Evaluation of canal water conveyance and on-farm water application for a small-scale irrigation scheme in Ethiopia

This study was conducted to identify and understand the current level of canal water conveyance and on-farm water application efficiency of Lemchek-Sewur small-scale irrigation scheme in Ethiopia. The water conveyance efficiency of canals was determined by estimating discharge at different segments. On-farm water application efficiency was evaluated from the amount of water actually applied and from soil moisture measurements. Primary data were collected through flow measurement, transect walk, household surveys and group discussions, whereas secondary data were collected from different sources. Microsoft Excels and Geographic Information System software were used to analyze the data. The mean values of water conveyance efficiency of main, secondary and tertiary canals were 86.17, 86.26 and 55.97%, respectively. Mean value of the overall on-field water application efficiency was 53.13%. Generally, the performance of the irrigation scheme was poor mainly due to illegal water abstraction, sedimentation of canals and inadequate operation and maintenance provisions. Therefore, adequate maintenance and suitable management approaches are required to improve the irrigation system performance. Key words: Lemchek-Sewur SSI scheme, conveyance efficiency, application efficiency, evaluation, Ethiopia.