Assessing the impacts of land use and land cover change on water resources in the Upper Bhima river basin, India

Abstract

Rapid economic development in India has intensified the changes in natural land cover and thus affects the availability of water resources. The present study aims to analyze past land use changes for three time periods and assess their impacts on water resources in the Upper Bhima basin. An object-based image analysis (OBIA) technique was used to identify the progressive land use changes for the year 1992, 2000, and 2009. The Soil and Water Assessment Tool (SWAT), an open source hydrological model was used to simulate hydrological processes and assess the impacts of land use change on surface runoff, groundwater flow, lateral flow, percolation, and evapotranspiration in the basin. The model was calibrated and validated for a baseline period (1985-1994) using 1992 land use/land cover (LULC) map. The model calibration and validation was found to be satisfactory. The optimized SWAT model parameters along with 1992 and 2009 LULC maps were used to quantify the impacts in the Upper Bhima basin. The major land use changes were identified as conversion from wastelands and agricultural land to built up area (2.6 % in 1992 to 7.3% in 2009). The modeling results showed that urbanization has a significant (p<0.001) positive relation with surface runoff (R = 0.96), water yield (R = 0.57), and a negative relationship with baseflow (R = -0.95), and percolation (R = -0.99). The study also revealed that the nature of LULC change has differential impacts at both basin and sub-basin scale. At basin level, the overall impacts of LULC change on hydrological parameters are small however at sub-basin level, the surface runoff and water yield has increased up to 13.6%, 8%, respectively. Similarly, the lateral flow changed from -9% in sub-basin 42 to 10% in sub-basin 20 and evapotranspiration changed from -3% in sub-basin 43 to 59% in sub-basin 6.