The Xinan River in China has been seriously polluted due to economic development. A study analyzed water quality during different periods and found that pollution was severe during low-water periods, with high levels of COD, ammonia nitrogen, and total phosphorus. Water quality improved during level and high-water periods, but ammonia nitrogen and total phosphorus remained a concern. Tributaries like Lubao River had good water quality, while others like Damian River were heavily polluted. The study identified industrial, agricultural, and domestic sources of pollution and suggested corresponding control measures.