MODELLING THE WATER BALANCE OF NATURAL LAKE UNDER LIMITED DATA SITUATION FOR IMPACT ASSESSMENT: THE CASE OF ABAYA AND CHAMO LAKES, ETHIOPIA

摘要

Little information is available regarding the water resources systems of Abaya and Chamo Lakes which are found in Southern Rift Valley Region of Ethiopia. In this paper, modelling of the water balance components and there by impact of water use, sediment transport and deposition are highlighted. In order to be able to develop the water balance model, the watersheds of the lakes system are developed under GIS and the watershed characteristics are derived. The morphometry of the Lakes are investigated by undertaking bathymetry survey. The hydro-meteorological component of the system have been also investigated by developing relevant database and information system and establishing regional relationships as well as rainfall-runoff model. These information systems have been integrated to model the water balance of the Lakes which simulates the water level. Based on the simulations result and computation of life expectancies, it is found that sediment inflow and deposition threaten the Two Lakes.