Simulation of rainfall-runoff process using HEC-HMS model for Balijore Nala watershed, Odisha, India

Hydrological modeling is a commonly used tool to estimate the basin's hydrological response due to precipitation. In this paper HEC-HMS model is used to simulate rainfall-runoff process in Balijore Nala Watershed of Odisha, India. To compute runoff volume, peak runoff rate, base flow and flow routing methods SCS curve number, SCS unit hydrograph, Exponential recession and Muskingum routing methods are chosen, respectively. Rainfall runoff simulation is conducted using 24 random rainstorm events covering four year (2010 – 2013) data. Out of these, 12 events are selected for model calibration and the remaining 12 for model validation. For calibration of model the statistical tests of error functions like mean absolute relative error (MARE) and root mean square error (RMSE) between the observed and simulated data are conducted. The results indicate values of MARE of 0.20 and 0.25 for runoff depth and peak discharge, respectively. Similarly the values of RMSE between the observed and simulated data are obtained as 2.30 mm and 0.28 m³/s for runoff depth and peak discharge, respectively. However after parameter optimization the above mentioned error functions reduce to 0.10, 0.12, 0.75 mm and 0.09 m³/sec in sequence. The calibrated model with optimized parameter is used for model validation. The model validation was found to be satisfactory with low values of statistical error functions.