Assessing Climate Change Impacts on Water Resources in the Songhua River Basin

The Songhua River Basin (SRB) in Northeast China is one of the areas most sensitive to global climate change because of its high-latitude location. In this study, we conducted a modeling assessment on the potential change of water resources in this region for the coming three decades using the Soil and Water Assessment Tool (SWAT). First, we calibrated and validated the model with historical streamflow records in this basin. Then, we applied the calibrated model for the period from 2020 to 2049 with the projected and downscaled climatic data under two emission scenarios (RCP 4.5 and RCP 8.5). The study results show: (1) The SWAT model performed very well for both the calibration and validation periods in the SRB; (2) The projected temperatures showed a steady, significant increase across the SRB under both scenarios, especially in two sub-basins, the Nenjiang River Basin (NRB) and the Lower SRB (LSRB). With regard to precipitation, both scenarios showed a decreasing trend in the NRB and LSRB but an increasing trend in the Upper Songhua River Basin (USRB); and (3), generally, the hydrologic modeling suggested a decreasing trend of streamflow for 2020-2049. Compared to baseline conditions (1980-2009), the streamflow in the NRB and LSRB would decrease by 20.3%-37.8%, while streamflow in the USRB would experience an increase of 9.68%-17.7%. These findings provide relevant insights into future surface water resources, and such information can be helpful for resource managers and policymakers to develop effective eco-environment management plans and strategies in the face of climate change.