Simulation of surface runoff using semi distributed hydrological model for a part of Satluj Basin: parameterization and global sensitivity analysis using SWAT CUP

摘要

The ideal allotment of controlled water assets for diversified schemes is needed for continuous and controlled advancement. In present study SWAT (Soil and Water Assessment Tool), a physically based semi-distributed hydrological model was applied in the Satluj Basin (Suni to Kasol) for hydrologic modeling. 23 sub-basins were demarcated from the study area, which consists of 325 Hydrological Response Units (HRUs) with regard to specific slope, soil and land use combination. SWAT-CUP (SWAT-Calibration and Uncertainty Programs) is one of the new developments for calibration/sensitivity analysis of watershed models that incorporate a semi-automated approach SUFI-2 (Sequential Uncertainty Fitting) which includes both manual and automatic calibration and incorporating global sensitivity analysis. Parameters for Sensitivity Analysis used to measure statistics for goodness-of-fit. For the study area, CN2, SOIL_K, RCHRG_DP, CH_K2 were considered as the most sensitive parameters. The model Calibration (1986-1998) and Validation (1999-2011) were executed with initial 3 years considered as a warm-up period (1983-1985) at Kasol site which is considered as anoutlet of the study area. The statistical performance of the model was assessed using the coefficient of variation (R-2), and Nash-Sutcliffe efficiency (NSE), during model Calibration, RA(2) for the daily runoff was obtained as 0.98 with Nash-Sutcliff of 0.96 respectively. The validation also signified satisfactory results with R-2 of 0.96 and NSE of 0.94 respectively. The results have shown excellent correlation between observed and simulated discharge on daily time steps. The results and ensuing inferences would be of immense help to the hydrological fraternity and the water resource managers.