Sensitivity analysis of the GIUH based Clark model for a catchment

For estimation of runoff response of an ungauged catchment resulting from a rainfall event, geomorphological instantaneous unit hydrograph (GIUH) approach is getting popular because of its direct application to an ungauged catchment. It avoids adoption of tedious methods of regionalization of unit hydrograph; wherein, the historical rainfall-runoff data of a number of gauged catchments are required to be analyzed. In this study, the GIUH derived from geomorphological characteristics of a catchment has been related to the parameters of Clark IUH model for deriving its complete shape. The DSRO hydrographs estimated by the GIUH based Clark model have been compared with the DSRO hydrographs computed by the Clark IUH model option of the HEC-1 package and the Nash IUH model by employing some of the commonly used error functions. Sensitivity analysis of the GIUH based Clark model has been conducted with the objective to identify the geomorphological and other model parameters which are more sensitive in estimation of peak of unit hydrographs computed by the GIUH based Clark model. So that these parameters may be evaluated with more precision for accurate estimation of flood hydrographs for the ungauged catchments.