COMPARISON OF MUSLE, EPM AND PSIAC SEDIMENT ESTIMATION MODELS: CASE STUDY GEREB-SEGEN DAM WATERSHED, TIGRAY, ETHIOPIA

Abstract

Sedimentation of the dam reservoir is a series problem in Ethiopia. It also a major problem in many developing countries causing significant loss of water storage ,loss of agricultural productivities, loss of electrical supply and ecological changes. The MUSLE, EPM, and PSIAC models are tested for the prediction of sediment yield at Gereb-segen watershed, Tigray, Ethiopia. Poor land use practices and improper management systems have played a significant role in causing high soil erosion rates, sediment transport and loss of agricultural nutrients. The main objective of this study is comparison of sediment yield of the Gereb_segen dam reservoir, using the MUSLE, EPM and PSIAC models with the observed data and selection of appropriate model for the area. The research integrates the three models with Geographic information system (GIS), Remote sensing and Digital elevation model. Rain fall data, soil data , Geological data , Temperature, land use and land cover, crop management and conservation practices, infiltration rate of soil at filed level were used as input data sets to generate the three model factor values. As a result, MUSLE estimates that sediment yield of the study area to the range between 3.89 & 26.45 ton/ha/yr where as EPM estimates the sediment yield in the range of 84.20 to 344.09 ton/ha/yr and PSIAC also estimate 0.16 to 8.90 ton/ha/yr. As they were, compared the three models used to estimate sediment yield of the target area with the measured data which studied by Haregeweyni et al.(2008) sediment yield of 11.82 ton/ha/yr, the MUSLE similar with 82.06% and the PSIAC model similar with 12.35% while the EPM model it is more differ from the measured data. Using the MUSLE model the Gereb-segen watershed sited 0.28% under low, 4.29% moderate, 48.64% high and 46.79% very sedimentation classes.