A modeling study of catchment discharge to Poyang Lake under future climate in China

Abstract

Poyang Lake, the largest freshwater lake in China, is an important water resource and iconic ecosystem in a region that has been subjected to extreme droughts and floods in recent decades. The lake’s water level is heavily influenced by the watershed inflows and also by the Yangtze River from the north of the lake basin. Assessing the impact of future climate change on the watershed inflows and the subsequent influence on changes in the lake water level is important for developing effective management strategies for local water resources and for mitigation of future droughts and floods. In this study, the large-scale, distributed hydrological model, WATLAC, was applied to the Poyang lake watershed to study the possible impacts of future climate change on both inflow generation and changes in lake water level. The Global Circulation Model ECHAM5 was used to predict future climate conditions for the watershed. Simulations of WATLAC show that annual catchment inflow will increase by 2.9% and 6.5% for A1B and B1 scenarios, respectively, and will decrease by 5.2% for A2 scenario for 2011–2050 compared to that for 1961–2000. Further analyses demonstrate that changes in monthly distribution of catchment inflow will result in an increase of lake water level of 0.10–1.34 m from February to July and a decrease of 0.32–1.31 m from September to February under the three climate change scenarios. It is concluded that climate change impacts on Poyang Lake are expected to be manifested with more extreme droughts and floods in the future.