Water quality assessment of Lugu Lake based on Nemerow pollution index method

In this paper, three monitoring sections were set up in Lugu Lake, and water samples were collected in 2019, 2020, and 2021 for the determination of physical and chemical properties such as permanganate index, chemical oxygen demand, biochemical oxygen demand (BOD₅) and so on. By using the single factor pollution index method and the Nemerow pollution index method, the water quality of three monitoring sections and the whole Lugu Lake was assessed, and the temporal and spatial changes of water quality were analyzed. The findings demonstrate that Lugu Lake's overall water quality is excellent, and that it has not altered significantly in three years.The results of evaluating the water quality by the single factor pollution index method show that, in the past three years, the water quality of the three monitoring sections and the whole of Lugu Lake is Category I, which belongs to no pollution, and the measured indicators all meet the water quality standard of Category I. It can be seen from the evaluation results of the Nemerow index method that the water quality pollution index of Lugu Lake is between 0.22 and 0.34 in the past three years and the water quality evaluation of Changdao Bay, Lake center, Zhaojia Bay and the whole are Category I standards in 2019, 2020 and 2021. In terms of time changes, the water quality of Lugu Lake has remained stable between 2019 and 2021, and the water quality has been good. From the perspective of spatial changes, in 2019 and 2020, the water quality in Lake center is better than the monitoring sections of Changdao Bay and Zhaojia Bay.