Spatiotemporal pattern of water age in Dongting Lake before and after the operation of the Three Gorges Project

• Published in: Journal of hydrology. Regional studies Vol. 55; p. 101902
• Main Authors: Long, Yuannan, Cao, Jinsong, Xiong, Wei, He, Huaiguang, Ren, Ping
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2024; Elsevier
• Subjects: Dongting Lake; EFDC Model; Three Gorges Dam; Water Age; Water Exchange; Water Age; Water Exchange; Three Gorges Dam; Dongting Lake; EFDC Model
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2024.101902

Dongting Lake Basin of China. Dongting Lake is the first large-scale interconnected river–lake systems in the middle-lower reaches of the Yangtze River and the second-largest freshwater lake in China. Dam operation on the upper reaches of the Yangtze River dramatically affected the hydrological condition of Dongting Lake. Therefore, this study established a hydrodynamic-water age model to assess the effects of the Three Gorges Dam (TGD) on the spatiotemporal pattern of water age in Dongting Lake. The results show a significant spatial and temporal variation of water age in Dongting Lake. Water age in the floodway is lower than that in the shoal, meanwhile, water age in spring and summer is lower than that in autumn and winter. By establishing a hydrodynamic-water age model, several factors influencing water age in Dongting Lake were analyzed, i.e., the influences of the Jingjiang Three Outlets' triage from the Yangtze River, the water level of the mainstream of the Yangtze River, and the flow pattern. The TGD could influence the water age in Dongting Lake by altering the hydrodynamic conditions of the Yangtze River. Results from this study provide support for flood control and dispatch management of Dongting Lake and provides a reference for water exchange studies in other large shallow lakes. [Display omitted] •Using the EFDC model can accurately simulate the water age of Dongting Lake.•Investigated the Spatiotemporal pattern of water age in Dongting Lake through simulation of different scenarios.•water age distribution in Dongting Lake exhibited Significant temporal and spatial characteristics.•The Three Gorges Dam(TGD) affected water age of Dongting Lake by influencing the mainstream of the Yangtze River.•The TGD had the greatest impact on water age in West and East Dongting Lakes.