The impact of land use on water quality at different spatial scales in the area around Chaohu Lake region.

This study focuses on the area around Chaohu Lake region, utilizing data from the 2021 national surface water quality monitoring stations and land use data from territorial surveys. Employing GIS spatial analysis, non-parametric tests, Spearman correlation analysis, and redundancy analysis (RDA), the research examines how land use types within different buffer zone scales affect water quality. The findings indicate: (1) The dominant land use types in the study area are cultivated land, construction land, and water areas. (2) Overall, water quality is better in the dry season than in the rainy season, with higher concentrations of CODMn and TP occurring in the rainy season, and higher concentrations of DO, NH-N, and TN in the dry season. (3) Cultivated land and construction land are positively correlated with all water quality indices, whereas forest lands and water areas generally exhibit a negative correlation. The correlation between grasslands and water quality indices alternates with changes in spatial scale. (4) Within a buffer zone of 3,000 m, land use has the greatest impact on water quality, making it the optimal scale for assessing the influence of land use on water quality indices in the area around Chaohu Lake region (93.35%).