Performance evaluation and assessment of quashni small scale irrigation scheme, in Amhara Region

Abstract

Optimizing the use of irrigation water is of vital importance in conserving land and water resources as well as maximizing crop yield utilizing available water. Evaluating an irrigation system performance should measure and show the effectiveness of existing irrigation practice, provide remedial measures if necessary, as well as determining the impacts of the factors which affect the performance parameters. This study attempted to evaluate and assess the performance of Quashni irrigation scheme using internal and external performance indicators. Two irrigation seasons in the 2018 (February–May) and 2018/2019 (October–January) were carried out. Primary data, e.g. soil moisture before and after irrigation, discharge measurements, irrigation depth and soil physical properties, were collected. Secondary data, e.g. meteorological data and irrigated area per crops, were also collected. CROPWAT 8.0 computer model was used to calculate the CWR. The conveyance and application efficiency of the scheme was estimated as 71.8% and 51.2% respectively, which led to an overall scheme efficiency of 36.8%. RWS and RIS of the scheme were 1.24 and 1.12, respectively. Irrigation ratio of Quashni irrigation scheme was found to be 0.84, which implies that 16% of the command area could not be provided with irrigation coverage. In general, the evaluation and assessment indicated a low performance of the Quashni irrigation scheme.