PERFORMANCE EVALUATION OF ARIYO-KULANO SMALL SCALE IRRIGATION SCHEME IN KUCHA WOREDA, SNNPR, ETHIOPIA

Abstract

Evaluating performance of existing irrigation schemes is vital to compare their potential and current service. The main objective of performance evaluation of Ariyo Kulano small scale irrigation scheme was to assess the problems and suggesting possible remedial measures. Studying its performance level is very important to share the information to government and donating organizations. The performance of Ariyo Kulano Small Scale irrigation scheme was evaluated by estimating water delivery performance indicators, water conveyance efficiency, water conveyance losses, water use/supply, maintenance, physical, agricultural and economic performance indicators. The water delivery performance indicators adequacy, efficiency, equity and dependability varied widely from head to tail reach and, during the crop season from October to December with overall average values equal to 0.83, 0.77, 0.26 and 0.31 respectively. Thus, the irrigation scheme when compared with Molden and Gates standards was found under fair condition in adequacy and efficiency and under poor condition in equity and dependability. The main canal average water conveyance efficiency, water conveyance losses and losses in 100m per l/s varied from 65.33% to 96.02%, 3.98 to 34.67 % and 2.55 to 6.39l/s respectively. Analyses of water-use performance showed that relative water supply, relative irrigation supply and water delivery capacity were ranked as 1.1, 2.24 and 1.14respectively.The water distribution was not according to crop water demand in the case of relative irrigation supply. The relative water supply was categorized under acceptable range. Actual discharge capacity at system head was greater than the intended one. There was averagely 20% decrement deviation of water surface elevation (DWSE) at full supply level (FSL). Effectiveness of infrastructure was found to be 35.3%. Economically, the scheme had serious problem about the collection of water fees (13.2%), financial self-sufficiency (0.59), and gross return on investment (31%). Physical performance, evaluated in terms of irrigation ratio (0.75), cropping intensity (0.81) and sustainability of irrigated land (2.42), were relatively fair. Keywords: Ariyo Kulano irrigation scheme, water delivery performance, external water delivery performance, conveyance efficiency and loss