Implications of the Projected Future Climate on Water Resources in the Indian Sub-continent Basins

Abstract:

Sustainability of water resources is vital for agricultural and socio-economic development in India. In the recent few decades, India has been witnessing erratic nature of the Indian summer monsoon, which accounts for about 80% of the total annual rainfall. While there is a large uncertainty in the precipitation projections during the summer monsoon from the regional and global climate models, we need to understand sensitivity of water resources in the Indian sub-continental river basins under the projected future climate. This is particularly important as the Indian sub-continent is one of the most populated regions of the world. We evaluated changes in water budget in the 18 Indian sub-continental basins under the projected future climate using the Variable Infiltration Capacity (VIC) model. The VIC model was calibrated and evaluated using the observed streamflow as well as satellite derived evapotranspiration and soil moisture. After the successful calibration and evaluation, we performed a sensitivity analysis for the water balance variables. Finally, we used downscaled and bias corrected climate forcings to develop scenarios of changes in water balance under the future climate. Despite the intermodal variation, Indian basins are projected to experience wetter and warmer climate in future. Results indicate positive changes in evapotranspiration and runoff under the projected future climate; however, increases in total runoff are projected to be significant in most of the basins in the sub-continent.