The study looked at how the flow of water from the Yangtze River to Dongting Lake changed over time. They found that the amount of water diverted depended on the water level in the Jingjiang River and the erosion/deposition depth of the diversion channels. From 1955 to 1990, the flow decreased due to lower water levels and more sediment in the channels. From 1990 to 2002, there were small changes in these factors and the diversions. After the Three Gorges Reservoir was built, sediment discharge decreased, leading to changes in the flow of the diversions. The water level in the Jingjiang River didn't drop much, but the riverbed elevation in the outlets decreased, so the diversion ratio stayed the same.