Testing of coupled SCS curve number model for estimating runoff and sediment yield for eleven watersheds

The soil conservation service (SCS) methodology for computing direct run-off, using soil-cover-moisture complexes involves the selection of a runoff curve number (CN) for such complex events. This method has been further simplified by introducing an assumption on initial abstraction, with only one unknown parameter CN, which is represented by the potential retention capacity of the watershed (S). In this study, coupled SCN-CN with USLE model was used for the estimation of the runoff and sediment yield for eleven watersheds of different land uses (urban, agricultural, and forest) from Damodar Valley Corporation (DVC), Hazaribagh district, Jharkhand, India. For the validation, runoffsediment yield model is employed to a large set of rainfall-runoff-sediment yield data (68 storm events) observed from eleven watersheds. Model performance was assessed by using Nash and Sutcliffe statistical method. The efficiency of results was varying from 60.42 to 92.99 % for sediment yield and 54.23 to 96.12 % for runoff; this efficiency showed a reliable performance of model for estimating the sediment yield and runoff.