Rainfall, Runoff and Soil loss, relationship on different land uses in the Upper Lake Tana Basin

Abstract

Understanding the basic relationships between rainfall, runoff and soil loss are crucial task for effective management and utilization of natural resource. Hence, modeling the relationship between rainfall, runoff, and soil loss for climatic conditions prevailing in the Upper Lake Tana basin is a crucial task. The watershed instrumented with raingauge and rectangular weir to measure important parameters. Soil infiltration rate exceeded 9.4% of the time by the rainfall intensity, in which infiltration excess runoff is not a dominant runoff mechanism. A simple sediment model was developed. It predicts sediment with Nash Sutcliffe coefficient (E) and the coefficient of correlation (R2) of observed and simulated runoff is 0.9 to 0.91 and 0.88 to 0.96 for validation. The model predicted event based surface runoff with reasonable accuracy, this noticeable model's performance showed probably due to the applicability of the model to estimate sediment loss despite the smaller data size. Keywords: Modeling, Runoff, Sediment loss, Grazing land