Date of Graduation

9-2025

Document Type

Thesis

Degree Name

Master of Science in Geology (MS)

Degree Level

Graduate

Department

Geosciences

Advisor/Mentor

Covington, Matthew

Committee Member

Brian Haggard

Third Committee Member

Kevin Befus

Keywords

Caves; Geology; Water quality

Abstract

The Ozark Cavefish is one of multiple species of conservation concern found in Cave Springs Cave and Logan Cave in Northwest Arkansas (NWA). Over the past two decades, the urbanization of NWA has negatively impacted the recharge areas of both caves, and in turn the water quality of both cave streams. The changing climate has also altered temperature and precipitation, which influence many aspects of karst groundwater. These effects are shown in the historical water quality records for both caves. However, these records are from varied sources and have never been comprehensively compiled and analyzed. This thesis approaches the issue of degraded water quality for these biologically significant caves through compiling a historical database of physical and chemical water measurements for analysis and comparing water quality trends with changes in land use and climate in the recharge areas, as well as comparing trends between each cave. The analysis identified significant differences, trends, and correlations with water temperature, dissolved load, nutrients, and metals. Total dissolved solids, alkalinity, pCO2, calcium, magnesium, and barium concentrations were significantly higher at Cave Springs compared to Logan Cave. Orthophosphate was significantly higher at Logan Cave compared to Cave Springs. At Cave Springs, water temperature, barium, and magnesium increased from 1999 to 2025. At Logan Cave, pH, inorganic nitrogen, and magnesium increased. Before 2015, nitrate concentrations were significantly higher at Cave Springs, but after 2015 the concentrations were higher at Logan Cave. Water temperature was positively correlated with air temperature at Logan Cave, but not at Cave Springs. Calcium was negatively correlated with discharge, and both barium and magnesium were positively correlated with discharge. Both land cover and climate change are likely to contribute to these results, especially with water temperature, nutrients, and metals. The similarities in climate conditions between the two caves indicate many of their differences can be attributed to the different land cover in their recharge areas, as well as to how those land cover differences exacerbate or buffer climate change signals. The analysis was limited by uncertainties in measurement data and constraints of the statistical calculations. Due to the various sources, measurement frequency, conditions, and methods were inconsistent. Both the chemical and statistical calculations required assumptions that simplified the actual conditions. Future research will need to continue monitoring both sites, as well investigate more comprehensively the agricultural operations and urban developments of the recharge areas beyond the scope of the National Land Cover Dataset. The data collected for this thesis will be publicly archived for future use in the conservation and management of these biologically significant caves.

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