Effect of spatial resolution of climatological data on streamflow simulations using the SWAT : A case study

Abstract

Data quality always affects the accuracy of model output. Rainfall is the basic data required in hydrological modelling as rainfall to runoff conversion is the core of all such models. Regional modelling studies required high resolution spatio-temporal data and availability of data at appropriate resolution also greatly affect the modelling results. Therefore, efforts have been started to record climatic variables at finer resolution so that they will be useful for block level and gram Panchayat level studies. In this study, an effort has been made to identify the effect of using various resolution climatic data on streamflow simulation in the Kesinga catchment of the Mahanadi river basin. Three types of rainfall sets with spatial resolution of 0.25° × 0.25° and 1° × 1° from IMD and one set of recorded rainfall data of the Special Relief Commissioner (SRC), Govt. of Odisha is used in combination with IMD 1° × 1° gridded temperature to simulate streamflow at the Kesinga gauging station using the Soil and Water Assessment Tool (SWAT) keeping other parameters constant. The three simulations were analyzed using NSE, R², RMSE, PBIAS, P-factor and R-factor. The results depicted that IMD gridded rainfall data sets predicted similar flows compared to the SRC recorded rainfall data which proves the fairness of IMD gridded data is at par with the recorded rainfall data of SRC, Govt. of Odisha.