Discharge and sediment yield modeling in lake Tana region,Ethiopia

Land degradation is a major watershed problem causing significant loss of soil fertility and productivity in the Ethiopian highlands. Soil erosion is one form of land degradation. To develop effective erosion control plans and to achieve reductions in sedimentation, it is important to quantify the sediment yield and identify areas that are vulnerable to erosion. The objective of this study was to formulate sustainable land management options that alleviate soil erosion. The study was conducted in a small watershed located about 80 km North East of Bahir Dar. The runoff depth was measured and sediment sampling was performed during the 2010 main rainy season. Twenty three piezometers were installed and water level measurements were taken for a 5 month period. In addition, infiltration rates were measured. A simple saturation excess water balance model was used to simulate the flow and sediment processes in the watershed and to identify runoff and sediment source areas. The watershed landscape was divided into saturated, degraded and hill slopes areas to understand the hydrologic behavior. Finally, the model output was compared with the sediment and runoff data observed at the outle