Irrigation Scheme Operation and Maintenance is the tenth in the series of training manuals on irrigation prepared jointly with ILRI (International Institute for Land Reclamation and Improvement). The manual presents some of the difficulties that irrigation organizations confront in undertaking their duties and provides some orientations on how to resolve them. The paper then proceeds to discuss the methods of operating an irrigation network and the working principles involved. The maintenance tasks are discussed. To draw similarities and differences the maintenance of a motorcycle is used as a reference for the corresponding activities in an irrigation scheme. Finally, a reference is made to the need for having an effective financial control whereby the management of the system has enough resources to undertake the operation and maintenance tasks. The manual is addressed to small and medium schemes and assumes that the management organization is already in place.

Initially associated with hi-tech irrigated agriculture, drip irrigation is now being used by a much wider range of farmers in emerging and developing countries. This book documents the enthusiasm, spread and use of drip irrigation systems by smallholders but also some disappointments and disillusion faced in the global South. It explores and explains under which conditions it works, for whom and with what effects. The book deals with drip irrigation 'behind the scenes', showcasing what largely remain 'untold stories'. Most research on drip irrigation use plot-level studies to demonstrate the technology’s ability to save water or improve efficiencies and use a narrow and rather prescriptive engineering or economic language. They tend to be grounded in a firm belief in the technology and focus on the identification of ways to improve or better realize its potential. The technology also figures prominently in poverty alleviation or agricultural modernization narratives, figuring as a tool to help smallholders become more innovative, entrepreneurial and business minded. Instead of focusing on its potential, this book looks at drip irrigation-in-use, making sense of what it does from the perspectives of the farmers who use it, and of the development workers and agencies, policymakers, private companies, local craftsmen, engineers, extension agents or researchers who engage with it for a diversity of reasons and to realize a multiplicity of objectives. While anchored in a sound engineering understanding of the design and operating principles of the technology, the book extends the analysis beyond engineering and hydraulics to understand drip irrigation as a sociotechnical phenomenon that not only changes the way water is supplied to crops but also transforms agricultural farming systems and even how society is organized. The book provides field evidence from a diversity of interdisciplinary case studies in sub-Saharan Africa, the Mediterranean, Latin America, and South Asia, thus revealing some of the untold stories of drip irrigation.

Calculation of crop evapotranspiration; Selection of crop coeficient; Calculation of field irrigation requirements.

In the context of improving water productivity, there is a growing interest in deficit irrigation, an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. Under conditions of scarce water supply and drought, deficit irrigation can lead to greater economic gains than maximizing yields per unit of water for a given crop; farmers are more inclined to use water more efficiently, and more water-efficient cash crop selection helps optimize returns. However, this approach requires precise knowledge of crop response to water as drought tolerance varies considerably by species, cultivar and stage of growth. The studies present the latest research concepts and involve various practices for deficit irrigation. Both annual and perennial crops were exposed to different levels of water stress, either during a particular growth phase, throughout the whole growing season or in a combination of growth stages. The overall finding, based on the synthesis of the different contributions, is that deficit or regulated-deficit irrigation can be beneficial where appropriately applied. Substantial savings of water can be achieved with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behavior is required, as crop response to water stress varies considerably.

This report contains a collection of papers from a workshopâ€"Strengthening Science-Based Decision-Making for Sustainable Management of Scarce Water Resources for Agricultural Production, held in Tunisia. Participants, including scientists, decision makers, representatives of non-profit organizations, and a farmer, came from the United States and several countries in North Africa and the Middle East. The papers examined constraints to agricultural production as it relates to water scarcity; focusing on 1) the state of the science regarding water management for agricultural purposes in the Middle East and North Africa 2) how science can be applied to better manage existing water supplies to optimize the domestic production of food and fiber. The cross-cutting themes of the workshop were the elements or principles of science-based decision making, the role of the scientific community in ensuring that science is an integral part of the decision making process, and ways to improve communications between scientists and decision makers.

Introduction about what this manual is covering concentrating on Large Scale Irrigation (LSI), diversion barrage or weir, intake (with auxiliary structures), and most common conveyance structures suitable for LSI. A very brief overview of an approach to match water needs with water availability (demand vs supply) with references and links to Food and Agriculture Organization (FAO) literature that is covering the topic in detail. A brief reference to the most common methods to obtain necessary hydrological parameters for IRR scheme design. A very brief overview of the importance of knowledge of geological conditions and the investigation needed to obtain geotechnical design parameters (including the most common geotechnical tests to obtain design parameters). Planning phase considerations regarding diversion and intake structure, discussing the role of the main components. More technical discussion on each component of the weir or intake, including formula and worked examples (hydraulic and structural computations). Conceptual, hydraulic, and structural considerations of main conveyance components, with emphasis and more detail on most used components (such as canals, siphons, aqueducts, retaining walls, etc.). A very brief overview of the approach to irrigation water management and Operations & Maintenance (O&M), with references and links to FAO literature that is covering the topic in detail. Standard specification for irrigation construction material.

In December 2002, a group of specialists on water resources from the United States and Iran met in Tunis, Tunisia, for an interacademy workshop on water resources management, conservation, and recycling. This was the fourth interacademy workshop on a variety of topics held in 2002, the first year of such workshops. Tunis was selected as the location for the workshop because the Tunisian experience in addressing water conservation issues was of interest to the participants from both the United States and Iran. This report includes the agenda for the workshop, all of the papers that were presented, and the list of site visits.

Introsuction; Performance indicatores for comparison; Features of the selected indicators; The indicators; Application; Temporal and spatial variation of indicators within a project; Limitations of the indicators; Interpretation of results; Discussion; data requirements to calculate performance indicators; Calculation example of performance indicators; World markrt prices of agricultural; products in constant 1995 dollars.