Research on the Integrated Analysis of Water Quality and Spatial-Temporal Changes in Qionghai Lake

This paper used data from 2019, 2020, and 2021 to assess the water quality of Qionghai Lake using the traditional and improved Nemerow pollution index methods. To analyze the pattern of change in water quality between different Qionghai monitoring sections, a spatial-temporal change rate calculation was conducted. According to the traditional Nemerow pollution index method, assessment results for 2019, 2020, and 2021 show that Qionghai as a whole, along with the Qinglong Temple water quality monitoring section, the Qionghai Hotel, and the lake center, all had Class I, superb water quality. However, Qionghai's water level was Class I in 2019 and 2021, according to the results of the improved Nemerow pollution index method, while the water quality assessment for 2020 showed that the water quality was Class II, with good but inconsistent water quality across the 3 years. From 2019 to 2020, the overall lake quality and the water quality of the lake center, Qionghai Hotel, and Qinglong Temple section have all experienced a significant decline of more than 20%. In 2021, there will be more than 20% substantial improvement in water quality. Qionghai Hotel experienced a slight decline of 10% to 20% in 2019 and a sharp deterioration of more than 20% in 2020. There was no significant difference in water quality changes between Qionghai Hotel and the Qinglongsi section between 2019 and 2020, and the change range was less than 10%.