Climate-induced hydrological impact mitigated by a high-density reservoir network in the Poyang Lake Basin

The Poyang Lake Basin (PLB) is expected to see more precipitation and higher temperature by 2050. Due to climate change, it is advisable to identify the vulnerable area and to investigate if the local reservoir network of hundreds of larger reservoirs and thousands of smaller reservoirs can effectively mitigate the climate-induced hydrologic variation. Therefore, the local high-density reservoir network is integrated into a distributed hydrologic model (HMS) through a fully coupled reservoir module. We then apply the extended HMS in a one-way coupled mode to the bias corrected Coordinated Regional Downscaling Experiment in East Asia (CORDEX-EA) regional climate simulations under two Representative Concentration Pathways - RCP4.5 and RCP8.5. Results indicate that climate change poses new challenges to water resources management for the PLB, with a likely decrease of water availability in the dry season but an increase of water availability, flood magnitude and flood frequency in the flood season till 2049. The local reservoir network can mitigate climate impacts by displacing excessive water resources in the flood season to the dry season and mitigating floods across the basin. Despite that, much of the southern basin is likely to see a higher risk of water shortage in the dry season, while most of the northern basin is expected to see a higher flood risk. The approach and findings are expected to improve the understanding of the role of reservoirs in the context of climate change, and provide implications for water resources management and climate change adaptation strategies on a regional scale.