through the left Rhine Valley at a depth of about 400 metres, ie, within the basement rock formations. Nevertheless, it is believed that this could still be accomplished economically if novel tunnel drilling machines were used.

While the problems of refilling the excavated pits with the necessary quantities of water might be solved, it is impossible to predict how the water quality may develop. Numerous investigations conducted during past decades show that the natural state of the gradually filling basins is very much dependent on such factors as subsurface conditions encountered, weathering influences, prior depositions (overburden, ashes, debris), and the fill-up water as such. It is initially characterized by high sulphate concentrations and chloride contents with low temporary hardness in most cases. The concentration of soluble salts reduces in the course of the years.

If Rhine River water were to be added to accelerate the fill-up process it must be expected that natural eutrophication and enrichment with undesirable ingredients and/or component substances will increase. Comprehensive research and investigation is being carried out at present to determine the importance of these phenomena and possible precautions to be taken.

avoiding the difficulties most likely to be raised by increasing water requirements, not only in the Erft River area which is influenced by the mining activities, but also in the neighbouring Cologne and Neuss districts.

After exhaustion of the lignite deposits and the end of lignite mining, there will be

Apart from drawing groundwater from the deeper groundwater aquifers or by meeting the

9 3

Another possibility would be to speed up the filling process, namely, by transferring

A connecting tunnel would

The project to connect the residual lakes to the Rhine River might be the best way of

i 90

Cone lusion

111-2.4.6 Residual depressions

So far the mining companies have tried to make the worked out areas suitable for further use by filling up the excavated pits. They have also tried to keep the rate of land requirements down to a minimum. Yet it is almost inevitable that residual depressions are left, (see Sec- tion 4.5) (Gärtner, 1972).

These abandoned lignite mine pits fit reasonably well into the recultivation scheme from a landscaping aspect. They are part of the recreational areas (water sporting lakes) and vast natural parks (forests, lakes) that help to improve the quality of living in such a highly stressed region which has lignite opencast mining, agriculture, housing and indus try.

to shaping the banks and to stabilizing them with suitable timbers. The development of biozanosis of the lakes has not been influenced by man. A primary growth which automatically takes place very quickly, changes in the course of the years to what is called a climax community. Very interesting investigations by Herbst (1966) have described the phenomenon of how nature takes possession of an artificial water body.

Man’s creative activities on opencast cavities to provide forest lakes are restricted

111-2.5 CONCLUSION

As the foregoing comments indicate, the exploitation of lignite in the opencast mines of the Lower Rhine is continuously being rationalized by such things as concentration of the number of opencast mines to but few intensely utilized pits, development of large-scale mining equipment of increasing capacity and improvement of power plants. It is expected, therefore, that lignite will maintain its place shown in Table 5 as a source of primary energy during the next decades.

Table 43. Shares of energy carriers in covering the electric power requirements of the Federal Republic of Germany (Frewer , 1972)

Energy Carrier 1960 %

1970 1980 1990 % % %

Nuclear power O 2 28 59

Natural gas 1 5 8 4

Hydro power 11 7 4 3

Crude oil 3 16 21 14

Lignite 27 26 22 14 Pit coal 54 40 16 6

Others 4 4 1 O

In the course of such a development as this there is constant transition to deep-level opencast mining with increased overburden volumes, ie, with an increased overburden to lignite ratio. The economic problems created thereby are expected to be compensated in part by rationalization and increased yields. A very important problem is created by the residual cavities and piles of redeposited overburden.

Braunkohlenwerke AG, KÖln, has accomplished exemplary achievements. Of the approximately 2500 ka2 Rhinish Lignite mining area it has exploited since the last century, a total of 154 km2 of land of which about 91 km2 have so far been recultivated - approximately 45 km2 for forestry, approximately 34 km2 for agriculture and approximately 12 km2 for highways, housing areas, and recreational areas - and some 63 km2 are currently in use (Leuschner, 1971). The re-established area has been structured in accordance with the latest findings of regional landscape and settlement planning as well as agricultural and forestal techniques. Here the rare opportunity was seized to plan the structure and utilization of a landscape (Rheinische Braunkohlenwerke AG, 1971).

The forest-lake area of Bruhl-Liblar near Cologne, more than 20 km2 in extent, has thus become one of the most beautiful recreation areas. By systematic landgcaping and structural

It is in this connection particularly, that the lignite mining company, the Rheinische

“7%

191

References

development a recreational area was produced which nowadays attracts at weekends more than 20 O00 visitors from the metropolitan areas of Cologne, Bonn and Dusseldorf. The main attrac- tions are the numerous lakes for all types of water sporting activities. Where man had influenced and changed the natural landscape to such an unequalled extent in his attempts to establish the necessary energy supply for concentrated areas, a new landscape was born to fulfill a vital task in compensating the consequential effects of densely populated areas.

111-2.6 REFERENCES

Dalldorf , H. F. 1970. Umsiedlungen im Rheinischen Braunkohlenrevier . Revier und Werk,

Diesel, E. 1963. Die Grundwasserbeschaffenheit im linksrheinischen KÖlner. Wirtschaftsraum Ministerium fur Ernahrung, Landwirtschaft und Forsten, Düsseldorf.

Eskuche, U. 1962. Eerkunft, Bewegung und Verbleib des Wassers in den Böden verschiedener f?flanzengesellschafter des Erfttales. Ministerium fur Ernahrung, Landwirtschaft und Forsten, Düsseldorf.

Friedrich, G. (Erf t/Niederrhein) Mitteilungen der Landesanstalt fur Gev&serkunde und Gewässerschutz NW, 33 , Krefeld. Frewer, H. 1972. Energieverbund zwischen nuklearen und konventionellen Kraftwerken Atomwirtschaf t.

Gärtner, E. peicher zur zukÜnf tigen Wasserversorgung Sonderdruck aus "BraunkohZe Heft 2.

G'artner , E. 1972. Bergbau und Umwelt (Manuskript eines Referates anlaBlich des Welt- Bergbau-Kongresses in Bukarest.

Grober Erftverband. 1971. Bericht \ber die Verbandsiatigkeit im Jahre 1970 Eigenverlag, Bergheim/Erf t.

Grober Erftverband. 1971. Basisplan Nr. 1 zur Sicherung der Wasserversorgung im Verbandsgebiet Eigenverlag, Bergheim/Erft.

Heitkämper, J. 1971. Wasserwirtschaft im Rheinischen Braunkohlenrevier Sonderdruck aus DAI - Deutsche Architekten- und Ingenieur-Zeitschrift, 9 (5) . Herbst, H. V. ungsgebieten der Brau-nkohle-Industrie im FPlner Raum Ministerium fur Ernahrung, Landwirt- schaft und Forsten, Dusseldorf.

Leuschner, H. -J. 1970. Entwickl-ungstendenzen '70 der Tagebautechnik des rheinischen Braukohlenbergbaues BraunkohZe, Warme und Energie, 22, 370.

Leuschner, H.-J. 1971. Das rheinische Braunkohlengeb,iet als landschaftspragender Faktor M<tteiZungen aus dem Markscheidewesen, 7-8 (4). Lindner , W. 1963. Die wasserwirtschaftlichen VerhAltnisse im Erftgebiet Soqderdruck UUS "Die Wasserwirtschaft", 53

Lindner, W. und Stein, A. 1971. Moglichkeiten fur Grundwasseranreicherung und Grundwasser- speicherung im Gebiet des groBen Erftverbandes Bergheim/Erft.

Raack, W. 1962. Der Braunkohlenberghau in der Bundesrepublik Verlag Gluckauf GmbH, Essen.

Rheinische Braunkohlenwerke AG: 1971. Blickpunkt Braunkohle Eigenverlag, Koln.

Rheinische Braunkohlenwerke AG: 1971. WO neue Walder wachsen Eigenverlag , Koln.

202, (10).

1973. Ökologische Untersuchungen an einem thermisch anomalen FlieBgewässer

1968. Die Ausbildung des Erftbeckens als oberund unterirdischer GroBwassers- Wärme und Energie 'I,

.. 1966. Limnologische Unters-uchungen von TagebaugewaSsern .in den Rekultivier-

..

.. ..

..

Siemon, H. 1967. EntWAsserung der Braunkohlentagebaue im Rheinischen Braunkohlenrevier Sonderdruck aus "BraunkohZe Stein, A. 1969. Gedanken zur Sicherung der Wasserversorgung im Gebiet des GroBen Erftver- bandes Neue DELIWA-Zeitschrift, 3.

Wärme under Energie 'I.

192

3 Effects of industrial waste water and sludge on the self purification of rivers in the Federal Republic of Germany

by

Klaus Heuss and Herbert Massing

Northrhine - Westphalia


Introduction


Urban settlement and growing industrial production, combined with rapidly increasing demands for water, are causing water management problems. One of the most important of these is the contamination of surface water with liquid and semi-liquid waste, and with waste water and sludge where domestic sewage consisting of organic omponents is mixed with different types of liquid industrial waste with a variety of origins.

Cities and rural communities were faced with waste water and solid waste problems even in earlier, pre-industrial centuries. Epidemics of past centuries have been attributed to water, waste water and solid waste, situations which at the time were corrected by engineering measures such as sewer construction, waste removal and medical precautions such as vaccination , medicines, personal hygiene , etc.

Waste water removal and, in part, solid waste removal have transferred the problems into the surface water. Initially, no purification of the waste water was carried out, for surface water bodies have a self-purification capability through a natural process which incorporates the contamination and foreign matter carried by waste water into the metabolism of the biotope, or discharges it as harmless matter.

affected by the concentration of urban areas and industries as follows: - the concentration of waste water in urban centres causes overloading. - types of waste water are also generated that cannot be incorporated into the natural purifi-

This process, characteristic of any surface water body, is upset, degraded, or toxically

cation process, or only after negative effects have been caused. Even in the 'domestic' area of sanitary sewerage, the waste water generated in past dec-

ades assumed a strongly chemical character, and high load of substances foreign to nature. Agriculture, can also be responsible for degrading the surface water bodies by generating

runoff from animal husbandry units which contain predominantly organic components; from the use of mineral fertilizers; and as a result of chemical pest control, but, these effects will not be discussed in this paper.

Frequently, the first step in controlling the problems that exist in surface water bodies is to purify the effluent from sewage treatment of plants, action which may have been initiated already in many instances. Nevertheless, the discharge from treatment plants may still carry a residual load which can be very high, especially in urban areas.

grade their power of self-purification. Such substances originate from a wide variety of sources in industry, in the cities and in agriculture, but the chemical industry with its liquid and sludge-type wastes is particularly important.

The primary task is to protect surface water bodies against toxic substances which de-

111-3.2 BIOLOGICAL SELF-PURIFICATION

Lauterborn (1911), defined natural self-purification as 'the capability of a surface water body to process waste water, so that, after a variable distance from the point of introduction, a river will show approximately the same condition as above the contamination point'. It should be added here that stagnant water bodies also have a 'capability' for natural self- purification .

the important role of water bacteria in self-purification. are introduced into the receiving water with the waste water. Thus, from human sanitary systems alone, 12.5 to 40.0 x lo7 coliforms per person per day are added to sewage. the reproduction of bacteria under favourable conditions of growth depends within broad limits , primarily on the nutrient concentration , surface water bodies carrying especially high concentrations of quasi-natural waste, characteristically show a high bacterial content. This direct proportionality between degree of contamination and bacteria density is due to the fact that the contaminants can be exploited in the growth and metabolism of bacteria, break- ing down high-molecular compounds, such as hydrocarbons, protein, fats, into low-molecular substances, and gaining energy in the process.

These reduction processes take place in stages as a result of the successive activity of 3ifferent groups of micro-organisms. The organic substances involved are broken down at very different rates, depending on their composition and on environmental conditions. As a rule, protein is reduced first, followed by sugar, fatty substances, and finally the high- molecular substances such as chitin, cellulose, lignin, and the like.

At the turn of the century Mez (1898) and Spitta (1936) recognized and described fully In most instances these bacteria

Since

194

Study of natural self-purification and its interference

Putrefying bacteria which can use protein substances as a nutrient dominate in surface water. The hydrocarbons are reduced in several intermediate stages involving a great number of bacteria groups, but also myxobacteria and fungi. Fatty compounds are split by bacteria with the aid of lipase; hydrolysis results first in glycerol and fatty acids, of which glycerol is usually oxydized very rapidly and is an important source of energy.

result in firstly aromatic rings incorporating hydroxyl groups almost exclusively. Subsequ- ently, these rings are split, the oxygen required for this process being incorporated catal- ytically by oxygenases. The reduction of aromatic hydrocarbons plays an important role in the purification of industrial sewage such as waste water discharge by the chemical industry and refineries. In addition to some yeasts and other fungi, it is primarily the representatives of the bacterial genera of Pseudomonas, Vibrio, Spirillum, Flavobacterium, Achromob- acter, Bacillus and Nocardia that are capable of oxydising the aromatic hydrocarbons (Fuhs, 1961).

tances of flow, the question arises as to what mechanisms inteact in this process. For this purpose we must keep in mind that, normally the bacteria counts are reduced only when the available level of substances which the bacteria can reduce to acquire energy becomes very low. First of all, sedimentation processes contribute to the scarcity of bacteria; often the settling suspended particles will coagulate, adsorbing the bacterial cells and burying them in mud. In addition to this pudy physical process, however, a biological aspect must be kepf in mind; organisms in the water feeding on bacteria, such as rhizopoâs, flagellates and ciliates, will decimate the bacteria population. Finally, the myxobacteria and bacterio- phages must be mentioned as important elements of this purification process. Moreover, growth substances discharged by the bacteria themsleves, by fungi, and by different types of algae have a bacteriostatic or even bacteriocidal effect. Among the Metazoa it is primarily the rotarians which feed on bacteria.

ing fish, or part of the food chain.

purification are varying concentrations of phosphates and nitrates. Both are considered important nutrients for autotrophic organisms. Enrichment with these substances and the resulting processes in surface water are described by the term 'eutrophication'. growth of algae, found particularly in over-fertilized stagnant waters, can be retarded by the development of small crustaceans (Cladocera, Daphnia for instance) by the so-called 'grazing effect'. The purification efficiency of these biological filtering mechanisms results in water bodies previously turbid from vegetation, now appearing clear again ('clear water stage').

tion cycle which is shown schematically in a diagram by Bick (1964).

a sequence of organisms, bacteria - ciliates - algae - cladocera - fish, which is controlled by the prevailing nutrient situation hut at the same time is fitted into the food chain.

Toxic substances, such a a number of hydrocarbons, e.g., the phenols,or heavy metals - mercury, lead, copper, zinc, can occur in such high concentrations in the receiving water that some groups of organisms, or even the entire population, are damaged, thus eliminating a part or all of the self-purification process

Even the aromatic hydrocarbons can be attacked by micro-organisms. Their reduction will

Considering the reduction in bacteria counts experienced over often remarkably short dis-

Ciliates can become the food of other ciliates, of suctoria, some vertebrates and hatch-

Yet another group of organisms must be considered. The end products of natural self-

Potential mass

The foregoing indicates that a succession of organisms is involved in the' self-purifica-

Consequently, if we simplify the process, we can state that self-purification involves

111-3.3 STUDY OF NATURAL SELF-PURIFICATION AND ITS INTERFERENCE

While sewage has an unfavourable effect on the oxygen content of surface water by introducing organic substances which consume oxygen and cause an undesirable increased growth of biological matter in the water, industrial waste water can cause additional damage to the micro- organisms in the water, as a result of specific substances included in their effluents as described previously. primarily effected by micro-organisms.

Water toxicology procedures in the Federal Republic of Germany (FRG) based on the use of the physiological reactions of aquatic organisms involved in natural self-purification as the evaluation criteria. Here it is not so important to determine whether the natural self- pur- ification has been adversely affected; the point of interest is the quantitative one, i.e./ a statement as to the boundary to which the detoxification or dilution of the waste water

This will upset the basic processes of natural self-purification

I95

. * :.> I

+ 100

+ 00 - $ + 60 .G ai

\

Figure 26. Diagram of assimulation-and-demand test, so called A-2 test, of waste water from a chemical plant located in the Lower Rhine.

I96

Study of natural seZf purification and its interference

must be carried in order to achieve biologically tolerable conditions in the receiving water.

111-3.3.1 Study of the incipient retardation of enzymes

Enzyme tests can be considered a preliminary stage in physiological or biochemical investigations. Their object is to determine the intensity of the enzyme production by the bacteria present in the waste water to be tested. Koppen (1954) described such a test which can be used to determine the incipient reductase inhibition caused by toxic substances in waste water.

in waters has been incorporated in the German standard procedures for water, waste water, and sludge analysis. This procedure (Bucksteeg and Thiele, 1959) permits a distinction to be made between reversible and irreversible damage to the bacterial population. This is possible because the activity of dehydrogenases, unlike the activity of other enzymes, terminates with the death of the cell. Consequently, the presence of dehydrogenase proves the presence of living cells. If the dehydrogenase activity declines during the test, it demonstrates a much more serious degradation in the test matter than, for instance, a reduced oxygen consumption. For, while an inhibition of dehydrogenase activity is indicative of dying bacterial cells, reduced respiration rates can also be reversible phenomena. Even very small concentrations of cyanides (CN), for example, will inhibit the incorporation of oxygen by the cell without actually resulting in the death of the organisms, provided the exposure is relatively short. The activity of the hydrogenases is identified by 2, 3, 5-triphenyltetrazolium chloride (TTC). A control comparison with test matter containing none of the waste water specified above, or only small concentrations, will permit a quantifiable statement on the inhibition or increase of dehydrogenase activity caused by the waste water, or by individual substances contained therein.

the species and the physiological situation of the bacteria involved in the test are defined.

Another procedure for testing the retardation of proteolysis caused by toxic substances

The reproducibility of these test results is poor since neither the bacteria count nor

111-3.3.2 Study of the incipient retardation of oxygen metabolism

These tests are based on the concept that the effect of waste water or the individual substances it contains can be measured by changes in the oxygen metabolism. The number and activity of the bacteria contained in a water sample can be deduced from the respiration rate.

In the test used in the FRG (Kopp, 1964) , called 'Zusatzliche Zehrung' , an excess of nutrient (peptone and glucose) is provided in order to test the reaction of the protein or hydrocarbon reducing bacteria contained in the water. If the bacterial population is intact it will react to this excess nutrient by exhibiting increased metabolism and division rates. This increased bacterial activity is measured via the oxygen reduction taking place in the test vessel. If the bacteria fail to react to the extra nutrients it is probable that their activity is being inhibited by intoxification of the water body from which the water and bacteria sample were taken.

can be used in water toxicology to determine the incipient inhibition of oxygen metabolism; other oxygen-generating autotrophic organisms such as algae can also be used. This is another technique developed by Knopp (1960) for measuring the reaction of the phytoplankton to the type and concentration of substances contained in the water. The difference between the oxygen content of two samples at the end of this test is called the oxygen production potential (SPP). This oxygen production potential defines that quantity of oxygen which can be generated by the phytoplankton of a body of water. Since the determination of the oxygen production potential takes place under constant conditions of illumination intensity, and temperature, these SPP values must be considered as relative only. Combined with quantitative plankton analysis, this technique permits conclusions to be made as to the activity of the phytoplankton.

during natural self-purification, i.e., bacterial performance and phytoplankton performance measured via the oxygen consumption (respiration, 2) and oxygen production (biological production, A). By comparinq of samples of waste water with different dilution ratios with samples of receiving water it is possible to determine very precisely that waste water concentration (threshold value) which will just cause a disturbance of the physiological react-

However, the oxygen-consuming heterotrophic bacteria are not the only organisms that

Finally, the procedure devised by Yaopp (1961) combined the two basic values observed

I97

Study of natural self-purification and its interference

ions described above. Consequently, this procedure allows prediction as to whether the receiving water is sufficient to dilute the waste water to a concentration which will he harmless from the point of natural self-purification, or whether the insufficient dilution will be disastrous, and that further treatment of the waste water is required without fail before dumping. This A-2 test is more sensitive than other toxicological analysis techniques using the survival rate of organisms as an indicator (such as toxicological fish tests) , since the physiological disturbance threshold is, of course, located below the lethal concentration. This procedure has the advantage of using the same type of populations or organisms and water quality found in the water bodies to be investigated. water quality but also the population of test organisms is subject to change between successive samples, so that the exact reproducibility of results is no longer ensured in longer term series of analyses.

Its disadvantage is that not only the

111-3.3.3 Study of the incipient degradation of defined model organisms involved in biological self-purification

Evaluation procedures involving other techniques (Bringmann and Janicke, 1963; Bringmann and Kuhn, 1959a and b, 1960a and b; Bringmann and Meinck, 1964) have been developed to eliminate the deficiency of poor reproducibility of measured results over longer-term series of analyses. These meet the following requirements: maximum precision; strict reproducibility of measured data; recognition of the different types of basic processes involved in biological self-purification. Exactitude of method and strict reproducibility of test results presupp- ose the use of defined species ized population density and which are suitable for use regardless of the season of the year. The complex process of 'natural self-purification' is subùivided into logical partial processes. test, or by certain substances contained in that water, is tested via specific reactions of test organisms, all belonging to the same species.

The retardation of glucose reduction is used as the model for the effect of toxic substances in waste water on the bacteria and their physiological performance. isms are bacteria of the genus Pseudomonas. value during specified reaction periods, in the sewage-free control cultures, and in the test cultures containing varying quantities of waste water. Incipient biological degradation is inferred if differences occur between the pH values in the control sample and a certain dilution stage of the test culture.

the production of monocellular algae. This process, exploited as a toxicological procedure, is considered to be more sensitive to toxic substances contained in sewage than the inhibition of the oxygen production of algae. Thebiomass of the selected test algea, Scenedesmus quadricauda, generated over the test period, is determined by nephelometry. Lesser turbidity equivalents in certain dilution ranges of the test cultures, compared with those of the control cultures, identify the inhibition of cellular division in the green alga Scenedesmus.

The ingestion of bacteria by Protozoa can be inhibited by intoxicants contained in waste water. Test procedures in the FRG use a test strain of Colpoda maupasi, a holotrichous cili- ate. ure and the test culture, each containing different quantities of waste water. The incipient inhibition of the ingestion by Protozoa is considered to take place at that dilution ratio where the turbidity values of the test culture are first located above those of the control culture - ied from the moribund degradation of the motion (stating the IC501 of small crustaceans of the Daphnia genus in progressive dilution series of waste water and receiving water.

the fish. The fish tests have two important advantages over the techniques described, namely: - fish can be handled and observed easily without elaborate apparatus, and - the tests can be operated on a continuous basis.

A fish monitor test for continuous measuring operation was developed, for instance, by the 'North Rhine Westphalia Institute of Hydrology and Water Protection', and by the 'Baden Wuerttemberg Institute of Hydrology' (Juhnke and Besch, 1971). The test fish are located in a test space subdivided by grilles, through which the test water flows constantly. When the

of test organisms having a standardized history and standard-

Each individual partial process and its possible degradation by waste water under

The test organ- The measured quantity is the alteration in pH

The measure for the degradation of algae is the inhibition of cellular division, i.e.,

The Colpoda are fed a defined suspension of Escherichia cozi in both the control cult-

The effect of intoxicants contained in water on the lower-order Metazoa can be identif-

Finally, test procedures are carried out using the last link in the aquatic food chain:

198

Practical effects on natural! self-purification in the River Rhine

fish are in an undegraded condition they will swim opposite to the flow in the test space (positive rheotaxis). As soon as a critical degree of intoxication is exceeded, the co-ord- ination of the motions of the test fish is disturbed to such a degree that they drift against the terminal grille of the test space. Here changes in the condition of the test fish caused by toxic substances in the water can be detected without delay, by means of photoelectric recording or load-sensitive signal pickups with transducers. These types of early warning systems are required particularly by those water processing plants drawing their raw water from surface water bodies where danger of pollution is always present, as for instance, in the case of the Rhine Water Works which draws water from the River Rhine.

natural self-purification are summarized in Table The different procedures available for determining the degradation of partial areas of

Table 44. Review of methods for physiological tests of the effects of pollutants contained in waste water (after Bringmann, 1970)

Test-organisms Test -pr oc edur e of determination Method of test Type

Species History Number of organisms

Retardation of Bio- Unknown enzyme-activity chemical

Retardation Physio- Unknown of oxygen logical metabo 1 ism

Inhibition of Physio- Known biological self- logical purification

Degradation Physio- Known of test fish logical

anatomical

Not Not Incipient retardation of standardized standard i z ed enzyme-ac tivi ty Not Not Incipient retardation of standardized standardized oxygen demand and oxygen

production

Standardized Standardized Incipient retardation of representative life processes of the biological self-purification a) the bacterial degrad-

ation of organic carbon compounds

b) the rate of growth of algae producing oxygen

c) the ingestion of bacteria by protozoa

d) the feeding activity of crustaceans

Optional Optional Incipient degradation of test fish

111-3.4 PRACTICAL EFFECTS ON NATURAL SELF-PURIFICATION IN THE RIVER RHINE

Two major approaches are needed to solve these problems: on the one hand, individual organic and inorganic pollutants and/or waste water mixtures of the type encountered under practical circumstances are tested. On the basis of these findings a quantifiable description of the potential effects of the waste in the receiving water can be made. On the other hand, the effects caused by the waste water discharged into the receiving water can be measured in the water body itself. The first approach is taken if prognosis is the objective, i.e., during the design and scaling of sewage treatment facilities. The procedures described by Bringmann and Kuhn and the A-Z test by Knopp are suitable for this purpose. If the objective is corrective measures in the water bodies themselves, the reactions are measured in the receiving water. This can be accomplished by means of the Knopp procedure for acquiring the oxygen production potential, and the excess consumption of peptone and glucose. The procedures

199

Practica2 effects of natura2 seZf-purification in the River Rhine

of Bringmann and Kuhn can also be used.

111-3.4.1 Waste water testing for potential inhibition of natural self-purification

In principle, these tests involve the determination of threshold values for the reactions of individual test organisisms or unknown mixtures of species taken from individual receiving waters to pollutants contained in waste water. Some typical results are listed in Table 45.

Table 45. Incipient retardation of glucose reduction by Pseudomonas flourescens (after Bringmann and Kuhn, 1960b).

Harmful element / Tested as- compound

Concentration p .p .m.

Ag H9 Cu Ni Cr Pb

Silver nitrate Mercuric chloride Copper sulphate Nickel chloride Potassium dichromate Lead nitrate

O. 004 O .O06 0.05 0.12 0.14 0.19

Phenyl mercuric acetate 0.004 Quinone 0.2 Formaldehyde 2 .o Phenol 70 .O

Incipient retardation of cellular division by Scenedesmus quadricauda (after Bringmann and Kuhn, 1959a) .

Harmful element/ Tested as Concentration p .p .m. compound

Hs Mercuric chloride O .O3 Ag Silver nitrate O .O5 Cu Copper sulphate 0.15 Cr Potassium dichromate 0.7 Ni Nickel chloride 1.5 Pb Lead nitrate 2.5

Methylene blue Formaldehyde Quinone m-nitrophenol

o .l 0.3 6 .O

28 .O

200

Practical effects on natural self-purification in the Riuer Rhine

Incipient retardation of ingestion by Colpoda maupusi (after Bringmann and Kuhn, 1959b).

Harmful element] compound

Tested as Concentration p.p.m.

Ag Silver nitrate O .O3 Ni Nickel chloride 0.05 Cu Copper sulphate O .O5 Hg Mercury chloride 0.15 Cr Potassium dichromate 0.21 Pb Lead nitrate 1.25

Methylene blue Quinone Formaldehyde Phenol

0.2 2 .o 5 .O

30 .O

Degradation of motion (IC 50) by Daphnia magna (after Bringmann and Kuhn, 1959a).

Harmful element/ Tested as Concentration p.p.m. compound

H9 Mercuric chloride o .o2

Cu Copper sulphate 0.1 Ag Silver nitrate O .O3

Cr Potassium dichromate 0.7 Pb Lead nitrate 5 .O Ni Nickel chloride 6 .O

Quinone Methylene blue Formaldehyde Phenol

0.4 2 .o 2 .o

16.0

In addition to establishing individual threshold values, these tests allow a further conclusion: relatively few substances in water have the same threshold level of toxicity for three or four groups of the test organisms used. In the majority of cases, the toxicity of the waste water has a selective effect directed against one group of test organisms most sensitive in the case in question. Again,this can be demonstrated in tabular form (Table 46).

Because of this variable toxicological sensitivity, each of the four group of organisms i.e., bacteria, algae, ciliates, and small crustaceans, is exposed to the waste water under test.

water needed to avoid disturbanceof natural self-purification in the receiving water.

characteristics (A) and comsumption characteristics (2) , resulting from different degrees of

Table 48 shows the required dilution ratios of individual types of industrial waste

The results of the A-% test permit similar conclusions. Figure26shows the assimilation

20 1

Practical effects on natural self-purification in the River Rhine

dilution [in this case by non-toxic aquarium water). The tested waste water which was discharged into the Rhine River in this form originated from a large chemical plant.

Table 46. Selective toxicity of industrial waste water towards one group of organisms (after Bringmann and Meinck, 1964)

Type of waste water Small

crustaceans Protozoa Bacter ia Algae (Pseudomonas (Seenedesmus) (CO Zpoda 1 (Daphnia)

Retarded Retarded Retarded Degraded glucose cellular ingestion motion reduction division after 24 after 48 hrs. after 16 hrs. after 14 days. hrs.

to a dilution of waste water:

Waste water from a spun rayon/plant. Waste water from a galvanotechnical plant.

1:4000

1: 400

Waste water from a di-isopropylbenzene plant. 1:

Waste water from an explosives plant. 1: 100

1: 100 Vapour condensate from a cracking plant.

1: 64 Condensate of the top-distillation of a petroleum refinery. Filter effluent from an azo-dyes plant. Condensate of the desulphuration - plant in a petroluem refinery. Lye of powerformers in a petroleum refinery . Effluent from deodorizers in a petrol- - eum refinery. Oil separator effluent from an ethylene - plant in petrochemical works.

-

-

1: 32

1: 4

1: 2

1: 16

1: 16

i : ao0

1 : 100

1: 16

1: 16

1: 16

O

1:400

1: 16

1: 2

1: 32

1: 8

1: 32

1 : 800

1: 64

1: 32

1: 16

1: 2

~

1: 400

1: 64

1: 8

1: 16

1: 16

1: 64

1: 64

1 : 1000

1 : 1000

1: 800

1: 200

The consumption test indicates that the lowest waste water concentration tested (dilution 1:lOOO) has a toxic range of about 40 to 50%, rising to a level of 80 to 90% in the concentration range from 1:lOO to 1:20. Considering a waste water generation of approximately 2 m3/ sec at a mean low-water rate of flow (MNQ) of about 800 m3/sec in this river section according to the consumption characteristics, the resulting dilution would be 1:400, which corresponds to an inhibition of bacterial activity by about 65 to 70%. charged does not immediately mix with the entire receiving water but remains initially in the form of a sewage band, a calculation of MNQ/2 would be more realistic. MNQ/2, the inhibition of bacterial activity rises to 75%.

While the assimilation rate still rises slightly in the concentration range from 1:lOOO to 1:500 (rising by about 5 to 10% at 1:1000), the further profile of the assimilation characteristics indicates a strong toxicity by a concentration as low as 1:200, even with respect to biological oxygen generation in the receiving water. In the concentration range from 1:lOO to 1:20 the intoxication rate is about 40 to 50%. According to these findings, the waste water sewer must be considered as extremely toxic to both the bacterial reduction processes and the assimilation of green plant life. Even the noteworthy flow rate of the River Rhine in this section (MNQ of about 800 m3/

Since the wastewater dis-

At a mixing rate of

A similar pattern is indicated by the assimilation test.

202

Practica2 effects on naturai! self-purification in the River Rhine

sec). is not sufficient to dilute pollutants in the waste water to the point of becoming ineff- ective.

111-3.4.2 Receiving water testing for inhibition of natural self-purification

We shall now discuss the findings of some chemical analyses of receiving water on the basis of the threshold values determined by Bringmann and KÜhn. For this purpose the heavy metals will be selected from the many possible pollutants in the water. Moreover, we shall discuss only their water-soluble component because, initially, only that component has an effect on biological self-purification. Heavy metal compounds insoluble in water (analysis after acid treatment) are found in the sediment or in suspension. solve under certain conditions (e.g., under low pH-values) and thus transformed into an effective pollutant, see Table 47.

Table 47 records the presence, even after dilution of waste water in the giant receiving water represented by the River Rhine, of temporary heavy metal concentrations which inhibit almost all partial processes of natural self-purification, as for example in the case of copper and nickel. According to these findings, only the propagation of algae would still be intact. However, it should be added - and this will considerably aggravate the situation - that a large number of other substances can be identified in addition to copper and nickel, although they are found in concentrations below the threshold value. We must expect that the effects of some of these substances in water will not just be cumulative but exponentlal.

Moreover, this compilation of heavy metal analyses also shows that the river's mean flow rate of 2400 m3/sec near Emmerich is inadequate to maintain the contamination by some individual substances at an average level, many of which can fluctuate by an order of magnitude. It is these fluctuations and the concentration maxima which put a very great strain on the biocoenosis and regulatory mechanisms.

of the known threshold values and the concentrations of waste water pollutants, has been the subject of comprehensive investigation (Knöpp, 1968). For this purpose excess consumption of peptone and glucose and oxygen production potential have been measured in a series of samples taken along the lower River Rhine.

Figure 27 shows that contamination with putrefying organic material increases in the area between the 650 and 850 kilometre marks of the lower River Rhine. This is substantiated by the biological oxygen demand (BOD) determined in a conventional fashion. Moreover, the values of potassium permanganate (KMnO4) consumption and of organically-bound carbon also follow this trend. Theoretically, this rise would have to be associated with a continuous increase of microbiological reduction activity, corresponding to the 'Zusätzliche Zehrung' (= additional demand). This, however, is not the case. Reduction activity in this area of the river is on the decline, in spite of an increase in the BOD by at least 30 to 50% - no doubt the result of degradation by waste water of the river's self-purification capability. The extent of such pollutants not reduced because of this affect is estimated to be equivalent to not less that 100 to 150 BOD/day. The financial outlay involved in adequate sewage treatment (construction and maintenance of sewage treatment plants) to compensate for this deficiency in reduction would be gigantic. The result would be that 'this function of the water body alone (self-purification performance) represents a capital value in excess of five billion Deutsche Mark over the area of the daily flowing distance under discussion here', (Knöpp, 1968).

er River Rhine.

River Rhine, (Table 48). The degree of pollution is estimated to be equivalent to not less than 80 to 100 tonnes 02/day over a day's flowing distance.

ermination of the oxygen production potential in quite a different context. Chemical ditch- cleaning techniques have become widespread in recent times. Submerged and emerged aquatic plants are eliminated by herbicides to maintain proper flow conditions in drainage ditches. Immediately following the application of different herbicides Heuss observed a considerable reduction in the biological generation rate caused by damage to the phytoplankton, 1972).

Although these findings, primarily concerned with the lower River Rhine, demonstrated a frightening picture of the degree of damage done to that river, it is still surprising that

They are toxically inert but may dis-

This problem of interference with self-purification in the River Rhine, obvious in view

Furthermore, biological oxygen generation is subject to serious interference in the low-

This is demonstrated by the decreasing rates of oxygen production potential in the lower

Other interference with biological oxygen generation has been identified through the det-

(Heuss,

203

O H m e O N w i c d

Figure 27. Diagram of Zusatzliche Zehrung (22) [additional demand) in the Lower Rhine in 1965, (after Knopp, 1968).

\

Figure 28. Diagram of assimilation oxygen of phytoplankton (biological aeration) in the Lower Rhine in 1965, (after Knopp, 1968).

204

Practica% effects on natura% seZf-purification in the River Rhine

Table 47. Comparison o$ the heavy metal content Cmy/l) and toxicity thresholds of the River Rhine and two tributaries, Cafter Klein et al., 1972) Ccf. Table 45 )

Fe Cu Zn Pb Cr Mn Ni Sr

River Rhine near Bimmen Min 0.2 0.014 0.025 0.01 0.02 0.01 0.02 - (German-Dutch border) . Max 1.0 0.128 0.280 0.07 0.13 0.12 0.25 - Mix of daily samples, July 1972. Mean 0.6 0.035 0.132 0.05 0.06 0.07 0.06 - River Rhine at point 727.3 km (below metal-working plant, February 9, 1972).

- 0.015 0.19 - 0.025 0.13 0.03 -

River Wupper mouth, June 6, 1972. 0.26 0.085 0.118 - 0.036 0.09 0.07 0.06

River Fossa Eugeniana, mouth. 0.07 0.038 0.065 - 0.012 0.11 0.06 1.0

Incipient inhibition, glucose reduction by Pseudomonas. Incipient inhibition, cellular division of Scenedesmus.

Incipient inhibition, ingestion Colpoda.

- 0.05 0.16 0.19 0.14 - 0.12 -

- 0.15 1.0 2.5 0.7 - 0.9 -

- 0.05 0.45 1.25 0.21 - 0.07 - IC 50 of Daphnia. - 0.1 1.8 5.0 0.7 - 6.0 -

the river has not become an abiotic water body long ago, if we consider the total number of pollutants introduced into it ( the foregoing discussion dealt only with the contamination by heavy metals and the effects of a single industrial waste water discharge point). There must be regulatory mechanisms in operation which have prevented the most devastating effects up to date. In addition to the decisive phenomena of the adaption of organisms to the contaminated environment, especially by the bacteria, there are also the physio-chemical processes, such as adsorption and sedimentation. Thus, for instance, a large part of the zinc contained in the waster water discharged by rayon and viscose staple plants is retained in the suspended matter and sludge of the receiving water over a period of time, (Kaeding and Oehme, 1964). This explains the fact that the bottom sediments upstream of the weirs located below these viscose staple plants show particularly high zinc content.

Throughout the whole of the River Rhine contamination with insoluble suspended matter is very high, (Table 48 ).

The suspended matter discharged into the River Rhine consists primarily of industrial waste such as fibres, carbon particles and minerals. These components will often interlock and agglomerate, mainly due to the action of adhering bacteria, so that under the microscope these concretions appear as inhabited flocculae, or locations of advanced metabolism.

205

Prevention or reduction of intereference wieh self-purification

Table 48. Monthly mean of solids content of the River Rhine near Kleve-Bimmen (German- Dutch border) compared with other water bodies, (Klein et al., 1972).

Settleable solids Insoluble matter Transparency mi /i itr e mg/i itr e cm

Rhine River

August September October November December

Niers River (Goch)

Sept ember December

Schwalm River (Swaimen)

August November

1971 1971 1971 1971 1971

1971 1971

1969 1969

1.1 0.9 1.1 0.9 0.8

0.1 0.1

102.4 80.7 116.6 99.5 65.4

8.4 40.5

8 .O 6 .O

4.5 5 .O 4.1 4.3 5.1

27 .O 33 .o

111-3.5 POTENTIAL MEASURES FOR THE PREVENTION OR REDUCTION OF INTERFERENCE WITH SELF-PURIFIC- ATION

111-3.5.1 Problems of locality

The most damaging and harmful effects on the self-purification of surface water bodies are caused by the waste water and sludge dumped by industry. The primary interference is due to toxic substances from metal processing, non-ferrous metalworking plants, chemical and petrochemical industries, wood and cellulose processing, and the like. Toxic effects on organisms are a problem of concentration; consequently, dilution of the waste water in the receiving water acquires great significance when certain threshold values are exceeded. In the FRG, past industrial development has taken place on the basis of certain factors of locality, the most significant being communication routes, energy supply (such as water power) , and availability of natural resources. While water condition was not considered initially, it has become a restrictive locality factor of the first order during recent decades. One example of the change is the innumerable small metal working plants located in the central mountain regions; their small receiving waters, the plants' main source of energy, were found to be adequate to carry the waste water load. In the course of industrial development, Germany's major rivers and their tributaries become locality factors of ever increasing significance. The urban centres of Rhine/Main and Rhine/Ruhr represent examples of industrial concentrations formed at localities offering favourable conditions for sewage disposal.

industry, even the River Rhine with its high average drainage of 2400 m3/sec and its very uniform flow rate with the maximum to minimum level equalling 20:1, is no longer adequate. for instance, high salt content, have been moved to the seaboard, or else certain types of waste waters are being carried out to sea by ship; such an example is the shipping of diluted acids (20% sulphuric acid) via River Rhine barge to the sea, carried out by a large chemical company generating this acid in the production of titanium dioxide.

The investigations discussed above have shown that in view of the rapid development of (at Emmerich)

As a result of water protection measures, industries generating waste water with,

206

Prevention or reduction of interference with self-purification

111-3.5.2 In-plant measures

The best and most economical method for the prevention of waste water damage is the rnodific- ation of industrial production techniques. Industry in the FRG is today making increasing use of such 'positive environmental' production techniques.

a. Conversion to other raw materials or production aids: Examples include; the petrochemical industry's use of crude oil have a lesser sulphur

content and reducing the use of oil emulsions in metal processing by converting to the use of oil (the reduction of consumed emulsions is difficult) , (Bundesminister des Innern, 1971) .

b. Modification of production techniques: Industry has already made widespread use of these techniques, one such example being the

conversion from a wet chemical process to an electrothermic process in the production of phos- phoric acid to prevent the generation of enormous quantities of gypsum, (Mann, 1970).

c. Closed-cycle production techniques: This type of technology is used increasingly by industry, since it frequently permits

the acquisition of by-products in addition to reducing the waste water load. An example is the closed rinsing water cycles used in galvanic processing plants which recover metal salts by means of ion exchangers, (Meinck, Stooff and Kohlschütter, 1968).

d. Recovery of pollutants (recycling) : If economically justified, and under the pressure of the protective measures imposed by

the water management authorities, recovery techniques are used in most industries. In addition to the many known procedures, new methods are now being developed in the area of elect- rolysis, reverse osmosis, flocculation, and flotation.

111-3.5.3 Industrial in-house sewage treatment plants

The technology for the purification of industrial waste water - including toxic waste and water with a maximum load of organic matter - is highly developed in the FRG, and is now in the process of making rapid advances.

quires the following expensive measures throughout the plant: In most instances the meaningful operation of an industrial sewage treatment plant re-

- Separation of the individual waste water flows within the plant, such as cooling water, waste water with inorganic contamination, e.g. diluted acid, water with organic contamination, and water with toxic contamination;

(cf. 111-3.5.2 above) ;

ing water after temperature reduction, discharging diluted acid into the sea after ship transport.

- Treatment measures at the individual waste water generating points within the plant,

- Discharging separate individual waste water flows: for instance, discharging the cool-

Many industrial sewage treatment plants have been built in the FRG in recent decades. One example is the treatment plant of a large petrochemical enterprise located on the lower River Rhine, which represents Europe's largest industrial sewage treatment plant. waters treated in this plant, have the maximum contamination and extreme toxicity generated by the various production capabilities of a petrochemical industry, including pesticides, synthetic fibres, synthetic rubber and a variety of plastics. Its purification capacity corresponds to that required by a facility treating all the sewage of a major city of 1.3 million inhabitants. The sewage treatment process, developed in more than a decade of pioneering effort, takes place in a pH control system, measuring facility, preliminary settling tank, pump station, biological tank, final settling tank, and sludge treatment facility. A special aeration system was invented for biological treatment with ejectors feeding oxygen at a rate of 2.6 to 2.9 kg 02/kilowatthours. The sludge generated by this plant (about 120 tonnes of dry substance per day) is dehydrated in chamber-type filtering presses after treatment in nozzle separators (centrifuges) , and subsequently supervised by a monitoring station and a waste water laboratory.

111-3.5.4 Combination of public and industrial sewage treatment plants

The results have shown that the organic waste water generated by chemical industries can be treated by means of biological techniques if the organic contamination in the waste water can be ingested by bacteria.

The waste

With respect to the biological activity a distiction can be made

207

Pre&ntion or reduction of interference with se Zf-purification

between easy-to-reduce and difficult-to-reduce substayices Ccf. sectjoyi above). In particular the various organic substances containedin the waste Water generated by chemical industries are very difficult to attack by bacteria. As a xesult, most industrial sewage treatment plants have aeration stages requiring an extended period Of stay; frequently dual-stage techniques are selected where the biotope of the first stage adiipts to the available nutrient of easy-to- reduce contamination, while the biotope of the second stage adapts to the others consisting of difficult-to-reduce substances, (Mann, 1970).

In many instances the available nutrient is insufficient for the system's biotope to effect the biological reduction of substances susceptible to bacterial processing, so that additional nutrient must be introduced. Many experiments have shown that the admixture of domestic sewage from public sewage systems will yield good purification results. These have led to the establishment of several combination public/industrial sewage treatment plants in the FRG. The plant located in Leverkusen on the River Rhine is one such example.

point where the River Wupper enters the River Rhine Here sanitary sewage from the Wupper, amounting to some 70 O00 m3/d and with a contamination corresponding to 15000 kg/d BOD5, is processed in combination with waste water generated by a large chemical company at a rate of 65000 m3/d with a contamination corresponding to 98000 kg/d BOD5. Purification takes place in the following stages:

The first stage of a sewage treatment plant, commissioned in 1972, was situated at the

a. b.

d. e.

g. h. i.

C.

r I.

j -

Initial neutralization of the industrial waste water with lime; Mechanical purification of the sewage; Admixture of industrial effluent and sewage; Second neutralization of the sewage mixture with lime ; Preliminary purification by settling (3-4 hours); First aeration stage (8 hours); Intermediate settling stage (3-4 hours); Second aeration stage (18 hours); Final settling stage (3-4 hours); and Sludge processing (water reduction, thermal treatment, dehydration via filtering process).

A large dumping ground next to the sewage treatment plant, available as a result of moving the beds of the Rivers Wupper and DhÜnn, is used to deposit the deydrated sludge together with the solid waste and incinerator residue of this industrial plant.

111-3.5.5 Artificial aeration of surface waters

The measures indicated above cannot prevent a certain residual contamination of surface water bodies with waste water and sludge. Even this residual contamination proves hazardous to self-purification, and makes it necessary to adopt additional measures to restore the water to its natural condition. The self-purification of a 'natural' body of water is a biological process under aerobic conditions, consequently, artificial aeration of the water is one of the most important supporting measures.

1971) : Techniques used in the Federal Repúblic of Germany include the following , (KfK-ATV-DVGW ,

a. Weirs and waterfalls; When water tumbles over structures built into a waterway there will be greater air contact

than on a smooth stretch of river. b. Aeration by turbines; Air is introduced into a turbine in the negative pressure region behind the rotor, or in

the excess pressure area in front of the rotor, resulting in intensive admixture to the water stream. However, if this is done in the negative pressure region the turbine's performance will be reduced, in the excess pressure region the energy expended for the compressor will increase the cost.

c. Air bubble technique; Compressed air is injected into the water so that the oxygen in the rising air bubbles

will diffuse into the water. Depending on the type of water body, this compressed air can be injected by means of loosely aggregated, porous filter plates, hoses, pipes, or vertical risers.

d. Surface aerators; Aerators are used frequently in waste water treatment; experience acquired in the FRG ha5

shown 'chat they are also well-suited for the oxygen enrichment of surface water bodies such a5

208

Re ferenees

the River Ruhr. The low-oxygen v{ater is aerated and sprayed oyer the surface of the surrounding water body in a highly turbulent pattern; the water being enriched with oxygen in the process.

e. Aeration by ship's turbines; At the present time studies are being undertaken in the FRG aimed at aerating the navigable

waterways by the propulsion systems of ships during periods of low oxygen content. ssed air is injected into the propeller wakes of the ship's turbines, resulting in fine distribution and good admixture with the water.

The compre-

111-3.5.6 Increasing the low water level (low-f low augmentation)

Low-flow augmentation is another excellent means of supporting the self-purification capability of water bodies. It is used frequently in the FRG, especially if the ratio of fresh water to dumped waste water deteriorates very badly.

Wupper is a pronounced central mountain region river (drainage area about 620 km2) , having an unusually high water-level fluctuation (maximum high water flow rate 320 m3/sec , minimum low water flow rate 0.69 m3/sec). contaminated by the drainage of large cities (Wuppertal and others), and by a highly developed industry having a long tradition. Chemical industries and metalworking plants with partially toxic contamination contribute largely to the waste water problem.

Past management of the River Wupper has been unable to prevent the flow rate at the Kluser Bridge gauge in Wuppertal from dropping to a level of less than 1 m3/sec over periods of several days during the dry season. Under extreme conditions, the River Wupper has even dried up. The direct or indirect removal of water from the River Wupper by industry and communities has increased greatly to about 60 million m3/annum. Even the exploitation of all possible engineering measures for purificationm still results in waste water contamination o€ the middle and lower reaches of the river to an unacceptable level.

with a capaciry of 25.9 million m3 This is a multi- purpose reservoir for flood control (especially for the city of Wuppertal) , hydroelectric power, recreation facilities, and low-€low augmentation. This will make it possible to maintain a flow rate of 5.0 m3/sec at the Kluser Bridge gauge in Wuppertal during normal years, and a flow rate of 4.0 m3/sec in dry years, so that a dilution of about four to five times can be achieved in relation to the expected waste water generation.

111-3.5.7 Summarv

The example of the River Wupper demonstrates a measure of this type. The

In its middle and lower reaches the River Wupper is heavily

At the present time in the upper reaches of the River Wupper near KrebcÖge, a reservoir (design ratio 19%) is under construction.

There are many ways of preventing interference with self-purification, but the standard problem at the forefront o€ all measures associated with the establishment of new industries and the expansion of existing facilities is the problem of zoning regulations. The prevention of the discharge of harmful waste into water bodies by in-house precautions must have precedence. Facilities for the purification of unavoidable waste water must assure purification to a degree that the residual contamination load can be handled by the receiving water. Aeration of water booies and low-flow augmentation are the least important considerations; they serve to support the biological self-purification process in the event of contamination that cannot be prevented economically by means of the engineering measures outlined above.

111-3.6 REFERENCES

Bick, H. 1964 Die Sukzession der Organismen bei der Selbstreinigung von organisch verunrein- igtem Wasser unter verschiedenen Milieubedingungen. Ministerium fur Ernahrung, Landwirtschaft und Forsten des Landes Nordrhein-Westfalen, DÜsseldorf, 139 S.

Bringmann, G. 1970 Physiologische Verfahren der biologischen Wasseranalyse. Handbuch der Lebensmittelchemie, 8 , 1/2, 1200-1228. Bringmann, G. and Janicke, W. 1963 Waschrohstoff vom Typ eines Alkylarysulfonates und biologische Selbstreinigung des Wassers . Bringman, G. and Kühn, R. 1959 Vergleichende wassertoxikologische Untersuchungen an Eakterien, Algen und Kleinkrebsen. Geszrnc?heits-.ï-ncpakur 80, 115-120.

Gesu?ad'eits-Ingen{em 84, 213-215.

209

References

Bringmann, G. and Kuhn, R. 1959b Wassertoxikoloqische Untersuchungen mit Protozoen als Testorganismen. &sunclheits-ïngenieur - 80 , 239-242. Bringmann , G. and KÜhn, R. 1960a Zum toxikologischen Nachweis von Insektiziden. Gesundheits- Ingenieur 81, 243-244. Bringmann, G. and K a n , R. 1960b Vergleichende toxikologische Befunde an Wasserbakterien. Gesundhei-t-s-Ingenieur - 81, 337-339.

Bringmann, G. and Meinck , F. 1964 Wassertoxikologische Beurteilung von Industrieabwässern. Gesundheits-Ingenieur 85, 229-236. ,

Bucksteeg, W. and Thiele, H. 1959 Die Beurteilung von Abwasser und Schlamm mittels TTC (2.3. 5 - Triphenyltetrazoliumchlo-rid) . Bundesminister des Innern, 1971 Materialien zum Umweltprogramm der Bundesregierung 1971 , zu Bundes tagsdrucksache VI/2 710.

Fuhs , G. W. 1961 Der mikrobielle Abbau von Kohlenwasserstoffen. hchiv F. MzXrobioZogie,

Heuss , K. Leistungen. Proc. Eur. Weed Res. Coun. 3rd int. Symp. Aquatic Weeds 1971, 139-146.

Heuss , K. 1972 Zur Wirkung einiger Herbizide auf limnische Protisten-Gemeinschaften. 2. Fachgespräch "Gewässer und Pflarzenschutzmittel" . Schriftenreihe des Vereins f. Wasser- Boden- und Lufthygiene (in print).

Juhnke, I. and Besch, W. K. 1971 Eine nene Testmethode zur Frulierkennung akut toxischer Inhaltsstoffe im Wasser. Gewässer und Abwässer 50/51 , 107-114. Kaeding, J. and Oehme , R. 1964 Betriebswassenuirtschaft und Abwasserbehandlung in den Chemiefaserwerken nach dem Viskoseverfahren. Mitt. Inst. f. Wasserwirtsch, 2. KfK-ATV-DVGW 1971 Die kunstliche BelÜftung von Oberflächengewassern (Empfehlungen und Hinweise) . Arbeitsblatt AW 161, Januar 1971 , ZfGW-Verlag , Frankfurt/Main. Klein, M., Heuss, K. and KlÖs , H. 1972 Wasserkontrollstation Rhein-Nord, Kleve-Birmnen, Arbeitsbericht und MeBergebnisse vom 1. July bis 31. Dezember 1971. Landesanstalt £Ur Gewässerkunde und Gewässerschutz Nordrhein-Westfalen , Krefeld.

Gas m d Wasserfach, Teil Flasser, 100, 916-920.

39 , 374-422. - 1971 Der Einflub von Herbiziden auf aquatische BiozÖnosen und deren physiologische

KnÖpp , H. 1960 Untersuchungen Über das Sauerstoff-Produktions-potential von FluBplankton. Schz3eiz. A. F. HydroZ. - 22, 152-166.

KnÖpp, H. Der A-Z Test, ein neues Verfahren zur toxikologischen PrÜfung von Abwässern. Beutsche GewässerlcundZ.

KnÖpp, H. Die "Zusätzliche Zehrung" - eine neue biochemische Kennzahl zur Bewertung von Selbstreinigungskraft and Verschmutzung. Gas- und Wasserfach, TeiZ Wasser, 105, 92-98. KnÖpp , H. 1968' Stoffwechseldynamische Untersuchungsverfahren fur die biologische Wasser- analyse. Int. Revue ges. Hydrobiol. - 53, 3, 409-441.

KÖppen , R. 1954 Verzogerung des katalytischen Wasserstoffperoxydzerfalls durch Gifte als Untersuchungsmethodik an Abwassern.

Lauterborn , R. 1911 Die biologische Selbstreinigung unserer Gewässer. Verh. naturhist. Verein. peuB. RheinZde. I 68 , 473-487.

Mann, T. 1970 MaBnahmen zur Wasserreinhaltung in der chemischen Industrie. Industrieab- wässer.

Meinck, F. , Stooff, H. , and KohlschÜtter, H. 1968 Industrie-Abwässer. Gustav Fischer Verlag, Stuttgart.

Mez, C. 1898 Mikroskopische Wasseranalyse. Berlin.

Spitta, O. 1936 Zur Entwicklung der Lehre von der Selbstreinigung der Gewässer. Gesunciheits- Ingenieur, 2, 363-367.

1961 Mitt. - 5, 65-73.

1964

KoZZoid-Z. - 139 , 172.

210

4 Some aspects of solid waste disposal in the Federal Republic of Germany

by '

Richard Zayc

Hydrological effects of uubanizafion (Studies and reports in hydrology, 18) Paris, The Unesco Press, 1974

Some aspects of soZid waste disposai! in the FRG

111-4 SOME ASPECTS OF SOLID WASTE DISPOSAL IN THE FEDERAL MPUBLIC OF GERMANY

An inescapable outcome of our civilization is a constantly increasing amount of garbage and refuse of various kinds which only partly reflects increasing needs. For a long time, the highly developed economies of technologically advanced countries have not only proceeded to meet needs but have artificially created new demands, again and again; demands for which a real need does not exist, or exists only to a very small degree. Furthermore, extensive rationalization in methods of production and marketing has led to a decrease in re- pair service, with the result that more and more often the acquisition of whole parts or assemblies or even complete items become necessary. Moreover, people are proüded into acquiring new things by fashionable design and promotional advertising, although in many cases the appliances or installations that they already have would serve their purposes adequately. Because the re-use of bottles and containers often requires the application of expensive cleaning processes, it is put more and more into the background. One-way packaging is of course economically profitable for the processing enterprise, and it also faci- litates marketing, but its overall economic effect remains unconsidered. This leads to a distortion in a consideration of its efficiency. In addition, more and more packaging material is used which not only excludes re-use but also raises new problems in its disposal.

An ever more rapidly rising pile of thrown-away goods can be noticed which is not explained by population growth or by essential augmentation of vital needs. This development differs accouding to the degree of technological advance and local circumstances. Here, too, as in other fields , urbanization has an increasing influence for it has been noticed that the amount of waste produced in crowded regions is about twice as large as that in agricultural areas - not including industrial waste. Domestic (including bulky waste) averages about 0.1 - 0.3 tonnes per person per year. This waste has a volume of about 1.0 - 1.5 m3 per inhabitant per year. an amount as large as 0.9 tonnes and up to 2.5 m3 per person per year; that this waste mass increases by 3 - 8% yearly. This means that we can expect a doubling in the amount of wastes in 15 - 20 years.

The amount of industrial and trade wastes differ according to the degree of industrialization. In typical crowded areas industrial waste is about three to five times as much as domestic waste, a situation aggravated by the limited possibilities for disposal in crowded regions and the following dangers and annoyances.

The indicated peak value in highly urbanized regions reaches it can be assumed

(1) Elements can be washed out of wastes by rain at waste disposal points and seep into groundwater where oxygen content and self-cleaning capacity are limited. water might therefore be contaminated and become unusable fox supply. Also, due to erosion on the sides of such waste dumps, heavy rainfall can wash out elements and carry them to surface water with detrimental effect.

The ground-

(2) Annoying smells and smoke from burning dumps, which often are self ignited, as well as evapprating solvents or even escaping poisonous gases, can cause air-pollution with consequent damaging effects to the environment.

(3) By dumping toxic substances, domestic animals and birds may be endangered. Rats and other vermin promote the spreading of diseases.

(4) Disorderly dumps disturb the landscape and affect the well-being of man as well as the aesthetic and recreational use of the landscape.

So far, efforts to dispose of wastes in a harmless way have only partly come up to ex- pectations. The most sensible method would be to compost them for agricultural use which VTould also solve the ever-increasing problem of disposal of sludge from sewage treatment plants; even the bacteria existing in the sludge would he killed to a great extent by composting. However, installations to make compost require a relatively large space and distribution of compost is often doomed to failure due to high transportation costs. Because of -the difficulties in separating household from industrial wastes in crowded areas , the waste may contain phytotoxic substances such as certain metallic compounds which survive the composting process. Therefore, agricultural use of even small amounts of garbage is risky and this method has been relatively little used so far.

212

Working Map Legend

Withdrawal of surface waters (without canal water) for public or industrial water supply with existing or proposed title

Ground-water withdrawales for public or industrial water supply (without agriculture) with existing or applied titles

Entnahmestellen an oberirdischen Gewässern (ohne Kanalwas- serent nahmen) zur öffentlichen oder industriellen Wasserversor - gung mit einem vorhandenen Oder beantragten Entnahmerecht von

Grundwasserentnahryestellen zur öffentlichen Oder industriellen Wasserversorgung. (ohne Landwirtschaft und Gartenbau) mit einern vorhandenen Oder beantragten Entnahmerecht

r, Brunnen O Brunnen, geplant

'+7~zd'ka Brunnengalerie 16

CCC-'~ .>?> Anlagen mit Zahl der Brunnen, wenn Einzeldarstellung. nicht möglich ist

o E u L.3 Sickerstrecke nona Sickerstrecke, geplant

Grundwassergewinnung aus Schacht Oder Stollen eines ehemaligen Bergwerks ;$

" Quelle U Mineralbrunnen dt Heilquelle, staatl. anerkannt

Recht, vorhanden Oder beantragt, zur Entnahme aus vorwiegend natürlichen Grundwasservorkommen Recht, vorhanden Oder beantragt, zur Entnahme von vorwiegend uferfiltriertem Oder angereichertem Grundwasser

00.1 1 5 i0 20 30 40 50 60 70 80 90 100hm3IJ I I I I I~~WilJ

Maßstab fur die Durchmesser der Kreisflächen, be¡ Entnahmerechten unter Oj h m V J entfällt eine Mengendarstellung. Bei Entnahmerechten von mehr .ais 0,5hmVJ werden die Inhaber derselben narnentlich

Zeche

Stadtwerke aufgeführt.

well well, planned well gallery plants with amount of wells if single graphs impossible

path of percolation path of percolation, planned

ground-water extraction from pit or gallery of a former mine

spring thermal spring mineral spring, confirmed by goverment existing or applied titles for withdrawal of natural groundwater

existing or applied titles for withdrawal of shore filtered or enriched ground-water

weniger als OJ hm3/J 0.1 bis 1 hm3íJ

of loss than 0,l hm3/year 0,l to 1 hm3/year 1 to 10 hm3/year 10 to 100 hm3/year more than 100 hm3/year

plants as above, planned

I bis 10 hrn3/J

10 bis 100 hrn3íJ mehr als 100 hm3/J

Anlagen wie vor. geplant

withdrawal for artificial ground-water enrichment

withdrawal for feed of navigable canal Entnahmestelle zur Einspeisung in Schiffahrtskanal

scale for diameter of circular surfaces: quantitative determination omitted for withdrawals under 0,l hm3/year.

mine in case of titled with drawals of more than city plant 0.5 hm3/year the owners are stated by n a m e Bodenabtragungen Oder Ablagerungen von Fremdstoffen mit

mehr als 10 O00 m2 Ausdehnung (gestrichelte Linien bedeuten Planungen)

Soil abrasion or deposit of foreign materials with more than 10 000 rn2 extension (--- lines mean plannings)

Grundwasserbewegun,g, Schutzgebiete und schutzbedürftige Gebiete

C- Grundwasserfließrichtung im 1. Grundwasserstockwerk,

<A- Grundwasserfließrichtung wie vor, vermutet

(. e Trinkwasserschutzgebiet, Zone II, festgesetzt

bekannt

/TL-"==:.; L-.. 4 . _. -".- ...

Pits or quarry (also former plants) for recovery of Ground-water movement, protected areas, and areas requiring protection

flow direction of ground-water known in upper ground-water level

presumed ground water flow as above

drinking water reservations, Zone Il, fixed

Grube oder Steinbruch (auch ehemallge Betriehe) zur Gewinnung von Sand, Kies S

L Lehm, Ton, Mergel F Felsaestein

sand, gravel loam, clay, marl rock-stone

pit, refilled again e;$* Grube, wieder verfüllt,

@?$ Geländeaufhohung Industrieflächen) bzw. (ohne Verkehrs- und bebaute rising slope (without commercial- and industrial surfaces) drinking water reservations, Zone 1 1 1 A, fixed Trinkwasserschutzgebiet, Zone üi A, festgesetzt

cultivated, respectively heaps (without dams + dikes) chiefly with M - waste J . industrial waste 6 - rubbish A . ashes, slag T - debries, rubble K - sewage sludge

, Aufhaldung (ohne Dämme und Deiche) mit vorwiegend

M MÜII J Industrie - Mu11 B Bergematerial A Asche. Schlacke T Trümmer-, Bauschutt K Klärschlamm

=y 2 c. =\ Trinkwasserschutzgebiet, Zone I[, vorgesehen LI&=& drinking water reservations, Zone 1 1 , proposed

(7 I:>,, Trinkwasserschutzgebiet, Zone üi A, vorgesehen

(Die Ausdehnung der Zone IUB ergibt sich aus der Grundwasserfließrichtung. 1st die Zone E nicht in A und B unterteilt, wird anstelle von üi A die gesamte Zone lü dargestellt)..

Ort Oder Ortsteil mit Trinkwasserversorgung aus

-2 C L 3 d

m< Hausbrunnen \\ Wasserwerke

Gebiet mit schutzbedürftigen . Grundwasserreserven Oder weiteres Einzugsgebiet äffentlicher

drinking water reservations, Zone 1 1 1 A, proposed

(Extension of Zone I I I B is resulting from the ground-water flow. Is Zone 1 1 1 not subdivided in A and 8, insteadt of 1 1 1 A the total Zone 1 1 1 is presented.)

e Abwasserteich, Schlammteich sludge bed, waste water pond areas with drinking water supply from house wells

Abwasserlandbehandlung G 7

agricultural sewage ut,ilization area with prohibitory ground-water reservation, or additional catchment area of Dublic water works

Natural park

Wasserdurchlässigkeit des Untergrundes zwischen Erd- und Wasseroberfläche des 1. Grundwasserstockwerks (Staunäcse in der oberen Verwitterungsdecke Oder in geringrnächtigen, porösen Deckschichten zählt hierbei nicht als 1. Grundwasserstockwerk)

Permeability of ground.between surface and water table of the upper ground-water level (stagnation moisture in the upper surface disintegration 'or in thin porous topsoil is not counted here as first ground-water level) Niederschlags- und Überschwemrnungsgebiete sowie Anlagen an

oberirdischen Gewässern on surface waters Precipitation catchment basins and flooded areas and plants

- - Hauptwasserscheide, oberirdisch, übernommen main watershed, taken from the water.economy m a p of the Ground-water Service

Ground-water Seivice

aus der Gewässerkarte des ---..- Nebenhasserscheide, Landesgrundwasserdienstes additional watershed, taken from the water-economy map of the

durchlässig (porös) porous

occurence of well conducting feeder possibie Vorkommen .gut leitender Kluftbahnen möglich

geringmächtige, undurchlässige Oder schwer durchlässige Deckschicht über durchlässigem (poräsem) Untergrund

geringmächtige, undurchlässige Oder schwer durchlässige Deckschicht Uber klüftigem Untergrund

- ----___ - Grenze des Überschwemmungsgebietes border of flooded areas

Pumpwerk zur Beseitigung von Vorflutstörungen

(ohne Angabe der Fordermenge) ,, L-I oder zur dauernden Grundwasserabsenkung

C G Pumpwerk wie vor, geplant

E d Freibad

PCD Teichwirtschaft

pump station for bettering the discharge, or of lovering of the ground-water table

thin impermeable or tight surface disintegration above permeable (porous) subsoil

thin impermeable or tight permeable surface disintegration above cleft subsoil pump station as above. planned

swimming-pool

fish pond insgesamt undurchlässig Oder schwer durchlässig impermeable or tightla permeable

Plate 2. Working map - Water economy basic map. Plate 3. Working map - legend

21 3

Some aspects of soZid waste disposal in the FRG

Combustion or incineration of solid waste reduces its original bulk to about 10 to 20%. However, the resulting energy can only be partly used because the ingredients of wastes generally vary with the season. In many cases additional fuel must be added to maintain a continuous burning process. The resulting residues are at least hygienically safe. Any other use, such as utilization as building material is still rare, and because metallic substances present may be toxic to plants, disposal by infilling or for soil improvement requires special attention.

gases incurs additional expense which may be as high as the cost of combustion itself. In addition, many kinds of waste, such as rubble, glass, etc. , cannot be burned; possibly up to 90% of industrial waste is not suitable for burning. for the purification of incineration gasses. After use, the filter water contains substances which require expensive treatment to prevent damage to receiving surface water.

to water damage. The residues also require a place for disposal although much less room is needed. Incinerators can only be operated fairly economically on a large scale. This means that an adequate amount of waste must originate in the immediate area, otherwise additional costs for transportation will arise with undesirable extra traffic on the transportation routes.

must still be disposed of by dumping. The result of a rough count in the Federal Republic of Germany showed the existence of 50 O00 dumps (of the type mentioned above) of which only 130 meet the standards. Very little volume reduction takes place in the dumps which therefore require considerable space, particularly scarce in crowded areas. In the Ruhr area these deposition areas already cover 7 per cent of the urbanized area. are a factor which has to be taken into account more and more in urban planning.

Suitable information for decision-making is being supplied by so-called waste disposal. Water management and geological situations are shown on Working Maps, such as Plate II and its Key Plate III , available only to a small circle of special offices. These show all water bodies , floodable areas , sources of water supply , fish ponds , dams , etc. The direction of the flow of groundwater is plotted as well as the size and location of catchment areas for drinking water. Furthermore, the permeability of ground formations is shown, with reference made to the extent of risk by infiltration, etc.

struction, shows those areas where dumping of wastes is possible or where dumping should take place only after special safety measures have been taken; ing is allowed. The catchment areas for drinking water reservoirs are again specified to guarantee their protection. Plate IV and its Key Plate V is a sample of such a Consequence Map. Original maps are furnished with an official topographical plan in grey print to simplify local orientation.

Working Maps are given a confidential status to safeguard information about the use of water in industry in terms of process or size of production. The Consequence Maps are also not intended for general distribution and are only made available to responsible authorities.

With the help of these maps it may be possible to take precautions against existing defects and satisfy requirements for future safe disposal.

These planned provisional measures may not always supply a solution to a problem, especially in crowded areas. A comprehensive plan for waste disposal must therefore include means for helping to dispose of existing dumps and establishment of large plants on a few selected areas, where necessary safety measures can be effected. In this way any adverse effects on ground and surface water can be avoided. During processing especially, appropriate measures should be taken to avoid any nuisance to neighbouring residential areas. Fresh wastes should be covered with earth daily and, if necessary, kept damp to minimise the release of odours or dust and an eventual outbreak of fire by self-ignition. Bulky waste should be reduced to small pieces because hollow spaces in dumps promote self- ignition and attract vermin. It is advisable to start growing protective plants on the outer borders of deposits and to extend planting in step with deposition progress.

idues from these also have to be deposited. Additionally, the sorting of combustible from uncombustible waste would be simplified. A crusher should also be installed. Certain

Incineration is the most expensive method and in crowded areas purification of exhaust

Wet filters are very often used

This shows that incineration installations can contribute to air-pollution as well as

Because of these difficulties, it can be assumed that in the future most solid waste

Consequently, they

A second type of map, made available to authorities responsible for supervision of con-

it also shows where no dump-

It is also advisable to equip such large dumps with combustion facilities, as the res-

214

Konsequenzkarte Karte fu r Gewässerschutz und Lagerung von Abfallstoffen

Maßstab 1 : 50000 (Zur Orientierung wird normaierweise der Grundriß der amtlichen topographischen Karte 1 : 50000 ais grauer Unterdruck verwendet)

Consequence Map M a p for waste disposal and for the protection of waters

Scale 1 : 50000 (Normally, the plan of the official topographic map 1 : 50000

is used as an under-print in grey for reference)

Consequence Map Legend

Lagerung von Abfallstoffen unzulässig Oder im Hinblick auf die wasserwirtschaftlichen Gegebenheiten Oder Planungen zu verrneiden, soweit nicht besondere technische Vorkehrungen zur Verrneidung einer nachteiligen Beeinflussung des Grundwassers getroffen werden

Waste disposai inadmissible, or to avoid with regard to water resources or water management plannings, as far as special technical precautions for avoidance of disadvantageous influences of the ground-water are not met.

area with drinking water suppla from house wells " " " Ort Oder ûrtsteil mit Trinkwasserversorgung aus Trinkwasserschutzgebiet, Zone .I u. II, festgesetzt drinking water reservations, Zone I + 1 1 , fixed I(.,/(> Hausbrunnen

I 1 Trinkwasserschutzgebiet, Zone üi A, festgesetzt drinking water reservations, Zone 1 1 1 A, fixed Gebiet mit schutzbedürftigen Grundwasserreserven Oder Wasserwerke weiteres Einzugsgebiet öffentlicher

area with prohibitory ground-water resources, or farther catchment area of public water works "'."., \%,,

I ] Trinkwasserschutzgebiet, Zone I u. If, vorgesehen drinking water reservations, Zone I + I I , proposed flooded area

natural park

---- C überschwemmungsgebiet c-,-- I , . I Trinkwasserschutzgebiet, Zone DIA, vorgesehen drinking water reservations, Zone 1 1 1 A, proposed

(1st die Zone IU nicht in A und B unterteilt, wird anstelle von EA die gesamte Zone üi dargestellt).

(Is Zone 1 1 1 not subdivided in A and E, insteadt of 1 1 1 A the total Zone 1 1 1 is presented.)

Naturschutzgebiet

1 Engeres Einzugsgebiet industrieller Oder gewerblicher closer catchment area of industrial or professional ground. Grundwassergewinnungsanlagen water recovery plant

Lagerung von Abfallstoffen in wasserwirtschaftlicher Hinsicht unter bestirnrnten Voraussetzungen rnöglich Waste disposal possible under certain provisions with regard water management

Bei der Ablagerung Sind besondere Maßnahmen zum Schutze von Gewässern nicht erforderlich, Special measures for the protection of water are not sofern ein seitliches Abfließen gewässergefährden- required for deposits, ar far as the lateral drain of water der Stoffe durch offene Gerinne Oder durch die dangering substances through open conduits, or through the oberen Verwitterungsschichten des Erdbodens in upper residual soi/ into prohibitive areas will be avoided. schutzbedürftige Gebiete vermieden wird.

I/ Are parts of the above stated areas characterized as protected areas with ground-water resources, or as areas with drinking water supply from house wells, the deposit of water dangering substances only is permissible with special precautions.

Sind Teile der oben ausgewiesenen Flächen als Gebiete mit schutzbedürfti- gen Grundwasserreserven Oder als Bereiche mit Trinkwasserversorgung aus Haushrunnen gekennzeichnet, ist die Ablagerung wassergefährdender Stoffe nur mit besonderen Schutzvorkehrungen möglich.

Die Ablagerung ist im Hinblick auf die Durchlässig- keit des Untergrundes Oder wegen der Nutzung oberirdischer Gewässer nur mit Einschränkungen möglich, die auf Grund von speziellen Untersuchun- gen und Erhebungen im einzelnen festzulegen sind. Be¡ der Ablagerung ist besonders darauf zu achten, daß wasserstauende Schichten oberhalb des .in der Tiefe vorhandenen Grundwassers nicht durch Erdbe- wegungen beseitigt werden Oder bereits entfernt worden sirid. Verfüllung von Gruben ist somit nicht ohne weiteres möglich.

1 Disposal individually limited in respect to the permeability of the subsoil, or because of the utilization of surface waters. Special reseyrches and findings are necessary.

Upon disposal special attention has to be paid to the fact that existing water damming layers above ground-water love1 are not removed, or have already been removed. Refill of pits therefore ist not allowed without further regulations.

i hlready existing deposits of foreign materials as well as soil abrasions, or deposits of foreign materials with more {han 10 O00 rn2 extension (--- lines mean plannings)

Bereits vorhandene Oder geplante Ablagerungen von Frerndrnaterial sowie Bodenabtragungen Oder Ablagerungen von Frerndstoffen mit mehr als 10 O00 m* Ausdehnung (gestrichelte Linien bedeuten Planungen)

waste water pond

agricultural sewage utilization

Grube oder Steinbruch (auch ehemalige Betriebe) zur ûewinnung von Sand, Kies Lehm. Ton, Mergel Feisgestein

Grube, wieder verfullt,

Pits or quarry (also former plants) for recovery of 6 3 Abwasserteich, Schlammteich Abwasserlandbehandlung sand, gravel

loam, clay. mari rock-stone

pit, refilled again

Geländeaufhöhung (ohne Verkehrs- und bebaute Industrieflächen) bzw.

rising slope (without commercial- and industrial surfaces cultivated), respectively

Aufhaldung (ohne Dämme und Deiche) mit vorwiegend MÜII Industrie - MÜII Bergematerial Asche. Schlacke Trümmer-, Bauschutt Klärschlamm

heaps (without dams + dikes) chiefly with M - waste J - industrial waste B. rubbish A - ashes, slag T - debries, rubble K - sewage, sludge

Plate 4. Consequence map - map for waste disposal and for the protection of waters. Plate 5. Consequence map - legend.

21 5

Some aspects of solid waste disposal in the FRG

refuse , eg automobile tyres, can only be destroyed at central plants. This is especially desirable in the case of automobile tyres, as not only can the space needed be reduced to a third, but also the stability of the dump will be improved, especially important for vehicu- lar access. Installations for shredding automobiles and large household appliances produce large quantities of unusable waste which have to be disposed of. For technical reasons these installations are extremely noisy and for economic reasons they have to be operated together, if possible. The noise aspect does of course make the choice of location difficult. One should, wherever possible, combine them with central deposition areas.

Ever-increasing demands on our now very restricted raw materials makes re-use more and more important. Metal producing and metal consuming industries have been using this method of re-using waste and scraps for some time. About 30-40 per cent of metallurgical production has been built on re-use of old material; the figure for copper, taken on a world- wide basis, is 50 per cent. Even in paper production up to 50 per cent re-use is possible. Re-use is possible to a great extent with building materials , fine coal , Thomas meal, etc. This application is not unlimited, however, because re-use of old material may cause a reduction in the quality of the new product or damage to machinery during the production process. Such limits, however, are seldom reached; the problem is usually more financial than techni cal.

Adjustment or change of a technological method can result in a decrease in waste or scrap. There has been some success in pickling plants by substituting hydrochloric for sulphuric acid, which can be recovered and regenerated so that there are less refuse acids. The resulting sludge has different properties and does not dissolve so easily in water. The dry removal of scale is another example of how, with a change in technological process, dangerous residues can be avoided.

Another large and increasing proportion of waste is made up of packaging material. Dense populations and their increasing impact on hygiene , and also on the rationalization of transport and marketing have resulted in the adoption of various methods of packaging, especially for food. One of the requirements of self-service is the hygienic and convenient packaging of goods. The return of containers and their cleaning is difficult and costly. There- fore , the general trend is towards one-way containers. But for profit reasons , such packaging is often too large, although some efforts are being made to save material, eg by using thinner glass. Unfortunately, disposal of glass is difficult by any method. It cannot be sorted by any machine and when broken it is very difficult to sort by hand; its presence is not appreciated in refuse composts. Thin glass hinders incineration as it melts easily and in several incinerating systems hinders proper burning because of crusting.

Re-use of glass in the production process would be possible for up to 30 per cent of new production but would mean a separate collection from individual buildings because, as already mentioned, sorting is costly.

In recent years more and more synthetic materials are being used for packaging as they are resistant and stable. From the hygienic point of view they have many advantages, are easily packed and stored. Difficulties in printing on them have restricted their use to a certain extent but on the whole, one must reckon with an increase in their use. Be- cause these materials are very durable and, not being of a biochemical nature, resist de- composition for a long time, they impede composting. Although not directly harmful to soil or plants, they have to be sorted, which is difficult to do mechanically.

Certain types of synthetic material , especially polyvinylchlorides (PVC) and their derivatives, can cause considerable disturbances to combustion. They have a damaging , corroding effect on incinerators and also release chlorine which is harmful to plants and animals. To separate such harmful synthetic material is not even practicable by hand because a general lack of distinctive features makes it difficult to identify. It would be advisable, if possible, to replace PVC by other synthetics, at least where the specific qualities of this material is not absolutely necessary.

posal areas as long as there is no burning. If the containers are bulky, as are many expanded polystyrene containers for appliances , for example, they must be reduced to small pieces. However, this is sufficiently accomplished by the pressure in vehicles dumping fresh wastes.

are so many varieties. In addition, more and more synthetic material is being used to

As they are stable and do not decay, these synthetics are not disadvantageous to dis-

Re-use of synthetics is difficult, hypothetical. and not very promising because there

216

Some aspects of solid waste disposal in the FRG

increase the endurance of other materials, such as paper, cardboard and metal, by covering them with synthetics.

Apart from the use of scrap material in new products, the use of slag offers many possibilities. Large amounts of slag can be used in building technology. Incorporation of slag, glass and certain synthetics in concrete or asphalt, might even have a positive effect because hardness and durability against wear are increased. The large demand for dam and isolation material could be met to a great extent by slag. A lot has been left undone with regard to orderly storing and necessary safety measures, because in the consideration of the costs for environmental improvement they have not been considered. Support from the authorities should be obtained to implement such measures, because otherwise it is only a question of whether buying new raw material is cheaper than the re-use of old. refining old oil has been started in the Federal Republic of Germany and attention has also been given to making such oil harmless. The subsidies paid have encouraged an increase in the purchase of old oil and have helped to decrease the pollution of waterways.

The waste problem is a civilization problem, which can be solved in densely populated areas only on a large scale, making it necessary to find appropriate solutions through regional planning.

disintegration installations, incinerators, and, if necessary, installations for making compost - they cannot be operated by each little community or individual industrial firm to dispose of its own waste. Adequate supervision and control must be exercised to insure that special and toxic refuse is diposed of at special installations. Furthermore, more thought should be given to the collection of waste and, with regard to re-use of certain materials, to the separation of material before its collection. There are certainly no difficulties in collecting separately large amounts of old paper and returning them as valuable raw material to the production process. On the other hand, the re-use of material should be encouraged by subsidies or additional fees and the use of some materials should be discouraged. Pricing policy as a basis of economy is undoubtedly a controlling factor.

Last but not least, the whole problem is one of self-discipline on the part of the producer and the consumer. Greater effort has to be made to make life in crowded areas more bearable.

A process of re-

Owing to the large-scale of the installations - if possible a combination of deposit,

217

5 Waste water dilution in rivers, lakes and reservoirs

Prepared by Prof. A. V. Karaushev in co-operation with a team of scientists at the State

Hydrological Institute

Hydrological efects of urbanization (Studies and reports in hydrology, 18) Paris, The Unesco Press, 1974

Introduction

III-5.1 INTRODUCTION

The protection of streams and reservoirs from pollution and the limitation of waste water discharge has become very important due to intensive urbanization. This is because increased water use causes an increase in water pollution since a large portion of the used water returns as sewage water into rivers, lakes, reservoirs, seas and underyround basins. During the last 40 years the amount of sewage water released into streams and reservoirs has become 20 times greater, resulting in a considerable concentration of pollutants.

sewage purification, reduction of water use per unit of industrial production, systems of closed circulation of water supply, etc., but also the possibilities for waste water self- purification in water bodies. Intermixing of sewage and river reservoir water is one of the most important factors in the self-purification of water masses, and several methods have been developed for a quantitative evaluation of sewage dilution in streams and reservoirs, (Aitsam, 1967; Aitsam et al, 1965 and 1967; Bestsennaya and Faustova, 1969; Zhukov ee aZ, 1962; Karau- shev, 1946; Fyodorov, 1968; Lapshev and Bezobrazov, 1960; Makkaveev, 1933; Rodziller, 1954 and 1965; Ruffel, 1955).

are characterized by turbulence such that the pulsation of stream velocities stimulates mixing of water masses. This causes a dilution of pollutants and, at a certain distance from the place of entry, sewage pollutants may appear to be evenly distributed over the cross-section of the stream.

pollutants in the most heavily polluted currents of water decreases and under certain conditions the concentration of pollutants in water may be reduced to insignificance. The process of turbulent diffusion is also accompanied by physical and chemical processes which in turn may depend on the kinetic conditions of the stream.

The dilution of polluted water may be accompanied by oxidation. The oxygen content of water is enriched by aquatic growth and by entry through the free water surface due to the aeration process, which becomes more intensive in the turbulent regime. Thus, self- purific- ation should be regarded as a combination of hydrodynamic, biochemical, chemical and physical processes leading to reduction of concentration of pollutants in water. Complete self-purification restores the natural- chemical composition and biological processes in the stream reservoir, and is possible where an intensive dilution process exists and quick decay of pollutants can occur. Self-purification is slow if the stream discharge is not large enough to dilute the pollutants, and where the biological and chemical processes are slow and the pollutants include considerable amounts of stable tGxic substances.

A hydraulic solution to a self-purification problem should be based on a knowledge of the rate of diffusion and the degree of dilution of the stable toxic matter. This solution may help considerably in determining the whole complex phenomena influencing the self-purification process, under the condition that numerical characteristics of physical, chemical and biochemical processes (e.g., the speed of decay of organic substances, the rate of oxygen absorption, etc. ) are introduced.

greater or lesser toxicity as well as non-toxic matter. Permitted concentrations of pollutants are governed not only by the characteristics of the pollutants themselves, but also by the type and conditions of water use. Estimates of the maximum concentration of pollutants allowed should take full account of the degree of dilution likely as water intakes for user needs may be situated at varying distances from the source of pollution.

The part of a river or reservoir where natural water is polluted by sewage may be called either the 'zone of pollution' or the 'zone of sewage influence', depending upon the type and degree of pollution. In most a zone of pollution and a zone of sewage influence both exist near the place of sewage entry.

the concentration of pollutants exceeds the permitted sanitary or other maximum limits is called the 'zone of pollution'.

The formation of the zone of pollution is a gradual process which begins from the moment when sewage structures are installed. Depending on the regime of the stream or reservoir and the regime of sewage input, the zone of pollution may either be stable in time and araor change in size and shape.

Nowadays, water management planning and water quality control has to consider not only

All natural streams and reservoirs with potential €or the introduction of sewage water

With an increase in the distance from the place of sewage entry, the concentration of

Polluted water discharged into rivers and reservoirs may contain different substances of

The area where the release of pollutants disturbs the natural biochemical processes and

220

Introduction

On rivers, the stable zones are formed as a rule on the river stretches situated immediately downstream from the places of constant and intensive sewage entry, while in inland reservoirs and seas, they are formed in gulfs and bays, or in shallows with weak currents near the shore where sewage water is released. appear in relatively deep open areas.

biochemical processes are not disturbed and the average concentration of pollutants does not exceed the allowed limits is called the zone of sewage influence.

The zone of sewage influence behaves in a peculiar fashion. It may contain wandering masses of water with high concentrations of pollutants, the movement of which depends on the direction and velocity of natural currents within the zone of influerce itself. The conditions under which these water masses move towards the outlying areas of the zone of sewage influence are determined by turbulent diffusion processes and the variability of the currents, which thus define its boundaries.

sediments. The settlement of suspended particles takes place mainly during periods when there is no current or when water velocities are very low. Pollution of the bed may become a source of repeated pollution of water. In a reservoir, for instance, this may happen when wind- generated currents and waves disturb the polluted bed sediments. Intensive turn over or inversion of water and the resultant removal of the polluted suspension by the current from the zone of pollution may result in a more or less thorough clearing of the bottom. This process of alternative accumulation of polluted sediments and bottom clearing prevents growth of the zone of the polluted bottom. In rivers, the process of repeated pollution of water and bottom clearing is related to the occurrence of floods.

as follows. First, the area of pollution concentration is contoured according to certain average hydrological conditions or for conditions meeting the design regime (e.g., 95% of river discharge frequency, or the minimum velocities of dominating currents in a reservoir). The zone where the concentration exceeds the allowed limits is then determined. This zone would be the instantaneous zone of pollution as it results from specific hydrometeorological conditions. For other directions of currents in a reservoir, the situation and the size of the instantaneous zone of pollution will be different. Final determination of the size and location of the zone of pollution is made by contouring the instantaneous pollution zones taking into account all possible locations of each zone under different hydrological conditions.

might be determined by comparing the pollution concentration values obtained with the values of natural changes in hydrochemical conditions of the water body being studied relative to a given substance. These changes are denoted by:

Unstable pollution zones on the other hand, may

That part of a stream or reservoir which is reached by sewage water but where the natural

Tne suspended matter in the sewage water settles on the bottom and thus pollutes the bed

The boundaries of the zone of pollution and the zone of sewage influence are determined

When sewage dilution is estimated, the outer boundary of the zone of sewage influence

1 - - - % 'n ('max m i n

where Smax and Smin are, respectively, the average maximum and the average minimilm concentration of a given substance in the natural water of a reservoir or river.

An additional criterion is necessary when determining the zone of influence of sewage in lakes and reservoirs. This is because the above method gives only a certain preliminary location of this zone, and it is essential to find the extent to which water masses can be really transferred from the zone of pollution under the actual observed conditions of current velocity and direction variability. If the duration of current in one direction and current velocity are such that polluted water masses can be transEerred at a distance not greater than 9. then it may be assumed for practical purposes that the possible distance from the zone of pollution to the outer boundaries of the zone of sewage influence would be no greater than 2 Thus, the initial location of the outer boundary of the zone of influence should be corrected.

When sewage water contains toxic matter its concentration should be regarded as the main factor in outlining the boundaries of the zone of influence.

When estimating dilution of sewage water it is more expedient to express the concentration value as the excess of a given substance in comparison to the natural concentration of this substance in river or reservoir water. If S is the actual concentration of a given pollutant at a given point of the pollution zone, the adjusted concentration in the given point is:

= s - s 'adj n

22 1

Types of water massas with respect to sewage dizution conditions

where Sn is the natural concentration of the given pollutant. pollutants in sewage water at the place of the release of sewage water into a stream or reservoir ssIadj is estimated as the difference:

The adjusted concentration of

- 'cladj - Ss - sn where Ss is the actual concentration of pollutants in sewage water. If the natural concentration is very small in comparison to s,, it is possible to neglect Sn in the computation and to use the actual concentration value S,.

111-5.2 TYPES OF WATER MASSES WITH RESPECT TO SEWAGE DILUTION CONDITIONS

The dilution conditions and sewage expansion depend on the peculiarities of each given water mass, e.g. its regime, hydraulic and morphometric features.

Water masses are subdivided into water courses (rivers and brooks) and water bodies (lakes and reservoirs); the latter are characterized by slow runoff or by the absence of runoff. Both water bodies and water courses may be subdivided into different types and groups according to the character of sewage water transport and turbulent exchange conditions, (Anon., 1970).

Streams are classified by taking into account the fact that turbulent conditions and transport of pollutants depend greatly on discharge values and current velocities. Rivers are subdivided into mountainous and plains rivers; they differ in slope and consequently in current velocities. Each type is subdivided into groups to distinguish between large, medium and small rivers and brooks, (Table 49).

Table 49. Drainage areas of water courses.

River Group Drainage area, km2

Brooks lo Small rivers 10 - 5000 Medium rivers 5000 - 50 O00 Large rivers 50 000

Table 50 presents types of water courses according to those characteristics which determine the water mixing conditions in them. duce certain abbreviations indicating the type and the group to which a given stream belongs. Types and groups are furnished with a definite index: a Roman numeral (I-IV) indicating the type, with symbol 'r' (river) and a letter which indicates the group ('1' - large, 'mi - medium, 's' - small, 'b' - brook). As part of the mapping an Arabic numeral (1-3) is added to the index which indicates the degree of river meandering.

To make mapping easier it is convenient to i?tro-

The rate of meandering is characterized by the value expressed by the following formula:

where kbed is the length of the stream measured along the river channel, and k, is the length of the same section of the stream measured along a straight line. Arabic numerals indicating the degree of river meandering correspond to the following values of p: index 1 for 1 to 1.2 (relatively straight channels); index 2 for 1.2 to 1.4 ( moderate meandering); and index 3 for greater than 1.4 (intensive meandering). For example, a small mountain river with a moderate rate of meandering should be represented by the following index: lrrrsr2.

lowest C values correspond to the most intensive turbulent exchange, and for greater C values under equal conditions turbulent mixing is less intensive. en in Table 50.

respect to external and internal water exchange. The external water exchange depends on res-

One of the most important hydraulic parameters of streams is Chezy's coefficient, C. The

The most typical C values are giv-

Classification of reservoirs by the degree of sewage water dilution should be made with

222

Types of uuter musses with respect to sewage dilution conditions

ervoir flow, while the internal exchange depends on reseryoir surface area and depth. The dilution process also depends on the shape of the shoreline, that is, On the occurrence of stagnant water areas. The intensity of water mixing is directly related to reservoir depth. When estimating the conditions of water mixing in reservoirs attention should be paid to the difference between üynamic processes in the deep and shallow parts of a reservoir, especially in the shoreline zone.

Table 50. Types of water courses classified according to mixing conditions.

Chezy I s Type Group Mixing Index Ground coefficient River

Mountain medium- rather good I Rocks, 20-35 R. Chirchik at village of Khoj- rivers sized pebble , ikent. R. Mzymta at settlement

gravel. of Kepsh. small good I Ditto 15-30 R. Tefter at settlement of Madagiz brooks good I Rocks, 10-20

pebble.

Foothill medium- good II Pebble, 20-40 R. Gelaya at town of Sterlitamak. rivers sized gravel. R. Kuban at town of Krasnodar.

sand.

Plains rivers

large , good

medium- moderate sized

small, weak

brooks moderate

III Gravel, 40-70 R. Ob at town of Barnaul. R. Desna sand , at town of Chernigor. silt.

III Ditto R. Sura at village of Knyazhikha. R. Ob at town of Kaluga. R. Pronya at village of Budino (2. Dneper basin) -

III Sand, 30-50

III Ditto 10-30 silt.

Plains rivers moderate IV Gravel, 25-60 with multi- or weak sand , branched silt. channels

A Classification of water bodies is presented in table 51; water bodies with an area of less than 50 km2 are classified as small lakes, from 50 to 250 km2 as medium-sized lakes, and more than 250 km2 as large lakes.

The index consists of a Roman numeral followed by the symbol '1' (lake), indicating the type, and the letter '1' for large, 'm' for medium or Is' for small, indicating the group. The classification does not give a subdivision of water bodies by shoreline configuration. ousity is taken into account by ascribing letter 'a' (simple configuration) and 'b' (complex configuration) to the water body index.

When mapping, a certain index is ascribed to types and groups.

When mapging, shoreline sinu-

223

Selection of method to compute dilution

Table 51. Classification of lakes and reservoirs according to the effects of flow and size on sewage mixing.

Group

surface area)

Character of mixing (by water Index Water body

Deep , with medium-sized irrtensive flow small good

I 1,m L. Teletskoye , 'Lenin Lake ' Res.

I 1,s Ortotokoyskoye Res. (Kirgizia)

Deep, with large II 1,l L. Issyk-Kul, L. Baikal low flow medium-sized moderate II 1,m Mingechaurskoye Res.

small II 1,s L. Gek-Gel (Azerbaijan)

Shallow,with medium-sized moderate III 1,m Volgogradskoye Res. intensive small mod er at e III 1,s L. Vagat (Karelia) flow and weak

Shallow, with- large moderate IV 1,l Aral Sea, L. Chany out flow and medium-sized and weak IV l,m Tsymlyanskoye Res. with low flow small weak IV 1,s L. Guryevskoye (Leningrad dist .)

L. Valdayskoye

11-5.3 SELECTION OF METHOD TO COMPUTE DILUTION FOR RIVERS AND RESERVOIRS FOR DIFFERENT WAYS OF DISCHARGING WASTE WATER

Selection of the relevan?.. method for calculating dilution is determined first of all by the place into which waste water is discharged, i.e., into streams or into reservoirs.

The method of classification of rivers and reservoirs outlined in the previous section in terms of conditions of turbulent mixing indicates what mixing intensity should be expected under existing conditions of a given water body.

charge that will operate. Two possibilities exist: a steady release of pollutant into a stream with permanent discharge or an episodic ural conditions, changes in river discharge usually occur slowly, therefore in most cases the calculation of dilution is made separately for every characteristic phase of river regime, the process being established in every section where there is a continuity of sewage discharge.

Sewage may be discharged either from the shore by canals or conduits, or mixed with the water from streams into which pollutants were released. For such process, dilution may be calculated using the method based on the equation of established turbulent diffusion, developed by V M Makkaveev (1933; 1940).

(1946). Descriptions of this method, for conditions of the 'areal' problem both with and without cross-section circulation taken into account and for conditions of the 'flat' problem , are given in Karaushev's works (1948; 1960; 19691, as well as in 'Practical recommendations for computation of dilution of waste water in rivers, lakes and reservoirs', (Anon. , 1970). For most important cases the method used for conditions of the 'areal' problem takes into account the cross-section circulation and also irregularity of depth distribution, (Karaushev, 1969).

version (ñestsennaya, 1965) is recommended. For approximate calculations, Frolov-Rodziller's method (1954) is used, as well as the rapid method developed by M A Bestsennaya (1962).

moves with the stream and increases in area, while the pollutant concentration becomes weaker on account of its dilution with the river water. In this case the dilution is calculated by a simpliEied method, (Kaxaushev, 1968; Anon. , 1970).

Once the river type is established it is possible to determine the kind of pollutant dis-

one with simultaneous releases. Under nat-

Solution of the equation by Makkaveev in finite difference form is given by A V Karaushev

For cases when this method is unacceptable because of the time required, a simplified

When pollutants are released intermittently into a stream the resultant pollution mass

224

Se Zection of method to compu-be dilution

For a stream regime with a regular or little varying stream length, as well as in all approximate estimations of definite dilutions of waste water, the computation is made using the average characteristics of the whole stretch where dilution takes place. For a highly irregular stream regime and for improyed calculation the river reach under study is divided into design stretches, within the limits of which the values of discharge, cross-sectional area and other hydraulic elements are assumed to be constant. Any change in these elements is considered to be spasmodic at the boundaries of these stretches. When calculating dilution, a special method of meeting of pollutant concentration field at the boundaries is used, which satisfies the condition of indissolubility for the pollutant. Calculation is made successively from one stretch to another, the section line of pollutant discharge being considered as the initial section line of the first stretch.

Calculating unestablished dilution is more approximate and is therefore done without dividing the river into stretches, using instead the averaged values of hydraulic elements of the river stretch for which the calculation is made.

Preliminary estimation of possible dilution intensity when waste water flows into a water body, depends on the determination of the type of the latter. Depending on the hydrological background and the character of the discharge, different variants of waste water accumulation and dilution are possible. -

Where the polluted water (Qw.w = constant) (over a long period) regularly enters a water body that has, at the place of waste water discharge, a steady streamflow which carries the pollutants out to the o;?en water or along the shore. In this case the dilution is calculated by the method of finite differences as in the case of rivers with an established process of sewage discharge , (Karaushev , 1946 , 1960 and 1969) . Where polluted water is released regularly into a water body stream currents at the place of discharge are practically absent or have minimal velocity and are unsteady in direction. The pollutant accumulation takes place near the discharge site, and is accompanied by the diffusion of pollutants over the periphery of the pollution area. Under the conditions considered here, the process of turbulent diffusion is not established and the dilution is calculated by a method especially developed for water bodies, i.e. solution of the diffusion equation in cylindrical co-ordinates , (Karaushev, 1967 and 1969). When releasing pollutants into water bodies, combinations of the above stated variants can be encountered. For instance, if during a definite period of tine the regular release into the water body is made when currents in the discharge zone are practically absent, then a steady current is developed, under the influence of which tl-e pollution mass starts moving while still being connected with the source of poliution. To calculate dilution under such conditions, one should use the methods mentioned in (a) and (b) above; i.e. before the current has developed calculate as in (b) and after development of steady currents as described in (a). When the release is made for a rather short period of time (volley discharge). Such a release is possible as a result of certain tmes of cleansing and in the case of an accident. The dilution computation for such conditions should be made by the method mentioned in (b) above. When, after a prolonged absence, steady currents appear and make the pollution mass move as well as separate it from the pollution source, the calculation is made as described in (b) above, but taking into account the fact that the waste water discharge in the centre of co-ordinates is equal to zero. The starting point of the co-ordinates moves with a velocity equal to that of the current. When making an approximation of the established dilution, and in all cases when calculating unestablished dilution, the computation is made using averaged elements of that part of the water body, where pollution may expand according to preliminary estimations and suppositions. utation proceeds by design stretches, (Anon. , 1970). ~f the duration of the pollutant dilution process in the zone of pollution and the pollution body motion require a sufficiently long time process of organic pollutant disintegration is taken into account when calculating the unestablished diffusion , (Anon. , 1970) .

When making an improved computation of established dilution, comp-

(days , weeks , etc. ) , then the

A further condition is when polluted water comes from multiple pollution (a) When polluted water comes from several pollution sources successively situated along

a river, the calculation is iriade by a method based on solution of the turbulent diff-

sources.

225

SeZection of initia2 hydrologica2 vazues and hydrau2ic elements

111-5.4

usion equation using a finite difference scheme, (Karaushev, 1946, 1968, 1968). Initial concentrations of all sources are assumed as absolute values (g/m3) or reduced to a unified system of relative values (expressed as a percentage). latter, concentrations of waste water discharged from different sources are expressed as a percentage of the source with the maximum concentration, which is taken as being 100%. The calculation is made in the downstream direction, beginning at the first pollution source and ending at the section line of the second source. For the second pollution source the computation is made in like manner, although in this case the background level is represented by the concentration field, the value of which is obtained from the calculation of pollution dilution of the first source. When determining the initial conditions for the second source, the waste water discharge and pollutant concentration are taken into account as before. An analogous scheme is used for the calculation of any subsequent pollution sources. For a dispersed waste water release and equal waste water discharges from all sources, A V Karaushev's method is used. In this case the calculation is made initially only for one release, i.e., conditions of dilution for all releases are assumed to be similar. Then, taking into account the size of design stretches and distances between the neighbouring release points, the distance is determined from the point of discharge to the section line, where the polluted currents coming from neighbouring discharges meet. Beginning from this section line all discharge contributions are taken into account in the calculation.

For the

SELECTION OF INITIAL HYDROLOGICAL VALUES AND HYDRAULIC ELEMENTS NECESSARY FOR CALCU- LATION OF DILUTION IN RIVERS, LAKES AND RESERVOIRS

When calculating the dilution of waste water in rivers, the low-water discharge is taken as the design discharge, because during low-water periods the correlation between the discharges of river and waste water is at its most unfavourable for dilution. In most cases the 95% frequency discharge is assumed for the design rate, and where measurements have been made directly at the discharge section line the design discharge is taken as the minimum of all measured discharges. However, in some cases it is necessary to calculate waste water dilution in connection with other values of discharge, right up to maximum values. In such cases the computation of intensive discharges of waste water, accumulated during a low-water period, may be classified.

To calculate waste water dilution, one must have the isobathic plan of the river. If calculation is made without dividing the river into Stretches, then average values of morphometric and hydraulic elements are calculated for that part of the river of computational interest. After selection of the design discharge, the corresponding cross-sectional area, water surface slope, average current velocity, average width and depth of the river, Chezy's coefficient and turbulent exchange coefficient are determined, as well as the parameter characterizing variability of depth along the river length, (Bestsennaya and Faustova, 1969). After this the rad- ius of curvature is found, averaged for the part of the river under study, and then the average value of the cross-section component of current pulsation velocity is calculated, (Bects- ennaya and Faustova, 1969).

determined for every design stretch.

the effective diameter of bed load, Chezy's coefficient, stream velocity and turbulent exchange coefficient. All these characteristics, excluding depth and effective diameter, may be obtained by calculation, (Karaushev, 1964; Shvartsman and Makarova, 1972; Anon., 1970). To determine the depth an isobathic plan of the whole water body is necessary or an isobathic plan of that part of the water body for which dilution is to be calculated. without division into stretches, all the above noted values are determined as averages for the zone under study, and when computing by stretches they are determined as averages for every stretch. erent velocities and directions are considered; the computation can also be made for a zero wind velocity.

If dilution is calculated by design stretches, then all the above mentioned values are

It is sometimes necessary to obtain information on the depth in the stretch under study,

When calculating

In this case, the hydrological conditions in the water body related to winds of diff-

226

References

111-5.5 REFERENCES

Aitsam, A. M. aze ot rascheta Prodolnoy diffusii. tion of the longitudinal diffusion) , Tr. TPI, S1. statei no sanit. tekhnike, IV.

Aitsam, A. M., Velner, H. A. and Paal, L. L. 1965 O teorwticheskikh osnovakh inzhenernogo rascheta smeshenia stochnykh vod v vodoyemach. Nauchnye doklady PO voprosam samoochichshenia vodoyemov i smeshenia stochnykh vod (Theoretical background for computation of waste water mixing in reservoirs. Scientific reports on the problems of self-purification of reservoirs and waste water mixing)., Tallin.

Aitsam, A. M., Velner, H. A. and Paal, L. L. 1967 Oraschete prodolnogo smeshchenia veshches- tva zagryaznenia v vodotokakh. (On the computation of longitudinal shifting of pollutants in streams). Tr. TPI, sb. statey PO san. tekhnike, IV.

Bestsennaya, M.A., and Faustova L. I. 1969 Priblizhennyi uchet poperechnoi tsirkulyatsii i izmenchivosti glubin pri raschete smashenia stochnykh vod v rekakh. (Approximated estimation of cross-sectional circulation and depth variation in computation of waste water dilutions in rivers). Tr. GGI, vyp, 175, L.

Bestsennaya, M. A. 1972 Usovershenstvovanie ekspress-metoda rascheta razbavlenia stochnykh vod v rekakh. (Improvement of express method for computation of waste water dilution in rivers). Tr. GGI, vyp.191.

Fyodorov, N. F., and Shifrin, S. M. 1968 Kanalizatsia (Sewerage) Izd. Vysshaya Shkola, Moscow.

Karaushev, A. V., 1946 Turbulentnaya diffuzia i metod smeshenia (Turbulent diffusion and method of mixing) . Tr. n.i. uchr. , Ser. IV, vyp. 30, Leningrad.

1967 Dvukhrasmernaya diffusia yeshchestya sagryazneniya v vodojemakh pri otk- (Two-dimensional diffusion of pollutants Without estima-

Karaushev, A. V. 1960 Problemy dinamiki estestvennykh vodnykh potokov (The problems of dynamics of natural water courses). Gidrometeoizdat, Leningrad.

Karaushev, A. V. 1964 Vzmuchivanie i rasprostranenie zon mutnosti v vodokhranilishchakh. (Formation and distribution of turbidity zones in reservoirs) Tr . GGI , vyp , III , Leningrad. Karaushev, A. V. 1967 Raschet razbavlenia stochnykh vod v vodokhranilishchakh i morskikh bukhtakh (Computations of sewage water dilution in reservoirs and bays). All-Union scientific- technical Conference on protection of surface and underground water against pollution, Tallin.

Karaushev, A. V. 1968 Priblizhenny sposob rascheta rasplastyvania oblaka zagryazenia v rech- nom potoke (The ‘approximate method for computation of pollution cloud spreading in river) . Proc. XXII Hydrochemical Conference, vyp. II.

Karaushev, A. V. 1969 Rechnaya gidravlika (River hydraulics) , Gidrometeoizdat, Leningrad.

Lapshev, N. N., and Bezobrazov, J. B. 1960 Uchet poperechnoy tsirkulyatsii pri raschetakh smechenia stochnych vod v izvilistykh ruslakh (Accounting of the cross section circulation when computing sewage water dilution in sinuous river channels). Tr. LIST, No. 50.

Makkaveev, V. M. and Konovalov, I. M. 1940 Gidravlika, (Hydraulics) , Rechizdat, Leningrad.

Makkaveev, V. M. 1933 O rasprostranenii rastvorov v turbulentnom potoke i o khimicheskom metode izmerenia raskhoda (On distribtuion of solutions in turbulent currents and on chemical method of discharge computation). Zapiski GGI, v. X, Leningrad.

Anon., 1970 Practicheskie rekomendatsii PO raschetam razbavlenia stochnykh vod v rekakh, ozerakh i vodokhranilishchakh (Practical recommendations on computation of waste water dilution in rivers and reservoirs) , Leningrad.

Rodziller, I. D., 1954 K voprosu o raschete smechenia stochnykh vod v rekakh (On the problem of computation of waste water dilution in rivers), Moscow, Laboratory of biological purification of industrial waste water. Information material No. 5.

Rodziller, I. D. 1965 Razbavlenie stochnykh vod v vodoyomakh (Waste water dilution in water bodies). Scientific reports on the problems of water body self-purification and waste water

227

References

dilution. Proc 1st All-Union Symp., Tallin.

Ruffel, M. A. 1955 Sanitarnaya okhrana vodokhranilishch ot zagryaznenia stochnymi yodami (Sanitary protection of reservoirs against pollution by sewage water] . USSR scientific works for 1954) , Medyiz. Shvartsman, A. J. and Makarova, A. i. 1972 Usovershenstvovanie metoda rascheta vetro-volnoyo vzmuchivania waves). Tr. GGI, vyp. 191, Leningrad.

Zhukov, A. I., Mongait, I. L. and Rodziller, I. D. 1962 Kanaiizatsia promyshlennykh predpri- yatiy (Sewerage system of industrial enterprises). Stroyizdat.

(Annotations of AMs

(The improvement of the method for computation of turbidity caused by wind and

228

6 Synthetic detergents and water quality in the United Kingdom, 1946- 197 1

bY

T Waldmeyer ESC FRIC

Department of the Environment

Hydrological efects of urbanization (Studies and reports in hydrology, 18) Paris, The Unesco Press, 1974

Introduction

111-6 SYNTHETIC DETERGENTS AND WATER QUALITY IN THE UNITED KINGDOM


The development and use of synthetic detergents over the last quarter of a century, a major social change rivalling the introduction of synthetic fibres, has had a world-wide effect on water quality. The pollution problems caused by man's introduction of these new types of surface active agents have been severe. However, the challenge has been met and gives hope that other contemporary pollution problems, caused by urbanization, will be solved in time given the same degree of co-operation and effort. This paper will describe the way in which the synthetic detergent problem has been virtually solved in the United Kingdom

Following the general introduction, in 1949, for domestic purposes, of anionic surface active agents the consumption of active material in the United Kingdom increased from 13 to 41 thousand tons in 1956 and this figure is estimated to have increased to 60 thousand tons in 1966 and to over 70 thousand tons in 1969. The average concentration of detergent residues in our rivers increased to a peak in 1957 as shown by values for the Thames and the Lee (Table 58). Laboratory work was carried out on an alternative straight chain alkyl ben- zene sulphonate which was found to be more amenable to biological oxidation (ie to be 'soft') than the 'hard' PT (branched chain alkyl) material than in use. With the co-operation of the manufacturers, a full-scale trial of this material was carried out and this became known as the 'Luton Experiment' . Supplies of the 'soft' JN detergents were distributed first in the Luton area only (starting in August 1958 and reaching a peak in late 1960) but later the limited available stocks of JN were distributed more widely covering a much larger area of the south eastern counties of England. This meant that, by 1962, in some areas eg the Luton and West Hertfordshire area, the proportion of 'soft' material used was less than in 1960. The results achieved have been described in 4 papers presented to the Insti- tute of Water Pollution Control in 1960 (Squire et a$.).

gent industry gave an undertaking to cease, after the end of 1964, the manufacture, for use in the United Kingdom, of anionic detergents based on the old 'hard' PT alkylate. It was found that there was a time lag of some 6 months before sufficient of the 'hard' domestic detergent had been displaced from the shops for the effect to become apparent in the concentration of anionic detergent found in sewage works effluents. It took a further 4 months before the full effect was established. An even longer period elapsed before there was any clear evidence of a change in the concentration level in rivers and even then the significance of the results was in doubt because of the abnormal wet weather prevalent in 1966. There is some evidence that the newer materials are so readily degradable that some decom- position takes place in the sewers and that the overall removal of detergents between the kitchen sink and the river is greater than the figures recorded (Standing Technical Commi- ttee on Synthetic Detergents, 1967).

should be remembered that the general progressive replacement of soap products by synthetic surface active materials, which has been most marked since the end of 1964, has been slower than that observed in other countries such as in North America and in Germany. In 1969, for the first time, the amount of soap products sold was less than the quantity of finished detergents manufactured for the domestic market. Some comparative figures are given in Table 52 . Details of the trend in other countries have been published (Hill, 1969).

The total quantity of anionic surface active material continues to increase but fortunately the biodegradability of the basic chemical used (LAS : Linear Alkylbenzene sulphonate) has been improved and one large detergent manufacturer is using substantial amounts of a mixture of tallow (long chain) alcohol sulphate and LAS which is more highly degradable. The net result has been to maintain the low concentrations of surface active materials in river water which have been achieved in the last 5 years.

Rrrangments were made for large-scale manufacture of the new material and the deter-

In comparing results obtained in the United Kingdom with those in other countries it

230

Detergent concentration at sewage works

Table 52. UK consumption of soap and synthetic detergents in thousands of tons

1963 1964 1965 1966 1967 1968 1969 1970

Anionic Surf ace Active

Materi al

Total

52 56 59 60 64 69 72 -

Finished" Detergents

Total Wholesale/ Retail

(Domes tic)

239 195 246 206 253 210 274 221 297 2 40 312 2 54 372 316 372 313

Soap* Products (as sold)

367 367 326 321 299 2 90 250 245

"Published figures from 'Board of trade business monitor, Production series : Soap and synthetic detergents , Her Majesty's Stationery Office, London.

111-6.2 DETERGENT CONCENTRATION AT SEWAGE WORKS

West Hertfordshire Main Drainage Authority

The Maple Lodge works of the Drainage Authority deals with a sewage which is mainly domestic in character. About 20 to 25% of the flow consists of trade effluents. served by the works has been increasing continuously: with the pollution load increasing by 89%;. The design figure for the works was reached in 1959 and since then over E2m have been spent on extensions; capacity being increased by 60%. These last extensions started operating in January 1966. For the year ended 31 March 1965, the average BOD of the raw sewage was 447 mg/litre (Sus- pended Solids: SS 425) the corresponding figures for settled sewage being 253 and for final effluent 17.3 mg/litre (68318.1). Figures for the anionic detergent concentration are given in Table 53.

Table 53. Average concentration of anionic detergent (expressed as Manoxol OT in

The population 26% in 9 years - from-1956 to 1965 -

the biological treatment plant

mg/litre) at Maple Lodge Works

Flow cumecs Anionic Detergent Population % Removal

= 1 m3/s works on crude sewage 1 April Year (19 mgd) served by crude sewage settled sewage final effluent calculated on

5.8 58 327 .O00 1955 - 13.9 - 1956 1957 1958 1959 1960 1961 19 62 1963 1964 1965 1966 1967 1968 1969 1970

1.02 1.03 1.22 1.18 1.10 1.11 1.20 1.29 1.55

15.0 17.1 16.4 14.3 16.4 12.2 16.8 16.5 17.1 17.4 14.0 13.3 14.7 16.3

- 9.2 12.4 11.2 11.7 12.9 10.7 9.7 11.1 13.7

6.1 6.7 5.3 4.6 2.7 2.6 3.8 3 -9 3.4 3.6 O. 8 o. 5 0.5 O. 5

59 61 67 68 84 79 77 76 80 80 94 97 96.6 96.9

341 000 383 O00 396 O00 408 O00 418 O00 434 o00 451 O00 460 O00 469 O00 481 O00 489 000

23 1

Detergent concentration at sewage works

The percentage removal increased from 58% in 1955 to 68% in 1959. In 1960, the concentration of the anionic detergent in the final effluent was almost halved compared with the average for the prev3.ous 3 years. The average removal for the year increased from 65% to 84%. The average BOD of the final effluent at this period was about 15 mgjlitre. By 1962 the average percentage removal had increased to 77%. Tests on samples taken in December 1962, by the method developed by the Laboratory of the Government Chemist showed that, with the anionic concentration in crude sewage at 13 mg/litre, the percentage of 'soft' anionic was 62%; for final effluent, the concentration figure was 4.5 mg/litre and 19% of the total anionic present was 'soft'. By 1962, the purification plant was showing signs of overloading and the second stage extensions were in progress. Considerable interference with plant availability was experienced in 1964/65. From June 1965, when the concentration in the final effluent was 5.2 mg/litre, lower figures were observed: 3.9 in July, 2.2. in August and 1.5 mg/litye in September. started in January 1965. Since March 1966, all the monthly average concentrations in the final effluent have been below 1 mg/litre and below 0.6 from July to December 1966. level the final effluent no longer foams by itself.

ally high in the last few years. constant and shows hardly any seasonal variation. This is partly due to the high standard of effluent which has been discharged since the completion of the 1966 extensions. Another factor is that nearly all the surplus activated sludge is pumped directly to the anaerobic heated sludge digestion tanks and then removed from the works by tanker for disposal on farm land.

Greater London Council Hogsmill Valley Works

This was no doubt due to the general introduction of softer detergents which

At this

The removal of anionic synthetic detergents achieved at this works have been exception- The concentration in the effluent has also been remarkably

Records for these works have been available since 1958. In a period of 4 months, to October 1958, the anionic detergent concentration in crude sewage was 14.8 mg/litre, in the settled sewage 11.6 and in the final effluent 1.9 mg/litre. The works had only recently been commissioned and a fully nitrified activated sludge effluent was being produced with a BOD of 7.5 mg/ litre and nitric-nitrogen content of 16.5. The works deals with a sewage which is largely domestic. the end of 1962 but averaged 3 mg/litre in the first 6 months of 1963. the period 1964-70 inclusive are given in Table 54.

Table 54.

The detergent figure for the final effluent remained at about the same level up to Average figures €or

Hogsmill valley works of the Greater London Council. anionic detergent (as Manoxol OT) in mg/litres - Figures supplied by the s ci entif ic advis er

Average concentrations of

Quarter Flow Removal ending mgd Crude Settled Final calculated on or (19 mgd -sewage sewage effluent crude sewage Year = 1 m3/d) per cent

Mar. 1964 June Sept Dec Mar. 1965 June Sept Dec 1966 1967 1968 1969 1970

7.8 8.8 7.3 7.9 8.4 7.8 8.8 10.0 9.3

15.3 13.9 15.9 18.3 19.2 16.2 17.4 23.4 13.9 11.2 10.4 15.2

8.4 7. a 8.1 12.7

2.7 2.2 1.4 2.8 2.6 1.8 1.9 3.1 1.2 O. 5 O. 4 O. 5

82 84 91 85 86 89 89 87 91.5 95 96.2 96.7

Detergent concentration in rivers

The average percentage removal for 1965 was 88% and for 1966: 91.5%, the anionic detergent concentration in the final effluent being 2.4 and 1.1 mg/litre respectively. effluent was still well nitrified. In 1961, tests showed that 50% of the anionic detergent present in crude sewage was of the 'soft' type. Generally the removal of synthetic detergents at this works, judged on the percentage removal calculated on the cmde sewage figure, has been higher than the average in the country generally due to the maintenance of nitrify- ing conditions in the diffused air activated sludge plant. Difficulties due to foam however have been severe at times.

The

Slough Borough Council Cippenham Works

Data for the sewage works are recorded in Table 55. Slough was within the area where there was a distribution of 'soft' JN detergent which approached 100% in 1960.

activated sludge mechanical aeration plant followed by biological filtration. Extensions have been brought into operation in 1971. An account of some of the problems caused by synthetic detergents at this works has been published (Wood et al., 1970).

The sewage contains a substantial proportion of industrial wastes. Treatment is by

Table 55. Borough of Slough (Cippenham Works) - Average concentrations of anionic detergent (as Manoxol (3") in mg/litre

Total Removal =/d calculated Defoamant

crude sewage sewage (per cent)

Flow Anionic Detergent

(19 mgd Crude

Year ended mgd in on crude used

mg/ 1 Settled Final

31 March = 1 m3/s) sewage sewage effluent

1956 1957 1958 19 59 19 60 1961 1962 1963 1964 19F5 1966 1967 1968 1969 1970

4.5 4.9 4.8 6.0 5.5 7.6 6.4 6.7 7.6 7.5 7.4 8.0 7.3 9.5

18.1 18.7 16.5 13.9 16.1 14.9 16.3 16.3 14.6 17.3 18.2 14.9 19.1 18.1 21.6

10.9 14.1 11.2 12 -9 12.8 11.8 13.7 14.5 11.7 15.1 14.4 16.6

6.3 6.6 4.6 5.4 5.3 4.9 5.4 3.6 2.2 1.6 1.5 1.9

837 890 1126 1036 1092 1105 1278 1355 1185

55 59 69 67 67 66 69 80 85 91.6 91.2

3.5 3.7 4.3 5.6 4.5 5.4 6.2 6.4

111-6.3 DETERGENT CONCENTRATION IN RIVERS

The River Trent

The anionic detergent concentration, expressed as Manoxol OT, in samples of river water taken at Trent Bridge have been determined at intervals since November 1956. The results are of particular interest since, according to Lester, the Chief Pollution and Fisheries Officer, the river water quality at this point has not changed significantly over the previous decade. Lester reported that, during the period 1957-1960, the maximum and median concentrations of anionic detergents, based on about 100 samples, were 1.9 and 0.5 mg/litre respectively and that, in the period 1961-1964 inclusive, the figures were 2.0 and 0.72 mg/litre.

Details of the estimated river flow on the days of sampling were also recorded and corresponding figures were given for ammoniacal nitrogen and chloride. The average summer flow of the Trent at Nottingham is of the order of 500 mgd (26 cumecs) but flows can reach a peak

233

-Detergent Concentration in rivers

of over 13 O00 mgd (684 cumecs) (December 1960). Attempts were made to plot the total amount of detergent present, in lbs, by multiply-

ing the flow by the concentration but the resultant figures showed more variation than the original detergent concentrations. Inspection of the corresponding chloride ion and detergent figures - and of the flows - showed similar anomalies. Hoather, in a paper on the chemical characteristics of the River Great Ouse water, found that the total amount of chloride ion did not remain constant but tended to increase with increasing flows. To determine the trend of detergent concentration it has been found best to plst a moving average of the figures for a given number of consecutive samples, 10 being a convenient number to take.

From February 1957 to May 1959 (running) average varied from a minimum of 0.45 to a maximum of 0.94 with an average of about 0.7 mg/litre. to a peak of 1.3 mg/litre in October 1959 , at the end of the very dry period in the summer and autumn of that year. The samples between July and October in 1959 were taken when the flows were estimated to be between 350 and 400 mgd. This was followed by an exceptional fall to 0.25 in December 1960, the period of high flow mentioned above. From September 1961 to October 1964 the average figures varied only between 0.6 and 1.1 the mean being about 0.8 mg/litre. No detergent analyses were made between October 1964 and July 1965. From July 1965 to February 1967 (38 samples) the running average has been below 0.4 mg/litre. Apart from the abnormal period at the end of 1960, this is well below the figures obtained since 1956 and represents a drop of over 50% in the anionic detergent concentration in the River Trent at Nottingham. Recent figures are given in Table 56.

The average value then rose steadily

Table 56. Trent River Authority Pollution control and fisheries department Anionic detergent concentrations (as Manoxol OT) in mg/litre

River Trent

Nottingham

No. of Mean daily samples flow: cumecs Year at

1965 15 O. 37 - 1966 16 0.28 - 1967 40 O. 24 - 1968 23 o. 22 - 1969 87 O. 32 10 3 19 70 55 0.24 152

(to April)

The River Thames: above Teddington Lock

The Metropolitan Water Board keep a very close watch on the chemical quality of the water drawn from the Thames into the Board's storage reservoirs. The two top sections of Table57 record the annual averages of the anionic detergent concentration in the River Thames, at the Laleham and Walton raw water abstraction points.

The figures show that, from 1954 to 1964, allowing for normal variations to be expected from year to year, there has been little evidence of any long-term trend around the average value of about 0.32 mg/litre. The average annual value is derived from the results of analyses of weekly samples. The figures for August to October 1954 were about 50% higher than the annual average. In October and November 1964 - a dry period - the monthly averages were 0.50 mg/litre compared with the annual average of 0.33. December 1965 was 0.06 mg/litre and subsequent figures up to December 1966 were generally below 0.1 mg/litre. These figures show conclusively that the reduction in the concentration of anionic detergents observed in the River Thames was related to the general introduction of softer synthetic detergents.

The results given in Table 57 for the anionic detergent concentration in Kempton Park and Walton filtered water indicates that there had already been some reduction in the 3 years 1963 to 1965 and this may have been due to the partial introduction of softer detergents in SouthemEngland following the Luton experiment. the monthly averages in 1966 were generally 0.02 mg/litre or less.

The monthly average for

Since completion of the changeover in 1965 , Results for subsequent

234

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235

Detergent concentration in rivers

years (Table 58) show that the average concentration of anionic detergents has been maintained at a very low level being almost insignificant in the treated water going into supply.

Table 58. Metropolitan Water Board Water Examination Department Anionic synthetic detergents (as Manoxol CYT) in mg/litres

19 67 19 68 19 69 1970

River Thames Laleham intake O. 06 O. 06 0.05 0.05

Ashford Common Finally treated water 0.01 o. 02 0.02 0.03

River Lee Girling Intake O. 08 O. 08 0.08 O. 06

Lee Bridge Finally treated water O. 03 0.03 0.03 O. 03

River Great Ouse

The records of chemical analyses of river water samples taken from various points on the River Ouzel and of the River Great Ouse include figures for anionic detergents - expressed as Manoxol OT - and cover a period from 1955 to date. Samples of water from the River Great Ouse at the Bedford intakes are taken weekly. The long-term average flow of the river, at Bedford Bridge, is 180 mgd (9.5 cumecs) but the flow can drop to as little as 10 mgd (0.5 cumecs) in a dry s m e r period,

to 1967 together with the respective BOD and PV* values. The PV and BOD figures, whilst varying about the mean value, did not show any signs of a long-term increasing or decreasing trend. detergent concentration figures lie within limits of 0.15 mg/litre and 0.5 mg/litre with an average of about 0.3 mg/litre. Results for 1966 appear to show lower values; in the summer months of 1966 the average of 21 weekly saïples of river water at the Bedford intakes was 0.21 mg/litre. For the same period the average concentration in the River Ouzel, at a sampling point above Newport Pagnell, was 0.40. The River Ouzel contains a higher proportion of sewage effluent than the upper reaches of the Great Ouse. The averages for the remainder of 1966 are only half the above values but river flows at Bedford for the last 3 months of the year averaged nearly 500 mgd (26 cumecs) (on the sampling days), much higher than normal. For the 6 months ending 30 June 1967, the average for the Bedford intake samples was below 0.1 mg/litre with river flows averaging 280 mgd (15 cumecs). The concentration in the Ouzel has also been halved (at 0.2 mg/litre) has been a substantial reduction in the amount of anionic detergent residues present in the rivex. More recent figures are given in Table 60.

Detergent results fox the River Great Ouse at Bedford were plotted for the period 1962

Apart from some exceptional values in the winter of 1964/1965, most of the anionic

By 1967 there appeared to be little doubt that there

Yorkshire rivers

Tables recording anionic detergent concentrations in the River Don, at Doncaster, in the River Calder at Wakefield and in Lhe River Aire, above and below Castleford, have been included as appendices to the Committee’s Ninth and subsequent Progress Reports. For the Don the annual average rose from 0.8 in 1955 to 3.6 in 1962, was 1 mg/litre in 1966 and averaged 0.9 for 1967. Subsequent annual averages have been lower: 0.5 mg/litre in 1970. The 1966 average for the River Aire - 0.7 - below CastleCord, was only about half the figure for 1963 and 1964 - 1.3 and 1.2 respectively. For 1967 the average anionic concentration was also 0.7 mg/

* Permanganate Values (4 hours chemical test)

236

Eutrophication and effects of phosphates on water quaZity

litre, and this appeared to confirm the trend to lower values. Averages for the years since 1967 have not decreased further and the figuxes may indicate a deteriorating trend with increasing concentrations.

The River Aire, before it is joined by the River Calder just above Castleford, contains sewage effluents discharged from Keighley, Bradford (Esholt) and Leeds as well as smaller quantities of effluents discharged directly by factories. The River Calder carries the sewage and trade effluents from Holmfirth, Sowerby Bridge, Halifax, Elland, Huddersfield, Brig- house, Bradford (N. Brierly), Dewsbury and Wakefield and other towns. The concentration of nonionic detergents in these rivers is high. Their presence is responsible for aggravating the foaming tendencies of the river water due to anionic surface active agents. This syner- gistic enhancement of foaming is also affected to a marked degree by the presence of polyglycols (Patterson et az., 1967; 1970) at concentrations of about 0.2 mg/litre, in the River Aire below Castleford. Concentrations of poJ-yglycol above O. 4 mg/litre (maximum of O. 75) but only traces were found in the River Aire, above Castleford.

The unique situation in the Yorkshire area regarding synthetic detergents has been discussed (Progress Reports and Patterson, 1966). The River Authority's Annual Reports contain detailed tables of water and analyses, including figures for anionic detexgents and related flows, which cover the main rivers in the area.

Table 59 shows the average annual values for anionic detergents in 5 of the cleaner rivers in Yorkshire. Water is abstracted from some of these rivers for water supply, for example, from the Dement at Elvington. For the 3 years to 31 March 1966 the average values showed little Change and compared favourably with the concentrations found in the River Thames and in the River Lee (Table 58). Averages for the year ending March 1967 were at lower iev- els which have been barely maintained in recent years. probably due to low river flows as indicated in Table 61.

Five out of ten samples taken from the River Calder in 1966/67 had

The averages for 1969/70 were higher

Table 59. Average concentrations of anionic detergents (as Manoxol ûT) in river water concentrations in mg/iitres

Year ending 31 March: 1964 1965 1966 1967 1968 1969 1970 RIVER SAMPLE

POINT

D ement E lvington 0.06 0.04 0.07 0.02 0.05 0.02 0.05

Swale Leckby 0.06 0.06 0.08 0.05 0.04 0.03 0.06

Esk Ruswarp Weir 0.06 0.04 0.05 0.03 0.04 0.01 0.05

Ure Boroughbridge 0.05 0.09 0.06 0.03 0.04 0.02 0.04

Wharfe Tadcaster 0.10 0.09 0.08 0.07 0.09 0.07 0.08

111-6.4 EUTROPHICATION AND EFFECTS OF PHOSPHATES ON WATER QUALITY

A review of the effects of synthetic detergents on water quality would not be complete without reference to the problems claimed to be caused by the use of phosphates in packaged detergents. These problems have been most sevexe in North America and in European countries where rivers are large and slow-moving and in areas where there are many lakes. Fortunately, in the United Kingdom, the excessive growth of algae and the problems of eutrophication have not been of great significance and only a few lakes and reservoirs have been affected. There has been no evidence that the increase in phosphate content of rivers, due to the phosphate content of detergent products, has caused any increased difficulties in operating water supply storage reservoirs prone to algal growths.

extent, in groundwater, in solution together with bicarbonates, nitrates, silicates, sulphates and fluorides etc. In addition to the phosphate derived from mineral rocks and soil, some phosphate originates from the leaching of phosphatic fertilisers used on land and from farm

Phosphates are inorganic materials present in practically all surface and, to a lesser

237

Eutrophication and effects of phosphates on water quality

Table 60. Bedfordshire Water Board - Average concentration of anionic detergent (as Manoxol (YT) in mg/litres

River flow Great Ouse cume cc Year Ouzel

1967 O. 25 o. 12 10.1

1968 O. 40 O. 15 13.2

1969 o. 33 o. 11 11.1

19 70 o. 37 o. 11 10.7

Table 61. The Yorkshire Ouse and Hull River Authority Pollution Prevention Department Average concentrations of anionic (as Manox01 OT) and nonionic (as Lissapol NX) detergents and polyglycols . Concentrations in mg/litres

River Aire River River Calder at Wakefield Don at

above Castleford below Castleford Doncas ter

Anionic Nonionic P-g+ Anionic Nonionic P-g+ Anionic Nonionic P-g+ Anionic

1966 B 0.75 0.50 0.13 0.72 0.40 Trace 0.8 0.41 0.10 0.9

1967 A 0.97 0.69 0.36 0.80 0.51 0.01 0.7 0.42 0.07 0.8

B 0.97 0.56 0.42 0.96 0.49 0.03 0.7 0.23 0.05 0.9

1968 A 1.13 0.53 0.33 0.83 0.39 0.02 0.8 0.38 0.14 0.9

B 0.69 0.22 0.16 0.68 0.18 0.02 0.56 0.15 0.09 0.53

1969 A 0.88 0.38 0.27 0.76 0.26 0.03 0.62 0.20 0.08 0.63

B 1.47 0.72 0.66 1.16 0.50 0.08 0.92 0.40 0.17 0.67

1970 A 1.07 0.62 0.43 0.86 0.48 0.21 0.59 0.42 0.29 0.56

B 0.87 0.38 0.31 0.77 0.24 0.06 0.71 0.31 0.17 0.48

1969 A Average flow on 416 525 941 400

B Sampling days 219

1970 A (mgdl 334 3 B 19 mgd = 1 m /s 319

274

449

393

493

783

7 12

173

49 3

2 70

A = January - June B = July - December (+) P-g: polyglycol

Table 61gives average results for anionic and nonionic detergent concentrations in the River Calder, and in the River Aire, both above and below Castleford Weir, where an intractable foaming problem has persisted since the advent of synthetic detergents.

23 8

Eutrophication und the effect of phosphates on water quality

animal wastes. * Sewage effluents contain an appreciable amount of phosphate derived- from excreta and in

recent years this has been augmented by phosphate derived from detergent products. Phosphates may also be discharged to rivers in industrial effluents either directly or via the sewers of the local authority. Phosphates may also be present in surface water drainage and originate from the industrial use of phosphates in cooling water systems.

Phosphorus is one of the essential plant nutrients (together with nitrate and silicate) and the change in concentration from the levels found in mountain areas to that of Windermere and to lowland lakes and reservoirs is part of the process known as eutrophication, a natural process which is speeded up by the discharge of effluents containing phosphorus (and other nutrients) derived from human activities.

the growth of algae and diatoms. In spite of intensive research the nutrient requirements of most algae are not known precisely, but it is known that the critical levels of phosphorus which can cause excessive growth of algae (blooms) is below 0.01 mg/litre for most species, a concentration which is exceeded in many pure groundwater supplies and in other natural water sources. In the past 5 years the relation between algal growths and the rate of eutrophication of surface waters has received attention at international level (OECD, WHO, UNESCO, International Biological Programme) and in this country research is being carried out by various organisations. The Society for Water Treatment and Examination held a symposium on eutrophication in March 1970 and the published papers provide an excellent review of the position in the United Kingdom (Downing, 1970). A later survey was published by the Water Pollu- tion Research Laboratory (Ministry of Technology, 1970).

litre, as phosphorus, and remained at this level until 1952. In 1969 the average was about 8 times this figure. The concentration in the River Lee water, abstracted at Chingford, is much higher, due to the high proportion of sewage effluents in the river water. There is only a slight reduction in the phosphate level during storage and filtration. (Table 62) .

the concentrations are similar to those observed at Chingford on the River Lee. A survey carried out at a point about 10 miles downstream of Bedford showed that about 80% of the phosphorus present was derived from sewage effluents.

The Water Pollution Research Laboratory has reported that the sewage phosphorus content of some 20 sewage effluents was about 7 mg/litre with one detergent-free effluent about half this figure. At one works of the Upper Tame Main Drainage Authority the phosphorus content of the effluent increased from 3.2 to 6.3 mg/litre between 1942 and 1962. centration in the crude sewage is about 14 mg/litre.

averaging between 0.1 and 1.0 mg/litre (as phosphorus). March 1969 the concentration of phosphate does not appear to have increased generally.

The amount of phosphate discharged with sewage effluents would be about half the amount which arrives at the sewage works. It is known that most of the residual phosphate could be removed, if necessary and at a high cost, by coagulation with lime or alum.

The Concentration of phosphate in groundwater may vary from less than 0.01 to 0.05 mg/ litre (as P). Concentrations in lakes such as Windermere is of the order of 0.0001 mg/litre. The phosphorus content of the River East Stour (Kent) a clean chalk stream, is 0.05 mg/litre at Ashford increasing to nearly 1 mg/litre below the discharge point of the Ashford sewage works effluent to the Great Stour. The concentration of phosphate in a fairly clean river such as the River Cherwell is about 0.25 mg/litre, although the sewage effluent from Banbury which is discharged into the upper reaches contains more than 10 mg/litre (as P).

The concentration of phosphates in the Metropolitan Water Board's King George VI reservoir lies between 0.1 to 0.8 mg/litre and is subject to seasonal changes. Difficulties have been experienced in this country in the operation of waterworks for more than 50 years where water supplies were drawn from rivers such as the Thames and Lee. In such cases algae are a major factor in purification economy and eutrophication affects the quantity and quality requirements in many ways. The Thames Valley storage reservoir system is probably the largest in Europe illustrating the biological consequence of advancing eutrophication. Stoxage reservoirs may have to be put out of use when a 'bloom' occurs - an explosive outbreak of growth of a particular species of algae when concentrations of algae may exceed 400 million

The presence of phosphorus and other nutrients in water is one of the factors affecting

In 1939, concentrations of phosphate in the rivers Lee and Thames were about 0.1 mg/

At Bedford, where the abstracted water contains a high proportion of sewage effluents,

At Slough the con-

Rivers in the Mersey and Weaver River Authority areas have phosphate contents usually In the period from April 1958 to

239

Eutrophication. and effect of phosphate on water quatity

cells per litre in a storage reservoir outflow. In less severe cases control may require the use of algicides such as the addition of copper sulphate. In any case the rate at which the stored water can be filtered will depend largely on the type and quantity of the algal cells present. When the algae develop and die they can cause taste problems, or affect the quality of the water by deoxygenation. The growth of one type of algae in reservoirs can give rise to trouble such as causing a flocculent deposit when tea is made, or when mineral water is manufactured from tap water, in spite of the fact that the water is of the highest quality when judged by chemical and bacteriological tests. Experience shows that careful management of reservoirs satisfactorily overcomes any problem.

may be aesthetic aspects of eutrophication which are important. Growths of algae may cause 'pea-soup' deposits or floating scum masses near the shallow shores of such a reservoir. This has happened at Grafham Water. Where the semi-dried growtlis die and decompose smells may be produced. Some species of algae produce toxic products which can cause fish mortali- ties in closed waters or slow moving rivers or canals. Such cases, as far as we know, are rare. It is aiso claimed that cattle can be killed by drinking algal-rich waters. There have been several cases in the United States of America.

It seems to be generally accepted that there has been a general increase in the incidence of growth of water weeds in some areas, Cladophora is a type of water weed that grows in long streamers in some rivers and excessive growths can interfere with fishing, clog inlet water screens and reduce the hydraulic capacity of the river channels. Research is being carried out into the subject but the causes of such growths are not yet established. It is possible that the concentrations of phosphate present in the river water may be one of the nutrient factors irivolved. There is as yet no firm evidence that increased phosphate concentration beyond a minimum level is responsible for excessive growths.

cial in controlling corrosion particularly where the water supply is soft. In the case of the C1atworth.y surface water reservoir supply, which is used by the West Somerset Water Board, severe and extensive corrosion problems with mains, supply pipes, fittings and boilers were eventuall-y overcome (1966) by the controlled addition of 3 mg/litre of Calgon (sodium hexa- metaphosphate (x) one of the polyphosphates in widespread commercial use) to the water supply. Where hot water systems were seriously affected 'micromet' (small packages of glassy x) was added at individual cold water storage tanks.

of hard water in domestic and industrial cooling water systems including cooling towers at Power stations.

will be provided mainly by food and drink with the intake from water probably being negligible. Daily excretion of phosphorus is about 2.5g per person. The contribution from synthetic detergents is probably of the same order or slightly higher but it is not known whether the phosphate residues in the sewage effluent are present in the same proportions as in the incoming sewage. Most of the complex polyphosphates are broken down to the orthophosphate form in passing through the sewage works and polyphosphates are not usually found in rivers.

It is not proposed to discuss the use of possible substitutes for phosphates such as NTA (nitrilotriacetate generally in the form of its trisodium salt). The manufacturers in the United States have agreed to stop using the material and the position in Sweden is uncertain. It appears that the biodegradability of this type of chemical is temperature-sensitive and that significant residues could reach rivers at times of low temperature '(Bouveng, 1968).

Where reservoirs axe used for recreational purposes such as fishing and sailing there

The presence of phosphate in waters used for domestic and industrial supply is benefi-

Similar products are used on a large scale to prevent corrosion and overcome the effects

Phosphorus is an essential element in human nutrition. The total quantity absorbed daily

240

Enzymes in washing powders

Table 62. Metropolitan Water Board -- Water Examination Department Phosphate content of the Board's supplies (as P in mgllitres)

Sample Point Average Phosphate Content 1966 1967 1968 1965 1570

River River River River water River water

Thames , Walton 0.69 0.72 0.78 0.88 0.58 Lee, Chingf ord 1.14 1.11 1.24 1.47 1.57 Lee, New Gauge 0.65 0.62 0.72 0.72 0.88 Thames-derived filtered passing into supply 0.55 0.62 0.65 0.69 0.88 Lee-derived filtered passing into supply 0.95 0.88 0.91 1-01 1.17

New River-derived filtered water passing into supply 0.49 0.46 0.55 0.52 0.55

111-6.5 BORON IN SEWAGE EFFLUENTS AND RIVERS

Perborates are used in relatively large amounts in packaged detergents sold in the United Kingdom although not in North America. The Committee has studied the problems that might be caused by the possible harmful effect of increased concentrations of boron residues gres- ent in sewage effluents and in river water that might be used for agricultural irrigation. The general conclusions were that the boron residues at existing concentrations in water supplies did not represent any health hazard and that their presence in sewage effluents would not cause significant damage when such waters were used for irrigation. This last conclusion was based on the view expressed by the Ministry of Agriculture, Fisheries and Food qualified by an assumption that the concentration of boron in the irrigation water was unlikely to exceed 1 mg/litre as B and that normally no more than 150 mm of irrigation is applied to an outdoor crop. The risks from boron in water supplies are likely to be at a maximum under glass where large quantities of water are used and there is no winter rain to leach excess boron from the soil. The Committee were agreed that, in some areas, there might be little margin to spare and that they would continue to watch developments in this field.

ers in the United Kingdom has been published by the Water Pollution Research Laboratory (Wagqott, 1969). tions of boron are not grown in this countrj. The situation is different in the United States (Wilcox and Durum, 1967) and in some areas the river water has to be diluted with boron-free borehole water before use for irrigation.

Board's raw and treated water supplies are shown in Table 63 . It has been reported that laboratory experiments have shown that concentrations of boron up to many times those likely to be encountered in the water supply failed to have any effect on the malting of barley (Crabb, 1970).

There appears to be only a small removal of boron during treatment at sewage works, the average concentration in normal effluents being about 1.0 to 1.5 mg/litre. been, at least in some areas for which results are available, no significant change in the last 3 years.

A review of the problem that might be caused by increasing boron concentrations in riv-

Fortunately most of the crops which are most sensitive to low concentra-

A summary of the analytical records of determinations of boron in the Metropolitan WatPr

There has

111-6.6 ENZYMES IN WASHING POWDERS

Enzyme products have been introduced into some domestic detergents to remove protein and other difficult stains. These products were first used on a very large scale in the United States in 1967 and in the United Kingdom in 1969.

241

Enzymes in washing powders

Table 63. Metropolitan Water Board r Water Examination Department Boron determinations (as reported to Standing Technical Committee on synthetic detergents). Average of monthly samples. Results in mg/litres as B

July 1968 to April 1969 to April 1970 to March 1969 March 1970 December 1970 Up to June 1968

Number Number Number Number

samples samples camp les samples of Range of Range of Range of Range

River Thames water (Laleham intake) 3 O. 15-0.33 9 o. 12-0 .o2 River Thames treated water (Ashford Common) 4 o. 11-0.20 8 O. 14-0.20

River Lee New Gauge - - - - River Lee (Chingf ord

River Lee treated water (Lee Bridge) 2 O. 19-0.24 9 O. 36-0.47

intake) 3 O. 35-0.68 9 O. 29-0.67

10 O. 13-0.47 8 O. 18-0.42

10 0.08-0.40 8 O. 15-0.39

10 O. 39-0.70 8 O. 23-0.84

10 . 0.26-0.60 8 0.20-1.1

10 O. 37-0.83 8 O. 33-0.73 ~ ~~~

Wieg, 1969, reviewed a number of products and the effects of different factors on enzyme activity. They are extracted and purified from special strains of Bacillus subtilis, a bacterium which is normally present in the environment. The product is incorporated in the spray-dried washing powder to the extent of about 1%. Swisher, 1969, has pointed out that similar enzymes are already present in domestic sewage at concentrations comparable with those that might be expected to be derived from the present composition of enzyme washing powder and that bacterial action rapidly destroys them.

There has been no evidence that the introduction of enzymes has caused any difficulties at sewage works - such as solubilisation of protein matter in suspension - and there is no reason to believe that the natural level of similar enzymes in river water could be affected significantly. The use of enzyme-containing packaged products has had an indirect beneficial effect on the quality of river water. This has resulted from the fact that one major United Kingdom manufacturer of domestic products has been able to use surface active materials that are more highly degradable than the previously used standard base material.

The enzymes employed in household detergents are of the proteolytic type.

111-6.7 OTHER CONSTITUENTS

It is known that the formulation of synthetic detergent products can vary substantially according to the specific use of the packaged material ( Dsvidsohn & Milwidsky, 1967). There is a lack of information on the biodegradability of some of the organic compounds which are csed for auxiliary purposes in detergent formulations and residues from materials such as

242

Other constituents

optical brightening agents (Stensby, 1968) and of perfumes could reach rivers from sewage works outfalls. Optical brightening agents and perfumes added to household washing powders are generally in concentrations that may range between 0.3 to 0.5% and 0.1% and 0.15% of the detergent base respectively. The concentration residues that may be present in sewage from this source would therefore be small. Research into the nature of organic matter present in river water is being carried out in the United Kingdom and the work will no doubt cover this aspect of the problem.

gent products such as caxbonates and silicates (condensed phosphates and perborates having been mentioned above) do not appear to affect water quality in rivers. Water Board has reported average annual figures for the concentration of silica in water derived from the Rivers Thames and Lee. There has been no increase since 1953 and the concentration of silica has remained at a level of about 12 mgllitre.

The other main inorganic 'builders' that are used in large amounts in synthetic deter-

The Metropolitan

111-6.7.1 Biodegradability o£ anionic detergents

The extent to which surface active agents are degraded or removed during sewage treatment has been extensively studied in recent years. An authoritative work on this subject has recently been published by Swisher (1970) and a paper on methods of assessment of biodegradability by test simulating sewage treatment, by Eden et al, is in the press (1971). The standard screening test used in the United Kingdom was recommended in 1966. Members of the Standard Technical Committee are taking part in collaborative work, under the auspices of the Water Management Research Group of OECD, with the aim of achieving international agreement on methods of testing.

111-6.7.2 Nonionic surface active agents

The Committee's reports have stated that the reduction of anionic degergent residues in sewage effluents would fail to reduce foaming to acceptable levels unless the concentration of nonionic detergent residues was also reduced. In spite of the almost complete change-over to the use of soft biodegradable nonionics by the major manufacturers of domestic products, the concentration of nonionic surface active agents in rivers does not appear to be falling and in particular industrial areas, such as the West Riding of Yorkshire where the textile industry predominates, such residues remain obstinately at a high level (Table 61).

In industrial uses a substantial amount of the total usage (possibly up to one half) was claimed to be fully biodegradable, nonionic products being used for specialised purposes in a wide variety of industries. Because of this widespread use and the complexity of the mixture of substances used in any given product it has not been possible to assess the quantity of hard materials used by industrialists, a further difficulty being that many of these products are sold under trade-names and the constituents are not readily identifiable.

In attempting to assess the biodegradability of nonionic surface active agents, their effect on sewage works, the concentration in effluents and the ultimate fate of nonionic residues in rivers, the Patterson thin-layer chromatographic (TLC) method of analysis has been used as standard in the United Kingdom (Standing Technical Committee on Synthetic Detergents, 1966). Alternative chemical methods have not been satisfactory at low concentrations but a recent paper (Hey and Jenkins, 1969) has claimed that these difficulties could be overcome. Analytical data has been published in the Committee's Twelfth Progress Report.

111-6.7.3 Pol~glycols

Reference has already been made to the effect of polyglycols in the section of this paper dealing with the Yorkshire rivers. In the Committee's Ninth and Eleventh Reports it was stated that polyglycols were widely used in industry and made a significant contribution to the foaming problem, particularly in the textile areas of Yorkshire. There the problem is mainly confined to the effluents discharging to the River Calder above the confluence with the River Aire. The concentration of polyglycols in these rivers is shown in Table 61.

down of the soft nonionic surface active agents derived from straight chain fatty alcohols. The polyglycols of higher molecular weight are resistant to biological attack and, when present, they aggravate to a marked degree the foaming tendency of river water containing other surface active residues.

The presence of polyglycols in these rivers can also arise from the biological break-

243

References

111-6.7 REFERENCES

Anon. 1956. Report of the Committee on Synthetic Detergents, HM Stationery Office, London.

Anon. 1970. Notes on Water Pollution, No.49.

Bouveng, €1.0. 1968. Vatten, 24, 348. Crabb, D. 1970. "Effect of Boron on barley germination and malting". J. Inst. Brew., 76, 14. Davidsohn , A. , Milwidsky , B.M. 1967. Synthetic Detergents, Leonard Hill , London. Downing , A.L. 1970. "Review of the National Research Policy on Eutrophication Problems" Wat. Treat. Exam., (ZS), 3, 233. (See also Part 4 p.328-409).

Hey , A. E. , Jenkins, S. H. 1969. "The determination of Non-Ionic detergents in sewage works samples", Water Research, 3, 887 . Hill, H.A.W. , Butler, T.H. , Moffett, J.G. 1969. "Detergent Alkylate - World Status" sow, Chem-icaZ Specialities, 37. Patterson, S.J. , Tucker, K.B.E. , Ccott, C.C. 1967. "Detergent and Polyglycol foaming in river waters" , Water Pollution Control, 66, (3) , 286. Patterson, S.J. , Tucker, K.B.E. I Scott, C.C. 1967. "Non-ionic detergents and related substances in British waters" , Proc. 3rd Int. Conf. on Water PoZZution Research, Munich 1966, Water Pollution Control Federation, Washington.

Patterson, S.J. , Tucker, K.B.E. , Scott, C.C. 1970. "Nonionic Detergent Degradation, III", J. Am. Oil Chemists' Soe., 47, (2) , 37.

Squire, G.V.V. 1961. The Manufacturers' part in the Luton Experiment, J. Proc. Inst.Sezj. purif, (1) , 27 (and following papers). Standing Technical Committee on Synthetic Deterqents. 1966. B I HM Stationery Office, London.

Standing Technical Committee on Synthetic Detergents, 1960. Third Progress Report, HM Stat- ionery Office, London.

Standing Technical Cornittee on Synthetic Detergents , 1967. Ninth Progress Report, HM Stat- ionery Off i ce , London. Stennett, G.V., Eden, G.E. (in press). "Assessment of biodegradability of synthetic surfac- tants of tests simulating sewage treatment" Water Research, 1971, 5.

Stensby, Per S. , 1968. "Optical brighteners as detergent additives" J.Am. Oil. Chem.Soc.,

Swisher, R.D. 1970. "Surfactant Biodegradation" Dekker , New York. Swisher , R. D. 1969. "Detergent Enzymes : Biodegradation and Environmental Acceptability", Bioscience, (12).

Waggott, A. 1969. "An investigation of the potential problem of increasing boron concentrations in rivers and water courses" Water Research, 3, 832. Waldmeyer, T. "Analytical records of synthetic detergent concentrations 1956-1966" Water Pollution Control, 67, (1) 1968, 66 (and following papers up to p.123).

Eighth Progress Report , Appendix

45, 497.

Wieg, A.J. 1969. "Enzymes in Washing Powders" Process Biochem., 30.

Wilcox, L.V. , Durum, W.H. 1967. "Qual.ity of Irrigation Water", "Xmigation of AgricuZturaZ Lands", Agricultural Monograph No. 11, Am.Soc. of Agronomy, p.104, Ed Hagan, R.H. et aZ, Madison Wis.

Wood, A.A. , Claydon, M.B. , Finch, J. 1970. "Synthetic Detergents - Some Problems" Water Pollution Control, 69, (6) , 675.

244

7 The effect of opencast mining on the water balance of an area

V. V. Kuprianov and I. N. Obraztsov

State Hydrological Institute Leningrad, U.S.S.R.


Introduction

I 11-7.1 INTRODUCTION

Opencast mining is usually accompanied by the construction of roads, buildings, etc., which modify the natural cover of the area. This creates conditions for the increase of surface runoff, decrease of subsurface runoff and increase of precipitation and snowmelt intensity over the area where construction is taking place.

It often happens, however, that the effect of opencast mining on the various water balance elements of river basins may extend far beyond the limits of the areas under construction as a result of drainage from the opencast mining. The resulting lowering of level (or head). of subsurface water may cover areas from a dozen up to tens of thousands of sq km, and is usually the subject of hydrogeological research to decide the best methods of subsurface water use and the control of its regime. Water level lowering, however, is of a great scientific and practical importance for hydrologists as well, since it may affect different stages of the water cycle of river basins.

Hence, for example, when the groundwater table is shallow (e.g., less than 1 m below the surface) any decrease in its level may considerably decrease evapotranspiration from river basins. When precipitation is constant, this must cause an increase in the total runoff from the area. Further, lowering of the water table may decrease natural groundwater outflow into the river network which ultimately results in a decrease in total river runoff.

drainage water discharge into the river network which can increase river runoff. Thus, the drainage of opencast mining may create a number of factors potentially affecting the increase or decrease of natural river runoff. Similar phenomena take place following the exploitation of subsurface water for water supply. Depression cones are formed and these are typlcal of the majority of industrial regions.

At the same time, however, the drainage of opencast mining is usually accompanied by

111-7.2 KURSK MAGNETIC ANOMALY TERRITORY

The present paper gives a short description of the research results on the effect of iron ore excavation on runoff within the Kursk Magnetic Anomaly (KMA). Observational data from hydrological stations of the Hydrometeorological Service of the USSR have been used together with material from expeditionary investigations made by the State Hydrological Institute in this area in 1962-69.

Two areas of water-level depression were investigated. The first one is located in the north-western part of the KMA in the Svapa basin (left-bank tributary of the Desna river) , where the Mikhailovski pit is excavated. The other one, where the Lebedinski pit is worked, is situated in the eastern part of the KMA territory and covers the Oskolets river basin (right-bank tributary of the Oskol river).

raphy comprises plains with low hills disected by ravines and gullies: 62% of the whole territory is ploughed, forests cover a further 20%, and ravines and gullies occupy the remaining 14% of the area. The soil is loamy. Normal annual precipitation is 700 mm; 80% of this amount is lost by evaporation, 14% forms surface runoff while 5% is related to subsurface runoff. Snow storage in the fields before spring starts is80 mm. Rivers drain 'superkelloveic' water-bearing strata. The 'subkelloveic' water-bearing strata are isolated from the 'superkelloveic' strata by a thick 'kelloveic' aquiclude. It is drained by the edges of the Mikhailovski iron ore pit and wells. the site were initiated in 1959. By 1967 the pit was 95 m deep. Drainage from the pit caused a lowering of water level in the subkelloveic water-bearing strata. The effect of the pumping exceeded 1000 sq km.

The second area differs in having a greater ploughed area (70%) and less forest (6%). The amount of precipitation is less, about 630 nun, and snow storage before spring in the fields is 65 mm on average. Mean annual runoff of the Oskolets (area 493 sq km), before considerable water level depressions took place, was 132 mm of which 50% was contributed from spring snowmelt runoff, 17% from flood runoff and the remainder (33%) came from subsurface waters. The river drains abundanteMaastricht-Turonian and Senoman-Albian water-bearing horizons. These horizons have been developed in Cretaceous and sandy deposits and form a unique water-bearing group.

1964 the area of the depression cone extended over 314 sq km. The maximum depression of sub-

Thefirst region is characterized by the following physiographic features. Its topog-

Water level depression observations at

Water level observations within the Lebedinski pit were started in December 1957. By

24U

Kursk magnetic anomaly territory

surface water level was 85 mm. Methodological investigations have been made on two aspects. Firstly, the total effect

of opencast mining exploitation on river runoff was determined. To this end, runoff was studied at sites located away from the depression cones and points of drainage water discharge. Annual long-term data on runoff in the basins under study and in analogous basins have been used. Data for the period before mining began provided a basis for the establishment of quantitative relations between the principle characteristics of natural runoff of the rivers under study and their analogues, and provided estimated values of natural runoff for the period of mining disturbance. The comparison of actual and theoretical runoff gave the approximate values of runoff changes caused by the effect of economic factors. For visual analysis, graphs of cumulative values of runoff were plotted for the rivers being compared. A similar method was used for the analysis of long-term variations of precipitation in the basins under comparison.

The first part of the research established the existence or absence of river runoff disturbance and the evaluation of its sign and value for every year; it did not explain the nature of such disturbances. To do that, it was necessary to determine the nature of runoff disturbances in individual areas within the basin under study to see how they behaved under different conditions and external influences.

These problems were solved by analysing the lateral inflow of subsurface water of characteristic river stretches. This was determined by a residual term in the equation for the water balance of the channel, written in general as follows:

'1 = where Q1 is the water discharge at the lowest discharge site; Qu is the water discharge at the inflow site; Qlat.in.sub. and Qlat.in.surf. indicates lateral surface and subsurface inflow to the site; Qdis. and Qwith. indicate discharge into the river and water withdrawal along the river stretch; Qx and Qz indicate respectively precipitation and evaporation from the water surface; and QAV is the change of water storage in the channel for a design time interval.

results of these surveys indicated the need for a series of rapid discharge measurements on rivers at the boundaries of the selected stretches, and measurements were made for all water intakes and discharges. The measurements were made during a period when no floods occurred, assuming a stable regime of discharges and water intakes but making it necessary to neglect some elements in the balance calculations. The calculation of lateral inflow of subsurface water was made according to the following equation:

(1) + (Qdis - Qwith) + (Qx - Qz)t QAv + Qlat.in.sub. + Qiat-in surf.

The balance calculation was made on the basis of so-called hydrometric surveys. The

Qlat. in. sub. = Ql (Qdis. - Qwith. 1 - Qu (2)

where all the terms in the equation except the discharge of lateral inflow were determined in a hydrometric manner.

water inflow at the design stretch into the river, while a negative sign indicated loss of channel water from the river.

turbed conditions, but they do not provide inflow changes compared with natural conditions. This problem may be solved at least indirectly by means of a special evaluation of natural

-

Positive results from the calculation were interpreted as an availability of subs'urface

These calculations explain the values of lateral inflow at the given stretch under dis-

lateral inflow at the design stretch (Q* 1 . Then the change of lateral inflow

AQ1at. in. sub. 1at.in.sub. is equal to:

- AQlat. in. sub. 'Q*lat. in. sub. Qlat. in. sub. (3)

In the study of the KMA area, natural lateral inflow for stretches of the river with disturbed water regime was calculated by analogy with the nearest stretches with natural runoff. The results of the analysis may be mapped. It is also convenient to plot graphs of lateral inflow variations along the river length or according to the basin area. In the case of the KMA, such graphs were plotted in combination with the profiles of subsurface water levels. The graphs provided a basis for the selection of the following zones in the river system: (1) the zone of natural river recharge (beyond the limits of zero depression of subsurface water level); (2) the zone of reduced recharge (from zero depression up to the points of equal

247

ConcZusions

marks of channel bottom and the reduced subsurface water level); (3) the zone of complete cessation of subsurface recharge and transit water seepage out of the river channel (on the stretches of reduced subsurface water levels below the bottom marks of river channels).

able, it is possible to make an approximate evaluation of the dimensions of the above-mentioned zones for each year. recharge for previous years. number of years in advance.

from the discharge site, a general change in river runoff is marked only by the decrease of subsurface river recharge. charge (minus water withdrawn from the river):

Where depression cone profiles for different years of the exploitation period are avail-

This makes it possible to calculate the changes in natural subsurface Forecasts of future water level dpression may be calculated a

The type of calculation cited may be used to forecast changes in river runoff. Upstream

Downstrepm from the discharge site it includes the amount of dis-

- - - ''gen . "1at.in.sub. i- 'dis. 'with. (4)

It is reasonable to call this equation the balance of disturbances. lations for the river basin for prev.ious years and for comparisons with runoff changes obtained by comparing the rivers and their analogues.

Since the balance of disturbances may be computed for the future as well, it may serve as the basis for the forecast of river runoff changes.

For the evaluation of river runoff changes on river stretches of KMA territory the following considerations were taken into account. takes place all over the area of the depression cone, while the discharges are concentrated at individual points. Above a place of discharge the first factor is involved, while below it both factors are involved. value downstream, and that of discharges remains constant. Due to the increase of river water volume in the downstream direction, the amount of discharged water becomes relatively smaller. These are the peculiarities in the mechanism of distorted water exchange in 'river- subsurface water' system, that determine the final result of the combined influence of these factor s.

It may be used in calcu-

The decrease in subsurface river recharge

The decrease in underground recharge grows larger in absolute

111-7.3 CONCLUSIONS

The research made on the KMA territory by the above methods led to the following principal conclusions :

The lowering of the level of relatively deep groundwater does not change the value of the evaporation from river basins; because of this, climatic conditions of recharge of subsurface water resources (precipitation minus evaporation) in regions of water lowering are not changed. The artificial lowering of groundwater level changes the natural hydrodynamic conditions of river/underground recharge basins. Depression of groundwater level may lower the volume of subsurface recharge to the river: however, the range of this lowering varies greatly for different hydrogeological conditions e Where lowering of the water level in aquifers in the reduced water-exchange zone, the decrease in subsurface river recharge is not great and may amount to as little as 0.2 up to less than 1 litre/sec per km2 on the average for the area of a depression cone. For the Svapa basin (area 3600 km2) this lowering amounted to 3 mm/year , i .e. 2% of the total river runoff or 9% of its basic component. The lowering of water level in aquifers, in the intensive water exchange zone in the area of local development of depression cones, may decrease considerably the subsurface river recharge and even bring about its complete disappearance. At river stretches coinciding with central zones of cones, where the groundwater level falls below the channel bottom, the rivers may divert some part of their flow into the cone; under such conditions some river stretches may become completely dry during low water period - for the Oskolets river basin (area 493 Km2) in the KMA region, the decrease in subsurface recharge to the river in 1964 was 0.61 m3/sec and seepage from the river was 0.48 m2/sec, or 29 and 23% respectively, of the total river runoff, 85 and 67% of its basic component. The water withdrawn to lower the groundwater level and for use is returned to the river lower downstream. Consequently , the total water volume of river systems is not changed;

248

Cone Zusions

it is only the redistribution of runoff that takes place, for instance, the decrease of underground recharge in the Svapa basin is completely compensated for by discharges, the result of which is that the river water volume remains constant. The water volume of rivers is increased by groundwater moving into the river network from deep aquifers. Under natural conditions it does not constitute the river runoff. Stric- tly speaking, this movement increases local surface water resources because river recharge decreases at the location of the aquifer discharges. The final result, in absolute values, of water volume variation at particular river stretches depends on the balance of disturbances in a river basin. For the Oskolets river in 1964 the runoff increase was 1680 l/sec, while it lost seepage 1090 l/sec, resulting finally in an increase of the total annual runoff at the river mouth of 590 l/sec on account of deep groundwater that is not drained by this river under natural conditions. The actual value of the variation in volume of rivers depends on their relative volumes - for small rivers it may be rather great, while for large rivers it may be inconsequen- tial, i.e. within the limits of accuracy during hydrometric recording of runoff - the change of water volume of 590 l/sec for the Oskolets (area 493 km2) amounted to 28% of the normal annual runoff, while for the Oskol river downstream at the village of Sorokin0 (area 2960 km2) it amounted to only 5%. The forecasting of river runoff variations is possible where long-term observations are available on river runoff below the regions of water level lowering and data are available on the volume of discharges and water intakes over river basins. The forecasting error by the methods established for the Oskolets river does not exceed

1: 15%.

249

8 Water management in the Netherlands and the effect of urbanization with particular respect to runoff in polder areas

Ir. F. C. Zuidema

and members of the Scientific Department of the Ijsselmeerpolders Development Authority, Lelystad


Introduction ,


Special attention will be given in this chapter to actual and future measures of water control and regulation for a country that has one-third of its area situated below mean sea level. This low part of the country already has a very high population density and will become nearly totally ubanized (see also 11-3). Effects of urbanization and industrialization thus continue to grow in importance in water management.

Water control and regulation refer to the water which is at the service of man and nature as well as to the water against which man has to be on the defence. The first category comprises among other things: drinking water; water for industrial use; water as a means of transportation; water for outdoor recreation; open water as a vital part of the landscape; groundwater as a natural resource for plants, animals and man; and water as one of the most important elements of the ecosystem. The second category deals with: man's fight against sea and river floods; intensive rainfall; and salination and pollution of surface water and groundwater.

will be explained as a background for a discussion of water regulation, especially in polders, in relation to changes in land use. from research under way in the Eastern Flevoland polder.

Several water management measures will be described and some climatic characteristics

Indications will be illustrated by means of some results

111-8.2 CHANGING ASPECTS OF WATER MANAGEMENT

The unique geographical setting of the Netherlands in the delta o€ the Rhine, Meuse and Scheldt leads to the popular supposition that in these low lands sufficient water will be available to serve future demands of the population, industry and agriculture. Nothing could be further from the truth. water supply have been stated in several governmental notes (1,2) . (1972) described expected consequences of the present situation, especially from a qualitative point of view, with regard to both the safety and the optimal use of groundwater and surface water. However, it appears that: the quantity of groundwater that can be won lags behind water use more and more (Table63); and the quality of the surface water leaves much to be desired. The River Rhine Eor example has among other things, a very high chloride content due to discharges from French potash mines and German coal mines as well as sea water which pene- trates inland by way of the open estuaries and open rivers. The consequence is that more use of storage will be necessary at times when relatively good qualie water can be collected. Moreover, future linking of the two major parts of the water management system will be desirable to facilitate the exchange of water between the different fresh water basins (Figure 29) in dry periods.

The projected water demands of four categories for around the year 2 O00 in a dry summer (April to September, on an average frequency of once every 20 years) are as follows:-

The present situation and expected future trends of water management and Recently Snijdellaar

for domestic use for industry for agriculture for the fight against

salination

803 million m3 (= approximately 20 mm) 2 700 million m3 (= approximately 65 mm) 3 300 million m3 (= approximately 80 mm)

10 800 million m3 (= approximately 270 mm)

Assuming present-day sources and technical potential a fairly large water reserve will still be available in the year 2 OOO. The rational utilization of the available sources is a more pressing problem than that of actual shortages of water. This involves considerations such as augmenting the storage of water, combatting the inorganic pollution of surface and groundwater, controlling the qualiky of the water of the Rhine and the Meuse and using water more than once for specific purposes.

One point has to be mentioned here, the quality of the groundwater, which is found beneath the higher parts of the country, is very good, although the quantities are not large enough to meet the water needs of the population and industry, as Table 63 shows.

252

L E G E N D

>< SLUICE

I WEIR

FRESH WATER BASIV

+ TRANSPORT DIRECTION

O STORAGE BASIN

I

Figure 29. Linkage of the two main parts of the waker management system.

253

Climate

3 Table 63. Water use by population and industry in millions m .

Year Use Groundwater Surface water

1968 19 80 2000

1 375 2 500 4 500

9 50 1'500 1500

425 1 O00 3 O00

Because it is necessary to increase the usage of surface water, companies supplying drinking water must rely principally on the rivers. to store water withdrawn from the rivers in surface and sub-surface reservoirs.

can be divided in the year 2000 to safeguard the drinking water supply.

For reasons of quality they are obliged

Figure 30 shows how the storage of surface water in surface and sub-surface reservoirs

For more information the reader is referred to the national case study, 11-3 (4). There is an additional aspect in the field of polder development. This is the drainage

of these, mostly large, areas where urbanization is taking place. (Figure 31). This topic is discussed in 11-4 & 11-5.

111-8.3 CLIMATE

111-8.3.1 General

The Netherlands have a maritime sub-humid climate with moderate temperatures. Figure 32 shows the average values of precipitation and evaporation of open water over a period of 30 years. The average yearly precipitation amounts to about 750 mm and the evaporation of open water amounts to more or less the same value. In Table 64 average monthly and yearly values of evaporation according to Penman's method have been collected from three stations in the north, the centre and the south of the country. The evaporation values near the coast (Den Helder) and in the south (Maastricht), are higher than at the central station (De Bilt) . This is understandable because of the regional differences in temperature and in the influence of wind and sunshine, which are larger than that of the relative humidity (Kramer, 1957).

, Table 64. Precipitation (P in mm) and evaporation (Eo in mm) according to method of Penman, at three stations in the Netherlands: Den Helder (north), De Bilt (centre) and Maastricht (south). Average monthly and yearly values of the period 1945-1969. (Taken from monthly weather reports of the Royal Netherlands Meteorological Inst)

Mon th I II III IV V VI VI I

Station Eo P E Eo O Eo Eo O

P E P E O

~~~~~ ~

Den Helder 66 10 50 21 42 40 47 81 42 109 43 127 66 125 De Bilt 66 4 55 17 48 41 53 78 55 107 66 124 77 116 Maas tri ch t 62 6 56 19 47 43 53 79 62 107 67 122 79 118

Mon th VI11 IX X XI XII Total

Eo

De Bilt 105 93 71 61 60 28 72 io ao 3 808 682

P E O

P E EO O Eo O

P E Station P

Den Helder 88 108 80 76 82 41 84 19 77 10 767 767

Maas tri cht 90 95 63 65 51 31 69 12 71 6 767 704

254

L E G E

[y] .: ............_._.. . :.>:::;:::jj:::::: I....... . . :.:.:. .,._ . . . . . . . .

O

Figure 30. *

Plan for the storage of surface water in surface and subsurface reservoirs for potable supply in the year 2000.

255

Figure 31. Urban areas in the polders.

256

I jan. dec.

Figure 32. Mean monthly rainfall and waporation in the Netherlands, Cmillinetres) .

257

Climate

When precipitation exceeds evapotranspiration, a surplus of water has to be drained off. This is particularly the case in winter. The average value of the yearly surplus (precipitation minus evapotranspiration) varies approximately from 150 to 450 mm, depending on the predominant type of land use.

(1954), in a statistical review of the precipitation during the period 1926-1948, defined a heavy storm as any storm with an average intensity of 0.2 m/min or more; and the longest part of a storm with an average intensity of 0.2 mm/min or a value very close to this figure

On the average, of the 181 storms per year, one heavy storm occurs in the winter and 18 occur in the summer. Table 65 gives some information on heavy storms.

Ln winter, the maximum intensity of precipitation is much lower than in summer. Levert

Table 65. Heavy storms at De Bilt (K.N.M.I.) near Utrecht in the Netherlands for the period 1926-1948 (based on Levert, 1954)

Average Minimum Total number intens i ty (mm/min . ) ímm)

quantity in 23 years

L 0,2 12 18 24

30 16 3

> 0,3 12 20 18 8 24 2

The relationship between the maximum precipitation rate and the period length proves to be a logarithmic up to a period length of 180 days, as Figure 33 shows (Wind, 1967). Although the intensities in summer are higher than in winter, the drainage criteria for rural areas are based on the situation in winter. In this connection, the summer situation has only slight relevance to runoff, because these rainstorms seldom lead to high discharges. Figure 33 shows the relationship for the months September to December, the period with high intensities of precipitation and discharge (Van Montfort, 1966) .

Figure 34 shows that this relationshop over the year is more or less the same for several meteorological stations in the Netherlands. Thus it may be concluded that the relationship is also applicable in summer, when the rain water sewers are discharging in urban areas.

of rainfall in the first days of August 1972 given below, illustrates this pdint. The distribution of summer rain storms is characteristically local. The distribution

111-8.3.2 Rainstormcon 1. 2 and 3 Auaust 1972

In the first days of August 1972, unstable air masses moved on southern winds from the southern part of the North Sea (a low-pressure centre at that time) to the Netherlands. Numerous rain storms developed, mostly with thunder. Heavy thunder storms also occurred in the Federal Republic of Germany. The amounts and intensities of the precipitation were very high. Figure 35 and 36 show the distribution of the precipitation in the Eastern Flevoland polder. Locally the amount was more than 100 mm within 24 hours, which is exceptionally high; in the Netherlands daily rainfall seldom exceeds 70 mm. The largest daily amount of precipitation in August, which is exceeded on the average once in 30 years,is 45 m for a large area of the country, and 60 mm for a small part of the hilly Veluwe-region (Royal Netherlands Meteorological Institute, 1972) . recorded: 15.1 mm in 36 min., which is an intensity of 25.2 m/hr and 45.0 m in 45 min. with a maximum recorded intensity of 85.2 mm/hr (Figure 40) . According to Levert (1964) the recurrence period of such a storm, is once in 55 years. The highest rainfall intensity, recorded in the rural catchment area in the southwestern part of Eastern Flevoland was

In the urban catchment area of the new town Lelystad, two heavy rain storms were

258

Prrcipitation raie fmm i day) 50r 40

20

10

5

4

2

1 I I l 10 100 1000

Period length idaysl

Figure 33, Storm duration - intensity curve for Utrecht, September to December.

Precipitation rote Immldayl s 50

II I I I I 10 100 1000

Days

Figure 34. Storm duration - intensity cuxve for some other stations.

259

260

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rl F 6

H ai

c, m a W F:

..-I 26 1

Drainage and drainage requirements

28 mm/hr (Figure 41). The hydrological effects of these storms is discussed below.

111-8.4 DRAINAGE AND DRAINAGE RFQUIREMENTS

About one-third of the total area of the Netherlands, covering 33 000 km2 , lies below mean sea level, another third between this level and 10 m above sea level. Over many centuries a fierce fight has been waged to win or reconquer land from the sea, and to control the flood water of the rivers. In the Netherlands, in spite of all endeavours, some 500 O00 ha of land have been lost since the early Middle Ages but in view of the fact that from the 16th century, land has also been won, it would appear at the present time that the losses have been compensated. The principal objective of reclamation is to win agricultural land, thwgh in a number of cases other considerations have also played a role, such as the promotion of the safety of adjoining areas or improvement of the water management system (Bom, 1970). Figure 37 shows the areas of the Netherlands that would be flooded if there were no sea dikes or river dikes.

It is clear that the lowlands cannot be protected against floods by dikes alone. Drainage of a high standard is essential. This consists of detailed drainage and main drainage systems assisted by pumping. Moreover, the design of the system has to be adapted to the various types of land use.

alone has determined the pattern of management of water and the design €or runoff. In the last ten to fifteen years a number of investigations have been made to find the experimental criteria from results of research and to refine requirements based on the results of older investigations. Recently, a great deal of attention has been paid to the effects of runoff from areas with different kinds of land use (urbanized area, arable land, grassland, forest) on the water management. This has been achieved by means of catchment research areas.

There are five factors which influence the daily volume of runoff in a polder area, namely the climatic conditions, the storage capacity of the soil, the extent of upward seepage, the present detailed drainage system (type and spacing) and the various kinds of land use which require different drainage conditions. The daily runoff, the storage of the open waterways and the accepted rise of the water level above the design level lead to the drainage requirements for the whole polder.

per unit afea will be relevant normally for the detailed drainage system. discharge has to be linked to the desired groundwater level, so that a steady state flow approach can be applied. As a result of several investigations a number of requirements for various land uses have been compiled for the Dutch climate, based only on hydrological considerations, Table 66. This list is not complete; it can be extended to other things including the widespread requirements for natural conditions.

fluence the runoff requirements of a main drainage system of an area, when the use of part of the land is changing as a result of urbanization and industrialization. In the same way the dimensions of the drainage system in a newly reclaimed or re-allocated area have to be adjusted to such situations.

The open water storage of a polder (the percentage of the total area which consists of open water) varies from 1 to 5 per cent. In well drained polders the value is about 1 per cent. This situation applies in Eastern and Southern Flevoland. The requirements of the main drainage system and the pumping cclpacity amount to the equivalent of 10 to 13 mm/24 hrs per unit area, figures based mainly on experience. This value is considerably higher than that used before the year 1850, when only the equivalent of 4 to 6 m/24 hrs per unit area could be drained by means of windmills (if the wind was favourable). This resulted in inadequate drainage of the soils for a long period of the winter. The introduction of steam extended the draining (pumping) capacity to the equivalent of 7 to 8 mm/24 hrs per unit area.

In the course of the centuries many polders have been reclaimed and drained. Experience

Under Dutch climatic conditions, a design discharge equivalent to 5 to 10 mm/24 hours This design

The variation in the detailed drainage requirements, shown in Table 66, can also in-

111-8.5 HYDROLOGICAL EFFECTS OF TWE RAIN STORMS ON 1 to 3 AUGUST 1972

The heavy rain storms in the first days of August 1972, which have been described in paragraph III-9.3.2 and Figures 35 and 36 , influenced the hydrological situation of the Flevo- land polder (Eastern and Southern) considerably.

262

O 20 40 60 80 100km

Areas subject to flooding if sea dykes were lacking Areas subject to flooding if river dykes were lacking

Figure 37. Areas of the Nekherlands protected by dykes against high water levels.

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264

HydroZogicaZ effects of -the rain storms, 2-3 August 2972

111-8.5.1 Main drainage system

In the areas with well matured clay soils the storage capacity and the hydraulic conductivity are high as a result of an intensive fissuring in these young marine sediments. discharge of the excess precipitation was rapid. This was caused m n g other things by the fact &at a large amount of precipitation (about 30 mm) had already fallen in the preceding week, so that the moisture content of the soil had risen substantially, locally even to the point of field capacity. In addition the influence of runoff was being felt.

siderably above normal in the canals, as Figure 38 shows, among other things due to the circumstance in which the pumping station 'Colijn' started its work on 3 August only at 08-00 hours. Records for the whole polder indicated that the open water levels moved down- wards to normal values within 1 to 2 days.

Here the

The water level rose 60 to 80 cm in the minor and major ditches. It also rose con-

111-8.5.2 Urban ,area of Lelystad

As part of construction works in the new town of Lelystad, a sandy layer of 1 m thickness is generally deposited, by pumping, on top of the original soil profile. Such measures are required because of the need for a sufficiently high infiltration rate and hydraulic conductivity to facilitate the progress of the works as well as the final drainage conditions of the urban area. Parks and gardens require some mould (top soil), which will be exchanged with the top of the sandy layer. (See profile in Figure 39). The new soil surface is about 3.20 m below mean sea level, but will become about 50 cm lower due to subsidence under the load of the sand.

The open water level in the town has been fixed at 5.40 m below mean sea level, which is 80 cm above the water level of the low polder section. Consequently the urban main drainage system is separated from the main drainage system of the polder by means of weirs.

can be distinguished:

1. The domestic and industrial wastewater discharge, which is pumped through a closed

2. The storm water sewer discharge (precipitation on the impervious parts of the town

3.

As a result of the construction of a separate sewerage system the following discharges

, pipe system to a purification plant and the effluent discharged into the polder water.

- paved areas and buildings). The discharge of the subsurface drainage system (precipitation on the pervious parts, such as gardens , parks and roadsides). These special circumstances presented an opportunity to use urban catchment areas for

research into rainfall-runoff relations, in order to determine the design criteria for rain- sewers and subsurface drainage systems (Kraijenhoff van de Leur and Zuidema, 1969). The project is being undertaken jointly by the IJsseimeerpoiders Development Authority and the Agricultural University of Wageningen. So far, the following research areas have been incorporated into the project: a residential quarter (2.0 ha; impervious area 44%) ; a parking place (1.0 ha) ; a shopping centre (3.0 ha) with two flat roofs (250 and 450 m2) for detailed runoff studies; and a waste urban area (8.0 ha). Data collection is continuously made selectively at 13 to 27 sec intervals to meet changes in the variables.

The response of discharge from the storm water sewer, groundwater level and subsurface drainage discharge for the rainstorms of 2nd and 3rd August 1972 are given in Figure 39. It can be seen that the main pipes of the storm water sewer system in the catchment areas were always full. This explains the direct reaction of the storm water runoff. The direct reaction of the groundwater table is remarkable. The rapid rise in the groundwater level was caused by a substantial amount of precipitation during the days preceding 3rd August when the soil reached the point of field capacity.

The time lag between the start of the heavy rainstorm on 3rd August and the start of the runoff was 6% min. This can be derived from Figure 39. A comparison of fourteen storms with varying amounts of precipitation duration and maximum intensities , shows that if the storm starts with a high intensiw this time-lag can be established as 4 to 6 minutes. At low initial intensities the time-lag is different (mostly higher values). The time-lag between the moments of maximum rainfall intensity and peak flow of the storm of 3rd August was 5 1/3 min. From the above-mentioned number of storms it can be deduced that this

265

watei.\evel in m below mean seu ievel

-550

560

-570

-58C

-599

- 600 -SIC

-620

-633

-64C

I I , 8 1 1 I I I 1 4 4 0 12 16 20 1 ; 0 12 1 6 2 0 1 4 12 16 20 I 4 0 12 16 20

2-1 -1972 I 3 - 1 - 1972 I 4-8-1972 I 5-8-1972

I I I I I i d 12 16 20 4 b 1 ' 2 1 6 2 1 0 I 4 ' ' 8 12 " 16 20 4 a 1'2 16 20

2- U - 1972 I 3 - a - 1972 I 4 - a - 1912 I 5 - 1 -1972

Figure 38. Water levels in the main canals at the pumping stations of the polders Southern and Eastern Flevoland during the period 2-5 August 1972. Zuyderzeeworks) .

(Source: Board of the

266

'igure 39.

raph of rainfall, storm water runoff, groundwater level, and discharge of subsurface drainage during the eriod 2-4 August 1972 in an urban catchment area of the new town of Lelystad. rea (a residential quarter with an impervious area of 44%) is 2.0 ha).

(The size of the catchment

267

HydpoZogicaZ effects of the rain storms, 2-3 August 2972

pealr-time-lag has an average value of 4 to 6 minutes and a minimum value of 2 minutes. In view of the small number of storm occurrences these values should be considered as an approxi- mati on.

In addition there are some points of interest concerning the general situation during the heavy storm of 3rd August. As already stated, the open water level in the polder rose fast (Figure 38). Before 11.00 p-m. the open water level in the town was still higher than the level in the other part of the polder, but approximately at that moment the same level (5.27 m below mean sea level) was reached upstream and downstream of the weir. During the rain storm and shortly aEterwards, water was standing everywhere on the streets, due to a tempcrazy inadequacy of sewer capacity. This situation continued for one half to one hour. Surface runoff from the non-paved area also appeared, but within a somewhat shorter period.

111-8.5.3 Rural areas

Ac stated in paragraph 111-9.5.1, the water levels in the major and minor ditches rose 600 to 800 mm in a short time. This was the result of firstly, the fast drainage of the heavy loam and clay soils with a high hydraulic conductivity, secondly, the delay in application of maximum pumping capacity and thirdly, local plant growth in the ditches which partly blocked the culverts. It was almost impossible to measure the run-off of sub-surface ärain- age in the rural areas, because the outlet of the hain pipes was below the water level in the ditches. or vegetation cover to rain storms must be restricted to changes in the groundwater level. In Table 67 some data have been assembled concerning the groundwater level in different soil types with various land use. The following conclusions can be formulated from this table and other information:

Thus, regrettably, comparisons of the reactions of land under different crop

l .

2.

3.

4.

5.

6.

A flood situation has occurred only on the soil type characterized by heavy loam (thin top layer) on very find sand. This profile is characterized by a poor hydraulic conductivity and a low storage capacity. This soil type is found mainly in the northwestern part of Eastern Plevolar-d, which happens to be the area with the highest amount of precipitation (see Figure 36). Thus, the water ponded on the soil surface and there was surface runoff to ditches. In spite of this, the damage done to field crops was limited. There is a different reaction of the heavy loam and clay soils which h m e matured well (parcels F 47, R 18, etc.) or moderately well (parcels W 39 and X 69). In the forests of light loam and sand soil types, a slight difference in groundwater level has been observed between clean and congested open field drains. The figures measured in the forest in the parcels D 14 and F 47 show that the reaction of the groundwater to the rain storms has been determined by the drainage conditions and the physical behaviour of the soil. The forests are too young and the information on the groundwater level too limited to draw any conclusions about an eventual influence of interception and mulch production. At this stage there is not much difference between the hydrological reaction o£ forest and arable land. In shallow-drained grassland (parcel X 69) the groundwater level rose nearly to the soil surface, which is an unacceptable situation.

Point 6 above can be amplified by considering details affecting the drainage discharge on parcel X 69 (drain spacing 8 m, drain length 100 m) (Figure 41). The soil profile consists of 80 cm of clay on Pleistocene sand. Upward seepage is considerable (more than 10 m/24 hours). On parcel X 68 the drains have been laid in the sandy sub-soil at a depth of 1.30 m below the soil surface; and on parcel X 69 the drains are at a depth of 600 mm in the clayey top soil. The better physical and drainage conditions of the soil in parcel X 68 cause a quicker lowering of the groundwater level as well as of the piezometric head, compared with parcel X 69 (muderate phase of maturing, low hydraulic conductivity &ü low storage capacity) .

Lel-ystad, the following points, from about ten other rain storms, are noteworthy: The time-lag between the start of a rain storm and the start of the increase of runof€ depends

In accordance with the remarks on the rainfall-runoff relation in the urban area of

268

a L

.æ

- u e, O h

I I

rbaJ

CS

fdci

269

Table 67. Groundwater levels (cm below soil surface) in various parcels in Eastern Flevoland before, during and a£ter the heavy rainstorm on 3rd August 1972

Details of Groundwater level drainage (cm below soil surface)

Soil type Parcel Land-use and drainspacing 21/7 27/7 2/8 3/8 4/8 7/8 9/8 17/8

Heavy loam on very fine sand

Homogeneous heavy loam and clay

Heavy loam and clay on medium fine sand

Light loam and sand

G 14 G 16 H 130 J 5 S 13 G 150

D 14

F 47

M 111

R 17

R 18

w 39**

X 68

X 69

O 72

o 73

P 96

P 95

Grass land II

II

Arable land

Forest ( 4 years old) Forest (5 years old) Forest (5 years old) Forest (5 years old) Forest (10 years old) Arable land

II II

Or chards *

Forest (2 years old)

Subsurface 8 m 8 m 8 m 12 m 12 m 12 m

II

II

II

II

II

Open field draiins 48 m Open field drains 24 m Subs Ur f ace drains 48 m Subsurface drains 24 m Subsurface drains 24 m Subsurface drains 4 m Open field drains 13 m

Grass land Subsurface (deep) dr. 8 m Subsurface (undeep) dr. 8 m

II





Open field drains 12 m (cleaned) Open field drains 12 m (not cleaned) Open field drains 8 m (cleaned) Open field drains 8 m (not cleaned)

114 8 91 + 1 86 6 141 5 144 34 15 8 20

131 56

136 73

91

87

170

133 139 130 50

70 45 33

>60 55 26

21 41 2

44

39

65

44

55 84 87 5 51 66 43 88 88 52 91 96 58 82 lo0

93 108

93 124

97 122

153

96

73 92 126

89 104 116

54 66

45 55 <60

25 43 46 51

58 75

49 64

65 85

50 75

* experimental field

** poorly matured profile

270

I

d m n discharm

Figure 41. Graph of the average rainfall at 30 minute intervals, groundwater level, piezometric head and discharge of subsurface drainage &ring the period 26 3uly-11 August 1972 on grassland in Eastern Flevoland. (Parcels X68. and X69) .

27 1

Ref er ence s

on the maximum rainfall intensity and the groundwater level. With initially high intensities the time-lag will be shorter than at initial-ly low intensities. The time-lag i.s about 3 to 5 hours after a dry period and about l to 3 hours when the soil has been wetted during the preceding days. The time-lag between maximum rainfall intensity and peak flow is about $5 to 2'5 hours. Generally, the peak flow is reached more or less at the end of the storm. The great difference between urban and rural reactions, which is also evident from the runoff pattern, is re-emphasised: 4 to 6 minutes" (Lelystad) as opposed to 1 to 3 hours (rural area). For the management of a new or redesigned polder such figures are of great value.

111-8.6 SUMMARY

The peculiar situation of the Netherlands, in the delta of the rivers Rhine, Meuse and Scheldt, gives rise to considerable problems in the field of water management, water supply, water quality, etc. drainage and drainage requirements of polder areas with various urban and rural configurations. The hydrological effects of the heavy rainstorms in Eastern Flevoland on lst, 2nd and 3rd, August 1972 are discussed for different kinds of land use.

After a short description of some of them, particular attention is paid to the

(*: Under catchment conditions of mainly filled storm sewer system).

111-8.7 mFERENCES

Bom, F. L. van der. 1970. Planning and Development in the Netherlands, Vol. IV, nr. 1.

Kraijenhoff van de Leur, D. A. and Zuidema, F. C. 1969. A study on the relation of rainfall and run-off in an urban area at Lelystad (Dutch, with English Summary). H20, 2 , nr. 4. Kramer, C. 1957. Computation of the mean value of evaporation for various parts of the Netherlands according to Penman's method. Uitgeveri jbedri j f.

Levert, C. 1954. Precipitation, a statistical study (Dutch) . K.N.M.I. (Royal Netherlands Meteorological Institute) , de Bilt. Medelingen en Verhandelingen 62.

Montfort, M. A. J. van. 1966. Statistical dissertations about precipitation and discharge (Dutch, with English Summary). Unpubl. thesis, Wageningen.

Royal Netherlands Meteorological Institute. 1972. Climate atlas of the Netherlands - 's Gravenhage , Staatsuitgeveri j . Snijdelaar, M. l'ijdschmft v. Econ. en Soc. Geogr. 63, 3, p. 211-225. Wind, G. P. , 1967. A simple relation between discharge capacity, water storage and precipitation rate (Dutch, with English Summary). Lmdbomkwadig tijdsehrift 79-4, p. 110-113.

(Dutch) 's Gravenhage , Staatsdrukkeri j-en

1972. Water Management of the Netherlands, The struggle for water.

272

Annex I Respondents to questionnaire sent by the IHD Secretariat to the National Committees for the IHD Respondents are listed in order of the date of their response rather than by

surname or nation.

Mr. J. B. Williams, Director Geological Survey Department Hope Gardens P.O. Box 189, 191 Kingston , 6, JAMAICA

Mr Mahmoud Baker, Secretary National Committee for I. H. D. Ministry of Elec. and Water Ground Water Department P.O. Box: 516 KUWAIT

Mr. Jose Salvadore Gandolfo Presidente Comite Argentina del Decenio Hidrologico Internacional

Comision Nacional Argentina Para La Unesco Buenos Aires, ARGENTINA

Mr. Lars Jorgen Andersen, Secretary Danish National Committee for the

International Hydrological Decade Dansk Hydrologisk Dekadakomite 31, Thoravej , DK-2400 Copenhagen NV, DENMARK

Mr. C. Phanartzis, Hydrologist Department of Water Development Nicosia, CYPRUS

Mr Saleh Al Mosa'ad, Deputy Chairman National Committee for the IHD Water Resources Development Dept. Ministry of Agriculture and Water Riyadh, SAUDI ARABIA

Mr. Elton D. Wyke, Director Water Resources Survey Government of Trinidad and Tobago P.O. Box 145 Port-of -Spain, TRINIDAD

Mr. Sigurjon Rist I. II. D. National Committee c/o Sigurjon Rist Skridustekkur 4 Reykjavik, ICELAND

Dr. I. C. Brown, Secretary c/o Environment No. 8 Building Carling Avenue Ottawa 1, CANADA.

Mr. William E. Stewart Ministry of Lands and Mines Monrovia, LIBERTA

Mr. Alberto Sanchez de la Calle Division de Hidrologia SCMI1 Ingeniero Jefe Bogota, D.E. 1, Carrera 10a.

COLOMBIA No. 20-30 Pisa 6a.,

Mr. R. Hanreck, Secretary Israel National Committee for the

P.O.B. 884 Jerusalem, ISRAEL

Mr. Hiew Siew Nani, Chairman National Committee for the I.H.D. Public Works Department, P. O. Box 9009

National Development Bldg . Maxwell Road SINGAPORE 2

International Hydrological Decade

Mr. Prabhakar, Secretary I.H.D. National Committee Ministry of Agriculture Water Department P.O. Box 30521 Nairobi, KENYA

Mr. A. Crahay, President du Comite belge pour la decennie hydrologique International

1010 Bruxelles, le Cite Administrative de 1'Etat Quartier Vesale BELGIUM

Mr. V. Gama Ochoa, Secretaire Comissao Portuguesa para o Decenio Hidrologico Internacionaï

Palacio De S. Bento Lisbon 2, PORTUGAL

Officialia Mayor Ministerio DI Agricultura Ganaderia San Salvadore, EL SALVADOR, C.A.

Mr. Nii Boi Ayibotele, Secretary c/o Water Resources Research Unit P.O. Box M.32 Accra, GHANA

273

Mr. Rachmat Tirtotjondro, Director Mr. Emilio CuskodiQ Ministry of Public Works and Power Institute of Hydraulic Engineering 2 Kidang Panzndjung Subterranea Bandung, INDONESIA Comision Docente, SPAIN

National Comitiee of the IHI) Curso Internacional De Hidrologia

Mr. Arne Tollan, Secretary Boks 5091 Majors tua Oslo 3, NORWAY

Mrs. M. Falkenmark, Executive Secretary Swedish National IHD Committee Wenner-Gren Center Sveavagen 166 8 S-113 46 Stockholm, SWEDEN

Mr. A. Z. Touambona Ministere Du Pian, De La Cooperation Internationale Et Des Statistiques

Bangui, REPUBLIQUE CENTRAFRICAINE

Mrs. Sakuntala Bhodhiprasart Secretary of National Committee for

National Research Council Bangkok 9, THAILAND

the IHD

Mr. A. Kabbaj Le Directeur de l’Hydraulique Direction De L’Hydraulique Casier Rabat-Chellah, MOROCCO.

Mr. J. W. van der Made, Secretary IHD National Committee of the Netherlands The Hague Nieuwe Uitleg 1 THE NETHERLANDS

Mr. Paulo Poggi Pereixa, Secretary Brazilian Committee for the IHD Av. Pres. Vargas 62-5O Rio de Janeiro, BRAZIL

Mr. E. O. Adubifa Meteorological Division FederaJ Ministry of Agriculture and Natural

Lagos, NIGERIA Resources, Headquarters,

Sr. Andres Benitez G., Presidente Comite Nacional Para El Decenio Hidrologico

Morande 59-5O Piso Santiago, CHILE.

Internacional, Chile

214

Annex II Participants in International Workshop on,the Hydro1,ogical Effects of Urbanization, Warsaw, 8-10 November 1973

Prof. Juan Jacinto Burgos School of Agronomy of Buenos Aires

Casilla de Correo 5233, Correo Central Buenos Aires, ARGENTINA

University

Mr. A. P. Aitken Snowy Mountains Engineering Corp. P.O. Box 356 Gooma North 2630 N.S.W. AUSTRALIA

Mr. R. L. G. Thonnard Service Geologique de Belgique rue Jenner 13 Bruxelles 4, BELGIUM

Mr. Paul Poggi Pereira Secretary Brazilian Committee for the

Av. Pres. Vargas 62 - so andar Rio de Janeiro, G.B. BRAZIL

IHD

Mr. D. H. Lennox Chief, Hydrology Research Division Water Resources Branch Inland Waters Directorate Environment Canada Ottawa Ontario CANADA

Mr. C: Phanartzis Hydrologist Department of Water Development Nicosia, CYPRUS

Mr. J. Jacquet Electricite de France 6 quai Watier 78 Chatou, FRANCE

Prof. Dr. Herbert Buss Leiter Hessische Landesanstalt fur rimwelt 6200 Wiesbaden Kranzplatz 6-7 Federal Republic of Germany

Dr. Herbert Massing Landesanstalt fur Gewasserkunde und Gewas s ers chutz

4 Dusseldorf 1 Bornestrasse 10. Federal Republic of Germany

Mr. Richard Zayc President Landesanstalt fur Gewasserkunde und Gewas s ers chutz

4 Dusseldorf Bornestrasse 10. Federal Republic of Germany

Mr. Nii Boi Ayibotele, Secretary National Committee for the IHD c/o Water Resources Research Unit P.O. Box M.32 Accra, GHANA

Mr. Sigurjon Rist National Committee for the IHD Skridustekker 4 Reykjavik, ICELAND

Professor S. Inokuti Institute of Industrial Science university of Tokyo 22/1 Roppongi Minato-Ku Tokyo 114- JAPAN

Dr. Takeo Kinosita, Chief Research Division of Large-scale Experiment National Research Center for Disaster Prevention

1,15, Ginza 6

Tokyo, JAPAN Chuo-ku,

Mr. D. R. L. Prabhakar, Secretary National Committee for the IHD Ministry of Agriculture Water Department P.O. Box 30521 Nairobi, KENYA

Dr. Yousef K. Shuhaibar National Committee for the IHD Ministry of Electricity and Water Chief, Planning and Development for Water and Gas

P.O. Box 516 Kuwait City, KUWAIT

Mr. Samuel A. Ricks Assistant Director, Liberian Hydrological

Ministry of Lands and Mines Monrovia, LIBERIA

Service,

275

Mr. H. J. Colenbrander Water Board of the Province Gelderland Marks traat 1 Arnhem, THE NETHERLANDS

Mr. J. L. de Kievit Grontmij , Agricultural and Civil Consulting Engineers

" Houdringhe" De Bilt, THE NETHERLANDS

Mr. J. L. Koolen Government Institute for Sewage and Waste

Westeinde 3A Voorburg , THE NETHERLANDS

Water Treatment

Mr. J. A. Los Government Institute for Water Supply Parkweg 13 Den Haag, THE NETHEXLANDS

Mr. F. C. Zuidema Scientific Department Ysselmeerpolders Development Authority Zuiderwagenplein 2 Lelystad, THE NETHERLANDS

Mr. Arne Tollan I Secretary National Committee for the IHD Boks 5091 Maj orstua, Oslo 3, NORWAY

Dr. Mr. P. Baszczyk, Deputy Director Institute of Municipal Economy Bracka 4 00-501 Warsaw, POLAND

Dr. Mr. W. Meyer Institute of Meteorology and Water Economy

Podlesna 61 01-673 Warsaw, POLAND

I

Dr. U. Soczynska Institute of Meteorology and Water

U1. Podlesna 61 01-673 Warsaw , POLAND

Economy

Dr. D. Jurk Institute of Meteorology and Water Economy

UL. Podlesna 01-673 Warsaw, POLAND

prpf. Z. Mikulski University of Warsaw Institute of Geography Krakowskie Przedmiescie 30 00-325 Warsaw, POIAND

'Mr. J. Kindler Warsaw Technical University Institute of Environmental P1. Jednosci Robotniczej 1, 00-661 Warsaw, POIAND

Dr. K. Matui Warsaw Technical University Institute of Water Supply P1. Jednosci Robotniczej 1 , 00-661 Warsaw, POLAND

Engineering

Mr. A. Da Paha Carlos Director-General dos Servicos Hidraulicos 23 Rua de S. Mamede, ao Caldas Lisboa-2, PORTUGAL

Mr. Chang Kin Koon, Secretary National Committee for the IHD Drainage Branch, Ministry of the Environment, National Development Building Maxwell Road I SINGAPORE 2

Mrs. M. Falkenmark, Executive Secretary Swedish Committee for the IHD Wenner-Gren Center, Sveavagen 166-152 S-113 46 Stockholm, SWEDEN

Prof. Yngve Gustafsson Departmen.t of Land Improvement and Drainage Royal Institute of Technology 100 44 Stockholm 70, SWEDEN

Dr. Anders Hilmer Division of Hydraulics Institute of Technology University of Lund Fack 725 S-220 07 Lund, SWEDEN

Dr. Sven Lindqvist Department of Physical Geography University of Gothenburg Dicksonsgatan 4 S-412 56 Gotenborg, SWEDEN

Mr. Elton D. Wyke, Director Water Resources Survey Government of Trinidad and Tobago P.O. Box 145 Port-of -Spain, TRINIDAD

276

Dr. S. Buchan, Consultant Hydrogeologist 14 Monks Road Banstead, Surrey, UNITED KINGDOM

Mr. C. J. N. Cotton Engineers Department Kent River Authority 78 College Road Maidstone Kent , UNITED KINGDOM

Dr. R. B. Painter Institute of Hydrolog-- Maclean Building Crowmarsh Gifford Wallingford Berkshire, UNITED KINGDOM

Mr. David R. Dawdy U.S. Geological Survey, WRD 345 Middlefield Road Menlo Park, California 94102

Mr: A. O. Friedland, Principal Engineer Department of Public Works Division of Sanitary Engineering 770 Golden Gate Avenue San Francisco, California 94102

Dr. L. A. Heindl, Executive Secretary U.S. National Committee for the IHD National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418

Mr. C. F. Izzard 3304 North Vernon Street Arlington , Virginia 22207

Mr. S. W. Jens Reitz and Jens, Inc. , Consulting Engineers

111 South Meramec Avenue St. Louis, Missouri 63105

Mr. D. E. Jones, Jr. 6321 North 23rd Street Arlington , Virginia 22205

Dr. Marvin Lindorf Water Resources Engineers, Inc. 710 South Broadway Walnut Creek, California 94596

Dr. G. F. Mangan, Jr. Project Officer - OWRR Department of Interior Building 18th and C Streets, N.W. Washington, D.C. 20240.

Mr. M. B. McPherson, Director ASCE, Urban Water Resources Research Program 23 Watson Street Marblehead, Massachusetts 01945

Mr. T. Prawdzik, Engineer in Charge Sewer Engineering City of Milwaukee DPW Municipal Bui ldfng 841 North Broadway Milwaukee, Wisconsin 53202

Mr. J. V. Radziul, Chief R and D Division Water Department Municipal Services Building , 12th Floor Philadelphia, Pennsylvania 19107

Mr. W. J. Schneider U. S. Geological Survey National Center Reston, Virginia 22070

Mr. D. C. Taylor, Manager Research Servi ces American Society of Civil Engineers 345 East 47th Street New York, New York 10017

Mr. L. S. Tucker , Executive Director Urban Drainage and Flood Control District 181 East 56th Avenue Denver , Colorado 80216

Dr. G. L. Sokolov Hydrology State Institute V.O. 2 line, h.21, Leningrad, U. S. S. R.

Mr. L. A. Orihuela, Chief Community Water Supply and Sanitation Division of Environmental Health World Health Organization 1211 Geneua 27, SWITZERLAND

Mr . Roger Berthelot , Project Manager UNESCO C.O. 530 Porto Alegre, BRAZIL

Mr. Jose A. da Costa, Secretary Co-ordinating Council for the IHD , UNESCO , Place de Fontenoy 75700 Paris, FRANCE

Mr. F. H. Verhoog Division of Hydrology, UNESCO, Place de Fontenoy 75700 Paris, France.

277

Annex algae

alluvial

anaerobic

III Termnolorrv

antecedent precipitation

aquifer

artificial recharge

assimilative capacity

base flow

benthal deposit

biota BOD (biochemical oxygen demand )

catchment coastline

COD (chemical oxygen demand) - combined sewer

conduit consumptive use of water contamination

dilution

direct runoff

dissolved oxygen

domestic water use

domestic waste water

drainage area

dry-weather flow

U d

Primitive plants, usually aquatic, and capable of elaborating their food stuffs by photosynthesis. An adjective referring to material that has been deposited by streams. Requiring, or not destroyed by, the absence of air or free oxygen. Rainfall that occurred prior to the particular rainstorm under consideration. A porous, water-bearing geological formation. Generally restricted to materials capable of yielding an appreciable supply of water. Replenishment of the groundwater supply by means of spreading basins, recharge wells, irrigation, or induced infiltration of surface water. The ca.pacity of a natural body of water to receive: waste waters, without deleterious effects; toxic materials, without damage to aquatic life or humans who consume the water; BOD, within pre- scribed dissolved oxygen limits. That part of stream discharge that is not attributable to direct runoff from precipitation or melting snow. Accumulation on the bed of a water course of deposits containing organic matter arising from natural erosion or discharges of' waste waters. Animal and plant life of a stream or other water body.

Measure of waste water pollutional strength based on the amount of oxygen required by bacteria to oxidize organic waste. The area tributary to a lake, stream, sewer or drain. The strip of land surface that separates the land and the water surface of a sea or ocean. Measure of waste water pollution strength based on the oxygen consumption in a chemical reaction. A sewer intended to receive both waste water and storm (rainwater) or surface water. Any duct for conveying liquids. Any use of water which depletes the avialable supply. Any introduction into water of microorganisms, chemicals, wastes, or waste water in a concentration that makes the water unfit for its intended' use. Disposal of waste water or treated effluent by discharging it into a stream or body of water. The runoff that enters stream channels promptly by flow over the ground surface or through the ground without entering the main water table, or that portion of the runoff which is directly associated with causative rainfall or snow melt. The oxygen dissolved in water, waste water, or other liquid, usually expressed in mg/l, parts per million or per cent of saturation. Water supplied principally to dwellings, business buildings, institutions and the like. Waste water derived principally from dwellings, business buildings, institutions and the like. The area of a drainage basin or watershed. area. The flow of waste water in a combined sewer during dry weather. such flow consists mainly of waste water, with no storm water included.

Also called catchment

278

ecology

erosion

estuary evapotranspiration

flood plain

heavy metals

impervious

industrial waste water

inlet

interceptor

invert

land disposal

municiple waste water

opencast mining

open channel

open pit mining out f al 1

overflow overland flow

pollution

public sewer

public water

rainfall excess

rainfall intensity rain water sewer reach receiving body of water

recharge recycling

river basin

runoff

sanitary sewer

- That branch of biQlogy dealing urith the relationships between - Warin9 away of the lands by running water, glacAers, winds and - A pqssage in which the tide meet? a river current. - Water withdrawn from soil by evaporation and/or plant transpiration. Considered synonymous with consumptive use. - The area described by the perimeter of a flood of a given rare probability of recurrence. - Mineral elements such as mercury that are toxic in low concentrations to plant and animal life. - Not allowing, or allowing only with great difficulty, the movement of water. Impermeable, waterproof.

- Water containing wastes resulting from manufacturing processes. Trade waste water. - A form of connection between the surface of the ground and a drain or sewer for the admission of surface or storm water.

- A sewer in a combined sewer system that receives dry-weather flow from a number of transverse sewers or outlets and frequently additional modest quantities of storm water. - The floor, bottom, or lowest portion of the internal cross- section of a closed conduit.

- Disposal of waste water or sludge from waste water treatment onto land.

- Typically contains faeces and laundry wastes. (see domestic waste water). - Minerals removed by a method of excavation in which the working area is kept open to the sky, as opposed to underground mining.

- Any natural or artifical waterway or conduit in which water flows with a free surface.

- (see opencast mining). - The point, location, or structure where waste water or drainage

- (see sewerage). - The flow of water over the ground before it enters some defined channel. - A condition created by the presence of harmful or objectionable material in water. (see also contamination).

- A commrm sewer controlled by a governmental agency or such an agency's designate. - Water that is available to people at large or to any considerable numbers of members of the public indiscriminately.

- That part of the rain of a given storm that is available for direct runoff. Total rainfall of a storm less total abstractions (infiltration, depression, storage, etc .) .

organgsms and theAr environment.

wqyes.

discharges from a sewer, drain, or other conduit.

- Amount of rainfall occurring in a given unit of time. - (see storm sewer. (also rain sewer). - A comparatively short length of a stream, channel, or shore. - A natural water course, lake, or ocean into which treated - Admission of water to the zone of saturation. - An operation in which a substance is passed through the same series of processes, pipes, or vessels more than once.

- The area drained by a river and its tributaries. age area).

- That portion of the earth's available water supply that is transmitted through natural surface channels. - A sewer that carries liquid and water-carried wastes from residences, commercial buildings, industrial plants, and institutions, together with minor quantities of groundwater, storm water and suxface wqter that are not admitted intention- aiiy. (see waste water).

OP untreated waste water is discharged.

(see drain-

279

sanitary waste water sedimentation

self-purification separate sewers sewage sewer

sewerage

soft detergent soil moisture solid wastes

storm drain storm runoff

storm sewer

storm water

street wash

trade wastes transpiration

treated sewage

unit hydrograph

waste water waste water reclamation

waste water treatment

water use water withdrawals

zone of aey;ation

zone of satura.Ti.m

- Domestic waste water with stoxm and surface water excluded. - The process of precipitation and deposition of suspended matter - bee assimilative capacity). - (see sewerage). - The spent water of a community or industry. (see waste water). - A pipe or conduit that carries waste water or drainage water or or both.

- The conveyance of waste waters from their place of origin to a place where they are treated and disposed of involves a system of sewers. Sewers may be combined, for the conveyance of waste water and surface water, or separate (i.e. there may be two systems, one for waste water and another for surface water). A combined system cannot usually be designed to carry the total flow at times of heavy storms, nor could this volume of liquid be treated at a sewage treatment plant if it arrived there. Consequently, combined systems must have relief overflows, through which a mixture of sewage and surface water is discharged to a stream when the flow exceeds a certain rate.

in water by gravitakional action.

- A synthetic detergent that responds to biological attack. - Water content of the zone of aeration. - Garbage, rubbish, trash and related wastes with a nominal or

- (see storm sewer). - That portion of the total runoff that reaches a given point negligible water content.

within a relatively short period of time after the occurrence of precipitation. Also called direct runoff. - A sewer that carries storm water and surface water, street wash and other wash waters, or drainage, but excludes domestic waste water and industrial wastes. Also called storm drain or rain water sewer. - The excess water running off from the surface of a d.rainage area during and imnediately after a period of rain; containing pollutants such as animal faeces, chemicals and refuse from streets and agricultural fertilizers, herbicides and pesticides. - The surface runoff from streets that finds its way into sewers or storm drains. - See industrial waste water.

- The process by which water vapour is lost to the atmosphere from living plants. - Waste water that has received some degree of treatment in a water pollution control plant. - The hydrograph of the storm runoff at a given point on a catchment that will result from an isolated rainfall excess of unit duration occurring over the contributing drainage area and resulting in a unit of runoff. Also called unitgraph. - The spent water of a community or industry. Also sewage. - Processing of waste water for re-use, usually for agriculture or industry. - any process to which waste water is subjected in order to remove or alter its objectional constituents and thus render it less offensive or üangerous. - (see water withdrawals] - Quantities taken from surface water or grounüwater supplies. Indicates the amounts abstracted from the hydrological cycle. The term water use differs by representing an amount greater than the amount withdrawn by the degree of internal re-use or recycling exercised.

contairi suspended water - - The soil zone next to the gxoqnd surface that contains or can - The soil zone that contains groundwater usable for water supply.

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Documents

Hydrological effects of urbanization