A GIS and SCS-CN based integrated model for rainfall-runoff simulation of ungauged watershed

For the success of any of the watershed management projects, a scientific assessment of the hydrologic processes taking place in the watershed is very essential. Therefore, watershed modelling is very important in the context of water resources impact assessment and watershed management. Due to the complexity of the hydrological processes, watershed modelling requires data management tools such as Geographic Information Systems (GIS) other than the rainfall runoff models. SCS-CN method is one of the commonly used model to simulate rainfall runoff for un-gauged watersheds. In this study, the SCS-CN model has been used with the GIS to take into account the spatial variations of the data of the watershed considered. Effort has been made to integrate these two modelling tools to provide more efficient assessment procedures in watershed modelling. The integrated model is applied to an un-gauged watershed for the runoff simulation and the results are found to be satisfactory. Further, for the verification of the model prediction, the SCS model is applied to one Anas subcatchment for which observed runoff data is available. Reasonable agreement is observed between the measured runoff data and the model simulation results, showing the validity of the model.