Hydrological Modelling Using HEC-HMS and Estimation of the Flood Peak by Gumbel’s Method

This paper aims to develop a rainfall-runoff hydrological model for the Hasdeo River basin which is tributary of the Mahanadi River, Chhattisgarh, and Aghanashini River, Karnataka, to examine how rainfall affects surface runoff and peak discharges. In this study, the basin is delineated from DEM in HEC-GeoHMS as an import data for HEC-HMS model. Land use/land cover map were created using supervised classification of Sentinel 2 satellite data and merged with soil hydrological groups map to develop the curve number (CN) map. The SCS-CN, SCS unit hydrograph, recession, and Muskingum routing methods are used to calculate runoff volume, peak runoff rate, baseflow, and flood routing, respectively. The Nash-Sutcliffe efficiency (NSE), root mean square error (RMSE), coefficient of determination (R2), and percentage bias (PBIAS) of observed and simulated flow are used for the accuracy assessment of the model. The comparison and reliability of gridded precipitation data over rain gauge station data is shown, and fluvial flooding was assessed by Gumbel’s distribution method for 5-year, 10-year, 25-year, 50-year, and 100-year return periods. Finally, it can be concluded that the model may be employed in hydrological modelling in the Hasdeo watershed and Aghanashini basin with reasonable approximation. This study would help the local authorities for the development of sustainable flood forecasting and water conservation policies.