2.4 Statistical analysis and visualization
Before nutrient assessment, 10 water quality indicators were first briefly analyzed over time. Following this, Pearson Correlation Analysis was applied to analyze the correlation between water quality parameters. Afterward, CA and ANOVA grouped the sampling times of the reservoirs into clusters to analyze whether there was variability in the water quality parameters between the clusters. Finally, the TLI method was used to calculate the TLI( Σ ) for the three reservoirs and determine the degree of reservoir eutrophication. In this study, the geographic distribution of the reservoirs was drawn through ArcGIS 10.8 software, and each monitoring indicator was statistically and analytically analyzed using SPSS 26.0, and mapping was performed using Origin 2021 software (Liu et al., 2022).