Study on the water eutrophication evolution characteristics of Junshan Lake

Abstract

In this paper, the comprehensive nutritional status index (TLI) method was utilized to evaluate the water quality and nutritional status of Junshan Lake from 2018 to 2020. Combining the tools of ‘create fishnet’ and ‘inverse distance weight’ in ArcGIS, the spatial distribution map of the comprehensive trophic index of Junshan Lake was generated. The results show that: (1) The water quality of Junshan Lake was deteriorating year by year. The comprehensive nutritional index (TLI) of Junshan Lake in 2018, 2019 and 2020 were 24.12–31.93, 25.27–35.84, and 26.15–46.87, respectively. The nutritional status of Junshan Lake was dominated by Grade I (Oligotropher) in 2018, and by Grade II (Mesotropher) in 2020; the proportion of water in Grade II (Mesotropher) rose from 24.5% in 2018 to 78.6% in 2020; (2) Aquaculture makes a great contribution to the increase in the lake nutrition level, and the comprehensive nutritional index of the aquaculture area is relatively high; (3) The comprehensive nutritional index value of the water body in the southern part of Junshan Lake is higher than that in the northern part, and the risk of converting to Grade III (light eutrophication) is higher.