Assessing the Sensitivity of Water to Surface, Soil, Rock, and Cave Conditions in Fitton Cave, Northern Arkansas
University of Arkansas at Little Rock (UALR), Master of Science in Integrated Science and Mathematics program Little Rock, AR; [email protected]
Fitton Cave, located within the Buffalo National River in north-central Arkansas, offers a window into a relatively pristine portion of the Ozark Plateau Aquifer. This region is one of the largest karst aquifers in the United States, providing more than 1.8 million people with drinking water. Understanding what happens to water as it moves from the surface to subsurface is requisite for utilization, management, and sustainability of karst aquifers as water resources. As population pressures increase, assessment of geochemical and hydrologic processes from pristine systems such as Fitton Cave will prove extremely valuable for providing baseline conditions. By integrating vascular plant biomarkers and GIS, along with traditional dye tracing and geochemical methods, we are better able to define the sources of chemical change to water as it interacts along flowpaths with soil, rock, and cave conditions in the karst system.
Preliminary results indicate there are at least three distinct sources of water to the subsurface hydrology. Based on elevated EC, alkalinity, and manganese levels in one cave stream signify more extensive water-host-rock interactions compared to an adjacent stream, despite their morphologic, stratigraphic, and hydrologic similarities. Directly observed flowpaths in conjunction with total organic carbon concentrations from sinking streams illustrate strong influence of surface runoff and rainwater inputs to the cave system without protracted reservoir storage. By integrating the karst system’s geochemical heterogeneity, we are able to delineate likely flow paths and provide critical information about how karst aquifers respond under near-natural conditions.
AAPG Search and Discovery Article #90083 © 2008 AAPG Foundation Grants in Aid