Reality of irrigation water use and suggestions for better management: a comparison of two schemes from Sri Lanka

摘要

In the dry zone of Sri Lanka, where agriculture is the main livelihood, both farmers and water managers target the best use of water. System H is an area that had been developed for irrigated agriculture using diversions from the River Mahaweli. Study of water use practices was carried out in two irrigation schemes where farmers cultivate the same crop in one-hectare allotments under the support and supervision of the same regional authority. Records of water use and agriculture are not well maintained. Using field visits, discussions with farmers, and meetings with officials were used to fill data gaps and three water issue scenarios were compared. Results of each scheme varied because water release and rotation practices for crop growth are quite different from each other, canal efficiency assumptions are different, land preparation, water use and quantity are dissimilar, and water releases do not consider much about growth stages. The study indicated that use of challenging water issues considering co-ordinated and rational grouping of canals could lead to a saving of 10-30 cm of water per unit area. A discussion of the need for a critical evaluation of guidelines and the present practice of cultivation is included. [References: 4]