Assessing the Impact of Land Use and Climate Change on River Ravi Flows: A GIS and Hydrological Modeling Approach

Abstract

In the present study, the impact of Land Use and climate change on the flows of River Ravi has been assessed through GIS remote sensing and applying the hydrological model at the catchment scale. A Soil and Water Assessment Tool (SWAT) model has been applied to simulate the hydrological response of River Ravi considering the current and future Land Use and climate changes. The model was calibrated and validated for the periods of 1999–2002 and 2003–2005, respectively. The good fit values of NSE, R2, and PBIAS for the calibrated model are 0.85, 0.83, and 10.01 while for the validated model are 0.87, 0.89, and 7.2. By supervised classification techniques current and future Land Use maps were prepared for the study area using Landsat images and the TerrSet model for the prediction of future change in the built-up area. The result showed that the built-up area increased by 15.8% over the period 1990 to 2020 and the Future built-up area is expected to increase by 31.7% over the period 2020–2100. Climate change projections of precipitation and temperature under two Shared Socioeconomic Pathways SSP2 and SSP5 have been carried out, and statistical downscaling has been performed by the CMhyd model. The result indicated that over the period 2016–2100, precipitation is expected to increase by 10.9% under SSP2 and 14.9% under SSP5. Similarly, temperature is expected to increase by 12.2% under SSP2 and 15.9% under SSP5. The result of the SWAT model considering the increased precipitation over the period 2016–2100 shows the inflows of River Ravi are expected to increase by 19.4% by SSP2 and 25.4% by SSP5 in Scenario I. Similarly, the inflows of River Ravi are expected to increase by 22.4% by SSP2 and 28.4% by SSP5 in Scenario II. Based on the past observed data, it is found that average Groundwater depth decreased at a rate of 0.8 m per annum over the period from year 1996 to 2020.