172-5 Relationship between Human Activities and Changes in Water Chemistry: A case study of Falling Water River watershed, Cookeville Tennessee

Session: Urban Geochemistry

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Abstract:

The hydrochemistry of water is used to track water pollution, which emanates from human activities in watersheds. The sources of hydrochemicals are complex, and therefore, further research is required for a comprehensive understanding of the impact of human activities on water quality. The relationship between human activities and water chemistry is thus illustrated in this case study of the Falling Water River Watershed. To better understand the relationship between water chemistry and human activities, 18 hydrochemical data points were collected in three sub-watersheds: Cane Creek, Taylors Creek, and Falling Water River (upper). In the Falling Water River (upper) watershed, the largest proportion of land cover is forest (48.10%), followed by developed (28.62%), mainly the City of Cookeville, and cultivated (21.37%), vegetated. In Taylors Creek, cultivated (59.84%) land cover type is the dominant land use, followed by forest cover (29.29%) and developed (10.87%). Cane Creek is 51.62% cultivated, 27.98% forest, and 20.40% developed. The PCA plot separated the water samples into three groups. Falling Water River (upper) has the highest concentrations of Chloride (Cl), Sodium (Na), and Sulfate (SO₄), and a lower dissolved oxygen (DO) concentration. Taylor Creek and Cane Creek, some of the samples have the highest dissolved oxygen (DO), nitrate (NO₃), magnesium (Mg), Calcium (Ca), and alkalinity compared to the Falling Water River water quality data. The Cane Creek end member has increased potassium (K) concentration. Concentrations of Chloride (Cl) and Sodium (Na) strongly correlate and also positively correlate with Sulfate (SO₄), Calcium (Ca), and alkalinity (as CaCO₃). Also, nitrate (NO₃) strongly correlates with Mg, and they positively correlate with dissolved oxygen (DO) concentration. The Piper plot shows the pattern Ca-Mg-Alkalinity-NO₃ water in Cane Creek and Taylors Creek, and Na-SO₄-Cl water in the Falling Water River. Ca, Mg, and HCO₃ normalized by Na indicate freshwater changing from carbonate-dominated water to evaporite composition. The Falling Water River shows the most significant change towards evaporite composition. Correlation plots provided insights into the sources of ions present in waters. The study shows that the more urbanized Falling Water River watershed has a chemical composition distinct from Taylor’s Creek and Cane Creek. This study results have implications for city planning and studies in water-dependent ecosystems.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11265

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