Land Cover Effects on Stream Water Chemistry in the Upper Saline River Watershed

Author

Brandy Everett, University of Arkansas, FayettevilleFollow

Date of Graduation

12-2024

Document Type

Thesis

Degree Name

Master of Science in Environmental Dynamics (MS)

Degree Level

Graduate

Department

Environmental Dynamics

Advisor/Mentor

Haggard, Brian E.

Committee Member

Speir, Shannon

Second Committee Member

Munich, Rebecca

Keywords

Environmental Monitoring; Stream Chemistry; Watershed Management

Abstract

Non-point source (NPS) pollutants and the conversion of natural areas to anthropogenic uses are one of the most critical stressors on water quality. The Upper Saline River Watershed has seen an increase in anthropogenic land cover over the last two decades, leading it to be previously identified as a 319 NPS priority watershed in Arkansas. This study used publicly available data to assess the magnitude and trends of total nutrients (TN and TP) at both the watershed and site level scale. Results suggest a decrease of 2.6%/yr in TN concentrations and 1.5%/yr in TP concentrations at the watershed scale. While eight out of ten sites analyzed at the site level scale also showed decreasing TN and TP trends. Nonparametric change point analysis (nCPA) and classification and regression tree analysis (CART) were also applied to explore interactions between several watershed metrics and collected stream water quality data. Water samples were collected 11 times at 29 sites and analyzed for chloride (Cl-), nitrite-N (NO₂-N^-), dissolved nutrients (soluble reactive phosphorus (SRP), ammonia (NH₃-N), nitrate-N plus NO₂-N^- (N+N)), total nutrients, total suspended solids (TSS), turbidity, and conductivity. Based on the observed models, key thresholds were identified to protect water quality and reduce NPSs, areas with less than 25% catchment natural forest land cover, less than 75% catchment total forest land cover, less than 60% total forest cover within riparian buffer zones, an unpaved road density exceeding 1.0 km/km², and a stream density exceeding 1.0 km/km² are recommended to be prioritized.

Citation

Everett, B. (2024). Land Cover Effects on Stream Water Chemistry in the Upper Saline River Watershed. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5567