Climate Change Impacts on Water Resources in Mahanadi River basin (India)

Abstract:

Streamflow estimation using hydrological modeling and assessing the impact of climate change on it can increasingly help in dealing with the challenges that water resource managers and planners. In the present study, continuous distributed hydrological model named Soil and Water Assessment Tool (SWAT) is used for streamflow estimation at five gauging stations within Mahanadi river basin, Orissa, India. Further streamflow response to climate change has been examined. For this, the SWAT model has been first calibrated and validated for the period of 1951-2007. Then, with the aim of evaluating the impact of climate change on the basin hydrology for the period of 2010-2099, downscaled and bias corrected data from the CMIP5 (Coupled Model Intercomparison Project) models (i.e. bcc-csm1-1, inmcm4, mpi-esm-Ir, mri-cgcm3 and noresm1-m) under the RCP 4.5 and RCP 8.5 scenarios were used to derive the SWAT model. We find that streamflow variations are more sensitive to changing climate in the monsoon (JJAS) and pre-monsoon (FMAM) seasons than that of the post-monsoon season. Moreover, simulated runoff for the projected period (2010-2099) was found to be changing in a range of -17 to 59% in the monsoon, -18 to 65% in the post-monsoon, -76 to 451% in pre-monsoon under the RCP 4.5 scenario and for the RCP 8.5 streamflow changes have been assessed between -5 to 107% in monsoon, -0.45 to 105% in post-monsoon, -61 to 202% in pre-monsoon period.

Keywords: SWAT; Climate Change; CMIP; RCP; Mahanadi