ENVIRONMENTAL IMPACT ASSESSMENT USING ANALYTICAL HIERARCHY PROCESS AND EVALUATION OF HYDRAULIC PERFORMANCE OF MEGA IRRIGATION PROJECT: CASE STUDY OF OMO KURAZ IRRIGATION PROJECT M.Sc. THESIS

Abstract

In every region, the implementation of irrigation and agricultural water management has the potential to increase production and reduce climatic instability. Irrigation production has been described in Ethiopia as a key mechanism for promoting economic growth and rural development, as well as a pillar of food security and poverty reduction. The environmental impacts were assessed using six metrics, and weekly average discharge measurements were obtained for the investigation duration of June to August 2020 to assess hydraulic efficiency.The discharge measurement was performed at nine measuring stations on branch canal offtake by using the universal current meter. Water surface elevation measurement was also conducted along the secondary canal at twenty-four measuring locations to be used as an input for the calculation of water surface elevation ratio to support for operation and maintenance activity for decision-makers. According to AHP results of environment, the weight of Soil erosion accounts 33.1%, groundwater table rise 25.1%, drainage problems 22%, soil salinization 11%, irrigation water quality 5.7%, loss of vegetation cover 3.1%. The overall water delivery performance of the canal in relation to adequacy, efficiencydependability, and equity was found to be 0.99, 0.99, 0.03, and 0.02 respectively. Maintenance indicators like water surface elevations ratio, the effectiveness of infrastructure, and sustainability of irrigated area were found to be 100%, 94.62%, and 93.7% respectively. Generally, the water delivery performance of the canals was good. Therefore, to sustain the performance of the irrigation scheme at a good level continued evaluation, maintenance, and operation work on