Storm Runoff Analysis by Generalized Storage Function Model in a Semi-urban Watershed

Abstract

 The storage function (SF) models have been extensively used for the rainfall-runoff modeling in different parts of the world due to its simple structure. However, there is a need for an SF model that can be applied in all the watersheds, except urban watersheds with combined sewer system, without requiring the effective rainfall as their input. In this study, therefore, we aim to propose a generalized SF (GSF) model that satisfies the above criteria with a new parameter named as rainfall distribution factor (f). The GSF model without parameter f was also examined in order to check the effectiveness of f in the GSF model. In addition, three different time intervals were considered for the numerical solution method used in this study in order to identify the effect of time intervals on the model performance. The results revealed that the GSF model with f exhibited higher hydrograph reproducibility associated with the lowest error evaluation criteria which emphasize the effect of parameter f. It was also demonstrated that the model performance is changing for the same model at different time intervals which can be interpreted as the strong influence of time intervals on the numerical solution method and subsequent model performance.