Rainfall-runoff events in the Chaohe River watershed were studied to understand how pollutants move in flood seasons. The researchers monitored water quantity and quality during heavy rainstorms in 2018 and 2019. They found that heavy rainfall led to higher pollutant concentrations, especially total nitrogen and phosphorus. Different rainfall events caused variations in pollutant concentrations, with some events causing soil erosion and others not. Particulate pollutants were linked to soil erosion, while nitrogen and phosphorus forms were related to water flow. The Gubeikou station showed more significant changes in discharge and pollutant levels during heavy rainfall. These findings help predict and control water pollution in flood seasons.