Impact of the Three Gorges Project operation on the water exchange between Dongting Lake and the Yangtze River

The Three Gorges Project (TGP) is a world known project to utilize and manage the water resources of the Yangtze River. The reservoir stores water at the end of the flood season, and replenishes downstream reaches with water in dry seasons. In addition to such benefits, the TGP has irreversibly changed the hydrological process and the river-lake relation of the middle and lower reaches. In this paper, a hydrodynamic model was established to quantify the impact of the TGP׳s operation on the water exchange between Dongting Lake and the Yangtze River during 2009-2013. The results indicated that: the operation of the TGP has considerably reduced the peak discharge and the flood volume of the main stream and the Dongting Lake area. The inflow volume from the Yangtze River to Dongting Lake via three outlets decreased by 1.9-3.5 billion m3/yr, while the outflow volume from Dongting Lake to the Yangtze River at Chenglingji increased by 0.3-1.6 billion m3 in September and 0.4-0.6 billion m3 in October, respectively. This research provides valuable information for flood control, irrigation, and water allocation in the middle and lower reaches of the Yangtze River, and serves as a typical case for investigating the impact of other hydropower projects around the world.