Intermittent Water Supply under Water Scarcity Situations

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Intermittent Water Supply under Water ScarcitySituationsKala Vairavamoorthy a , Sunil D. Gorantiwar b c & S. Mohan da WEDC, Department of Civil and Building Engineering , Loughborough University , UKb WEDC, Loughborough University , UKc Associate Professor, Mahatma Phule Agricultural University , Rahuri, Indiad Head Department of Civil Engineering Indian Institute of Technology , Chennai, IndiaPublished online: 22 Jan 2009.

To cite this article: Kala Vairavamoorthy , Sunil D. Gorantiwar & S. Mohan (2007) Intermittent Water Supply under WaterScarcity Situations, Water International, 32:1, 121-132, DOI: 10.1080/02508060708691969

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121

The available water sources throughout the world

are becoming depleted and this problem is aggravated

by the rate at which populations are increasing,

especially in developing countries. The threat to water

resources has brought into focus the urgent need for

planned action to manage water resources effectively as

it is widely acknowledged that water is a major limiting

factor in the socio-economic development of a world

with a rapidly expanding population.

The United Nations in their Millennium

Declaration drew attention to the importance of water

and water related activities in supporting development

and eradicating poverty (UN, 2003). Water is

intrinsically interconnected with the eight Millennium

Development Goals (MDGs) agreed upon by the

international community in 2000. Halving “by 2015,

the proportion of people without sustainable access to

safe drinking water” is one of the 18 numerical and time

bound targets that are embodied in the eight MDGs.

Currently, some 30 countries are considered

to be water stressed, of which 20 are absolutely water

scarce. It is predicted that by 2020, the number of water

scarce countries would likely to approach 35 (Rosegrant

et al., 2002). More worrying is that it is the developing

countries that face the greatest crisis and it has been

estimated that by 2025, one-third of the population of

the developing world will face severe water shortages

(Seckler et al., 1998). For example:

• On the continent of Africa by 2005, 12 African

countries will be considered to be in a “Water

Stress” situation. A further 10 African countries

will be stressed by 2025 (a total of 20 out of the

29 countries). A total of 1.1 billion people or

two thirds of Africa’s population will be affected

(Dzikus, 2001).

• At the current rate of population growth in India,

combined with the growing strain on available

water resources, India could well have the

dubious distinction of having the largest number

of water-deprived persons in the world in the

Senior Lecturer, WEDC, Department of Civil and Building Engineering, Loughborough University, UK, Academic Visitor, WEDC, Loughborough

University, UK, and Associate Professor, Mahatma Phule Agricultural University, Rahuri, India and, Professor and Head, Department of Civil Engineering Indian Institute of

Technology, Chennai, India

This paper describes the recently developed ‘Guidelines for the design and control of intermittent

water distribution systems’. These guidelines outline a new approach to the design of urban water distribution

systems for developing countries in order to maintain adequate and equitable supplies under the common

conditions of water resource shortage. The guidelines are novel in that they recognise the reality of intermittent

supply and hence provide new methods of analysis and design, appropriate for such systems. Design objectives

expressed in terms of equity in supply, adequate pressure at water connections and duration or time of supply that

a new network analysis simulation tool coupled with an optimal design tool.

water supply, water shortage, distribution system, network analysis, intermittent, developing

countries.

International Water Resources AssociationWater International, Volume 32, Number 1, Pg. 121-132, March 2007

© 2007 International Water Resources Association

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IWRA, Water International,Volume 32, Number 1, March 2007

next 25 years (Singh, 2000).

Figure 1 indicates the total non-irrigation water

consumption (domestic, industrial, and livestock use)

for the different regions of the world (Rosegrant et al.,

2002), and highlights that it is in the developing world

where there will be a drastic increase in non-irrigation

consumption.

Migration of the rural population to urban centres

has resulted in towns and cities expanding rapidly. For

example between 1950 and 1990 the number of cities

with populations of more than 1 million increased from

78 to 290 and this is expected to exceed 600 by 2025

(Serageldin, 1995).

The problem of water scarcity in urban areas

in developing countries is of particular concern. For

example, it is estimated that by the year 2050, half of

India’s population will be living in urban areas and will

face acute water problems (Singh, 2000). The water

stress condition that exists in these countries is not only

due to source limitation but also other factors such as

poor distribution through pipe networks and inequalities

in service provision between the rich and the poor (UN-

HABITAT, 1999). For example it has been reported

that in India the water consumption ranges from 16

to 3 litres per day depending on the locality and the

economic conditions of the people (Singh, 2000).

Awareness of what happens when there is a lack

of water is all too apparent in many cities of developing

country, where poor living conditions and limited access

burden on the urban poor, who often constitute the very

labour source that generates the wealth of the cities

(UNESCO, 2003). Providing adequate water supply to

the rapidly growing urban populations is a challenging

task for governments throughout the world.

One of the most common methods of controlling

water demand is the use of intermittent supplies, usually

by necessity rather than design. This is where the water

is physically cut-off for most of the day and hence

limiting the consumer’s ability to collect the water.

For instance, in South Asia it is estimated that at

least 350 million people receive service as little as a few

hours daily and nearly all water supply systems in Indian

cities are reported to operate intermittently. Figure 2 (ADB,

1993) shows the average duration of water supplies for 8

major Asian cities. The situation is similar in other regions,

and in Latin America alone more than 50 million inhabitants

in ten of its major cities receive rationed supplies (Choe and

Varley, 1997).

The design of water distribution systems in

general has been based on the assumption of continuous

supply. However, in most developing countries water

supply is not continuous but intermittent, and this could

have been foreseen at the design stage. This has resulted

Intermittent Water Supply under Water Scarcity Situations

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in severe supply pressure losses and great inequities

in the distribution of water. Another serious problem

arising from intermittent supplies, which is generally

ignored, is the associated high levels of contamination.

This occurs in networks where there are prolonged

periods of interruption of supply due to negligible or

zero pressures in the system.

These serious shortcomings associated with

intermittent systems mean that wherever possible, the 24

hours continuous supply must be strived for. However,

where 24 hours supply provision is not a realistic option,

an attempt must be made to be proactive in the design

of an intermittent system to ensure adequate service

standards.

As stated above, there are serious shortcomings

with intermittent water supply. These include:

Intermittent water supply systems are designed based

on low per capita allocation, but with the assumption

that demand will be spread over 24 hours, but in reality

water is consumed in a short duration. Therefore the

greater than anticipated. This results in severe pressure

losses creating a generally low pressure in the network

Inequitable Distribution of Water

Intermittent systems are generally water starved and

consumers try to collect as much water as possible

during supply hours. The quantity they collect therefore

is directly related to pressure at their outlets and since

pressures vary greatly in the network the quantity they

collect is inequitable (consumers in high pressure areas

collect more water, denying those in low pressure

areas).

Water Contamination

Water contamination occurs in networks where there

are prolonged periods of interruption of supply and the

pipes are empty for many hours of the day at which

time pollutants can enter through leaks in the supply

pipes. The situation is particularly serious in cities

in open ditches close to water distribution pipes.

population has access to drinking water but only 20 per

cent of the available drinking water meets health and

safety standards. In Delhi, an intermittent supply and

the proximity of water and sewage pipelines were the

prime suspects of a paratyphoid fever outbreak in 1996

(Karpi, 1997).

Consumers’ Coping Costs

When the water supply is unsatisfactory, consumers

incur a cost to cope with the situation (UNDP, 1999).

Coping costs involved in an intermittent supply include

above and below ground storage tanks, alternative

water supplies, pumping, treatment facilities and also

the inconveniences to the public tap users in terms of

timings of supply (McIntosh, 2003). Table 1 presents

the estimated annual coping costs for a study conducted

in Dehradun (Choe et al., 1996), a city of 300,000

inhabitants in the state of Uttaranchal in India. Similar

the coping cost for the poorest families with intermittent

supply was estimated to be around 180% of water tariff

(Yepes et al., 2001).

As stated above, intermittent systems are often

adopted in a reactive way and hence operate poorly.

However, it must be recognised that where there is

extreme water scarcity, adoption of intermittent supply

is one of the most popular ways of conserving water.

Therefore it is important to recognise this reality and

highlight the problems associated with these types of

K. Vairavamoorthy, S. D. Gorantiwar, and S. Mohan

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4

8

12

16

20

24

Chennai Colombo Delhi Dhaka Jakartha Karachi Manila Mumbai

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systems, and provide recommendations and guidance

to alleviate or minimise some of these problems.

Recently, research has begun(Vairavamoorthy et

al., 2001; Vairavamoorthy et al., 2004) to develop a

series of design guidelines for intermittent water supply

systems that :

• Improve equity in supply

• Improve water quality in intermittent systems.

This paper focuses on the component of the

guidelines that deals with improved equity only. It

should be noted that these guidelines do not promote

intermittent water supply due to many serious

shortcomings as discussed earlier. However, where

24 hours supply provision is not a realistic option, an

attempt must be made to be proactive in the design

of an intermittent system to ensure adequate service

standards, in particular a more equitable distribution

of the limited quantity of water and improved water

quality.

The design guidelines are driven by a new set

of design objectives to be implemented at a minimum

cost. These objectives are equity in supply and peoples

in terms of 4 parameters (DTPO): Duration of the

supply; Timings of the supply; Pressure at the outlet

connection required and the locations of connections

(in particular for standpipes). It should be noted that

all the above objectives are taken for granted while

designing continuous systems, but are variables in

the design of intermittent water distribution systems.

All parameters of the DTPO are calculated using

methods and techniques that recognise the relationship

experienced at that connection. In order to achieve

these objectives new mathematical modelling and

intermittent water distribution systems.

Hence it is anticipated that the guidelines will

enable engineers to:

• Establish a set of ‘People Driven Levels of

Service Objectives’ (PDLS), by consulting the

local community being served by the scheme (by

performing surveys of the people in the supply

area).

•Develop Design Objectives that incorporate the

objective of equity in supply and the PDLS.

•Produce a detailed design of a water distribution

•Develop operational strategies to ensure that the

designed system meets the design objectives

throughout its design life.

The guideline manual consists of four main parts and

three supplemental documents.


Secondary Network

Data

Connection Type ?

ST+OHT or YT

Factors Affecting PDO

Pressure, Tank

Capacity, Supply

Simulation Model

Reservoir Routing

Secondary Network

Data

Connection Type ?

Factor Affecting PDO

Pressure, Supply

Duration, Time of

Supply (AM or PM)

Simulation Model

Queuing Theory

PDO

Coefficientsfor

Secondary Network

Economic

Status ?

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• Part 1 gives a “ ” of the entire

guidelines.

• Part 2, “ ”, describes methods

to establish a collection of feasible and practical

sets of levels of service objectives for the proposed

design.

• Part 3, “ ”, describes

techniques on how to design and perform surveys

of the people in the supply area, with the main

collection generated in Part 2.

• Part 4, “Detailed Design”, enables engineers to

produce a detailed network design that ensures an

equitable distribution of the limited quantity of

analysis and optimisation programs are provided.

• The (SD) provide

practical information to users of the guidelines.

and handling manual, a user guide which

describes how to use the analysis and design

software, and two example network designs.

As stated earlier, a major component of

guidelines is the development of new mathematical

for intermittent water distribution systems. These new

tools combined with optimal design algorithms with

the objective of providing an equitable distribution of

water at the least cost forms the basis of the guidelines.

tool and the optimal design procedures are given.

Intermittent supply at a low per capita supply

rate forces consumers to collect water in storage vessels.

Storage is an important feature of such systems since it

is the storage facilities that provide water during non-

supply hours. Because of the low supply rate of water

and the intermittent nature of supply, the demand for

water at the nodes in the network are not based on

notions of diurnal variations of demand related to the

consumers behaviour (as with networks in developed

countries), but on the maximum quantity of water that

can be collected during supply hours. The quantity

of water provided to the consumers often drops well

short of their requirements. In such systems it is logical

to assume that consumers will draw water from the

distribution system for the total duration of supply and

the quantity they collect will be dependent totally on

the driving pressure heads at the outlets.

There is a fundamental problem in the

assumption made by existing methods of network

analysis: the assumption that the analysis is demand

driven, i.e., the demands of the network will be met

irrespective of the conditions in the network. As stated

above, in intermittent water networks the quantity of

water collected by consumers will be dependent on

the driving pressure heads at the outlets and hence the


Primary Node P

Primary Node P

QP

HP

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relationship between the pressures in the system and the

demands are important, but it cannot be assumed that

demand will be met under all conditions. Therefore, the

application of standard methods of network analysis to

developed and included in the guidelines. The program

model consists of three main innovative components:

1. Demand Model:

Using queuing theory and reservoir routing,

(intensity and distribution of usage over a given period

of supply), for use with the secondary network model.

Components of demand model include: Connection

types (Standpipes, Yard Taps, Sump Tanks); Pressure

regime (indicates how quickly users are served and

hence how many consumers can be served over a given

duration of supply); Duration of supply (mostly apply

to standpipe users and accounts for the differences in


Optimal Least Cost Design

Real Coded Genetic Algorithm

Minimise Diversity in Pressure

Optimal Valve Location

Optimal Valve Settings

Real Coded Genetic Algorithm

Optimal Design

Network Model

s for

Primary Nodes)

Primary

Perform Secondary

Hydraulic Analysis to

No

Yes

i = i+1

HU & HL

limits on Primary Node P

PrimaryNode P

Calculate Q

HPU <= HP <= HP

L

HPi+1 < HP

L

Set i = 0;

Set HP i+1 = HP

i - α

HPi = HP

U

Establish PDO for Primary Nodeusing Hi and Qi

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consumers’ behaviour when observed under conditions

of long and short duration of supply). Figure 3 indicates

the components of the model and further details of this

model can be found in Akinpelu (2001).

Obviously it is impractical to model networks

as far an individual house connection, and therefore

methods must be developed to establish lumped PDO

functions for a single node (primary node), for a group

of nodes (secondary network). Such methods have

been developed and take into account the hydraulic

behaviour of the secondary network (Vairavamoorthy,

1994). This model initially assumes a primary node to

be a constant head (or reservoir) node, supplying water

to the secondary network (Figure 4). By performing

a series of simulations, varying the pressure at the

secondary network for these different pressures can be


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calculated. Figure 5 outlines the secondary network

modelling approach.

As mentioned above, the objectives of any

design using the method described in these guidelines

can be stated as follows:

1. Provide an equitable distribution of the limited

quantity of water

2. Meet the Peoples Driven Levels of Service

(PDLS).

3. Meet the objective (1) and (2) at least cost.

It may not be possible however, to address the

problem of achieving an equitable pressure distribution


0

1

2

3

4

5

43 46 49 50 52 55 59 61 64 66 69 71

0

500

1000

1500

2000

2500

43 46 49 50 52 55 59 61 64 66 69 71

-

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when sizing the network, since systems are often sized

to meet a future forecast demand and therefore will

always have excess capacity until the design conditions

requirements a two part design approach is proposed.

First, the minimum cost design is obtained

ensuring adequate pressures throughout the network

the objective to minimise the variability in pressure

is addressed by considering the strategic location and

setting of valves in the network (Vairavamoorthy and

Lumbers, 1998., Ali et al., 1998). The inclusion of

valves is considered progressively at time intervals

from the outset of the operation of the network to its

design horizon. The overall best valve locations are

established for a case study network in which the

valve settings will vary throughout its design life.

In order to achieve the minimum cost design and

optimal valve locations, formal optimisation methods

were developed and included in the guidelines. The

optimisation programs are based on real-coded genetic

algorithms (details can be found in Vairavamoorthy

and Ali, 1998 and 1999). The particular features of the

program include: least cost design objective, optimal

pressure management routines (to ensure a more

equitable distribution of water throughout the network),

and multiple objective function routines. Figure 6

presents the algorithms used in the optimisation.

applied to a network in South India incorporating PDO

zones; one zone (IIA) was selected for detailed study

(Figure 7). The network serves an estimated population

of approximately 38,120 (in 2001). The topography of

to 7 metres. There is an elevated service reservoir with

a total capacity of 1.2 mega-litres ( 13 of the total

demand). The system was designed originally for

a supply of 90 litres per capita per day supplied over 24

hours. In fact water is supplied daily for one hour from

the elevated service reservoir alone.

The results of the simulation corresponded well

conditions and the resulting inequities of supply were

highlighted by the analysis (Figures 8 to 10). Figure

10 indicates the total volume of water delivered to

standpipes at different locations and highlights the

inequities.


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The optimal design programs were then applied

to the network. In the design, it is assumed that the

demand increases by 50% evenly over 20 years (design

horizon). The minimum residual head required at all the

nodes in the primary network is assumed to be 7 metres,

to supply water to all underground storage tanks and

standpipes in the secondary network. The results of

the application to the case study network are shown

in Figures 11 and 12. The original network has been

valves, strategically placed to minimise the deviation

in pressure. Figures 11 and 12, show that effective

pressure management is possible in the early portions

of the network but the magnitude of the improvement

in pressure distribution diminishes as the design horizon

is approached. This is related to the presence of excess

capacity. In the early stages, the excess capacity is

greatest and therefore there is potential to reduce this

excess capacity in a way that improves the pressure

distribution. As the design horizon is approached, the

excess capacity decreases and there is less potential

for effective pressure management. However, the

process has improved overall pressure distribution in

the network and provided a more equitable distribution

of water.

This paper presents details of new guidelines for

the design and control of intermittent water distribution

systems in developing countries. In these countries the

availability of water is either inadequate or restricted due

recognise these realities when designing and operating

such networks. The new guidelines developed include a

optimal design tool.

set of design objectives to be met at least cost. These

objectives are Equity in Supply and People Driven

Levels of Service (PDLS). The PDLS are expressed in

terms of 4 design parameters, namely: Duration of the

supply; Timings of the supply; Pressure at the outlet

connection required and the locations of connections (in

particular for standpipes). All the four parameters are

calculated using methods and techniques that recognise

and the pressure experienced at that connection.

method suitable for simulating conditions of water

three main components: a demand model; a secondary

model. The simulation tool has been applied to several

networks in South India using data obtained during

In addition to the analysis method, details of

new optimisation methods based on real code genetic

algorithms are given for the least cost design of

distribution systems, while achieving the most equitable

distribution of water. These optimisation routines,

in combination with the simulation tools, have been

applied to the design of an urban network in South India.

Inequities in water distribution to different locations

were observed with the original network. The design

obtained with developed guidelines indicated that the

original network needs to be reinforced with additional

in pressure and obtain the equity. Thus, the developed

tools are important for the design of intermittent water

supply scheme under water scarcity situations.

is a Senior Lecturer in

the Water Engineering Development Centre (WEDC),

Department of Civil and Building Engineering at

Loughborough University. He has an M. Sc. degree

and Ph. D. in Civil Engineering from Imperial College,

London. He has expertise in the design, operation

and maintenance of urban water distribution systems.

In particular he has experience in researching and

developing innovative solutions to water supply

systems that operate under water shortage scenarios. He

has acted as a consultant on many projects for both UK

water companies and overseas clients. More recently he

has advised Indian water authorities on the management

of intermittent water supplies, implementation of

unaccounted-for water action plans, leak detection


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and other related issues as necessary. Email Contact:

[email protected]

is currently an Academic

Visitor to Water Engineering and Development Centre

(WEDC), Loughborough University and an Associate

Professor and Research Engineer, Groundwater

Project, in the Department of Irrigation and Drainage

Engineering, Mahatma Phule Agricultural University,

Rahuri, India. He has an M. Tech. degree in Water

Resources Development and Management from IIT,

Kharagpur, India and Ph. D. in Civil Engineering form

Loughborough University, Loughborough, UK. He has

expertise in water management of irrigation schemes

in developing counties, micro irrigation methods

and utilisation of groundwater for agriculture. Email

Contact: [email protected]

is a Professor and Head of the

Department of Civil Engineering at Indian Institute of

Technology Madras, Chennai, India. He has an M. Eng.

degree and Ph. D. in Civil Engineering from Indian

Institute of Sciences, Bangalore, India. His research

interests include Environmental System Analysis, Water

Quality Modelling, Water and Waste Water Treatment,

Water Resources System Analysis, Irrigation Water

Management, Evolutionary Computation. He has lead

and participated in several research and consultancy

projects in these areas, both nationally (in India) and

internationally. Email Contact: [email protected] Contact: [email protected].

ernet.in [email protected]

References

ADB. 1993. Water Utilities Data Book - 1st Edition,

. Philippines: Asian

Development Bank.

Ali, M., Vairavamoorthy, K., and Gunn, M. 1998.

Leakage minimisation in water distribution

systems using Genetic Algorithms.” Proceeding

of the Knowledge, Information and Data-Water

Conference, Edinburgh, U.K., April 27 – 28. pp.

169 – 183.

Akinpelu, E. O. 2001. “Development of Appropriate

Demand Modeling Procedure for Water

Distribution Systems in Developing Countries.”

Thesis Presented to the South Bank University, at

for the degree of Doctor of Philosophy.

Karpi, A. 1997. “Letter to the Editor.” Emerging

Infectious Diseases, 3: 3.

Choe, K., Varley, R., and Bilani, H. 1996. “Coping

with Intermittent Water Supply: Problems and

Prospects, Environmental Health Project.”

Activity Report No. 26. USA: USAID.

Choe, K. and Varley, R.1997. “Conservation and

Pricing-Does Raising Tariffs to an Economic

Price for Water Make the People Worse Off?”

Prepared for the Best Management Practice for

Water Conservation Workshop, South Africa.

Dzikus, A. 2001. “Managing Water for African Cities: An

Introduction to Urban Water Demand.

Conference on the Reform of the Water Supply and

Sanitation Sector in Africa – Enhancing Public-

Private Partnership in the Context of the Africa

Vision for Water 2025, Kampala, Uganda.

McIntosh, A. C. 2003. Asian Water Supplies, Reaching

the Urban Poor. Manila: Asian Development

Bank.

Rosegrant, M.W., Cai, X., and Cline, S.A. 2002.

“Averting an Impending Crisis.” Global Water

Outlook to 2025. Food Policy Report, International

Water Management Institute (IWMI), Colombo,

Sri Lanka.

Seckler, D., Molden, D., and Barker, R. 1998. “Water

Scarcity in the Twenty First Century.” IWMI

Water Brief 1. International Water Management

Institute (IWMI), Colombo, Sri Lanka.

Serageldin, I. 1995. “Towards Sustainable management

of Water Resources.” Direction in Development

Series. Washington D.C., USA: World Bank.

Singh, N. 2000. “Tapping Traditional Systems of

Resource Management”, Habitat Debate UNCHS,

6: 3.

Todini, E., and Pilati, S. 1988. “A Gradient

Algorithm for the Analysis of Pipe Networks.”

in Coulbeck, B. and Orr, C.H. (Eds.). Computer

Applications in Water Supply: Volume 1 - System

Analysis and Simulation. Taunton, UK: Research

Studies Press Ltd, pp. 1 – 20.

UN. 2003. Millennium Development Goals. New York:

United Nations. [Online] URL: http://www.


Dow

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ded

by [

Uni

vers

ity o

f N

ebra

ska,

Lin

coln

] at

10:

29 1

9 N

ovem

ber

2014

132


developmentgoals.org/Education.htm.

UNESCO. 2003. Water for People Water for Life -

The United Nations World Development Report.

Cultural Organisation, New York, USA.

UN-HABITAT. 1999. “Managing Water for African

cities - Developing a Strategy for Urban Water

Demand Management.” Background Paper No. 1,

Expert Group Meeting UNEP & UN-HABITAT.

Vairavamoorthy, K. 1994. “Water Distribution

Networks: Design and Control for Intermittent

Supply”, Thesis Presented to the Imperial college

of Science, Technology and Medicine, London

degree of Doctor of Philosophy.

Vairavamoorthy, K., and Ali, M. 1998. “Least Cost Design

of Water Distribution Networks.” Proceeding of

the First International Conference on New IT

for Decision Making in Civil Engineering, 11-13

October, Montreal, Canada.

Vairavamoorthy, K and Ali, M. 1999. “Application

of genetic algorithm for water supply System

design.” Computer-Aided Civil & Infrastructure

Eng, 15:374-382.

Vairavamoorthy, K., and Lumbers, J.P. 1998. “Leakage

reduction in water distribution systems: Optimal

valve control.” J. Hydraulics Division, ASCE,

124(11): 1146 – 1154.

Vairavamoorthy, K. and Ali, M. 1999. “Application

of genetic algorithm for water supply System

design”. Computer-Aided Civil & Infrastructure

Eng, 15: 374-382.

Vairavamoorthy, K., Akinpelu, E., Ali, M., Anand, S.,

Elango, K., Harpham, T., Lin, Z., and Patnaik, R.

2001. Guidelines for the Design of Intermittent

Water Distribution Systems. Report submitted

to Department of International Development

(DFID), UK.

Vairavamoorthy, K., and Elango, K. 2002. “Guidelines

for the design and control of intermittent water

distribution systems.” Waterlines, ITDG, 21(1).

Vairavamoorthy. K, Elango, K., and Totsuka, N. 2004.

“Intermittent Urban Water Supply Under Water

Starving Situation.” People Centred Approaches th

WEDC Conference, Laos.

Yepes, G., Ringskog, K., and Sarkar, S. 2001. “The High

Cost of Intermittent Water Supplies.” Journal of

Indian Water Works Association, 33(2).


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Documents

Intermittent Water Supply under Water Scarcity Situations