PERFORMANCE EVALUATION OF LAMO SMALL-SCALE IRRIGATION SCHEME IN TEMBARO WOREDA, KEMBATA TEMBARO ZONE, SNNPR

Abstract

The level of performance of irrigated farms is one of the most important issues that need to be addressed in Ethiopia where development of irrigation, in particular small-scale irrigation, is adopted as one of strategies to achieve food security. Lamo small-scale irrigation scheme operates under low level of performance due to poor water management and lack of timely maintenance of structures. The performance evaluation of Lamo small scale irrigation scheme was made by using internal performance indicators as a tool such as application efficiency, storage efficiency, distribution uniformity and deep percolation ratio. Six farmer’s plots located at head, middle and tail of the command area were selected and grown with two commonly grown vegetable crops in the command area viz, onion, and tomato. The average application efficiency, storage efficiency, distribution uniformity and deep percolation of the selected farmer's fields were found to be 48.12%, 81.90%, 79.80% and 51.88%, respectively. Based on the analysis of variance (ANOVA), the result indicated that inflow rate had significant effect (p<0.05) on different performance indicators (application efficiency, storage efficiency, distribution uniformity, and deep percolation ratio) at field level. Since farmers were using end-dyke furrow irrigation system, therefore no runoff was observed. The result of the study also showed that the irrigation water applied to farmers' fields (136mm) was much higher than the required depth to be applied per irrigation event. As a result, large amount of water was lost as deep percolation. Conveyance efficiencies of the main and secondary canals were found as 82.5% and 80.8%, respectively. Seepage losses of the main and secondary canals were found out as 16.70lit/sec/km and 14.70lit/sec/km, respectively. Operational and management, and status of physical structure of the scheme were analyzed using field observations and inventories. Moreover, poor irrigation management and operation of the scheme were identified as major problems at the study site