Estimation of Hydrologic Simulation in Upstream of KRS Reservoir using SWAT Model

Abstract

The simulation of hydrologic response of a watershed system using hydrologic models involves calibration and validation process. Carrying out these processes, indeed requires an intensive knowledge on the parameters that impact the hydrologic process in that particular system. In this study, Soil and Water Assessment Tool (SWAT) model was used to simulate the streamflow for upstream of Krishna Raja Sagar (KRS) reservoir, Karnataka, India for the period from 1982-2014. Sensitivity analysis, calibration and validation was carried out using SWAT CUP (SWAT-calibration and uncertainty program) along with SUFI-2 algorithm (sequential uncertainty fitting-version 2) for monthly time scale. The computational efficiency and performance of the model was evaluated using statistical metrics including Nash-Sutcliffe (NS), Coefficient of determination (R2) and Percent bias (P-bias), p factor and r factor. Sensitivity of the parameters were analysed by performing one-at-a-time technique. Calibration of the model was carried out for a period of 10 years i.e., 2002-2011 and validation period was 3 years i.e., 2012-2014 which is one-third of the calibration time period. Using 90 m resolution DEM, landuse and soil maps, observed and 0.25° gridded rainfall along with other observed weather data. NS and R2 for calibration and validation period were 0.62, 0.67 and 0.60, 0.60, respectively. Thus, result indicates that SWAT model can be further used to assess the impacts of management scenarios as it effectively simulated the hydrologic response in the KRS catchment.