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NATIONAL UNIVERSITY OF RWANDA FACULTY OF APPLIED SCIENCES
DEPARTMENT OF CIVIL ENGINEERING
PERFORMANCE EVALUATION OF WATER DISTRIBUTION SYSTEMS IN RUGERAMIGOZI
IRRIGATION SCHEME, RWANDA By
MUREKASHUNGWE Evergiste
A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science
In Water Resources and Environmental Management
December, 2007
ii
NATIONAL UNIVERSITY OF RWANDA
DEP G FACULTY OF APPLIED SCIENCES ARTEMENT OF CIVIL ENGINEERIN
In collaboration with
PERFORMANCE EVALUATION OF WATER
DISTRIBUTION SYSTEMS IN RUGERAMIGOZI
IRRIGATION SCHEME, RWANDA
By
MUREKASHUNGWE Evergiste
Supervisors:
Dr Eng Umaru Garba Wali
A thesis submitted in partial fulfillment of the requirements for the Degree of
December, 2007
Dr Eng F.O.K. Anyemedu
Master of Science in Water Resources and Environmental Management
iii
Declaration I, the under signed, declare that original work and has not been presented for a degree in any other university, and that all sources of material used
ame: MUREKASHUNGWE Evergiste
ignature:
this thesis is my
for the thesis have been duly acknowledged. N S
iv
Dedication
To Almighty God, To my
To all my families and friends, To my belov Thacienne.
mother Ramberta,
ed Nyinawinyange
v
Abstract The rational utilization of irrigation water is a fundamental aspect for achieving sustainable agriculture for food security and poverty alleviation. To achieve the objective of sustainable agriculture are involved, and irrigation water
is one of the most important. Consequently, its evaluation as well as the
Water management.
many factorsdeliverysearch for feasible solutions to problems detected during the evaluation could be of special interest. To help farmers in obtaining efficient and rational methods of water uses and to provide an adequate scientific and technical support to optimize management, it is important to conduct the evaluation of irrigation system in plots. This study analyzes the water management performance of small scale irrigation system in Rwanda. ILRI/IWMI water balance and maintenance indicators were used to test Rugeramigozi irrigation scheme as a base for the performance evaluation. Necessary data were collected from ECOTRA (the company that made the feasibility study and the design of the system) and from Byimana Meteorological Station. In the field, certain parameters including: type of crop, irrigation water discharge in channel, and field size were measured and/or observed before, during and after an irrigation event while farmers were conducting their normal irrigation practice. Survey related to water availability was also conducted among the farmers. The results showed that the source is delivering 40.15l.s‐1 while the water requirement is 114l.s‐1. The delivery is only 35.2% of the water requirement. The insufficiency of irrigation water, the type of irrigation system in use, the poor maintenance of irrigation structures and the farmer’s unawareness of irrigation practices were the main problems identified in the management and operations of the scheme. Some corrective measures have been recommended to improve the system. Among them are the following: (a) the selection of crops should be done by taking into account the availability of irrigation water, (b) tertiary channels need to be constructed in the scheme to avoid conflict related to water distribution, (c) rainwater harvesting systems need to be established in the scheme to avoid flooding that are occurring in rainy season and to store water for supplementary irrigation during the dry season, (d) awareness of irrigation practices needs to be created among farmers. Keywords: Biringanya, Irrigation Channel, crop, Water crop requirement, water balance indicators, maintenance indicators,
vi
Acknowledgments
I like to express my deepest gratitude to my academic supervisors Dr Umaru G. Wali and Dr Eng F.O.K. Anyemedu for their support, assistance and guidance, for all their sincere, faithful and imm r the accomplishment of this
work and to bring me here from the start, their unlimited and sweet advice that
a, Mrs. Adoratha, the Agronomist of
to Biringanya Scheme farmers for their honest information and cooperation
would
ense devotion to help me fothesissmoothened my educational journey, it couldn’t be otherwise, is printed in my heart, thus, much appreciation is expressed to them. Acknowledgment is expressed to the staff of WREM Program, especially to Dr Eng Innocent Nhapi and Dr Eng Aphrodis Karangwa for their valuable support and advices. To the ECOTRA staff, Mr. Valère NzeyimanNyamabuye Sector, Eng Ismael Ndamukunda, they provided me professional, technical and administrative support. So my appreciation may reach them all. I am indebtedfor the accomplishment of this study. In addition, the generous support and contribution of all my colleagues, friends, families and relatives are deeply acknowledged and emphasized in all cases of my future life. MUREKASHUNGWE Evergiste
vii
TABLE OF CONTENTS ............................................................................................................................. iii
................................................................................................................................iv
Abstract ..................................................................................................................................... v
2.
1 F2 T
4.3 O4.4 C
Declaration
Dedication
Acknowledgments ...................................................................................................................vi
TABLE OF CONTENTS ........................................................................................................vii
List of Tables ............................................................................................................................x
List of figures ...........................................................................................................................xi
List of appendices ................................................................................................................. xii
List of Acronyms and Abbreviations................................................................................ xiii
Chapter 1. INTRODUCTION ...............................................................................................1
1.1 Background .........................................................................................................................1
1.2 Statement of the problem..................................................................................................2
1.3 Objectives of the study .....................................................................................................3
Chapter 2. LITERATURE REVIEW......................................................................................4
2.1 Irrigation .............................................................................................................................4
2.2 Perspectives and objectives of irrigation.......................................................................4
2.3 Water Resources and Irrigation Development in Rwanda .........................................5
2.4 Small scale irrigation ........................................................................................................6
2.4.1 The problems of small‐scale irrigation........................................................................ 6
2.4.2 Intervention into small‐scale irrigation ..................................................................... 7
2.4.3 Farmer Managed Irrigation System (FMIS) and its importance ............................. 7
2.4.4 Purposes and need for small‐scale irrigation in Rwanda ........................................ 8
5 Performance of an irrigation system ..............................................................................9
2.5.1 How to conduct an irrigation system performance assessment? ............................ 9
2.5.2 Performance evaluation of small‐scale irrigation................................................... 11
2.5.3 Indicators for irrigation performance........................................................................ 13
2.5.4 Water balance indicators............................................................................................. 14 2.5.4. ield application ratio .................................................................................................................. 15 2.5.4. ertiary unit ratio.......................................................................................................................... 15 2.5. verall consumed ratio................................................................................................................ 16 2.5. onveyance ratio .......................................................................................................................... 16
viii
2.5.4 istribution ratio.5 D
2.5
2.51 I
5 I
2.6 M
2.6
Chapter 3.
3.1 L
3.2
Ch
4.
4.1.1.1 Flow measurement ....................................................................................................................... 34
1 C
4.2 D
4.2.1
5.
5. er a
5.5.2 Discussion ...................................................................................................................... 50
........................................................................................................................... 17 2.5.4.6 Dependability ................................................................................................................................ 17
.5 Maintenance indicators............................................................................................... 18 2.5.5.1 General ........................................................................................................................................... 18
ater level and head‐discharge relationship............................................... 182.5.5.2 Sustainability of w
.6 Properties of performance indicators......................................................................... 19 2.5.6. rrigation water use efficiencies .................................................................................................. 20 2.5.6. pplication efficiency.................................................................................................................. 212 A 2.5.6.3 Storage efficience .......................................................................................................................... 22 2.5.6.4 Distribution efficiency.................................................................................................................. 23 2.5.6. rrigation scheduling .................................................................................................................... 23
ethods of irrigation performance ...............................................................................25
.1 Data collection.............................................................................................................. 26 2.6.1.1 The Rapid appraisal approach .................................................................................................... 26 2.6.1.2 Participatory rural appraisal approach...................................................................................... 27 2.6.1.3 Remote sensing techniques.......................................................................................................... 28
DESCRIPTION OF THE STUDY AREA .........................................................29
ocation and Topography ..............................................................................................29
Rugeramigozi Irrigation scheme ............................................................................................ 30
3.3 Climate....................................................................................................................................... 31
3.4 Water sources............................................................................................................................ 31
apter 4. MATERIALS AND METHODS ........................................................................33
1 Methodology.....................................................................................................................33
4.1.1 Primary data collection ............................................................................................... 33
4.1.1.2 Discharge determination.............................................................................................................. 35
4.1.2 Secondary data collection ........................................................................................... 37 4.1.2. rop water requirements............................................................................................................. 37
ata analysis techniques ...............................................................................................38
Water delivery performance ........................................................................................ 38
4.2.2 Performance Indicators................................................................................................ 38
Chapter 5. RESULTS AND DISCUSSION .......................................................................41
1 Analysis of secondary data and visual observations ................................................41
3 Wat vailability ...........................................................................................................44
5.4 Water requirement ...........................................................................................................46
5.5 Water measurement .........................................................................................................47
5.5.1 Results ............................................................................................................................ 47
ix
5.6 Maintenance .....................................................................................................................52
5.6.1 Results ............................................................................................................................ 52
5.6.2 Discussion ...................................................................................................................... 53
Ch CO
6.
RE NC
ap 6. NCLUSIONS AND RECOMMENDATION ..................................................54
6.1 Conclusions.......................................................................................................................54
2 Recommendations............................................................................................................54
FERE ES.........................................................................................................................55
APPENDICES.........................................................................................................................59
x
List of Tables
ents for Cabbage and Carrots..............................................................46 ents for Beans dry ...............................................................................47
Flow measurement records for day 1 ...................................................................48 Table5. 4 Flow measurement records for day 2 ....................................................................49 Table5. 5 Flow measurement record .....................................................49
rges in different sites .......................................................................50
Table5. 1 Water requiremTable5. 2 Water requiremTable 5. 3
s for day 3 ...............Table5. 6 Calculated dischaTable5. 7 Common maximum attainable values of the field application ratio (efficiency)
..............................................................................................................................................51Table5. 8 Observed structures status ...........................................................................................53
xi
List of figures
ework for a performance assessment program of irrigation and drainage schemes (ICID). ...................................................................................................................10
Figure 2. 2 The setting of irrigation and drainage .......................................................................12
Figure 3. 1 Rwanda administrative ma .....................................................29 igozi marshland topographic map...............................................................29
.......30 Figu
...... Figure 5. 6 flooding problems......................................................................................................43
Figure 2. 1 Fram
p .................................Figure 3. 2 RugeramFigure 3. 3 Biringanya Irrigation System (ECOTRA)..........................................................
re 3. 4 Rugeramigozi stream under the dyke ........................................................................31 Figure 3. 5 Head regulator on Rugeramigozi stream...................................................................32
Figure 4. 1 The rectangular sharp-crested weir and its cross section (Bos, 1989). .....................35 Figure 4. 2 Measurement sites .....................................................................................................36 Figure 4. 3 Installation of a weir………………………………………………………………...... Figure 4. 4 Taking measurement…….. .......................................................................................37
Figure 5. 1 Participation in maintenance works…………………………………………………... Figure 5. 2 Training aspects………………………….................................................................42 Figure 5. 3 Irrigation water availability……………………………………………………… ....... Figure 5. 4 Crops under cultivation………….. ...........................................................................43 Figure 5. 5 Harvest aspects……………………………………………………………………
Figure 5. 7 Channel in Rainy season…………………………………………………………. ..... Figure 5. 8 Channel in dry season…………................................................................................44 Figure 5. 9 Rain water availability in the study area (Byimana Weather station) .......................44 Figure 5. 10 Discharge due to rainfall .........................................................................................45 Figure 5. 11 Water demand and supply in the study area (Byimana weather station) ...............46 Figure 5. 12 Problems related to poor maintenance ....................................................................52
xii
List of appendices
‐ A.1 QUESTIONNAIRE: Table A.2 Rainfall records Table A.3 Climatic parametersable A.4 Calculated discharge from rainfall
tors Kc
A
TTable A.5 Values of Crop fac
xiii
List of Acronyms and Abbreviations
CAADP: CIA: WR:
:
:
MIS:
:
I: INITERE:
SAT:
DR: :
:
Comprehensive Africa Agriculture Development Program
Crop Water requirement
nd Poverty Reduction Strategy
Irrigation System
Borozi ba Rugeramigozi ion and Drainage
d Reclamation and Improvement
Irrigation
de l’Eau, des Ressources Naturelles et de
gique pour la Transformation de l’Agriculture
port f Reclamation nt of Agriculture
gement
CECOTRA EDPRSFAO: FGDP: IABR: ICID: ILRI: IWMI: IPTRID IRW: MINAGRM NGOs: PRSP: PRPIP: SSI: TAW: UNWWUSBRUSDA:USUSC: WREMWU:
Central Intelligence Agency
Entreprise de Construction des Travaux Publiques et d’Aménagement Economic Development aFood and Agriculture Organization Farmer Managed Gross Development Product Impuzamashyirahamwe y’Abahinzi International Commission on IrrigatInternational Institute for LanInternational Water management Institute International Program for Technology and Research inand Drainage Irrigation Water Requirement Ministère de l’Agriculture et des Ressources Animales Ministère des Terresl’Environnement Non Governmental Organizations Poverty Reduction Strategy Programme StratéResearch Program on Irrigation PerformanceSmall‐Scale Irrigation Total Available Water United Nations World Water Development ReUnited States Bureau oUnited states DepartmeUnited States Soil Conservation Service Water Resources and Environmental ManaWater Users
1
Chapter 1. INTRODUCTION
1.1 Background As the world’s inhabitants increase, the water use also increases every where. Agriculture is the sector that uses most water worldwide. Currently, on a global basis, 69% of all water withdrawn for human use on an annual basis is consumed by agriculture (mostly in the form of irrigation); industry accounts for 23% and domestic use (household, drinking water, sanitation) accounts for about 8%. These global averages vary with considered regions. In Africa, for example, agriculture consumes 88% of all water withdrawn for human use, while domestic use accounts for 7% and industry for 5% (UN WWDR, 2003). The same situation is true for Rwanda. Rwanda is a landlocked country with a surface area of 26 338 km2. The population Rwanda is estimated at about 9.9 million inhabitants and the population density of about 370 inhabitants/km2 according to CIA World Fact Book in 2007. Thus it is regarded as one of highest densely populated countries in Africa. Rwanda’s economy is based on agriculture. To achieve sustainable economic growth and social development, leading to the increase and diversification of household incomes and ensuring food security for the entire population, the Government has adopted Agriculture to remain the driving engine of the economy for the period of Poverty Reduction Strategy (PRSP) implementation (2020 Vision). Agriculture is considered to be the tradable sector in Rwanda, ready to expand and make an impact on poverty reduction through increased incomes for the poor. In order to achieve the targeted annual per capita growth of 4‐5 percent, the agricultural sector needed to contribute with 5.3 percent of overall GDP growth. Therefore investment in marshland development is expected to increase. Rwanda has generally good rainfalls, surface water (rivers, lakes and other artificial water reserves), and underground outflows from different aquifer systems. However, utilization of these water resources to boost agricultural productivity has been a major challenge (CAADP, 2007). The total country cultivated area cover approximately 46% of the surface of the country divided into low‐size farms. More than half of Rwanda’s total marshland area is under cultivation, but the vast majority is being used without any intensification or sustainable management of infrastructure. The marshes occupy a surface estimated at 165,000 ha including 112,000 ha of small marshes (less 200ha)
2
and 53,000ha of t surface is only approximately 94,00 the marshes of the
Only appropriately developed marshlands surface is around 11,000 ha in 2006 (MINAGRI, 2004a). In the vision to ensure food security, marshlands
ped are supposed to increase from around 11,000 ha in 2006 20,000 ha in 2011 (CAADP, 2007). This means that high investments will have to
identify the origin of different problems identified through routine or when stakeholders are not satisfied with the existing levels of
he large marshes. The exploited total0ha, that is to say 57% of the surface of
country.
appropriately develotobe given in the agricultural sector. Consequently, reliable water use methods have to be established because without improvement in water management, irrigation demand will continue to increase but with low productivity, water supplies will diminish and conflict may come out between different water users, and the effort, and investments made in this sector would become meaningless. Hence, monitoring has to be conducted so that problems within the irrigated systems could get identified before failure occurs and possible solutions to these problems can get proposed and implemented. Diagnostic assessments also have to be carried out tomonitoring,performance achieved and desire a change. Through systematic observation, documentation and interpretation of the management of a project with the objective of ensuring that the input of resources, water delivery schedules, intended outputs and required actions proceed as planned. Diagnostic assessment supports both operational performance monitoring and strategic planning because weaknesses in planning and implementation (P&I) have been identified as one of the main reasons for the disappointing results of agricultural water development and management projects (Bos et al., 2005). To achieve sustainable production from irrigated agriculture it is obvious that the utilization of the important resources in irrigated agriculture, i.e. water and land, must be improved. The question of how is irrigated agriculture performing with limited water and land resources has to be satisfactorily answered. In this optic, a study on irrigated systems performance was conducted in Rugeramigozi Marshland with an overall purpose to assess its performance and to propose the practical ways of improving performance related to planning and implementation and thereby enhancing the returns on investments in agricultural water.
1.2 Statement of the problem Rwanda is a mountainous country and 68% of its marshes are classified as small scale with area of less than 200 ha. In all these marshes there is no reliable data that may be used for proper management. Access to sufficient and efficient irrigation
3
technologies is one of the mos importan aspects that can lead to increase i the agricultural productivity for small‐scale irrigation systems. However, this aspect has been given little or no attention at all. Recently, small‐scale irrigation developments have been gradually expanded through the initiative of NGOs and farmer cooperatives. For improvement in achieving the Millennium Development Goals and Vision improving food security and poverty reduction for the country’s welfare, one particularly pressing resource management challenge to Rwanda is to improve the performance of small‐scale irrigation systems. This implies the efficient management and rational use of available agricultural water. The management of agricultural water should be accompanied with daily water distribution measurement so hat irrigation service can get improved. The lack of records in a scheme is a problem since one cannot be sure of the performance of the system, whether or not water is equally distributed between users. Without these records available, we cannot improve services, allocation procedure is almost impossible, no account for losses is done and so far no strategic future planning is possible. This situation has also an impact on crop growth and also on the yield. To assess agricultural water management capabilities through irrigation and drainage projects with a view to improving the efficiency with which available resources are used is the aim of this study that was curried out in Rugeramigozi Marshland and precisely in Biringanya branch. With this study two of the following problems have to be answered: a) What are the water‐related constraints to on‐farm productivity? b) How can overall productivity be improved?
t t n
t
e using Maintenance indicators (effectiveness of infrastructures and the discharge
1.3 Objectives of the study The overall aim of this study is to evaluate the performance of Rugeramigozi Marshland irrigation scheme. The specific objectives of this study are: a) To evaluate the performance of Rugeramigozi irrigation scheme using water
balance indicators (application, conveyance and overall consumed efficiencies); and
b) To evaluate the performance of Rugeramigozi irrigation schem
efficiency).
4
Chapter 2. LITERATURE REVIEW
2.1 Irrigation Irrigation is the supply of water to crops by artificial means, designed to permit farming n arid regions and to offset the ffect of drought in semi‐arid regions. Even in areas where total seasonal rainfall is adequate on average, it may be poorly distributed during the year and variable from year to year. Where traditional rain‐fed farming is a high‐risk enterprise, irrigation can help to ensure stable agricultural production (FAO, 1997). Hence, irrigation is treated as a major component in an integrated agricultural production scheme in which crop yields and or profits are maximized by considering the influence of crop variety, planting density, soil aeration, and other management practices on crop yields (Hargreaves and Merkley, 1998).
2.2 Perspectives and objectives of irrigation
i e
provements in ic vitality of the region. Many
ns have been dependent on irrigated agriculture to provide the basis of their society and enhance the security of their people. Some have estimated that as
dwide total cultivated area is irrigated. Judging irrigated and non‐irrigated yields in some areas, this relatively small fraction
icfood
coaccou
in developing countries in the tropics and sub‐tropics, where of millions of farmers depend on surface irrigation to grow their crops.
method, frequency and duration of irrigations have significant effects on crop and farm productivity. For instance, annual crops may not germinate when
surface is inundated causing a crust over the seedbed. After emergence,
A reliable and suitable irrigation water supply can result in vast imagricultural production and assure the economcivilizatio
little as 15‐20 percent of the worlfromof agriculture may be contributing as much as 30‐40% of gross agricultural output (FAO, 1989). According to Jurriens et al. (2001), many countries depend on surface irrigation to grow crops for food and fiber. Without surface irrigation their agr ultural production would be drastically lower and problems of unreliable
supply, insufficient rural income and unemployment would be widespread. Ac rding to Hargreaves and Merkley (1998), estimation of surface irrigation
nts for 95 percent of the total 260 million hectares of irrigated land mainlyworldwide,
hundredsTheyieldthe
5
inadequate soil moisture can often reduce yields, particularly if the stress occurs during critical periods. irrigation is to maintain the soil an important
on. The technology of irrigation is more complex than many appreciate. It is important that the scope of irrigation science is not limited to diversion and
ms, nor solely to the irrigated field, or only to the drainage
moisture supply for plant growth which also transports nutrients; and (b) a flow of water to leach or dilute salts in the soil.
soil and the atmosphere to (FAO, 1989).
om 1300 mm to 2000 mm in the high altitude region with an average of 1200 mm
Even though the most important objective of moisture reservoir, how this is accomplished is
considerati
conveyance systepathways. Irrigation is a system extending across many technical and non‐technical disciplines. It only works efficiently and continually when all the components are integrated smoothly (FAO, 1989). FAO (1989) outlined the problems irrigated agriculture may face in the future. One of the major concerns is the generally poor efficiency with which water resources have been used for irrigation. A relatively safe estimate is that 40 percent or more of the water diverted for irrigation is wasted at the farm level through either deep percolation or surface runoff. Irrigation in arid areas of the world provides two essential agricultural requirements: (a) a essentialIrrigation also benefits croplands through cooling thecreate a more favorable environment for plant growth
2.3 Water Resources and Irrigation Development in Rwanda Rwanda possesses a dense hydrographical network. Lakes occupy of 128,190 ha, rivers cover an area of 7,260 ha and waters in wetlands and valleys a total of 77,000 ha. The country is divided by water divide line called Congo‐Nile Ridge. To the West of this line lies the Congo River Basin which covers 33% of the national territory and which receives 10% of the total national waters. To the East lies the Nile River Basin, whose area covering 67% of the territory, delivers 90% of the national waters. The annual rainfall varies from 700 mm to 1400 mm in the East and in lowlands of the West, from 1200 mm to 1400 mm in central plateau andfrper year (MINITERE, 2004). Nowadays the climate of the country is characterized by irregular precipitations which are in somehow the causes of low production in the zones of rain‐fed agriculture. To satisfy the food needs for the country’s increasing population, irrigation is seen as an essential and privileged way of agricultural development and to increase profits from agriculture. Thus, the Government of Rwanda has
6
adopted to make irrigated agriculture and notably small‐scale irrigation, since small marshes occupies about 68% of the marshes surfaces area of Rwanda, the driving engine to eradicate hunger and to promote small farmer income (CAADP, 2007).
2.4 Small irrigation scale
t
h a
rmers must be in the design process and, in particular, with decisions about boundaries,
the layout of the canals, and the position of outlets and bridges.
Rwanda small‐scale irrigation is defined according to the size and is considered
expected to solve problems of declining agricultural roductivity. Small‐scale irrigation in drought‐prone areas has two sets of
The term small requires some clarification as it means differen things to different people. In fact what is seen as large for some may be seen as small for others. Irrigation systems can be classified according to size, source of water, management style, degree of water control, source of innovation, landscape niche or type of technology. Dessalegn (1999) gives the three‐scale classification adopted during the Derg in Ethiopia as follows: Large‐scale irrigation schemes are those which have over 3000 hectares of area. Medium‐ scale schemes cover an area of 200‐3000 hectares w ile small‐scale irrig tion schemes involve those with total area of up to 200 hectares. According to Ian and Rod (1999) small‐scale irrigation can be defined as irrigation, usually on small plots, in which small farmers have the controlling influence, using a level of technology which they can operate and maintain effectively. Small‐scale irrigation is, therefore, farmer‐managed: fainvolved
Inas having a surface area under 200 hectares (MINAGRI, 2004b). Small‐scale can be defined also according to its management aspects. Here, we can talk of smallholder irrigation scheme. 2.4.1 The problems of small‐scale irrigation
Although small‐scale irrigation may have several advantages, it is never immune from problems. The problems have become more critical in drought prone areas where small‐scale irrigation ispproblems. The first category includes problems that are associated with the specific environmental characteristics of the agro‐ecosystem. The second category includes common problems that drought‐prone and degraded areas share with all other small‐scale irrigation systems, irrespective of their agro‐ecological context. These are:
7
a) Problems related to the physical nature of the irrigation systems, e.g. loss of water through seepage;
b) Problems related to the application of irrigation water, e.g. upstream users abstracting too much water;
) Problems related to marketing produce, e.g. transportation issues; security of land tenure; ms e.g. lack of experience in planning and
designing irrigation systems;
tphrates basin and 2,500 years in the central Andes.
‐scale systems were developed under state or royal patronage where there ‐o stability prevailed. But small‐
scale irrigation times, major schemes were in India in the late 19th century, followed by other parts of Asia, Egypt
cd) policy‐related problems, e.g.e) engineering‐related proble
f) Problems related to the irrigation economy, e.g. competition between rain‐fed and irrigated agriculture; and
g) Community issues, e.g. levels of farmer participation, (Aberra, 2004). 2.4.2 Intervention into small‐scale irrigation
Interventions into existing small‐scale irrigation systems cannot be done successfully unless the existing farming system is taken into consideration. If small‐scale irrigation is to make a substantial and positive contribution for people, it is essential that it fits into their livelihood systems. Experiences of countries that have had successful small‐scale irrigation show that such systems have very often developed as part of the indigenous farming system (Carter, 1989). 2.4.3 Farmer Managed Irrigation System (FMIS) and its importance
Irrigation has been practiced for more than 5,000 years in Egyp and China, 4000 years in India and the Tigris‐EuLargewere well rganized social systems and long‐term
must be even older. In more recentdevelopedand Sudan (Kedir, 2004). The large irrigation schemes in Egypt and the Sudan are smallholder schemes. These schemes are large in terms of area but they are made up of many small farms (often less than 2 ha). They are designed and constructed by government agencies that then take over the responsibility for managing the water supply system. They are often described as formal or large‐scale irrigation schemes and have borne the brunt of much of the criticism of irrigation development in sub‐Saharan Africa in the 1970s.
8
Government management characterizes formal irrigation rather than size. For ple, a 50 ha irrigation sexam cheme with 500 smallholders each with 0.1 ha where
sma would have all the characteristics of a `formalʹ or other key
farmers whereas A 50 ha
farm ernment support could equally be called a
no d small‐scale irrigation (SSI) in many developing
is much evidence that farmer‐controlled small‐scale irrigation has better manc le systems. The substantial ‐controlled small‐scale irrigation sector that exists in many countries in
technology can based on farmers existing knowledge; local technical, managerial and
skills can be used; migration or resettlement of labor is not usually p ts are and external input requirements are lower.
i(CAADP, 2007). Hence, small
arshlands are the one focused the more since they are about 68% of the whole
the water supply is managed by a government agency might be thought of as a llholder scheme. However, it
`largeʹ irrigation scheme because of the way in which water andagricultural services are organized independently of the irrigation scheme having 500 smallholders each with 0.1 ha managed by the
ers themselves without govsmallholder scheme (IPTRID, 2001). Despite the lack of available statistic, there is
oubt about the importance of countries. Irrigated fields are usually valued very highly. Thereperfor e than government‐controlled small‐scafarmerAfrica, often without government support, indicates that these systems are economically viable. Areas under farmer‐controlled small‐scale irrigation systems have grown rapidly over the past decades, and account for large and growing share of irrigated area in Sub Saharan Africa (McCornick et al., 2003). In general, according to McCornick et al. (2003) all small‐scale systems may have advantages over large‐scale systems. These advantages include that small‐scale beentrepreneurialrequired; lanning can be more flexible; social infrastructure requiremenreduced; 2.4.4 Purposes and need for small‐scale irrigation in Rwanda
Rwanda’s economy is mainly based on agriculture. With a rapidly growing number of population, rural community is increasing putting unsustainable pressure on natural resources leading to land and water depletion and degradation and/or ‘forced’ migrations to urban areas. In addition, the absence of off‐farm income in rural areas has also contributed to the high population pressure on arable land, which leads to fast deterioration of natural resources. To avoid the food crisis the Government of Rwanda adopted to increase investment in agriculture sector to make t to remain a driving engine of the economy under some programs such as PSAT, PRSP, EDPRS m
9
marshland’s surface area (MINAGRI, 2004b). Therefore sustainable farmed marshland areas have to be increased from 11,105 ha to 20,000 ha for year‐ round utilization to produce high‐value crops, particularly rice, and the share of area under irrigation from 1 percent to about 5 percent and to increase the area under hillside irrigation from 130 ha to 3,200 ha (CAADP, 2007).
2.5 Performance of an irrigation system 2.5.1 How to conduct an irrigation system performance assessment?
m Perfor ance assessment is carried out according to the guidelines given by ICID as stated by Rien (2000) and presented on Figure 2.1.
10
Pu
rpos
e an
d st
rate
gy
App
licat
ion
of
outp
ut
Furth
er a
ctio
n
Des
ign
of th
e pr
ogra
m
Who is the performance assessment for?
From who’s viewpoint will the performance assessment be carried out?
Who will carry out the performance assessment?
What is the purpose of the performance assessment?
What are the boundary conditions of the irrigation and drainage schemes?
What is the design for the performance assessment program? • What criteria are to be used? • What indicators are to be used? • What data is required? • By whom, how and when the data will be measured or collected? • Where will the indicators be applied? • What will be the form of output?
Implementation • Data measurement and collection • Data processing • Data analysis • Presentation of results (reporting)
What will be done with the results? • Nothing • Take corrective action (s) to improve performance • Look for cause of level of performance • Make comparison with other schemes
Do we need to revise the performance assessment strategy and program?
Figure 2. 1 Framework for a performance assessment program of irrigation and drainage schemes (ICID).
11
Sawa and Karen (2002) defined evaluation as a process of determining systematically of activities in the light of their objectives. It is an organizational process for improving activities in future planning, pro and Kumar, 1990). According to Bos et al. (2005) performance evaluation of irrigation and drainage, is the systematic of the management of an irrigation and drainage system, with the objective of ensuring that the input of resources, operational schedules, intended outputs and required actions proceed as plaproducts and services of institution respond to the needs of their customers or users, and the efficiency with which the institution uses or customers can use the resources at it uation is to achieve efficient and ainage performance by providing relevant feedback Performance evaluation is an activity that supports ). As such it may r performance is sa a need to be taken in order to remed According to Rie 2 objectives of performance evaluation are: to upgrade managem n in both public and private sector irrigation and drainage projects iciency with which available resources are used. In this context resources are not limited to the ‘classical’ resource water, but also to resources which can be influenced by management. These resource bor (skills). The principal objective of evaluating surface n systems is to identify management practices and systems that can tion efficiency. Evaluations are u u tions, particularly those that are essential o l. Evaluation data can be collected periodically from the system to refine management practices and identify the changes in r (FAO, 1989). Performance performance of irrigation and drainage heavily depends on the ‘water institutions’. Together with the ‘boundary conditions’ of irrigated agriculture these institutions determine its level of performance. Without a sound knowledge of the boundary conditions and the water institutions a diagnostic analysis of irrigation
the field that occur over the irrigation season or from year to yea should be assessed from the related disciplines, but the
s also include land, funds and la irrigatio
be effectively implemented to improve the irrigasef l in a number of analyses and opera t improve management and contro
s disposal. The ultimate purpose of performance eval effective irrigation and dr
to management at all levels. the planning and implementation process (Bos et al., 2005
in determining whetheassist management or policy makertive actionstisf ctory and, if not, which correc
2000). y the situation (Rien,
n ( 000) the wider e t capabilities with a view to improving the eff
nned. Rien (2000) defined Performance as the degree to which the
observation, documentation and interpretation
still in progress and for aiding managementgramming and decision‐making (Casley
and objectively the relevance, efficiency, effectiveness and impact
evaluation of small‐scale irrigation2.5.2 Performance
12
and drainage is meaningless (FAO, 2000). Small and Svendsen (1992) identify four interrelated purposes of performance evaluation:
evalua e d s
one season, or several years. One season may be the time horizon of special
differenta) Operational b) Accountability c) Intervention d) sustainability Operational performance tion relates to th day‐to‐ ay, season‐to‐ eason monitoring and evaluation of system or scheme performance. Accountability performance evaluation is carried out to assess the performance of those responsible for managing a system or scheme. Intervention assessment is carried out to study the performance of the scheme or system and, generally, to look for ways to enhance that performance. Performance evaluation associated with sustainability looks at the longer term resource use and scheme or system impacts. But, so far the four purposes cannot be separated from each other. The extent of the performance evaluation needs to be identified and the boundaries defined. The extent/boundaries can be categorized into two key dimensions: a) space b) time Space relates to the area covered (is it limited to one secondary canal within a system, to one system, or to several systems), time looks at whether the evaluation coversdiagnostic study. A common performance programme, however, should be a routine part of the management process. Defining the extent of the performance assessment programme in these terms defines the boundaries of the work required as presented on figure 2.2.
Figure 2. 2 The setting of irrigation and drainage
Water institutions • Water policy • Water low • Water administration
Boundary conditions • Political system • Legal system • Demography • Economic system • Resources • Environment
Performance of Irrigation and Drainage
• Water balance • Environmen • Operation & Maintenance • Economics
t
13
The evaluation of surface irrigation at field level is an important aspect of both
design of the system. Field measurements are necessary to gation system in terms of its most important parameters, to
in its function, and to develop alternative means for improving
s to be
system, which in turn can be considered part of an agricultural For each of the systems, process, output, and impact measures
nsidered. Process measures refer to the processes internal to the system
the second set relates to the performance characteristics its water delivery system (Oad and Sampath
performance indicator u d in the Research ogra formance (RPIP). Within ta are
d to quantify and test about 40 multidisciplinary rform n out by IWMI. These indicators cover water delivery, nance and sustainability n, environmental
pects s ics and management. it is not d indicators u e number
indicators you should use depends on the leve f ich one needs quantify (e.g., research, management, informa n on the number of disciplines with which on e d
drainage environment, nt). Thus, FAO (2000), groups of indicators to evaluate irrigation
management andcharacterize the irriidentify problemsthe system (FAO, 1989). 2.5.3 Indicators for irrigation performance
It is useful to consider an irrigation system in the context of nested systems to describe different types and uses of performance indicators (Small and Svendsen, 1992). According to Sawa and Karen (2002), indicators are a way of measuring progress towards the achievement of the goal, i.e. the targets or standardmet at each stage. They provide an objective basis for monitoring progress and evaluation of final achievements. An irrigation system is nested within an irrigated agricultural economic system.can be cothat lead to the ultimate output, whereas output measures describe the quality and quantity of the outputs where they become available to the next higher system (Molden et al., 1998). An irrigation system, consisting of a water delivery and a water use subsystems, can be conceptualized to have two sets of objectives. One set relates to the outputs from its irrigated area, and of , 1995). Bos (1997) summarizes the s c rrently usePr m on Irrigation Per this program field dameasured and collectepe a ce indicators setwater use efficiency, mainte of irrigatio
He also noteas , ocio‐econom d that nder all circumstances. Threcommended to use all describe
of l o detail with whto tio to the public) performance
e n eds to look at irrigation anand (water balance, economics,
Bos et al. (2005) defined the four manageme
14
and drainage performance of an irrigation system as drawn by ILRI/IWMI
s. ) Environment. Both irrigation and drainage are man‐made interventions in the
The non‐intentional (mostly ered in this group.
) Economics. This group contains indicators that quantify crop yield and the
ll as the rather more subjective concept of reliability that may ffect the users’ capacity to manage water efficiently, and the socially oriented
m; The primary task of the anagers of the ‘Irrigation System’, and of the managers of the sub‐systems is to
b c s
research program on irrigation performance from the list of 40 indicators for irrigation performance assessment of IWMI. The four groups resumed below: a) Water balance, water service and maintenance. The indicators in this group
refer to the primary function of irrigation and drainage; the provision of a water service to user
benvironment to facilitate the growth of crops.negative) effects of this intervention are consid
crelated funds (generated) to manage the system.
d) Emerging indicators. This group gives four indicators that contain parameters which need to be measured by use of satellite remote sensing. This emerging technology enables very cost‐effective measurement of data.
2.5.4 Water balance indicators
Water balance performance indicators are concerned with the assessment of the water supply function of the irrigation system. They cover the volumetric component that is primarily concerned with matching water supplies to irrigation water demand, as weaaspects of equity. These three aspects all represent facets of the concept of the Level of Service being provided to water users (WU’s). This focuses on the “core business” of the organization managing the irrigation system; the diversion and conveyance of water to the WU’s in the irrigation systemdeliver water in accordance with a plan (as intended). Indicators in this section are therefore those that guide managers in respect to water delivery performance. For such kind of evaluation to take effect, water alan e ratio have to be used. In general, the water balance indicators deal with the volume of water delivered
within a set time period (in m3/period), rather than the instantaneous flow rate (in
m3/s). The ratios quantify components of the water balance in a spatial context over a specific time period. As such, the same data on flow rates are needed as above.
15
2.5.4.1 Field application ratio
The ICID (1978) standard definition for the field application ratio (efficiency) is:
f
m
VV
rationapplicatioField = (2- 1)
is the volume of irrig
Vm
Vf ii
q
are
practical purposes we may assume that Vm equals the evapo‐transpiration by ctive part of the precipitation: ETp –Pe. The value
of use of models like CRIWAR (Bos et al. 1996) and (Smith et al. 1991).
ation water needed, and made available, to avoid undesirable stress in the crops throughout (considered part of) the growing cycle;
s the volume of irrigation water delivered to the fields during the considered b becaper od. The value of Vm is difficult to establish on a real time asis use many
complicated field measurements would be needed. The method which is used to ntify Vm, however, is not so very important provua ided that the same (realistic)
method is used for all command areas (lateral or tertiary units) within the irrigated a.
Forthe irrigated crop minus the effe ETp –Pe can be calculated by
CROPWAT
Thus, )(sfieldatdeliverdwaterofVolume
PETrationapplicatioField ep −= (2- 2)
The target water requirement at the field inlet then equals ( )PeETxRV pettaettf −= arg,arg, . The target value of the field application ratio depends
on the level of technology used to apply water, on the climate, and on whether you grow dry‐foot crops or ponded rice (Bos et al. 1996).
2.5.4.2 Tertiary unit ratio
The irrigation water requirement at the intake of a tertiary unit depends on the crop irrigation water requirements (ETp –Pe) in the unit, on the water delivery performance in the unit, on canal seepage, and on the (average) value of the above field application ratio (ICID, 1978). Hence, the tertiary unit ratio is:
d
m
VVV
ratiounitTertiary 3+= . (2- 3)
For practical purposes we may replace Vm by ETp –Pe, and assume negligible ‐irrigation water deliveries from the distribution system (V3 = 0). non
16
2.5.4.3 Overall consumed ratio
The overall (or project) consumed ratio, quantifies the fraction of irrigation water evapo‐transpirated by theNugteren 1974; Willardson et al. 1994). Assuming negligible non‐irrigation water
crops in the water balance of the irrigated area (Bos and
deliveries, it is defined as (Bos & Nugteren 1974):
1VVPET
RatioConsummedOverallc
ep
+
−= (2- 4)
Vc is volume of irrigation water diverted or pumped from the river or reservoir; V1 is inflow from other sources to the conveyance system. The value of (ETp –Pe) for the irrigated area is entirely determined by the crop, the climate and the interval between water applications. Hence, the actual value of the overall consumed ratio varies with the actual values of Vc and V1 being the volume of
ndicator that should be available for each irrigated area. For water management within an existing irrigated area is recommended to
target value, and to measure the actual overall consumed ratio at a monthly nual basis.
2.5.4.4 Conveyance ratio
ation system. It is defined as:
irrigation water delivered to the sub‐command area. Because the inflows Vc and V1 are among the very first values that should be measured, together with the cropped area, the cropping pattern and climatological data, the overall consumed ratio is the first water balance i
set a and an
The conveyance ratio quantifies the water balance of the main, lateral and sub‐lateral canals, including related structures, of the irrig
1
2
VVVV
RatioConveyance d
++
= c
(2- 5)
oir
ance ratio should be calculated over a (week, month) and a long (season) period. The rate of change of the ratio ainten nce. Flarge irrigation systems it is common to consider the conveyance ratio of parts of
s managed canal.
Vc is the volume of irrigation water diverted or pumped from the river or reserv(source of surface water), Vd is the volume of water actually delivered to the distribution system, V1 is inflow from other sources to the conveyance system, V2 is non‐irrigation deliveries from the conveyance system. The convey
shortis an indicator for e.g. the need of m a or
the system. Hence, we consider (a) the conveyance ratio of the upstream part of the system as managed by the Irrigation Authority and (b) of the WU’
17
2.5.4.5 Distribution ratio
The distribution ratio quantifies the water balance of the canal system downstream from the conveyance system up to the inlet of the fields. It thus, quantifies thwater balance of the canal system at tertiary unit level. The distribution ratio is
e
defined as:
d
f
VRatioonDistributi 3= (2- 6)
If the distribution ratio is determined for all tertiary units within the considered irrigated area, the uniformity of water delivery can be expressed by the standard deviation of the distribution ration values. If all tertiary units receive a (color) code for a given subdivision of ratio, the values of this uniformity of water supply can be visualized on a map.
2.5.4.6 Dependability
The pattern in whi
VV +
ch water is delivered over time, is directly related to the overall ratio of the delivered water, and hence has a direct impact on crop
concerned with crop survival than crop production.
The primary indicators proposed for
consumedproduction.
The rationale for this is that water users may apply more irrigation water if there is an unpredictable variation in volume or timing of delivered water, and they may not use other inputs such as fertilizer in optimal quantities if they are more
use in measuring dependability of water deliveries are concerned with the duration of water delivery compared to the plan, and the time between deliveries compared to the plan. They are:
DeliveryWaterofDurationIntendedDeliveryWaterofDurationActualDurationofityDependabil =
and
IntervalIrrigationActualDeliveryWaterofDurationIntendedIntervalIrrigationofityDependabil =
In addition to dependability in terms of timing, it is strongly recommended that
18
the predictability of the flow rate or the (canal) water level be included in this part y irrigation activities the flow rate (or water level) must
near the intended value for water use to be effective (Clemmens & Bos 1990). The simplest method to assess predictability of flow rate (or flow rate times
thly or bi‐weekly data appear to give a good indication of whether the discharge is more or less predictable.
d condition to minimize seepage and sustain canal water and designed discharge‐head relationship, and keeping water control
king condition. In irrigation systems the conveyance efficiency provides the best way of assessing whether canal maintenance is
By tracking the change in conveyance efficiencies over time it should be
more analytical approach.
rge and related water level is determined for each canal reach. The hydraulic performance of a canal system
For
e intended water division at canal bifurcation structures. The magnitude of alteration of the water distribution depends on the hydraulic flexibility of the division structures
1976). This change of head (level) over structures in irrigation canals is the single most important factor disrupting the intended delivery of irrigation water (Bos 1976; Murray‐Rust & Van der Velde 1994).
of the assessment. For manbe
duration of flow) is to determine the standard deviation of the water delivery performance ratio. The period over which observations are compared in this analysis will vary depending on the type of water delivery pattern adopted. In most irrigated areas, mon
2.5.5 Maintenance indicators
2.5.5.1 General
Maintenance is designed to accomplish three main purposes: safety, keeping canals in sufficiently goolevelsinfrastructure in wor
required.possible to establish criteria that will indicate when canal cleaning or reshaping is necessary. In many systems this is undertaken subjectively on appearance rather than using a 2.5.5.2 Sustainability of water level and head‐discharge relationship
During the design of a canal system, a design discha
depends greatly on the degree to which these design values are maintained.example, higher water levels increase seepage and the danger of overtopping of the embankment. Both, lower and higher water levels alter th
this
(Bos
An indicator that gives practical information on the sustainability of the intended
19
water level (or head) is: LevelIntendedLevelofChangeLevelWaterofChangelative =Re
For closed irrigation and drainage pipes (visual) inspection of heads (pressure levels) is complicated. The functioning of a conduit, however, should be quantified by the measured discharge under a measured head‐differential between the upstream and downstream end of the considered conduit (as used in the original design), versus the theoretical discharge under the same head differential. Hence, conduit performance can be quantified by the ratio:
eDischDesigneDischMeasuredActually arg
=RatioeDischarg
arg
be used to quantify the effective functioning of . Depending on the type of structure, the actual
then must be measured under the same (design) differential head s, culverts, etc.) or under the same upstream sill‐referenced head
The same discharge ratio canstructures in the canal systemdischarge(submerged gate(free flowing gates, weirs, flumes, etc.). Generally, a deviation of more than 5% would signal the need for maintenance or rehabilitation for flow control structures. As mentioned above, maintenance is needed to keep the system in operational conditions. For this to occur, (control) structures must be operational as intended. Hence, maintenance performance can be quantified by the following ratio:
StructuresofNTotalStructuresgFunctioninofNumber
tureInfrastrucofessEffectiven = umber
above three ratios immediately indicate the extent to which the manager is to control water. For the analysis to be effective, however, it must divide
ertiary and
ation.
Theablestructures up into their hierarchical importance (Main, Lateral, TQuarternary) and the analysis completed for each level. 2.5.6 Properties of performance indicators
A true performance indicator includes both an actual value and an intended value that enables the assessment of the amount of deviation. It further should contain information that allows the manager to determine if the deviation is acceptable. It is therefore desirable wherever possible to express indicators in the form of a ratio of the actually measured versus the intended situ
ValueIndicatorePerformancHence,AspectKeyofValuecriticalorIntended )(
AspectKeyofValueActual=
(Rien, 2000).
20
A good indicator can be hat current performance is in the system, may help
used in two distinct ways. It tells a manager w and, in conjunction with other indicators,
empirically quantified, statistically tested causal model of that part of The indicators must be quantifiable: the data
n of deviation should be related to the level of technology and nt (Bos et al., 1991). Provide information without bias: ideally,
ical
routine management, performance indicators should be technically feasible, and easily used by agency staff given their level of skill and moti
m. Most surface irrigation are designed‐in capacity constraints, which mean that they cannot run on
be evaluated at different levels of the system to characterise and regulate performance. Among those parameters we can
anspiration process and the volume that reaches the irrigation plots and indicates how efficiently the available water supply is being used, based on
him to identify the correct course of action to improve performance within that system: in this sense the use of the same indicator over time is important because it assists in identifying trends that may need to be reversed before the remedial measures become too expensive or too complex (Bos, 1997). Some of the desirable attributes of performance indicators suggested by Bos (1997) are: Scientific basis: the indicator should be based on an
the irrigation process it describes. needed to quantify the indicator
must be available or obtainable (measurable) with available technology. The measurement must be reproducible. Reference to a target value: this is, of course, obvious from the definition of a performance indicator. It implies that relevance and appropriateness of the target values and tolerances can be established for the indicator. These target values and their margimanagemeperformance indicators should not be formulated from a narrow ethperspective. This is, in reality, extremely difficult as even technical measurescontain value judgments. Ease of use and cost effectiveness: particularly for
vation. Further, thecost of using indicators in terms of finances, equipment, and commitment of human resources, should be well within the agency’s resources. In irrigation sector, the performance of the agricultural production and marketing processes are central to the performance evaluation and sustainability of the process. Farmer’s activities influence the performance of an irrigation systesystemsdemand. Thus, different parameters need to
say: 2.5.6.1 Irrigation water use efficiencies
Irrigation efficiency is the ratio between the volume used by plants throughout the evapotr
21
different methods of evaluation (Michael, 1997). According to James (1988), the performance of a farm irrigation system is determined by the efficiency with which water is diverted, conveyed, and applied, and by the adequacy and uniformity of application in each field on the farm. Mishra and Ahmed (1990) also said that irrigation efficiency indicates how efficiently the available water supply is being used, based on different methods of evaluation. The objective of these efficiency concepts is to show where improvements can be made, which will result
ficiency in the use of water for irrigation onsists of various components and takes into account losses during storage,
e
ency it is necessary to identify at least one of these losses as well as the of water stored in the root zone. This implies that the difference between
available at the time of irrigation igation be separated, i.e. the amount of
‐irrigation in the soil profile must be determined as well as the losses (FAO,
in more efficient irrigation. Among the factors used to judge the performance of an irrigation system or its management, the most common are efficiency and uniformity (FAO, 1989). The designs of the irrigation system, the degree of land preparation, and the skill and care of the irrigator are the principal factors influencing irrigation efficiency. Efcconveyance and application to irrigation plots. Irrigation efficiency can be measured in many ways and also varies in time and management (Roger et al., 1997). For instance, where water is very short, efficiency may be measured as crop yield per cubic meter of water used, or profit per millimeter of irrigation. It depends on what you want to know. Identifying the various components and knowing what improvements can be made is essential to making th most effective use of this vital but scarce resource. There are several publications describing the methods and procedures for evaluating surface irrigation systems, but the data analysis depends somewhat on the data collected and the information to be derived. 2.5.6.2 Application efficiency
According to Jurriens et al (2001), application efficiency is a common measure of relative irrigation losses and this definition is valid for all situations and all irrigation methods. Losses from the field occur as deep percolation and as field tail water or runoff and reduce the application efficiency. To compute the application efficiamountthe total amount of root zone storage capacityand the actual water stored due to irrunder1989). According to Roger et al. (1997), methods of determining application efficiency of a specific irrigation system is generally time consuming and often
22
difficult because it may vary in time due to changing soil, crop and climatic condition. Application efficiency does not show if the crop has been under‐irrigated. However according to Roger et al. (1997), it is possible to have high application efficiency and 50‐90% can be used for general system type comparison. FAO (1989) reported that the attainable application efficiency according to the US (SCS) ranges from 55%‐70% while in ICID/ILRI this value is about 57%. Lesley (2002) suggested that it could be in the range of 50‐80%. In general, according to Michael (1997) water application efficiency decreases as the amount of water applied during each irrigations increase. 2.5.6.3 Storage efficiency
Water stored in the root zone is not 100% effective (FAO, 1992). Evaporation losses may remain fairly high due to the movement of soil water by capillary action towards the soil surface. Water lost from the root zone by deep percolation where groundwater is deep. Deep percolation can still persist after attaining field capacity. Depending on weather, type of soil and time span considered, effectiveness of stored soil water might be as high as 90% or as low as 40%. Theoretically, the adequacy of irrigation depends on how much water is stored within the crop root zone, losses percolating below the root zone, losses occurring surface runoff or tail water the uniformity of the applied water, and the
deficit or under‐irrigation within the soil profile following an irrigation ciency is an indicator of how well the irrigation
its objective of refilling the root zone. The value of water requirement
asremainingpractice. The requirement effimeetsefficiency is important when either the irrigation tend to leave major portions of the field under‐irrigated or where under‐irrigation is purposely practiced to use precipitation as it occurs and storage efficiency become important when water supplies are limited (FAO, 1989). The adequacy of irrigation turn in terms of storage efficiency and the purpose of an irrigation turn is to meet at least the required water depth over the entire length of the field (Jurriens et al., 2001). The water storage efficiency refers how completely the water needed prior to irrigation has been stored in the root zone during irrigation.
23
2.5.6.4 Distribution efficiency
According to Jurriens et al. (2001) distribut on uniformity can be defined as the average infiltrated depth in the low quarter of the field divided by the average infiltrated depth over the whole field. When a field with a uniform slope, soil and crop density receives steady flow at its upper end, a waterfront will advance at a monotonically decreasing rate until it reaches the end of the field (FAO, 1989). Irrigation water lost to percolation below the root zone due to non‐uniform application or over‐application water run off from the field all reduces irrigation efficiency. To get a complete picture of an irrigation performance you need to know more indicator
i
s than just discussed above, because these are averages taken the entire length of the field or furrows (Roger et al., 1997).
might produce the same results for application and storage efficiencies, their distribution patterns could be different. One indicator
to represent the pattern of the infiltrated depths along the field length is the
on demand, some form of soil status monitoring can be used to determine when to irrigate. The amount of depleted from the crop root zone provides a guide for the depth of irrigation
applied (Hargreaves and Merkley, 1998). When surface irrigation methods are used, however, it is not very practical to vary the irrigation depth and frequency
overAlthough different cases
useddistribution uniformity. 2.5.6.5 Irrigation scheduling
Irrigation scheduling is the process of determining when to irrigate and how much water to apply per irrigation. Proper scheduling is essential for the efficient use of water, energy and other production inputs, such as fertilizer. It allows irrigations to be coordinated with other farming activities including cultivation and chemical applications. Among the benefits of proper irrigation scheduling are: improved crop yield and/or quality, water and energy conservation, and lower production costs (James, 1988). The purpose of irrigation scheduling is to determine the exact amount of water to apply to the field and the exact timing for application. There are several methods for deciding when to irrigate and how much water to apply. Many farmers use an irrigation frequency based on experience, and usually somewhat more water is applied than that required to bring the soil water content to the field capacity. If water is available by turns or rotation, the frequency of water availability may determine the schedule. When water is available waterwaterto
24
too much. In surface irrigation, variations in irrigation depth are only possible limits. It is also very confusing for the farmers to change the schedule all
e scheduled from
e irrigator’s strategy.
measurement of the volume of water applied or the depth of application. A farmer cannot manage water to maximum efficiency
withinthe time. Therefore, it is often sufficient to estimate or roughly calculate the irrigation schedule and to fix the most suitable depth and interval: to keep the irrigation depth and the interval constant over the growing season (FAO, 1989). Water budget method is more commonly applied these days to determine irrigation scheduling. According to Hargreaves and Merkley (1998) this method requires estimates of the daily crop evapotranspiration or for other suitable time periods. This approach requires knowledge of or an estimation of the amount of water available from rainfall and or shallow water tables. In some situations some of the supply can be contributed by fog or dew. The required amount not supplied by these sources must be applied by irrigation. Irrigation arestimates of the following: (a) crop evapotranspiration; (b) field capacity of the soil; (c) the allowable soil water depletion; (d) the effective crop root depth; (e) requirement for reaching; and (f) allowances that need to be made for uniformity and efficiency of irrigation application. How much water to apply is depending on th A critical element is accurate
without knowing how much water applied. Also, uniform water distribution across the field is important to derive the maximum benefits from irrigation scheduling and management. Accurate water application prevents over‐or under‐irrigation. According to FAO (1989), the total available water (TAW), for plant use in the root zone is commonly defined as the range of soil moisture held at a negative apparent pressure of 0.1 to 0.33 bar (a soil moisture level called ʹfield capacityʹ) and 15 bars (called the ʹpermanent wilting pointʹ). The TAW will vary from 25 cm/m for silty loams to as low as 6 cm/m for sandy soils. The net quantity of water to be applied depends on magnitude of moisture deficit in the soil, leaching requirement and expectancy of rainfall. When no rainfall is likely to be received and soil is not saline, net quantity of water to be applied is equal to the moisture deficit in the soil, i.e. the quantity required to fill the root zone to field capacity. The moisture deficit in the effective root zone is found out by determining the field capacity moisture contents and bulk densities of each layers of the soil (Mishra and Ahmed, 1990). According to Jurriens et al. (2001), the required depth is not usually the same as the applied depth, which is equal to the applied volume divided by the area. If the applied depth infiltrates the field area entirely, the applied depth equals the average infiltrated depth. Jurriens et al. (2001) further discussed on that,
25
the average depth of water that is actually stored in the target root zone is the storage depth. When the target zone is entirely filled, the storage depth will equal the target root zone depth. If the storage root zone depth is less that the target root zone depth, then there is under‐irrigation and if the storage root zone depth is greater than the target root zone depth, then there is deep‐percolation.
2.6 Methods of irrigation performance Two key factors affecting irrigation and drainage service delivery are the configuration of the physical infrastructure and the management processes, both of which effect control over the processes involved. Control needs to be exerted in some areas such us infrastructures, water delivery and management, maintenance, and income generation, to provide a reliable, adequate and timely irrigation water supply and effective drainage, and the potential benefits of such control. The management of the physical infrastructure leads to the provision of water for irrigation and drainage of excess water; this in turn leads to improved agricultural rop production and farmer income, some of which can then be used to pay for the
nvironment, such as is the case with governments reducing the funding vailable for supporting irrigated agriculture and transferring responsibility for
cservice provided or contribute to maintenance services. Within the internal processes of the service provider, financial, operation and maintenance control systems are required to support the delivery of the service (Bos et al., 2005). The level of physical control and measurement built into the irrigation and drainage system design has a fundamental impact on the level and type of operational performance evaluation that is: (i) required and (ii) possible. In general, the need for operational performance monitoring increases as the level of control and measurement increases. Monitoring and evaluation of scheme performance is carried out during the cropping season or year, and can be of a strategic (‘Am I doing the right thing?’) or an operational (‘Am I doing things right?’) nature. Strategic performance evaluation is typically done at longer intervals and looks at criteria of productivity, profitability, sustainability and environmental impact. It may also be required in response to changes in the external eamanagement, operation and maintenance to water users. Operational performance assessment carried out during the season supports a pre‐season plan which in general is drawn up in the commencement of the irrigation season and that is covering key aspects of the management, operation or maintenance of the system. It of course depends on the type of irrigation and drainage scheme, this planning and adjustment process. The flows in the canal network are regulated in
26
accordance with the implementation schedule and the discharges (and for some schemes, the crop areas) monitored as the season progresses. The performance of the system in relation to the seasonal plan is monitored during the season, and evaluated at the end of the season. The evaluation measures the performance against the seasonal plan, but may also measure the performance against the
objectives.
.6.1 Data collection
n from
strategic
2
There are two common approaches to understand system performance and diagnose problems. The first approach is to collect as much information as possible about the system and explain the functioning of the system through analysis. The second approach is to focus on and trace key cause–effect relationships. While the first approach can yield a broad understanding of irrigated agriculture, it is often expensive to collect measure and handle data on performance, and that is one reason why irrigation managers do not routinely do performance assessment (Bos et al., 2005). A specific methodology for assessing and understanding the performance of an irrigated agricultural system has evolved since the 1980s and has been applied to many irrigated areas (Lowdermilk et al., 1983; Clyma and Lowdermilk, 1988; Dedrick et al., 2000). The performance evaluation is takea variety of viewpoints, including the farmer’s, the irrigation manager’s and society’s. The experience and examples of performance evaluation have yielded a variety of specific methodologies crossing disciplines that are quite useful within and outside the context of this evaluation such as Rapid appraisal, participatory rural appraisal and remote sensing techniques (Oad and McCornick, 1989; Bos et al., 2005). 2.6.1.1 The Rapid appraisal approach
This method is used to give a quick overview of system performance. This is typically used in the initial steps of performing diagnostic analysis. As a result of a rapid appraisal, an initial hypothesis can be developed. At times, an overview based on a rapid appraisal can shed sufficient light on an irrigated area for decisions to be made. Rapid appraisal techniques rely on field observations plus the collection and review of available data and information. The following sources of information are useful: review of secondary data, interviews with individuals
27
and groups, and observations of various parts of the system. A rapid appraisal should provide key information to form a profile of the system, information on a few key indicators and other explanatory information to form the basis for key hypotheses. Rapid appraisals can sometimes quickly trace the origin of malfunction, allowing for application of corrective actions and sometimes eliminating the need for a detailed diagnostic analysis. The advantages of rapid
lie in the ability to quickly form an idea about the system’s functioning. appraisal can point swiftly to the origin of the malfunction, allowing for
and minimizing the time and effort for detailed iagnostics. The disadvantages are that it relies on the skills of the assessor.
community participates in the research by developing sketches and aps, transects showing resource use patterns, seasonal calendars, trend analysis
A, information that would have otherwise gone stakeholders in research and development,
is more likelihood of better acceptance of interventions.
appraisalRapidrapid corrective action, d 2.6.1.2 Participatory rural appraisal approach
This approach relies on the information delivered by people in the vicinity of an irrigated scheme. Locally, irrigation communities possess tremendous knowledge about the operation and performance of irrigation. This is an extremely valuable source of information, even for irrigation management agencies, in assessing irrigation performance. Participatory rural appraisal relies on local knowledge to identify problems and develop interventions. Participatory rural appraisal (PRA) is a family of approaches and methods to enable local people to share, enhance and analyze their knowledge of life and conditions, and to plan and act (Chambers, 1994). PRA is related to and evolved from the rapid rural appraisal techniques (Chambers and Carruthers, 1985; Yoder and Martin, 1985; Pradhan et al., 1988; Grosselink and Thompson, 1997). The local mand daily activity profiles. Through PR
unnoticed is tapped. By involvingthere A disadvantage is that the quantitative base of information may be weak. For example, this would not be used to generate data on water resources, although it could be helpful in developing a feel for the magnitude of flows when data are missing. While it is an excellent tool for deriving local knowledge, placing this knowledge in the context of broader issues such as basin‐wide water use may be missing. Similar to the rapid appraisal techniques, this technique also relies heavily on the skills of the assessor. PRA can be an excellent complement to other
28
tools when assessing performance. PRA techniques are ideally suited for developing and improving service arrangements between the providers and users. For diagnosis, PRA can be used both in initial screening and for a more detailed data collection (Bos e al, 2005).
2.6.1.3 Remote sensing techniques
These techniques are increasingly being utilized in performance evaluation and are in many situations quite useful for diagnostic assessments. The use of remote
t
ensing has several distinct advantages over traditional ground data collection.
ation over an entire area, while Data collection by remote sensing
not intrude into the day‐to‐day life of those in the irrigation community.
sRemote sensing can be used to gather informground data collection relies on sample areas. doesOften, the presence of observers changes the behaviour of those being observed, so the information collected does not reflect normal operating conditions. Data can be disaggregated to the resolution of the image, or aggregated up to useful units such as various service areas within an irrigation system. Because satellite images have been available since 1982, development trends can be established looking 20 years back. The cost of obtaining remotely sensed data is often cited as a constraint to its use. Prices are decreasing rapidly, and the quality and resolution of images are improving. For certain types of data like irrigated area, or land‐use cover, the cost of data collection is less than 25% of conventional data collection programmes. Nevertheless, remote sensing cannot substitute for local field‐level knowledge and experience and is applicable to a limited set of problems that may occur (Bos et al., 2005).
29
Chapter 3. DESCRIPTION OF THE STUDY AREA
3.1 Location and Topography
on figure 3.2 with its sub‐marshes is the southern province of Rwanda precisely in Muhanga District as shown
on figure 3.1.
Rugeramigozi marshland complex presentedsituated
Figure 3. 1 Rwanda administrative map
Figure 3. 2 Rugeramigozi marshland topographic map
30
3.2 R
eramigozi irrigation project, farmers in the lture. The agricultural production was poor
to insufficient rainfall during dry seasons and occurrence flooding in the rainy
duction in the area of Muhanga District. The project comprises of three sub‐marshes which are: Rugeramigozi I, 67.72ha, Rugeramigozi II, 121.65ha, and Biringanya 63.53ha. This study was conducted in Biringanya marshland Figure 3.3 which has about 950 farmers. At the beginning of the project every farmer managed his own plot separately. This created disputes among farmers. To settle the dispute, Rugeramigozi farmer’s association was established.
ugeramigozi Irrigation scheme
Prior to the development of the Rugvicinity depended on rain fed agricudueseasons. In 2001, NGO, GERMANY AGRO ACTION established an irrigationproject that cover an area of about 250ha with the aim of improving food security and poverty re
Figure 3. 3 Biringanya Irrigation System (ECOTRA)
31
3.3 Climate
Like everywhere else in Rwanda, the climatic conditions of the area comprises of four seasons which are two rainy seasons (March to June and October to December) and two dry seasons (July to September and January to February). This study was carried out in the dry season especially between June and August. According to the record of the nearest weather station (Byimana weather station) the mean annual rainfall in the area ranges from 1200 mm to 1300 mm, with the highest amount falling between March and June. The potential evapotranspiration of the area is about 1250 mm per year. The mean annual temperature ranges from 17ºC to 20ºC. 3.4 Water sources
Rugeramigozi stream is the main source of irrigation water to this project. The stream is also used for domestic water supply for the area. This stream passes under the dyke of the Kigali‐Butare road through two culverts to Biringanya scheme on the right hand of the road as shown by figure 3.4. Figure 3.5 shows a diversion head work in the form of head regulators for diversion of water to the off‐taking channels for irrigation purpose, constructed in 40 meters downstream the dyke.
Figure 3. 4 Rugeramigozi stream under the dyke
32
Figure 3. 5 Head regulator on Rugeramigozi stream
33
Chapter 4. MATERIALS AND METHODS
4.1 Methodology For this study a rapid appraisal approach has been used to evaluate the scheme’s internal performance, temporal and spatial information at on‐farm level have been collected. Data gathering was conducted in June, July and August 2007. These are the dry months in which farmers were expected to be irrigating their crops after the harvesting of rain‐fed crops was over. The field research used the following data collection instruments:
uced irrigation system was visited. Notes were taken from the conversations held with the farmers at the irrigation sites. Photographs of characteristics of the physical systems of irrigation were taken.
Interviews with key informants: detailed interviews were conducted with officials (The Sector Agronomist, The farmers’ Association representative and The Company that designed the irrigation system).
c) Archives: information was obtained from the files of ECOTRA. The contents of key correspondence and reports pertaining to irrigation in the study area were examined.
4.1.1 Primary data collection
Primary field data collection activities included: a) Frequent field observations that wer conducted to observe and investigate
the method of water applications, an practices related to water management techniques, the water delivery structures status and channels status in the whole scheme. Here we visited every structure constructed in the scheme and we noted its status to see the number of ones that are functioning adequately and the ones which are not functioning adequately.
Measurements of water flow at the main source. Based on this average discharge coupled with the total flow time, the total volume of water diverted by the irrigation scheme was estimated.
c) Household survey, interview with both irrigation scheme managers and farmers to get their different point of views on how irrigation activities are
a) Field observation and photography: the newly introd
various
b)
ed
b)
34
conduct survey, a questionnaire was administrated to a randomly composed sample of 63 farmers. It took place in on‐farm level where questions were asked to farmers
ily activities in the marshland. The questionnaire administrated to the farmers is presented in the appendix A‐A.1. Note that
e morning between 8h00’ and 10h00’ and in
.
With dge of flow rates it is usually difficult to quantify deliveries to users, which significantly impedes the ability to evaluate water
Irrigation Water management does not exist in the absence of flow measurement.
Weirs for Water flow
a) b) c) d) (Ha
figu
ed and how the practices are understood. For the
during their da
only questions that may have a direct influence on the performance of the irrigation system were analysed in this work.
d) Wooden weirs were constructed and installed at the entrance of the selected
secondary canal to measure the water flow entering the field and the discharge in the primary canal. Water level was forced to rise so that it could flow over the weir. When water got stabilized we took three successive readings to make sure that the head recorded is correct and when we found difference between readings we made an average. The weir reading activity was conducted twice a day, in ththe afternoon between 15h00’ and 17h00’ during irrigation event.
1.1 Flow measurement 4.1
out knowlewatermanagement practices. Hence,
In this study we used Rectangular Sharp‐crestedmeasurement due to their advantages that are presented below:
are capable of accurately measuring a wide range of flow rates; tend to provide more accurate discharge ratings than flumes and orifices; are relatively easy to construct; and allow floating debris to pass over the structure during measurement event. rgreaves and Merkley, 1998).
The model of a rectangular sharp‐crested weir used in this study is shown on
re 4.1.
35
re 4. 1 The rectangular sharp-crested weir and its cross section (Bos, 1989).
Figu
Discharge determination
The figure 4.2 shows locations at which weirs were installed in the channels and
n
the discharge of water flowing in the channel, a weir as shown by figure 4.3 was installed at the entrance of each
were recorded by
r as shown on
4.1.1.2
the respective sites in which measurements were taken, MS being the site of measurement i the main source which is Rugeramigozi stream, and S1, S2, S3, S4, S5 the different sites in which measurements were taken through the irrigation primary canals. To determine rectangularsecond channel and frequent readings were taken. During measurement, the average irrigation water depth passing over the weir to the fieldreading on the graduated staff placed in the upstream side of the weifigure 4.4.
36
Figure 4. 2 Measurement sites
discharges of water flowing into the channels were calculated using equation ‐1) as formulated by Kindsvater and Carter (1957). The formula uses the
rectangular sharp‐crested weir.
The(4principle of head‐discharge over a
23
1232 hbgCeQ e= (4- 1)
Q: the discharge in (m3/s) Ce: the effective coefficient of discharge g: the gravity acceleration (9.81m/s2) be: effective length of the weir crest (m) h1: head on the weir (m)
be kbb += kb is a correction factor to obtain a weir effective length, BLkb = . (4- 2)
he khh += with h the measured head over the weir.
Practically, for Suppressed rectangular sharp‐crested weirs:
andmhhe 001.0+= ph
Ce1075.0602.0 += (4- 3)
where p1 is the height of the weir from the bottom of the channel, and P the head of water on the upstream side of the weir measured from the bottom of the channel (Bos, 1989).
MS
Direction of flow
S1
S2
S3
S4
S5
37
Figure 4. 3 Installation a weir Figure 4. 4 Taking measurement
.1.2 Secondary data collection
ey keep.
irrigated area, irrigable area, and cal data and agronomic documents on different crops. Organizations visited are
N (GAA) Which is the NGO that financed the TRA the Company that design the
MANA Meteorological Station the nearest to as representative of Local Authority and
iation for the farmers in the entire marshland. Many secondary data from the above mentioned organization were collected. Interviews were cond of th rs about the water distribution within the project. Much effort was given to review of different d reliability and consistency of
4.1.2.1 Crop wa quirements
d the
a whole the CropWat for windows (CropWat 4 Windows 4.2) was used. This program uses the FAO (1992) Penman‐Monteith
equation for calculating reference crop evapotranspiration. The determination of the CWR by this model depends on the determination of the reference
of
4
Secondary data collection was carried out by visiting organizations related to theagriculture sector to gather further information through documents that thThis information include the marshland surface area, yields,
design discharge, volume of water designed, meteorologi
GERMAN AGRO ACTIOdevelopment of this marshland, ECOdevelopment plan of the scheme, BYIthe study area, NYAMABUYE SECTORIABR as the main Assoc
ucted using questionnaire in order to get the perception e farme
ocuments at different places to check thethese data collected.
ter re
To estimate the crop water requirements (CWR), irrigation scheduling anirrigation water requirement (IWR) of the irrigated crops at field levels andirrigation project asVersion
38
evapotranspiration values using the available climatic data. The determination of IWR was carried out after estimation of effective rainfall using USDA soil conservation service method. The water requirements were estimated according the FAO method which consists of comparing rainfall with the crop’s evapo‐transpiration. Sets of monthly rainfall data were used to establish these water requirements. The maximum crop evapo‐transpiration (ETM) was expressed in millimeters per month (mm/month) and then converted into continuous fictitious flow in liters per second per hectare (l.s‐1/ha) and this equals the part which can be used for irrigating the crops.
nique
.2.1 Water delivery performance
4.2 Data analysis tech s 4
The simplest, and yet probably the most important, hydraulic performance indicator is (Clemmens & Bos 1990; Bos et al. 1991):
waterdeliveredofvolumeIntendedwaterofvolumedeliveredActuallyeperformancdeliveryWater =
This measure enables an irrigated scheme water manager to determine the extent to which water is elivered as intended during selected period (may range from second to year) and at any location in the system. The primary utility of the Water Delivery Performance ratio is that it allows for checking of whether the flow at any location in the system is more or less than intended (Bos, 1997). Total water supply is Surface diversions plus net groundwater plus rainfall. 4.2.2 Performance Indicators
d a
performance indicators’ testing depends on the availability of data. Getting data required to calculate all the internal (the nine indicators) for each
as very difficult. The types of data recorded in this
t a
Thecompletesmall‐scale irrigation project wirrigation project have different natures and limited the application of all the nine parameters used in the performance indicators developed by IWMI for the same cropping season of an irrigation project. Hence, the analysis of performance of an irrigation project, minimum sets of internal indicators were applied with the available information gathered and analysis was made within and across the irrigation project. Based on the minimum se of performance indic tors, the
39
scheme performance evaluation and its trend were studied. The water balance indicators and maintenance indicators were used to evaluate the performance of Rugeramigozi irrigation scheme. Water balance indicators:
Field application ratio :
f
ep PETV−
1VVPET
c
ep
+−
1
2
VVVV
c
d
++
Overall consummed ratio :
Conveyance ratio :
Maintenance indicators:
Discharge ratio:
Effectiveness of infrastructures:
eDischDesigneDischMeasuredActually
argarg
StructuresofNumberTotalStructuresgFunctioninofNumber
ith:
oir;
W ETp:
Pe:
V1:
V2:
V3:
Vc:
the evapo‐transpiration by the irrigated crop;
the effective part of the precipitation;
the inflow from other sources to the conveyance system;
the non‐irrigation deliveries from the conveyance system;
the non‐irrigation water deliveries from the distribution system;
the volume of irrigation water diverted or pumped from the river or reserv
40
Vd :
Vf :
the volume of water actually delivered to the distribution system;
the volume of irrigation water delivered to the fields during the considered
Vm :
period;
n water needed, and made available, to avoid
undesirable stress in the crops throughout (considered part of) the growing
For practical reasons Vm = ETp – Pe and V3 is negligible and hence was taken equal to
the volume of irrigatio
cycle;
zero.
41
Chapter 5. RESULTS AND DISCUSSION
5.1 Ana secondary data and visual observations Originally the project was designed by ECOTRA under the sponsor of German Agro Actstill existi h primary and secondary canals are unlined earthen canals. There are
canals. All farmers were using border cascaded irrigation system under plots having an average length of 16 meters to 25 meters width.
ed metal gates are the equipments used to open and close the intakes they are irrigating their crops, whereas weeds and clay are used to close the way from one plot to another. During the reallocation of the farm fields to
members, each farmer on average has got 0.04 hectares of land. In general the developed area is 63.53 hectares, but the irrigable land is 58.38 hectares.
main crops grown in the irrigation project area are rice, cabbage, tomato, and sorghum. Among the mentioned crops, rice was the dominant crop covering around 66.8% of the irrigable land. During the study “dry the dominant crops were Cabbage and Tomato which were covering
33.2% of the irrigable land. Rice, maize and sorghum were grown in rainy and Vegetables are grown in dry season. Rainfall is not sufficient for crops
grown in rainy season and irrigation is therefore required for supplemental The farmers themselves, including their family, do all the farming practices maintenance of the irrigation system. According to the responses given
the farmers, 87.3% of the sixty three farmers interviewed confirm that they are to the works concerning the maintenance of the irrigation system and whereas only 12.3% said that they never participate in these works as shown of figure 5.1. The reasons that a number of farmers
not participating may due to the fact that most of them did not get training on cultivating practices and irrigation practices. As it is shown on figure 5.2, of interviewed farmers said that they have never had training as farmers.
lysis of
ion. The structures during the study were clearly poorly maintained, but ng. Bot
a number of division boxes “intakes” and in some areas “intakes combined with chutes” along the primary canals that are used to divert the water into the secondarysmallPrefabricatwhilewatertheschemeThemaize,grownseason”,aboutseasontowater.includingbyattachedstructures,maintenancearegood77.8%
42
Do you prticipate in maintanance works?
NoYes
Perc
enta
ge o
f
40
20
0
fa
100
80
60
rmer
s
60
have you ever had any training ?
don't knownonyes
Perc
enta
ge o
f
30
20
10
0
fa
50
rmer
s
40
Figure 5. 1 Participation in maintenance works Figure 5. 2 Training aspects
5.2 Crop cultivated and water availability The dominant crop of the area grown under irrigation is rice, but other crops are cultivated according to land conditions. In not adequately dominated land, maize and sorghum are cultivated. During the three consecutive agricultural seasons, rice’s farmers confirmed that they did not get required harvest. Some of them said that the situation is due to the water shortage and other said that it may be due to the crop types. According to the responses given by interviewed farmers, 44.4% of them confirmed that irrigation water is sometimes sufficient whereas 55.6% confirmed that irrigation water is not at all sufficient as illustrated by figure 5.3. The observation made on field made us to say that the ones that confirm this sufficiency of water are the ones whose plots are situated in the head part of irrigation system. Among ntervie ed farmers, 76.2% have cultivated rice and 23.8% had cultivated other crops such as maize and sorghum the last rainy season as shown by figure 5.4.
i w
43
Is available irrigation water sufficient?
Not at allsometimes
Per
cent
age
of fa
rmer
s
60
50
40
30
20
10
0
What type of crops have you been croping?
OthersRice
Perc
enta
ge o
f far
mer
s
80
60
40
20
0
Figure 5. 3 tio Irriga n water availability Figure 5. 4 Crops under cultivation
to farmers, showed that fficient, 20.6% confirmed that
was sufficient anywhere, so far 76.2% confirmed that harvest was not at all
The analysis of the questionnaire that was administrated3.2% of them confirmed that harvest was a bit suharvestsufficient, figure 5.5. The analysis showed that all of rice crop farmers confirmed that harvest was not at all sufficient whereas other crops’ farmers confirmed that harvest was sufficient anyhow.
Is there any increase in harvest with this project?
Not at allAbitSuff icient
Perc
enta
ge o
f far
mer
s
100
80
60
40
20
0
Do you get floding problems in this scheme?
Neversometimes
Perc
enta
ge o
f far
mer
s
60
50
40
30
20
10
0
Figure 5. 5 Harvest aspects Figure 5. 6 flooding problems
44
5.3 Water availability As more farmers confirmed that the lack of productivity is due to the shortage of water, we have done the rainfall analysis. As shown on figure 5.9, the highest rainfall occurs in April (206.4mm per month) whereas the minimum is in July (21.8mm). In rainfall season we have full flow in channels, Figure 5.7 whereas in dry season some of the irrigation channels are dry (no water is flowing in the canal) Figure 5.8. Among the farmers interviewed, 55.6% confirmed that they have sometimes flooding problems (mainly in April) whereas 44.4% said that they never have such problems as shown by figure 5.6.
Figure 5. 7 Channel in Rainy season Figure 5. 8 Channel in dry season
0153045607590
105120135150165180195210225
Jan
Feb
Mar
Apr
May Jun
Jul
Aug
ept
Oct
Nov
Dec
Month
Pre
cipi
tatio
n &
Runo
ff (m
m)
S
PrecipitationRunoff
Figure 5. 9 Rain water availability in the study area (Byimana Weather station)
45
Using this rainfall information which was available in Byimana weather station for about 31 years we have calculated the volume of the reservoir required to supply the irrigation requirement in water shortage periods. From the curve of the precipitation versus the evapo‐transpiration as represented on figure 5.11 we have estimated the volume of the reservoir to be 3.1 x 106 m3. We have also estimated the water requirement for crops that can be cultivated in the dry season since it is the one in which the situation is seriously uncomfortable. As we were interested in runoff, after calculations the figure 5.4 shows the monthly precipitation and its sultant runoff in millimeters, whereas figure 5.10re
discharge shows the runoff resultant
(Qr) in liters per second.
30.0
0.015.0
45.060.075.090.0
105.0120.0135.0150.0165.0180.0
Jan
Feb
Mar
Apr
May Jun
Jul
Aug
Sept
Oct
Nov
Dec
Month
Qr (
l/s)
Figure 5. 10 Discharge due to rainfall
46
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
atio
n an
d E
vapo
trans
pira
tion
(mm
)
Jan Feb Marc Apr May Jun Jul Aug Sept Oct Nov DecMonth
Pre
cipi
t
Evapotranspiration Precipitation
Figure 5. 11 Water demand and supply in the study area (Byimana weather station)
5.4 Water requirement Using rainfall data and the crop factor for cabbage which was grown in the dry season, we have calculated the water requirement for these crops. The results obtained shows that in the third stage of its development which is the one in which more water is required, the cabbage needs 26 liters per second and is less than the available water due to the precipitations (34.9 liters per second). This shows that vegetables may be cultivated in the scheme without any stress problem in the crops. Table 5.1 shows the computation made for cabbage water
son, using available rainfall records available at weather station.
Table5. 1 Water requirements for Cabbage and Carrots
Month
P
R ETP
Kc
ETM m3/month/ha
Need (l/s)
requirement in the dray seaByimana
June 35,6 28,8 91,0 0,45 41,0 409,50 9,2July 21,8 17,7 94,7 0,75 71,0 710,25 16,0August 42,3 34,3 111,9 1,05 117,5 1174,95 26,5September 88,7 71,8 114,8 0,90 103,3 1033,20 23,3
47
With:
P: R: ETP: Kc: ETM:
the precipitation (in millimeters); the runoff (in millimeters); the evapotranspiration given by the meteorogical data (in millimeters); the the
With the same requirement since this crop during the first agricultural development stage in which need 26.5 l.s‐1, whereas the available water from precipitation is estimated to be about 90.8 l.s‐1. This shows that we will use less than what is available and this made us to suggest the construction of reservoirs to collect this excess of rain water to be used in the
tation made for of water requirement for the bean dry crop.
s dry
s)
crop factor used to determine ETM; crop evapotranspiration (in millimeters).
procedure we have determined the bean dry water is the one that have been chosen to be cultivated
season. Computations made shows that in the third it requires more water to avoid stress, the crop will
water shortage period. Table 5.2 below shows the compudetermination
Table5. 2 Water requirements for Bean
Month
P
R ETP
Kc
ETM m3/month/ha
Need (l/
June 101,4 22,3 108,8 0,35 38,1 380,8 8,6July 142,3 31,3 103,4 0,70 72,4 723,8 16August 110,0 24,2 102,0 1,10 112,2 1122,0 25September 104,2 22,9 107,3 0,30 32,2 321,9 7
,3,3,3
These data made us to conclude that available water sufficient for bean dry crop to be grown in good conditions during the first agricultural season.
5.5 Water measurement
5.5.1 Results
T ischarge in ca is trol by manually op gates. Tdischarge of the ma n rie m t to tim long wi souRugeramigozi stre a ls ng roll a div eir. On p als ar s d ren uctu as intake
he d the nals con led erated he
in ca als va s fro ime e, a th the main rce, am th t is a o bei cont ed by ersion w the
rimary can e con tructe diffe t str res such chute, and
48
intake combined with chutes. The following tables contain records for water made in Biringanya scheme respectively on 22, 24 and 29 of August
canals.
.
Site Time p (cm) P (cm) h (cm) he (cm) l=be (cm) h/p ce Q (l/s)
measurementin 2007, with weirs installed in the primary Table 5 3 Flow measurement records for day 1
August 22, 2007
S1 a.m 32,0 36,7 4,7 p.m 32,0 37,1 5,1 4,9 4,90 88 0,1531 0,6135 17,30
S2 a.m 56,5 60,5 4,0 p.m 56,5 60,8 4,3 4,2 4,15 88 0,0735 0,6075 13,59
S3 a.m 46,5 50,0 3,5 p.m 46,5 50,6 4,1 3,8 3,80 88 0,0817 0,6081 11,71
S4 a.m 46,5 50,8 4,3 p.m 46,5 50,7 4,2 4,3 4,25 88 0,0914 0,6089 14,11
S5 a.m 32,0 35,6 3,6 p.m 32,0 35,8 3,8 3,7 3,70 88 0,1156 0,6107 11,30
MS a.m 12,0 19,4 7,4 p.m ,0 ,6 6 12 19 7, 5 ,50 02 0,6 0,6489 5 7, 7 1 250 40,1
49
Table5. 4 Flow measurement records for day 2
August 24, 2007
Site Time p (cm) P (cm) h (cm) he (cm) l=be (cm) h/p ce Q (l/s) S1 a.m 32,0 36,4 4,4 p.m 32,0 37,0 5,0 4,7 4,70 88 0,1469 102,0952 16,24
S2 a.m 56,5 60,8 4,3 p.m 56,5 61,4 4,9 4,6 4,20 88 0,0814 102,0528 13,72
S3 a.m 46,5 50,4 3,9 p.m 46,5 51,2 4,7 4,3 3,80 88 0,0925 102,0599 11,71
S4 a.m 46,5 51,0 4,5 p.m 46,5 50,7 4,2 4,4 4,30 88 0,0935 102,0606 14,11
S5 a.m 32,0 36,0 4,0 p.m 32,0 36,3 4,3 4,2 3,70 88 0,1297 102,0840 11,30
MS a.m 12,0 19,5 7,5 p.m 12,0 19,9 7,9 7,7 7,50 102 0,6417 102,4157 40,14
Table5. 5 Flow surem cord 3
August 29, 2007
Site Time p (cm P (cm) h h l= )
mea ent re s for day
) (cm) e (cm) be (cm h/p ce Q (l/s) S1 a.m 32,0 36,5 4,5 p.m 32,0 37,7 5,7 5,1 5,10 88 0,1594 102,0996 18,35
S2 a.m 56,5 60,1 3,6 p.m 56,5 61,2 4,7 4,2 4,17 88 0,0738 102,0461 13,46
S3 a.m 46,5 50,1 3,6 p.m 46,5 50,5 4,0 3,8 3,80 88 0,0817 102,0511 11,72
S4 a.m 46,5 48,5 2,0 p.m 46,5 53,8 7,3 avg 4,7 4,66 88 0,1002 102,0626 15,89
S5 a.m 32,0 35,3 3,3 p.m 32,0 36,1 4,1 3,7 3,70 88 0,1156 102,0723 11,30
MS a.m 12,0 19,0 7,0 p.m 12,0 20,6 8,6 7,8 7,78 102 0,6479 102,4049 43,16
50
p:
: height of thehead of water upstreamP
h: he: l: be: ce: Q:
weir side of the weir measured from the bottom of the canal
ad o r ab wfectiv d idth o weir
ffective idth of weir fectiv ffici disc
he disc e
Table lcula arg ifferen s
Site m) (cm) Qa s)
he f wate ove the eir ef e heaw f the e w theef e coe ent of harge t harg
5. 6 Ca ted disch es in d t site
he (C l vg (l/MS 5 102 40,15 7,S1 9 88 17,30 S2 88 1S3 8 88 11,71 S4 3 88 14,71 S5 3,7 88 11,30
4,4,2 3,59 3,4,
5.5.2 Discussion
Th easu nt made in strea he dry ason i Augus have shown that discharge wit stream lies the range of 36 44. per ond an age arge 40.1 rs pe con r sdesigned to 14li second for cultivation to e grow in the normal conditions. The stream is used ot onl r irrigation, bu is a o aDrinking w pumping station. The mping dry season is king abo 23.5 according to rep delivered by e Gihuma Electrogaz pumping station. In ary l wa ppo to be cula ‐1 and ow m eme how in th ft cana there is bout 17.40 l.s‐1 which is 30.35% of it acity d in th right ther 4.11 tha o %of apac he d ence ue to linkages in th tes and the situation implies that pumping stat anno t the me it ds. The eld application o w 4. R (2000) tated that for su ace irrigation this tio sho d be between 0.60 and 0 according to rig dhereas Jurriens et al. (2001) said that it should be 0.70 for surface border strip
e m reme this m during t se n t the hin the in and 3 liters
sec with aver disch of 5 teli r e s d hew eas wait be 1 ters per rice b n
n y fo t it lso a s urce for ater pu station in ta
ut l.s‐1 the ort th tin about prim cana s su s ed cir g l.s57
n easur nts s that e le l as cap an e one e is 1 l.s‐1 t are ab ut 24.75
its c ity. T iffer is d the e ga the io cn t ge volu nee
fi rati as 0.5 ien s rf ra ul .92 the ir ation system use
w
51
irrigation system which is the one which was applied in this scheme. In Adada e found varying between 0.43 and 0.86 with mean value of 0.6 ic value
io is far below the recommended one, this shows not adequately applied in the field.
le lues of the field application ratio (efficiency)
rie
Irrig aximum attainable ratio (efficiency)
sch me this ratio was wh h falls within the acceptable range (Zerihun and Ketema, 2006). The o taatb ined for the application rat
th irrigation water is Tab 5. 7 Common maximum attainable va
(Jur ns et al., 2001).
ation water application method M
Surface tion
Furrows er leveling
other quality levelling methods
Border strip, laser level
ther quality levelling methods
evel basins, laser leveling
lling methods
0.70
0.60
0.70
0.60
0.92
0.80
irriga
, las
ing
o
L
other quality leve
Tertiary ratio was not determined since in our system there are no tertiary channels available and therefore we cannot determine how water is distributed in the field from the tertiary channels. The Overall consumed ratio was determined to be 0.47, which is so far from the half of the ideal ratio, which is one. This shows that the available fraction of water even if not sufficient is not also used to irrigate crop. The situation is clear because we know that apart from the irrigation practices, the water made available in the scheme is also used to supply the drinking water pumping station. The ratio of 0.70 for the conveyance indicates a value near to one, which indicates e capacity of the main canal to meet peak crop demand. In generalth this shows
that if water is available the channel is able to convey it from the source to the fields.
52
Note that all of the indicators were not tested since it was the dry season and farmers were using buckets to water the cropped vegetables. Therefore we cannot know exactly all of the field water delivery related ratios.
5.6 Maintenance
h e shth rks,structures was still very poor. Figure 5.12 shows problems related to poor
5.6.1 Results
T e observation conducted in the schemat they participate in maintenance wo
owed that even if farmers confirmed the maintenance of the irrigation
maintenance.
Figure 5. 12 Problems related to poor maintenance
The irrigation structures also were not in good status as shown by the number contained in table 5.8 which shows each type of structure and the number of structures that are functioning properly.
53
Table5. 8 Observed structures status
Nr of Struct Part. Funct F. funct (%) functType Intake 11 8 3 27,3Chute Intake
5 0 5 100,0 & chute 5 4 1 20,0
Diversion weir 2 0 2 100,0
0,02 0 2 100,0
Total 32 14 18 56,3
Offtake 2 1 1 50,0Culvert 3 1 2 66,7Inlet 2 0 2 10Siphon
5.6.2 Discussion
Canal capacity can indicate problems related to sediment deposits, erosion, vegetation, or possibly inadequate capacity of some structures. The discharge ratio quantifies the effective functioning of structures in the canal system.
discharge ratio was 0.3. The discharge canal, divided by its designed capacity
between
he effectiveness of infrastructure is the number of structures in good condition, ivided by the total number of structures. Poor can be defined as not functioning dequately, or at risk of failing. Ideally, this ratio should be one. Surveys made in e scheme from June to August showed that this ratio was 0.56, which shows that tructures were still existing but not functioning adequately or poorly maintained.
Measurements made have shown thatratio is the actual capacity for the selected
the
and the ideal one would be 1. This ratio varies 0.47 and 0.99 in Adada scheme with mean value of 0.75. The value of 0.3 confirms that the canal is carrying less than half of its design capacity, which confirms that irrigation water is not sufficient. Tdaths
54
Chap 6. CONCLUSIONS AND RECOMMENDATIONS
6.1 Conclusions The ab the irrigation system supply wat according the ded supply een evaluated using th delivery performance ratios. T sults obtaine ganya Irrigatio System reveal both the nabili the system ater with respect to the amount of intend wat the inabilit system to deliver according to the op water uirem The values reveal that e overall performance the tion scheme or. a) aluation using water b indicato shows th conveyance
ficiency is good with a conveyance ratio of 0.7, however, the overall nsume ratio and a plication efficiency ratio are poor wit value of 0.47
and 0.54 respectively.
nance indicators are all poor with the value of 0.56 and 0.3 for effectiveness of the infrastructure and discharge ratio respectively.
users association to facilitate their participation in the maintenance of the scheme.
ility of to er to inten has b e he red for the Birin n i ty of to supply the w ed er andy of the cr req ent. of the indicators th of irriga is po
The ev alance rs at, theefco p h
b) The mainte
6.2 Recommendations a) It is recommended that a reservoir be constructed to store excess runoff for
use during water shortage periods. b) It is also recommended that awareness be created among the farmers within
the water
55
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os M.G, M.A. Burton, and D.J. Molden.2005. Irrigation and drainage performance ssm
Bos Msecond luation (case study) Mendoza, Argentina. Irrigation and
Systems, 5: 77‐88.
CAAD ve Africa Development Program in Rwanda. NEPAD and the Republic of Rwanda.
Rwanda.
on small‐scale irrigation in Africa. AGL Miscellaneous No. 15.
Casley itoring and Evaluation in Agriculture and Development Projects. Johns Hopkins University Press.
Clyma . I IAgricu ostic Analysis. Colorado State University, Fort
Colorado.
A.R., Bautista, E., Clyma, W., Levine, D.B., Rish, S.A. and Clemmens, A.J., Diagnostic analysis of the Maricopa‐Stanfield Irrigation and Drainage District area.
n and Drainage Systems 14, 41–67.
R., 1999. Water Resource Management in Ethiopia: Issues of Sustainability and Participation. Dessalegn Rahmato and FSS. Addis Ababa.
Y., 2002. Probdrought proofing in thV Bos M. G., 1989. Discharge measurement structures. Publication 20. International Institute for Land Reclamation/ ILRI.Wageningen, the Netherlands. Bos M.G. 1997. Performance indicators for irrigation and drainage. Irrigation and Drainage Systems, 11: 119–137, 1997. Kluwer Academic Publishers. Basse ent: Practical guidelines, Colombo, Sri Lanka.
. G., Wolters W., Drovandi, A. and Morabito J. A. 1991. The Viejo Retamo ary canal‐performance eva
Drainage
P, 2007. Long‐term framework for the implementation of the ComprehensiAgricultureKigali, Carter R., 1989, NGO casebookpapers
, D.J. and Kumar K, 1987. Project MonRural
, W and Lowdermilk M., 1988. mproving the Management of rrigated lture: a Methodology for Diagn
Collins, Dedrick,2000.Irrigatio Dessalegn
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COTRA, 2005. Etudes d’Aménagement Hydroagricole et Protection des Bassins
ation water needs (by Brouer c. and e
ation System: n and Drainage Paper. No. 45. FAO, Rome
d Management: n and Drainage Paper. No. 45. FAO, Rome.
roach: Land and Water Bulletin Rome.
n S. and Rod S. (1999). Small‐scale irrigation design, Bulletin 42. WEDC
n D., Boonstra, J. and Feyen J. 2001. SURDEV: Surface Irrigation Publication 59, ILRI, Wageningen.
E Hawke’s Bay. Lincoln Environment.
EVersants pour les Marais de Rugeramigozi amont, Biringanya et Kiryango. Gitarama, Rwanda. AO, 1986. Irrigation water management: irrigF
Heibloem M.). Rom , Italy. FAO, 1989. Guidelines for Designing and Evaluating Surface IrrigIrrigatio FAO, 1992. Cropwat: A Computer Program for Irrigation Planning anIrrigatio FAO, 1997. Irrigation Potential in Africa: A Basin AppFAO, FAO, 2000. Benchmarking for irrigation systems: experiences and possibilities, (by Gonzalez F.), Rome, Italy. Hargreaves H.George and Merkley P. Gary, 1998. Irrigation Fundamentals, Water Resources Publications, LLC, Colorado. IPTRID, 2001. Guidelines for Benchmarking Performance in the Irrigation and Drainage Sector (Malano H. and Burton M.), Rome, Italy. IaLoughborough University, Leicestershire LE11 3TU. UK James L. G., 1988. Principles of Farm Irrigation System Design. John Wiley & Sons, Inc. New York. Jurriens M., ZerihuSoftware. Lesley W. 2002. Irrigation Efficiency. Irrigation Efficiency Enhancement Report No 4452/16a, March 2002 Prepared for LandWISUSA.
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Kedir Y., 2004. Assessment of small scale irrigation using comparative performance
owdermilk, M.K., Clyma, W., Dunn, L.E., Haider, M.T., Laitos, W.R., Nelson, L.J.,
1: Concepts and Methodology. Colorado State University, ort Collins, Colorado.
2003. Integrated water and land anagement research and capacity building priorities for Ethiopia. Proceedings of a
Water Management Institute), Sri Lanka, and ILRI (International Livestock Research Institute), Nairobi,
A. M. 1997. Irrigation Theory and Practice. Evaluating Land for Irrigation
(Ministry of Water, Land, Natural Resources and Environment), 2004.
(Ministry of Agriculture and Animal Resources), 2004a. Plan Stratégique
fe et emploi (Mugenga J.),
Rwanda.
. Ahmed. 1990. Manual on Irrigation Agronomy. Oxford and IBH Co. PVT. LTd. New Delhi, Bombay, Calcutta.
J., and Charlotte de Fraiture. 1998. for Comparing Performance of Irrigated Agricultural Systems. Research
y‐Rust, D. Hammond and W. Bart Snellen. 1993. Irrigation System Performance Assessment and Diagnosis. International Irrigation Management Institute, Sri Lanka.
indicators on two selected schemes in upper awash river valley. Alemaya Univerity, Ethiopia LSunada, D.K., Podmore, C.A. and Podmore, T.H. (1983) Diagnostic Analysis of Irrigation Systems, VolumeF McCornick P.G., Kamara A.B. and Girma Tadesse.mMoWR/EARO/IWMI/ILRI international workshop held at ILRI, Addis Ababa, Ethiopia, 2–4 December 2002. IWMI (International Colombo,Kenya. MichaelCommands. Reprinted Edition, Vikas Publishing House Pvt Ltd, New Delhi, India. MINITERESectorial Policy on Water and Sanitation. Kigali, Rwanda. MINAGRIde Transformation de l’Agriculture au Rwanda. Gestion et Utilisation de l’Eau et des Sols (Ngarambe V. & GECAD). Kigali, Rwanda. MINAGRI (Ministry o Agriculture and Animal Resources), 2004b. Plan Stratégique de Transformation de l’Agriculture au Rwanda. InfrastructurKigali, Mishra, R.D., MPublishing Molden D. J., Sakthivadivel R., Perry C. IndicatorsReport 20. International Water Management Institute. Colombo, Sri Lanka Murra
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Nelson D. E., 2002. Performance Indicators for Irrigation canal system managers or water users associations (updated version of a presentation at the 18th International ongress on Irrigation and Drainage, Montreal Canada).
R. and Sampath R. K. 1995. Performance measure for improving irrigation
D. H., Lamm F. R., Mahbub A., Trooien T. P., Clark G. A. Barnes P. L. and
Irrigation and Drainage 14: 207–222, 2000. (Accepted 4 May 2000).
Working Papers on Irrigation ce No.1 International Food Policy Research Institute. Washington, D. C.
e, Harare, Zimbabwe.
2001. Water measurement manual.
wa area, : Irrigation and Drainage Systems (2006) 20: 83–98; Springer 2006.
a t
C Oad, R. and Mccornick, P.G., 1989. Methodology for assessing the performance of irrigated agriculture. ICID Bulletin 38, 42–53. Oadmanagement. Irrigation and Drainage Systems, 9:357‐370. Rien B., 2000. ICID Guidelines on Performance Assessment (Working Group on Performance Indicators and Benchmarking, Report on a Workshop 3 and 4 August). Rome, Italy. RogerKyle M. 1997. Efficiencies and Water Losses of Irrigation System. Irrigation Management Series. Kansas. Samad Sanaee‐Jahromi, Herman Depeweg and Jan Feyen, 2000. Water delivery performance in the Doroodzan Irrigation Scheme, Iran.Systems Small L. E. and M. Svendsen. 1992. A Framework for Assessing Irrigation Performance. International Food Policy Research Institute Performan Sawa P. A. and Karen F., 2002. Monitoring the Technical and Financial Performance of an Irrigation Schem UNWWDR, 2003. Facts and Figures: The different water users. USBR, Zerihun Bekele and Ketema Tilahun, 2006. On‐farm performance evaluation of improved traditional small‐scale irrigation practices: A case study from Dire DaEthiopia http://www. irninja.com/worldfacts/countries/Rwanda.h m.
59
APPENDICES
ARMER’S POINT OF VIEW ON WATER USE, DISTRIBUTION, AND
ate:
A‐A.1 QUESTIONNAIRE F
MAINTENANCE OF IRRIGATION SCHEMES DSector: Land and Crops
……………………………………………………………………………………………………………………
r No
. Is the increase in the harvest?
) If No what is the main reasons?.................................
es Three times
……………………………… ……………………………………………………………………………
…………………………
...........................
……
………. ) Season C ………………………………………………………………….
1. What types of crops were you used to cultivate before this project?
……………………………………………………2. How many times were you cropping a year?......................................................... ……………………………………………………………………………………… 3. Is there increase in cultivable land afte the construction of this irrigation project?
Yes 4Yes No a) If Yes what according to you is the main reason?................ ………………………………………………………………………………………………
……………………………… b………………………………………………………………………………………………
……………………………… 5. How many times are you cultivate per year after the construction of this irrigation roject? pOne Two tima) If One why?.................................................................................................... …………………………………………………b) If Two why?......................................................
…………………………………………………………………………………………………………………………………… c) If three why?..........................……………………………………………………………………………… ……………………………………………………………………………… 6. What types of crop do you cultivate each season? a) Season A…………………………………………………………… ………………………………………………………………….
b) Season B…………………………………………………………………. …………………………………………………………c
60
………………………………………………………………….
. Are these crops your own choice?
......................................................... ……………………………………………………………………………………………
) The government ) The association
onor (NGOs)
.........................
…………… ……………… ions?.................................................
………………………………………………
our plot(s)? The Governm
s)
hat are the conditions for allocation a plot?......................................................... ……………
…………
If No w ..........................................
7Yes No 8. If Yes why did you choose to grow it?............…
……………………………………………………………………………… 9. If No who makes the choice for you?abc) The d 10. Are you working in associations? Yes No 11. If No what are the reasons?..........................................................……………………………………………………………………………………… 12. If Yes what are the conditions to be approved as a member of an association?………………………………………………………………………………………………
……………………………………………… …13. What are your interests of working in associat…………………………………………………………………………
…… ……………………………………………… 14. How many plots do you have?.................................................................................. 15. Who has allocated you ya) ent b) The association c) The donor (NGOd) My father 16. W…………………………………………………………………………………
…… ……………………………………………………………… 17. Is the way in which plots are allocated fair? Yes No 18. hat should be done?............................................……………………………………………………………………………………… Water distribution and maintenance 19. Apart from irrigation water, which other purposes is this water source used for?
a) Drinking water
b) Usage in earthenware (e.g brick making)
c) Washing
d) Uncontrolled livestock feeding on irrigated crops
61
If any other purpose specify it…………………………………………….. …………………………………………………………………………….. 0. Does the use of this stream in livestock watering have any negative (if it is there) pact to the scheme?
No
stru s
wat r irrigation
n
munity wo muganda)
s/
maintenance of the irrigation scheme?
........ ……………………………………………………………………………………
........................................................................... 7. Do you use water for supplementary irrigation (During the rainy season)?
. If No why?................................................................................................................. …………………… ……………… . If yes, is the ava g the r season? Yes No . Is the available
2im Yes If yes what are they? a) They eat up the irrigated crops
b) They damage irrigation canals
c) They damage irrigation cture
d) They reduce amount of er fo
e) They cause land degradatio
Others/specify………………………………………………………………………………
………………………………………………………………
21. Do you have any personal water storage facility in your farm? Yes No 22. If yes where is it located?......................................................................................... …………………………………………………………………………………........ 23. How is the maintenance of the irrigation scheme done?
a) By members of associations
b) By the government
c) Using com rk (U
d) By donors
Other specify ……………………………………………………………..
………………………………………………………………………………
24. Have you ever participated in Yes No 25. If No why?.........................................................................................................…26. If yes how many times a month?....2 Yes No 28… ………………………………………………29 ilable water sufficient for cultivation durin ainy 30 water enough for cultivation during the dry season?
62
Yes No 31. If No what do you think should be done to increase it?............................................ ………………………………………………………………………………………………
o you have problems of flooding in this scheme? No
What a ces made in the hilly side of this hland?................................................................................................................................
What a crops ar ng? oding
ater to the cr
............................................ … …………
ution in this
… … …………………
. Have you ever h s farmers in the marshland?
. If yes who traine government institue association
……………………………………………………………………………………..
…
…
……………………………………………………………………………… 32. DYes 33. re you benefiting from these terra
mars.......................................................................................................................... 34. re canals related problems that your e facia) Water exceeds in rainy season and causes flob) Some of them are destroyed c) Some of them do not conduct w ops 35. Does water flow reach your plot sufficiently when it is available? Yes No 36. If No what do you think should be done?.....................…… …………………………………………………………………
and distrib37. Do you have any particular wish related to water usemarshland? Yes No
………………………38. If yes say it………………………………………………… ………………… ……………… ……………………………
39 ad any training on irrigation a Yes No 40 s you? Th tion ThThe Donors a) What subjects did they insist on?.
……………………………………………………………………………… b) What did you benefit from it?............................................
…………………………………………………………………………………………………… …………………………………………………………….. 41. What do you think your training should emphasized on?................................ …… ………………………………………………………………………………………
………………………………………………………………………………………
Thank you very much
63
Table A.2 Rainfall records Meteorological Station of Byimana 1960 – 1990
Geographic coordinates: 29°44’E, 2°11’S
Altit e :1750m ud
Year Jul Aug Sept Oct Nov Dec P(mm) Jan Feb Mar Apr May Jun 1960 2.2 71.7 45.2 969.711 97.6 137.3 273.7 39 1.6 3.5 25.2 52.5 110.2 1961 .3 1233.8 69.3 121.2 150.9 96.5 99.2 2.1 7 0.8 120.7 144.6 222.2 1991962 4.2 131.1 1412.2 168.5 31.4 130.4 123.2 199.3 15.5 18.4 93.4 104.4 272.4 121963 7.4 33.7 110.8 205.9 155016 99.9 80.2 205.7 408.4 47.5 0 43.8 146.71964 83.4 162. .5 13 4.6 70.4 1227.85 106.5 272 68.7 42.3 66 22.1 44 4.8 141965 87.9 6 8 0 42.5 103.7 11 6.4 48.1 1143.49 102.4 282.9 141 1.5 141966 30.7 164. 72.2 65 136.4 65.2 1062.45 163 179.8 61.9 22.7 0 100.8 .2 1967 40 30.9 143.4 193.9 1244.6 63 111.3 169.3 283.6 47.4 24 7.8 1301968 67.8 8.8 0.2 36.7 65.4 170.6 96.1 1238.7128.1 171.8 213.8 187.8 91.61969 8.9 4.2 838.48 85.7 123.1 131.7 135.4 1.4 0.3 0 65.5 65.3 106.9 41970 69.2 64.4 1363.7265.2 152.7 170.9 232 56.3 19.7 17.3 56.2 56.8 103 11971 2 121.2 1182103.7 132.3 80.8 193.3 197.6 0 16.8 126.6 51.6 42.9 115.1972 2 115.5 0 35 52.2 106.9 223.4 83.4 1160.4 63.3 225.2 68.3 84 103.1973 73.1 1379.185.5 104.2 84 258.9 232.7 4.7 0 38.4 204.8 105.3 189.51974 5.4 1252.288.5 32.6 276.5 173.3 202.4 105.9 87.9 7.8 84.7 34.5 121.7 51975 160.5 1276.713 82.6 73.9 231.8 142.7 3.4 52.4 14.6 136.2 151.1 6.5 921976 .3 82.5 101684.9 99.6 113.9 118.5 143.6 31.5 0 82.6 90 94.6 741977 7.2 5.5 66.3 119.3 121.7 161.6 109.2 1235.711 87.2 105.4 237.6.3 4 98.61978 3 12 22 0 39.5 37.1 55.4 106.1 106.9 1115.2125.2 85.1 237.1 17 7.81979 6 234.7 52.3 0 21.5 5.5 28.8 140.9 129.9 1196.9210.1 150.3 36.3 186.1980 86.2 204.5 160.1 3.8 0 8.9 153.6 110.4 182.9 122.5 1211.781.9 96.9 1981 62.2 69.7 150.2 186.9 17 0.2 0 148.8 107.5 79.7 82.4 77.4 1119.24.21982 68.2 83. 6.1 89.9 89.1 183.6 240.9 1299.83 45.3 247.5 224.6 41.3 01983 .7 177.4 151.4 1266.8 12 200.7 131.4 283.7 70.5 3.3 18.6 36.7 46.4 1241984 .9 993.878 88 97.5 181.5 26 0.2 65.9 42.2 24.9 171.6 149.1 681985 83 126. 16.5 157.9 143.3 1333.47 163.7 263.9 65.8 30.6 0 0.2 181.8 11986 0.1 1541.9 169.6 155.4 128 412.8 183.6 51.2 0 25.1 43.1 145.5 97.5 131987 7 163.3 344.3 80.8 1778.7 153.1 226.6 111.5 190.5 220.7 87.4 0 32.8 167.1988 0.3 56.1 1249.17 172.3 216.6 218.4 113.1 4.6 0.3 105.4 91.7 97.4 102.91989 4 1325.7143.5 160.5 190.5 220.4 153.5 53.9 21.1 57.9 38.9 76.9 65.2 143.1990 5 110.3 1075.4 65.9 120.9 191.3 187.2 59.2 0 0 24.4 88.9 90.8 136.
Average 104.2 120 131.6 206.4 146.8 35.6 21.8 42.3 88.7 101.4 142.3 110 1235
64
Table A.3 Climatic parameters
TeC)
R M
d /
ine hr
E
(mm
ip)
P. e=0
ff - )
BYIMANA meteorological station Altitude : 1750 m Coordinate : 29° 44’ E, 2° 08’ S
Month mp. (°
elativeoisture
%
WinSpeed Km h
Sunsh /d
TP mens.
)
Prec . (mm
ffic. (K .81)
P.e ETP (mm
Janu 9 77 107 ary 1 5.6 .3 105 85 -22.3 Feb 9. 78 92. 9 .1 ruary 1 2 5.6 5 119. 97 4.6 March 19.1 79 5.5 111 6 6. .2 131. 10 6 -4.6 Apri 8. 82 96 4 7. l 1 8 3.8 .1 206. 16 2 71.7May 8.5 80 86.5 6 7. 1 5 145. 11 9 31.4June 7. 68 91 .8 1 9 7.2 35.6 28 -62.2 July 7.8 61 7 94.7 .6 1 21.8 17 -77.1 Aug 8. 59 111 .3ust 1 7 6.8 .9 42.3 34 -77.6 Sept 9.1 66 11 .8 ember 1 6.4 4.8 88.6 71 -43 Octo 8.9 72 6. 108 1 .9 ber 1 1 .8 101. 81 -26.9 Nov 8.5 81 103. 3 5. ember 1 5.2 4 142. 11 3 11.9Dec 8.5 79 5 102 .9 -12.1 ember 1 .5 111 89 YEA 8.7 73 122 .2 13 .8 R 1 5-6 0.2 1251 10 .4 -206
65
Table A.4 Calculated discharge from rainfall
onth P (mm) R (mm) Peff (mm) Vp (m3) Vr (m3) Qr (l/s)
M
Jan 8 1 4 ,3 6,0104,2 22,9 4,4 01282 222821 8Feb 9 1 0 8,0 0
Mar 131,6 29,0 106,6 1279152 281413,4 108,6
Apr 206,4 45,4 167,2 2006 170,3
May 146,4 2,2 11 1 1,8
Jun 35,6 7,8 2 7,0 29,4
Jul 21,8 4,8 17,7 7,1 18,0
Aug 42,3 9,3 3 56 4,3 34,9
Sept 88,7 9,5 7 73,2
ct ,4 2,3 8 83,7
Nov 142,3 1,3 11 1 4,3 117,4
c 110,0 4,2 8 1 00 24,0 90,8
120,0 26,4 7,2 16640 25660 99,
208 441365,8
3 8,6 423008 31306 120,8
8,8 346032 7612
211896 4661
4,3 4111 9045
1 1,8 862164 189676,1
O 101 2 2,1 985608 216833,8
3 5,3 383156 30429
De 2 9,1 0692 2352
66
Table A.5 Values of the Crop factor (Kc) for various crops and growth stages
Crop Initial s
Crop dev.
Mid-season ge
ate season s
tage stage staL
tage Barley/Oats/W 0.3 .15 0.45 heat 5 0.75 1Bean, green 0.3 .10 0.95 0.70 1 0 Bean, dry 0.3 .10 05 0.70 1 .30 Cabbage/Carro 0.4 .05 0.90 t 5 0.75 1Cotton/Flax 0.4 .15 0.75 5 0.75 1Cucumber/Squash 0.45 .90 0.75 0.70 0Eggplant/Tomato 0.45 .15 0.80 0.75 1Grain/small 0.35 .10 0.65 0.75 1Lentil/Pulses 0.45 0.75 1.10 0.50 Lettuce/Spinach 0.45 0.60 1.00 0.90 Maize, sweet 0.4 .15 1.00 0.80 1 0 Maize, grain 0.4 .15 00 0.80 1 .70 Melon 0.4 .00 0.75 5 0.75 1Millet 0.35 0.70 1.10 0.65 Onion, green 0.50 0.70 1.00 1.00 Onion, dry 0.50 0.75 1.05 0.85 Peanut/Groundnut 0.45 0.75 1.05 0.70 Pea, fresh 0.45 0.80 1.15 1.05 Pepper, fresh 0.35 0.70 1.05 0.90 Potato 0.45 0.75 1.15 0.85 Radish 0.45 0.60 0.90 0.90 Sorghum 0.35 0.75 1.10 0.65 Soybean 0.35 0.75 1.10 0.60 Sugar beet 0.45 0.80 1.15 0.80 Sunflower 0.35 0.75 1.15 0.55 Tobacco 0.35 0.75 1.10 0.90 Source: (FAO, 1986)
