ASSESSEMENT OF IMPACT OF ABBAY BASIN /RR/GA TION DEVELOPMENT ON THE WATER RESOURCE OF THE RIVER (A CASE OF TRIBUTARIES DEVELOPMENT SCENARIO)

Abstract

This study was conducted to evaluate the future water requirement of Ethiopia while developing selected irrigation projects proposed on the tributaries of Abbay as specified on the master plan of Abbay river basin. The study has also investigated the probable water supply and demand condition of the projects under consideration. The reduction of flow at the border due to the implementation of the projects as compared to the existing mean annual flow of the river was also computed. Based on the required data availability on the master plan documents to run Water Evaluation and planning analysis (WEAP) model, 17 irrigation projects covering an area of 220,416 ha of land have been included in the analysis. From the analysis the total water requirement of these irrigation projects was estimated as 3 Billion cubic meter annually. The border flow volume reduction as a result of the implementation of these projects is only 6% of the estimated mean annual flow, 49.7 billion cubic meters. Among the studied projects, the unfulfilled water demand of Negesso and Rib is significantly high that needs further investigation. Moreover the water released for downstream users and ecological purpose needs due consideration for the