Multiple uses in water in irrigated areas : a case study for Sri Lanka

Other productive uses include fishing, harvesting of aquatic plants and animals, and a variety of other enterprises such as brick making. In addition, irrigation systems can have a positive or negative effect on wildlife habitats. The withdrawal of irrigation water thus affects the rural household, rural economy, and the environment in a number of ways. This paper argues that to ensure efficient, equitable, and sustainable water use, irrigation and water resources policies need to take into account all uses and users of water within the irrigation system. The multiple uses of water in the Kirindi Oya irrigation system are examined in terms of water accounting, water quality, household water use, the valuing of water for alternative uses, and the complementarities, competition, and conflicts among uses and users. Among the various management issues and problem areas identified, the allocation of irrigation water, particularly in periods of scarcity, is perhaps the most critical and the one that has provoked considerable conflicts in the past. The most appropriate water level to be maintained in the tanks is another critical decision, with evidence to suggest that improved management of the tank systems in the wet season could lead to savings of water and expansion of irrigated area in the dry season. Finally, the study highlights the importance of water quality not only for domestic use but also for fishing and wildlife. Because of the complexity of the issues involved, the results of this study are only a first step in developing a suitable methodology for studying the range of uses and interactions among them. While the exact uses and users of water and their relative importance will vary from one irrigation system to another, the issues identified in this pilot study of Kirindi Oya have broader implications for water management policies in Sri Lanka and elsewhere. These relate to the allocation of water between irrigation and other sectors; measures of water quality and efficiency of use; and mechanisms to involve all stakeholders in negotiations over water allocation and use. (Author abstract, modified)