PERFORMANCE EVALUATION OF ALIFIF MEDIUM SCALE IRRIGATION SCHEME IN EAST HARARGHE

Abstract

Ethiopia is one of sub-Saharan Africa country, in which rain-fed agriculture is the mainstay of the rural population. One of the challenges Ethiopia is facing in attaining food security and reducing poverty is high dependence on rain fed agriculture. To achieve food self-sufficiency, use of the available water resource for irrigation development is the most promising option. The Alfif irrigation project operates under a low level of performance due to poor water management and lack of timely maintenance of structures.The aim of this research was to evaluate the performance of the Alifif irrigation scheme using performance indices such as application efficiency (Ea), conveyance efficiency (Ec), storage efficiency (Es), distribution uniformity (DU) and outputs per units of land and water used. Overall activities in primary data collected included: field observation, interviewing beneficiary farmers, discharge measurements in the canals, determination of moisture contents of the soil before and after irrigation, determination of soil physical properties and measurement of depth of water applied to the fields. Secondary data were also collected from the secondary sources. For technical evaluation of both left and right schemes using performance indices, six farmers‘ fields were selected each from the head, middle and tail-end water users. Conveyance efficiencies of the Left and Right main canals for distance of 2650m were 55.85 % and 53.1 % respectively. Conveyance losses on primary canals were due to spillage, seepage and overtopping from conveyance systems. Relative water supply for crops are 2.4 on left and 2.5 on right canal indicates over supply of water for crops that have impact on yield reduction. Relative irrigation water supply is 2.9 on left and 3.1 on right that is greater than unity indicates unwise use of resource. The head, middle and tail-ends application efficiencies were in the range of 23.77 to 65.0 %. The losses were due to deep percolation as the basins are ridged from all sides. Delivery of water in the scheme showed that there was inequitable distribution in each head, middle, and tail reaches of canal system. Increasing of water turn, the type of irrigation system used, the ridged irrigation practice and the poor irrigation scheduling in the study sites were the main problems identified in the management and operations of the schemes; which causes the under- performance of the scheme. To improve the system, the corrective measures of previous problems, Proper design and layout of canals, on-farm training farmers and improvement of the physical structures of the scheme are essential.