Impacts of climate change on streamflow and sediment concentration under RCP 4.5 and 8.5: A case study in Purna river basin, India

Climate change has a significant effect on various hydrological processes in a large river basin. The assessment of these processes is also useful for water resource management and long-term sustainability of any hydrological project. In this study, an attempt is made to quantify the effects of climate change on streamflow and sediment concentration in the Purna river basin, India. Three Regional Circulation Models (RCMs) with two Representative Concentration Pathways (RCPs) 4.5 and 8.5 for the four future periods of P1 (2009-2031), P2 (2032-2053), P3 (2054-2075) and P4 (2076-2099) are considered. Differences in scenarios are compared with the base period 1980-2005. The SWAT is used on monthly basis for the period 1980 to 2005 with calibration period 1980 to 1994 and validation period 1995 to 2005. The projected precipitation and temperature show a significant increasing trend compared to the baseline condition for both RCPs. Similarly, the average monthly streamflow is projected to increase by 24.47 to 115.94m³/s whereas average monthly sediment concentration by 32.58 to 162.96mg/l under RCP 4.5 and 8.5. In particular, streamflow and sediment are expected to increase significantly from June to September at the outlet of the basin. The study results give insight into future hydrological scenarios which will be useful for policy makers to implement effective water resource strategies.