APPLICATION OF SWAT MODEL FOR RIVER BASIN PLANNING AND MANAGEMENT

Abstract

River basin management attempts to reduce the various losses such as water, soil and other nutrients form the non-point sources of pollution. Generally, the water budget is designed to find out the water gap between the basin’s water availability and water demand. Climate is changing, this climate change has shown its impacts on different hydrological water balance components and watershed management. Hence proper water security plan of the basin is needed to balance the effective and efficient water availability and demand of the basin in future scenarios. Tons river basin flows through the states of MP and UP finally joining to river Ganga with a total basin area of 17,440 km2 out of which 11,974 km2 is in Madhya Pradesh and the rest is in Uttar Pradesh. Natural resource profiling, Preparation of water budget at different administrative and hydrological units and preparation of the water security plan of the Tons river basin are the main objectives of this study. For agricultural watersheds, SWAT is well suited for assessing the water availability of the basin. The hydrological study of this river basin was carried out using SWAT. Hydrological and meteorological data were obtained from CWC and IMD respectively. DEM (ASTER), LULC and (FAO) Soil data were downloaded from a publicly accessible online server. Since, SWAT is a physically-based model with a large number of model parameters, sensitivity analysis of parameters proved helpful in selecting only a few critical parameters for calibration. The SWAT model was calibrated for daily discharge using the SWAT CUP/SUFI-2 algorithm for a period of 1984 to 1991 and validated for period of 1992 to 1999 where the warm up period of 1980 to 1983 was taken. The performance of the model was evaluated using various model performance criteria i.e. i) Nash-Sutcliffe Efficiency (NSE), ii) Percentage bias (PBIAS), iii) Coefficient of determination (R2) and iv) Ratio of root mean square error to the standard deviation of measured data (RSR). Value of NSE, PBIAS, R2, and RSR for daily flow calibration were 0.68, -11.87, 0.71 and 0.56 respectively and validation were 0.77, -0.49, 0.77 and 0.48 respectively. Based on these statistical results and graphical comparison performance of the SWAT model in the Tons river basin shows a good result at calibration and very good performance at validation. The water balance of the study area showed that out of total rainfall 1005.3mm more than 46.87% of water losses as ET while 39.39% of it contributed as surface runoff during the baseline period.