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Author: C. J. Jayatilaka
Publisher: IWMI
ISBN: 9290904224
Category : Irrigation
Languages : en
Pages : 50
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Book Description
Better water management in irrigation tank cascade systems is vital in achieving higher productive use of available water. To develop and implement management practices aimed at improving effective use of water, studies leading to the development of models that can predict available tank water in irrigation tank cascade systems are invaluable. This report presents a simple water balance model, Cascade, developed to predict tank water availability in the Thirappane tank cascade system in Anuradhapura, Sri Lanka. The report includes calibration of the model and its application to predict tank water availability for rice crops over a 10-year period.
Author: C. J. Jayatilaka
Publisher: IWMI
ISBN: 9290904224
Category : Irrigation
Languages : en
Pages : 50
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Book Description
Better water management in irrigation tank cascade systems is vital in achieving higher productive use of available water. To develop and implement management practices aimed at improving effective use of water, studies leading to the development of models that can predict available tank water in irrigation tank cascade systems are invaluable. This report presents a simple water balance model, Cascade, developed to predict tank water availability in the Thirappane tank cascade system in Anuradhapura, Sri Lanka. The report includes calibration of the model and its application to predict tank water availability for rice crops over a 10-year period.
Author: Rajib Shaw
Publisher: Emerald Group Publishing
ISBN: 184950699X
Category : Political Science
Languages : en
Pages : 210
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Book Description
Water is the key to human civilization. Most of the ancient civilization had its roots to river basins, where people-water interaction was the key aspect. This book offers analytical case studies on different aspects of water communities, which is defined as the human-water interaction process.
Author: Felix P. Amerasinghe
Publisher: IWMI
ISBN: 9290904615
Category : Irrigation
Languages : en
Pages : 37
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Book Description
Thousands of small irrigation reservoirs (tanks) exist in rice ecosystems in malarious regions of south Asia. The potential of these tanks to generate malaria-transmitting mosquitoes has not been adequately evaluated. Through a study of nine small irrigation tanks in north-central Sri Lanka, this report provides an assessment of the capacity of tanks to generate malaria and nuisance mosquitoes, factors that contribute to mosquito generation, and measures that could ameliorate the problem.
Author: Philipp Stanzel
Publisher: IWMI
ISBN: 9290904852
Category : Irrigation projects
Languages : en
Pages : 63
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Book Description
The extension of the Uda Walawe irrigation scheme in southern Sri Lanka may have a significant ecological impact on the development area and its downstream wetlands. The evaluation of this impact is the subject for a long-term study that is presently being carried out by the International Water Management Institute (IWMI). In this study, the pre- development environmental conditions in the area are being investigated and the changes caused by the new irrigation system will be monitored in the future. Part of this study is a hydrological assessment of the coastal lagoon (Karagan Lewaya) and its small catchment to the south of the evelopment area. The lagoon is likely to receive high quantities of drainage flows from the future scheme. This could deteriorate its water quality and hence affect the suitability of the lagoon as a habitat for migratory birds and might lead to flooding of adjacent settlements.
Author: B. Albinson
Publisher: IWMI
ISBN: 9290904712
Category : Farms, Small
Languages : en
Pages : 30
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Book Description
Smallholder irrigation systems–where farm sizes generally range from a fraction of a hectare to 10 hectares–pose special management problems, especially where the water available for irrigation is frequently less than the demand. The intensity of system adjustments required to meet individual farmer demands, and the administrative complexity of measuring and accounting water deliveries have generally proven excessive when attempting to meet “on demand†schedules, resulting in chaos (often characterized by illegal tampering with infrastructure, and vast differences of water use intensity at different locations in the system). The alternative–provision of a simple service, based on proportional sharing of available supplies on the basis of landholdings–has been resilient for many years over vast areas. The approach is based on a clear delineation between the part of the irrigation system that is actively managed (at various flow rates and water levels) and the part of the system that operates either at full supply level (with proportional division of water down to the level at which farmers rotate among their individual farms), or is completely shut. This operational design is known as a “structured†system, and has well-defined hydraulic characteristics, simplifying operation and management, in turn allowing a clearer definition of water entitlements and the responsibilities of agency staff and farmers. The approach is particularly suited to areas where water is scarce and discipline is needed to ration water among users. An additional benefit, which has been demonstrated in modeling studies using a well–proven model relating to water and yield, is that the productivity of water (which is more important than the more traditional productivity of land when water is scarce) is substantially increased when deficit irrigation is practiced–a widely observed and predictable response to rationed water supplies. Structured systems are most suited where water is scarce, clear definition of water entitlements is needed, management capacity is limited, and investment resources are limited. The approach to determining critical aspects of a structured system design is described in this report.
Author: Tushaar Shah
Publisher: IWMI
ISBN: 929090481X
Category : Farms, Small
Languages : en
Pages : 33
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Book Description
This report reviews several decades of global experience in transferring management of government-run irrigation systems to farmer associations or other nongovernmental agencies in an attempt to apply the lessons of success to the African smallholder irrigation context.
Author: Barbara C. P. Koppen
Publisher: IWMI
ISBN: 9290904801
Category : Farms, Size of
Languages : en
Pages : 36
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Book Description
A growing body of evidence on the impacts of irrigation management transfer (IMT) shows that IMT risks aggravating rural poverty. For governments that aim to continue irrigation management while ensuring that it contributes to poverty alleviation, a "pro-poor" mode of IMT needs to be designed and implemented. That is, a mode of IMT that benefits poor farmers while benefiting non-poor farmers equally, or perhaps to a lesser degree. The present research explores the scope for pro-poor modes of IMT in canal irrigation, focusing on large-scale canal irrigation schemes in India.
Author: Barbara Van Koppen
Publisher: IWMI
ISBN: 9290904682
Category : Irrigation
Languages : en
Pages : 52
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Book Description
Although gender issues are today a priority on the agendas of irrigation policy makers, interventionists, farm leaders and researchers, there is still a considerable gap between positive intentions and concrete action. An important but hitherto ignored reason for this is the lack of adequate generic concepts and tools that are policy-relevant and can accommodate the vast variation in irrigation contexts worldwide. The Gender Performance Indicator for Irrigation (GPII) aims to fill this gap. In any particular scheme, this tool diagnoses the gendered organization of farming and gender-based inclusion or exclusion in irrigation institutions. It informs irrigation agencies what they themselves can do for effective change-if necessary. The tool also identifies gender issues beyond a strict mandate of irrigation water provision. The Indicator was applied and tested in nine case studies in Africa and Asia. The research report presents the underlying concepts, methodological guidelines and selected applications of the GPII.
Author: C. J. Perry
Publisher: IWMI
ISBN: 9290904275
Category : Irrigation
Languages : en
Pages : 26
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Book Description
nadequate funding for maintenance of irrigation works and emerging shortages of water are prevalent. The use of water charges to generate resources for maintenance and to reduce demand is widely advocated. Examples from other utilities, and from the domestic/industrial sectors of water supply suggest the approach could be effective. In developing countries, the facilities required for measured and controlled delivery of irrigation are rarely in place, and would require a massive investment in physical, legal and administrative infrastructure. To be effective in curtailing demand, the marginal price of water must be significant. The price levels required to cover operation and maintenance (O&M) costs are too low to have a substantial impact on demand, much less to actually bring supply and demand into balance. On the other hand, the prices required to control demand are unlikely to be within the politically feasible range. Furthermore, water supplied is a proper measure of service in domestic and industrial uses. But in irrigation, and especially as the water resource itself becomes constrained, water consumption is the appropriate unit for water accounting. This is exceptionally difficult to measure. An alternative approach to cope with shortage would focus on assigning volumes to specific uses–effectively rationing water where demand exceeds supply. This approach has a number of potential benefits including simplicity, transparency, and the potential to tailor allocations specifically to hydrological situations, particularly where salinity is a problem. Data from Iran are presented to support these contentions.
Author: Mary E. Renwick
Publisher: IWMI
ISBN: 9290904399
Category : Fisheries
Languages : en
Pages : 43
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Book Description
Although irrigation projects often provide water for more than crop irrigation, water allocation and management decisions often do not account for nonirrigation uses of water. Failure to account for the multiple uses of irrigation water may result in inefficient and inequitable water allocation decisions. Decision-makers often lack information on the relative economic contributions of water in irrigation and nonirrigation uses. This report addresses this problem. It examines the relative economic contributions of irrigated agriculture and reservoir fisheries in the Kirindi Oya irrigation system, located in Southeastern Sri Lanka. The results of the analysis indicate the importance of both irrigated paddy production and reservoir fisheries to the local economy. They also demonstrate significant potential financial and economic gains to irrigated agriculture from improvements in water management practices. Since these water uses are interdependent, policy makers must consider how changes in water management practices may affect reservoir levels and water quality and the fisheries that depend on them.
