IRRIGATION EFFICIENCY IN THE DRY ZONE IN SRI LANKA

Abstract

Water resource economists and policy makers have suggested that by 2030 one third of the world population will be based along river basins and the scarcity of the water for agriculture will have a tremendous impact on their livelihood. In many parts of the country, productivity of paddy is below the potential level due to insufficient irrigation water and in the Yala season (Dry season) only 30 percent of cultivable irrigated paddy land could be used for growing due to lack of water. This study attempts to determine the actual usage of irrigation water at different water risk in the dry and wet seasons in large scale irrigation schemes in the dry-zone of Sri Lanka. Primary data were obtained from 360 paddy farm plots from Rajanganaya, Nachchaduwa and Huruluwewa irrigation schemes covering upstream and downstream farmers.Daily actual water usage at plot level measured by volumetric method. Under this method water is collected in a container of known volume and the time taken to fill the container is recorded. According to our study, on average, in the wet (Maha) season upstream farmers of Rajanganaya have used 4.8-acre feet (5921 cubic meter) and Huruluwewa upstream farmers 4.2-acre feet (5181 cubic meter) for paddy farming. Though water usage of Raganganaya farmers were 14% higher than that of Huruluwewa farmers in the wet season,the productivity variation was insignificant between two farmer groups.However, the downstream disparity of water usage in the dry season (Yala season) is much higher than the wet season. In the dry season, downstream farmers of Rajanganaya have recorded 5.7-acre feet and Huruluwewa downstream farmers have managed with 3.2-acre feet due to scarcity of water in the dry season. The present study suggests that collectivism is the most suitable way of common pool resource management rather than individualism, which is inorporated with the market mechanism.