The researchers studied water quality in Miju River and Erhai Lake from 2011 to 2016. They looked at six indicators to see how pollution levels changed over time. Results showed that the water quality in Miju River stayed fairly consistent and was only slightly polluted. Nitrogen was the main pollutant in the wet season, while dissolved oxygen and pH were important in the normal season. Overall, water quality was best in the dry season and worst in the wet season. Yinqiaocun and Jiangweiqiao sections had similar water quality trends.