Land use changes in a large lake watershed in China were studied using a tool called SWAT. Different land use scenarios were tested, showing that changes in land cover affect water flow patterns. Forest areas decreased water yield by 1.8% while agriculture areas increased it by 4.2%. Surface runoff was most affected, decreasing by 8.2% in forest areas and increasing by 8.6% in agriculture areas. These findings suggest that land use regulations can help coordinate flood and drought mitigation efforts in specific areas.