Urban stormwater runoff from different types of roads in Shenzhen, China can pollute rivers. The study looked at runoff from arterial roads, residential areas, and industrial areas. They found that runoff from residential areas was a major source of pollutants like ammonium, chemical oxygen demand, and total phosphorus in the river. To reduce pollution, controlling the first flush of runoff is important, especially during heavy rainfall. Different types of land use require different management strategies - reducing solid particles in runoff from roads is effective for arterial and residential areas, while collecting and reusing stormwater early on helps with soluble pollutants in industrial areas.