Assessing the impact of land fuse on water quality in the Chesapeake Bay Watershed

This study examines the relationship between land use composition and key water quality indicators: Total Nitrogen (TN), Total Phosphorus (TP), Total Suspended Sediments (TSS), and Dissolved Oxygen (DO) across tidal and non-tidal sub-watersheds of the Chesapeake Bay from 1992 to 2016. Principal Component Analysis (PCA) followed by clustering and statistical testing was conducted to assess differences in nutrient composition across land use types. Results reveal that agricultural land is strongly associated with elevated total nitrogen in non-tidal settings (PC1 loading = -0.69; TN = -0.77), and moderately in tidal settings (PC3 loading = -0.40; TN = -0.40), while urban development shows a stronger linkage with total phosphorus in non-tidal watersheds than in tidal watersheds (PC1 loading = -0.44; TP = -0.63). ANOVA results further indicate that dissolved oxygen significantly distinguishes tidal watershed clusters (p < 0.05), whereas total nitrogen is the primary variable differentiating non-tidal watershed groups (p = 0.019). PC scores were statistically significant with a p-value<0.001, suggesting that the nutrient composition differs significantly based on the land cover. While nutrient conditions improved in some regions, persistent degradation remains in the Susquehanna River basin, highlighting spatial variation in land use impacts and the need for targeted nutrient management.