Analysis on the Impact of Different Impoundment Schemes of the Three Gorges Project on the Water Level in the Middle and Lower Reaches During the Impoundment Period

Abstract

The impoundment of the Three Gorges Project has changed the hydrological situation in the middle and lower reaches of the Yangtze River. Based on the latest measured data of the middle and lower reaches, the authors construct a one-dimensional hydrodynamic model from Yichang to Datong, and analyze the impact of different impoundment schemes on the water level of the downstream control stations during the impounding period of the project. The results show that: (1)During the impounding period, the operation of the Three Gorges Reservoir reduces the water level of each downstream station to a certain extent. Under the same impoundment scheme, October has witnessed the largest ten-day average water level changes, while November has the least. (2)In terms of the water level variation at various stations in the middle and lower reaches, the variation of Shashi station is the largest, while that of Datong station is the smallest. (3)In different impoundment schemes, the actual scheduling practice has the least impact on the ten-day average water level of each station, with the level falling $0.45 \sim 0.75\mathrm{m}$. The preliminary scheme has the greatest impact on the ten-day average water level of each station, and the level of each station in the mainstream during the impoundment period falls $0.95 \sim 2.18\mathrm{m}$.