Streamflow Estimation in Ungauged Catchments Using Regional Flow Duration Curve: Comparative Study

Abstract

The study presents a comparative assessment of regionalization approaches for streamflow estimation at ungauged catchments that are independent of any hydrological models. Four regionalization techniques including area-index, inverse distance weighted (IDW), kriging, and stepwise regression were applied on 32 catchments in India to estimate daily streamflow. Each catchment was considered as ungauged in turn during regionalization. The area-index method was dependent upon the drainage area of the catchment, whereas stepwise regression method was based on the hydroclimatological and morphological attributes of the catchments. IDW and kriging were based on spatial distance between the donor and receiver catchments. The performance of each regional model was evaluated in terms of Nash–Sutcliffe efficiency (NSE), root-mean square error (RMSE)–observations standard deviation ratio (RSR) and percent bias (PBIAS). The results obtained from IDW and kriging were found to be superior to other techniques. An average NSE value of 0.6 was found to be better for these two methods than other approaches. The area-index method performed the worst, maybe due to the fact that it considers only drainage area.