The average Chl-a concentration (Fig. 5) in Qinshan Lake was 12.83 mg/m3 and CODMn concentration was 3.43 mg/L, with 4.38 mg/L being the highest in December and 1.78 mg/L being the lowest in February. The average trophic level index (TLI) of Qinshan Lake was 53 (Fig. 6), exceeding the minimum eutrophic criterion.