Assessing changes in total water storage in two large freshwater lake basins of China

Abstract

The quantitative assessment of changes in total water storage (TWS) is of great significance for regional water resources management in basins with large lakes. Here, the basins of Poyang Lake and Dongting Lake, the two largest freshwater lakes in China, were selected to assess TWS changes using multi-source datasets. The Gravity Recovery and Climate Experiment (GRACE) TWS anomalies (TWSA) increased by 8.8 mm a À2 (p < 0.01) and 8.3 mm a À2 (p < 0.01) from 2003 to 2016 for the Poyang Lake Basin (PYLB) and Dongting Lake Basin (DTLB), respectively. Four major components, namely lake water storage, soil moisture storage, groundwater storage and reservoir storage, contributed positively to the TWSA increase in the two lake basins.The TWSA increase was dominated by groundwater storage increase (52.6%) over PYLB and by reservoir storage increase (47.4%) over DTLB. The increases in soil moisture storage contributed 22.4% and 27.6% to TWSA changes for PYLB and DTLB, respectively, which were mainly caused by increases in precipitation. The contributions of lake water storage to TWSA increases were only 4.3% and 1.3% in PYLB and DTLB, respectively, indicating that the impacts of water storage in natural lakes on TWS were far lower than those of reservoirs, even in basins with large lakes. The results highlight that reservoir and groundwater storage play crucial roles in TWS partitioning, suggesting that attention should be paid to the two components of land surface and hydrological simulations in highly populated lake basins under global change.