The study looked at how the Three Gorges Dam in China affects the water flow in the Dongting lake downstream. By using a computer model, the researchers found that the dam reduced the amount of water flowing into and out of the lake, especially in October. This decrease in water exchange caused the lake's water level to drop and its volume to decrease. The dam also increased the speed of water flow in the lake, leading to changes in its overall hydrology. These findings help us understand how dam operations can impact large river-lake systems and provide insights for managing similar environments.