SEDIMENT YIELD AND INFLOW PREDICTION TO AYSERAWUM MICRO EARTH DAM, BLUE NILE BASIN, OF ETHIOPIA

Abstract

Estimation of runoff volume and sediment yield is a problem that directly affects the performance of dams due to the reduction in the storage capacity of their reservoirs and their effect on dam efficiency and operation schedule. The simulation models can be considered for evaluation of sediment potential if the continuous field measurements are not available. Soil and Water Assessment Tool (SWAT) was applied to estimate the annual runoff volume and sediment load for Ayserawum micro earth dam watershed area by transferring model parameter from Andit tid watershed. Six most sensitive parameters were identified for stream flow and ten for sediment load. During the course of calibration of stream flow, the performance indicators were found as R2 = 0.89, ENS = 0.85 and D =+8.58 and for validation R2 = 0.79, ENS = 0.73 and D =+5.32, and for sediment load R2 = 0.77, ENS= 0.73 and D =+12 for calibration and R2 =0.76, ENS = 0.73 and D =+17.5 for validation. Simulation output of the 36 sub watersheds was contributed varying degree of average annually stream flow of 0.38 m3/sec to 0.01 m3/sec, and sediment load 297.64 to 1.85 tons/ha/yr. Based on the hydrological simulation integrated watershed management plan should be implemented for effective land and water resource development. Hence, the result of the study could help stakeholders to plan and implement appropriate soil and water conservation strategies in the hot spots area.