Participatory irrigation management for efficient water use and enhanced rice productivity in Tamil Nadu, India

Abstract

Rivers, lakes, and wells are the main sources of irrigation water in India. The country has exploited its rivers as efficiently as possible during the last five decades. The number of dams constructed has increased from less than 300 in the 1960s to 4,300 today. The number of major and medium irrigation projects increased considerably during the 1960-95 planning periods. In spite of the impressive buildup of water resources, current per capita availability of water in India is only 2,200 m3, compared with 65,000 m3 in Japan and 62,000 m3 in the U.S. With increasing population, per capita availability of water in India may even be halved by 2025. In addition, poor transmission of water (50% wastage) is responsible for the sub-optimal operation of many irrigation projects, resulting in low efficiency (<35%) of a few major projects. The tank-irrigated area of 3.56 million ha in 1975 has now been reduced by 22% because of improper maintenance and siltation of tanks. Overexploitation of groundwater is also posing serious water-use problems for agriculture and other sectors. Data from the United Nations Development Programme (UNDP) show that rice output per liter of water was 0.5-0.7 g at research stations but only about 0.2 g in farmers' fields, suggesting a potential to develop and pro- mote improved technologies for efficient water manage- ment in irrigated agriculture.