The researchers analyzed how the Three Gorges reservoir affects the flow of the Yangtze River and Dongting Lake. They found that changes in lake inflow and river outflow are key factors in regulating the flow in the lake. After the reservoir was filled, the flow at different outlets varied, with some decreasing and others increasing. By studying the water balance, they identified a critical water level for Dongting Lake, which depends on the inflow and outflow rates. This study helps estimate how much the Three Gorges reservoir impacts the water levels in Dongting Lake.