Performance assessment of irrigation system plays a vital role for improvement of the future functioning of the system. This study was conducted to assess water delivery performances and to determine water conveyance loss in the gravity irrigation system that serves the irrigation area. Primary data were collected from fields by measuring the flows and questionnaire survey was conducted in order to get valuable information from the users. The velocity of the canals was measured by current meter

more »

... and float methods. Secondary data were collected from Chagni Metrological Station and other data from respective government offices and NGOs. CROPWAT software was used to calculate crop water requirement. The water delivery performance of the irrigation system was evaluated using adequacy, efficiency, dependability, and equity. The computed values of adequacy, efficiency, dependability, and equity were 0.78, 0.81, 0.27 and 0.28 respectively. This shows that adequacy, dependability, and equity of the system were poor but the efficiency of the irrigation system was fair. Annual relative water and irrigation supply were also used for indicating the adequacy of the supply. The results show that the annual water and irrigation supply in Buchiksi irrigation system was adequate with values of 3.6 and 2.4 respectively. In this study the conveyance losses at the off-takes were determined. The water conveyance loss at the main canal level was between 11.76% (0.267l/s/m) to 25% (0.44l/s/m). At the secondary canal level, the conveyance losses were between 8% (0.20 l/s/m) to 55.56% (0.1l/s/m). This result shows that the average conveyance loss increases from head to tail reaches in both main and secondary canals. The values of water surface elevation ratio, sustainability of irrigated area and effectiveness of infrastructure were found to be 87, 80.5 and 73.5 percent respectively. This reveals that, maintenance and operation work on the irrigation system were not sufficient. T [...]