Event-Based Soil Erosion Modeling of Small Watersheds

Abstract

This study deals with the estimation of sediment yields and sedimentographs of small watersheds. The proposed mathematical model is based on simultaneous solution of flow dynamics followed by dynamic erosions. The flow dynamics is based on the well accepted kinematic wave theory. As the storm rainfall proceeds, the process of generation of overland depth is a dependent function of the infiltration rates. This has been taken care of by the use of Phillip’s infiltration approach. Recent research has revealed that the flow resistance coefficients greatly influence the overland water depths. Therefore, the concept of depth dependent overland resistance coefficients has been incorporated in the overland flow computations to minimize the errors. The components of the soil erosion model have been modified for better prediction of sediment flow rates and sediment yields. The rainfall-runoff-sediment model as developed was applied to 34 storm events registered over six small watersheds located in different climatic regions of India and the United States. The model has satisfactorily reproduced the runoff hydrographs and the sedimentographs.