IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS OF SCIENCE IN IRRIGATION AND DRAINAGE ENGINEERING

Abstract

Performance evaluation of irrigation system and irrigation scheduling are very important to conserve the scarce resource of water through improving the performance of the existing irrigation schemes. Effective and efficient use of the available water is very crucial to practice irrigation in the area in sustainable manner. The objective of this study was to assess and evaluate surface irrigation system performance and irrigation scheduling using different performance indicators. To undertake this study, primary data like discharge measurements in the canals, field observations, water surface elevation measurement and determination of physical properties of soil were collected, and secondary data such as climatic, agronomical, command area, and irrigated area were collected from secondary sources. Besides that, the causes for malfunctioning structures were investigated through field observation and discussion across irrigation team, cane plantation team and contract administration team. The data were collected to determine the conveyance efficiency, the status the irrigation infrastructure, irrigation scheduling and other determinant indicators for performance. The average conveyance efficiency of the tertiary and field canals of the study area were 79.08% and 70.2%, respectively. The values of average condition of earthen canals, Infrastructures and Hand lifted gate are 76.86%, 86.73% and 78.58%, respectively. The irrigation scheduling based on the actual efficiency was recommended with respect to growing month and stage of growth sugar cane crop. Currently the study area is implementing an irrigation interval of 8-20 days for all soil type, growing month and stage of growth. The determined irrigation interval of the study area obtained for germination, initial, development and late stage vary with their growing month and averagely 5, 9, 10, 13, and 22 days, respectively. In general, it can be concluded that Tana Bales surface irrigation scheme needs improvement and measures should be taken to advance the performance of the scheme. As night storage is implemented, the scheme has a possibility to expand coverage area of surface irrigation