HYDROLOGICAL MODELING USING SWAT - A CASE STUDY OF KEN RIVER BASIN

Abstract

This study evaluates surface runoff generation and soil erosion rates for a medium basin of River Ken in India. The Ken River is the last major tributary of River Yamuna, which finally joints the holy River Ganga. The Ken basin lies between Latitudes 23°8'3"N & 25053'15" N and Longitudes 78030'57"E & 80037'53"E covering an area of about 28,671 km2, in the states of Madhya Pradesh and Uttar Pradesh. This study integrated remote sensing-derived products, gridded precipitation and temperature data, and the Soil and Water Assessment Tool (SWAT) within a geographic information system (GIS) modeling environment to simulate the hydrology and sediment transport in the basin. Sensitivity analysis carried out to determine the influential model parameters showed that Cn_2 and Ch_k2 are most sensitive parameter for both flow and sediment while Sol_Z, Sol_Awc, and Gw_Revap are relatively more sensitive to flow but less to sediment. Similarly, Ch_N2, Usle_P, and Spcon are more sensitive to sediment than flow. The SWAT model was calibrated for a 10-year period (1986- 1995), and predicted stream flows were validated for next 10-year period (1996-2005) on daily and monthly basis. Daily calibration results for flow was good (R2 = 0.06, NSE = 0.77 for calibration period and R2 = 0.04, NSE = 0.77 for validation period). The results were further improved (very good) on monthly basis (R2 = 0.08, NSE = 0.94 for calibration period and R2 = 0.07, NSE = 0.96 for validation period). The sediment concentration calibration and validation was considerable on daily basis (R2 = 0.43, NSE = 0.36 for calibration period and R2 = 0.38, NSE = 0.30 for validation period). On monthly basis, the R2 and NSE values were 0.75 and 0.62 respectively for calibration period, 0.72, and 0.57 respectively for validation period. The simulations of management and conservation practices were carried out in cultivable area of the basin with application of irrigation, VFS, and terracing. The water resources potential at diversion point of proposed KBLP was assessed which showed similarity with the NWDA study, with a small difference during non-monsoon season.