Minimum water levels. Before constr

Minimum water levels. Before construction of the TGR, there was a fuctuating downward trend of minimum water levels at the Yichang, Zhicheng, and Shashi hydrological stations, and the corresponding minimum discharge did not change signifcantly. Afer impoundment began at the TGR, the annual minimum water level and minimum fow began to increase (Fig. 3a,b, and c). Te Yichang, Zhicheng, and Shashi stations showed a decreasing trend in the corresponding water levels at the same fow rate in the 4 time periods of 1955–1968, 1969–1987, 1988–2002, and 2003–2016. Te minimum water levels and minimum fow rates at Luoshan Station and Hankou Station increased steadily, both before and afer the TGP was implemented (Fig. 3d and e). Tis change is related to the decrease of the shunt fow volumes of the three outlets of Dongting Lake along the south bank during the same period31. Te increase or decrease in the corresponding water levels at the same fow rate at Luoshan and Hankou stations in the 4 time periods of 1955–1968, 1969–1987, 1988–2002, and 2003–2016 was not signifcant