EVALUATION OF FIELD IRRIGATION EFFEICIENCIES IN MELKA HIDA SMALL SCALE IRRIGATION THROUGH SOIL MOISTURE MONITORING: GELANA DISTRICT, ETHIOPIA

Abstract

Substantial amount of diverted irrigation water is often lost because of poor water control, inefficient irrigation conveyance systems, poor on-farm water management and poor application practices. Evaluation of water application efficiency of the irrigation scheme can provide useful input to efforts towards improving scheme performance. However, the water application efficiency of the Melka Hida irrigation scheme has not been evaluated since its operation. Therefore, this research paper provides results of an evaluation of water application efficiency, distribution efficiency, storage efficiency and losses by deep percolation and tail water runoff in Melka Hida small scale irrigation system in West Guji Zone of Oromia Region. To realize the objectives of the study, field experiments were conducted including water application depth and continuous soil moisture monitoring for 36days and laboratory analysis was undertaken. Furrow parameters such as furrow slope, width, length, and shape geometry were measured. The result of this study indicate that irrigation application efficiencies ranged from 57% to 64% with an average of 61% indicating that about 40% of the applied water was not used by crops. The storage efficiencies ranged from 79.6% to 81.6% with an average of 80%. The soil moisture measurements showed that the crops were water stressed during the experiment period. Application efficiency decreases with increasing of steep slope and cutoff time, large applied depth, and high inflow rate in the study area. Unavailability of irrigation water control structure, weakness of WUAs and farmers toward maintenance of furrow and steep slope were the major causes of inefficient of Melka Hida irrigation scheme. Participation and commitment of irrigation professionals in community irrigation scheme should be encouraged to raise farmers’ level of understanding on irrigation system management.