The researchers used a model called SWAT to study pollution in the Three-Gorge Reservoir watershed. They looked at data from 2002 to 2008 and found that the model was successful in simulating stream flow and sediment, but less accurate for nutrients. They also found that surface runoff and sediment were closely related to precipitation, with sediment peaking earlier. Nutrient load, especially phosphorus, was linked to sediment. Crop fields were the biggest source of pollution, so changing cultivation methods is important to reduce pollution. The SWAT model can help control non-point source pollution in the area.