Water Quality Evaluation of Wenyu River Based on Single Factor Evaluation and Comprehensive Pollution Index Method

Wenyu River is the “mother river” in Beijing. In recent years, the research on the water quality of the Wenyu River has increased gradually. In this paper, the monitoring data at Shahe Reservoir, Lu Tuan Gate, Xin Bao Gate, and Ma Fang sections for each month in 2019 were adopted. The single-factor evaluation method and the comprehensive pollution index method were selected to analyze the current situation of the water quality of Wenyu River in the Chang Ping section and its temporal and spatial variation trend. The single factor evaluation method showed that the dissolved oxygen exceeded the standard seriously in all other months of the year except that the situation was better in May, June, and July. The ammonia nitrogen content reached the highest level in January, followed by a month-by-month decreasing trend. After June, each section basically met the requirements of Class v water quality. The comprehensive pollution index method shows that the water quality of Shahe reservoir varies greatly throughout the year, and it is in grade v for 6 months. The evaluation results of both methods show that the water quality of all sections of Wenyu River in 2019 was mostly in category v