Assessing the impact of climate and land-use change on the hydrological response of the upper Betwa River basin

Climate and land-use change have altered the regional hydrological cycle. As a result, the mean summer monsoon rainfall has decreased by 10 % over central India during 1950-2015. This study evaluates the combined effect of climate and land-use change on the hydrological response of the upper Betwa River basin in Central India. We use Landsat satellite images from 1990 to 2018 to compute the changes in various land-use types; waterbody, built-up, forest, agriculture, and open land. In the past two decades, we found that the water body, built-up, and cropland have increased by 63 %, 65 %, and 3 %, respectively. However, forest and open land have decreased by 16 % and 23 %. Further, we observed a significant increase in annual average temperature and a decrease in the mean rainfall in the study area during 1980-2018.

We then coupled the land-use change with weather parameters (precipitation, temperature, wind speed, solar radiation, and relative humidity) and setup the SWAT (Soil and water assessment tool) model to simulate the hydrological responses in the catchment. We have run this model for two different time steps, 1980-2000 and 1998-2018, using the land-use of 1990 and 2018. Calibration and validation are performed for (1991-1994, 2000-2004) and (1995-1998, 2005-2008) respectively using SUFI-2 method. Our results show that the surface runoff and percolation decreased by -21 and -9 %, whereas evapotranspiration increased by 3 % in the upper Betwa River basin during 2001-2018. A decrease in rainfall, runoff, and percolation will have considerable implications on regional water security.