29-1 Hydrochemical Signatures of Scarp and Dip-Slope Drainage in the Valley and Ridge Region

Session: Undergraduate Research, Part II (Posters)

Presenting Author:

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Abstract:

Mountainous watersheds in the southeastern United States exhibit complex subsurface flow pathways that strongly influence stream baseflow and downstream water quality. In the Valley and Ridge physiographic province, dipping sedimentary bedrock may create contrasting hydrologic behavior between dip slopes and scarp slopes. We hypothesize that streams draining dip slopes receive a greater proportion of baseflow from longer, inner-mountain subsurface flowpaths, while scarp slopes are dominated by shorter, more rapid flowpaths, influenced more by surface geology.

To evaluate the role of geologic structure in hydrologic connectivity, we analyzed hydrochemical signatures from  scarp and dip slopes of Brush Mountain, VA. Water chemistry samples were collected from ten sites over a two-month period and analyzed for major and trace elements, including Ca, Mg, Na, K, Si, and Sr. Streams draining the dip slope exhibited consistently higher concentrations of Li, Mg, Na, and Si, suggesting increased water–rock interaction and longer subsurface residence times. In contrast, scarp slope streams generally showed lower solute concentrations, consistent with more rapid flowpaths and reduced bedrock contact. Principal component analysis further distinguished dip-slope and scarp-slope sites, with several sites clustering according to geochemical signatures indicative of differing flow regimes. 

These results support the hypothesis that bedrock orientation exerts a strong influence on subsurface flow routing and water chemistry, with important implications for understanding hydrologic connectivity, water quantity, and nutrient transport in Appalachian landscapes.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

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