A DETAILED HYDROLOGIC STUDY OF THE SCOTT HOLLOW GROUNDWATER DRAINAGE BASIN, GREENBRIER AND MONROE COUNTIES, WEST VIRGINIA

Scott Hollow Cave is a major (>43 km) vadose conduit system developed within a mature karst upland in Greenbrier and Monroe Counties, West Virginia. Previous mapping and dye tracing revealed that the cave drains an estimated 48.2 km², with a major conduit transmitting water northward to discharge at the Greenbrier River. The majority of conduits are developed in the lower units of the Greenbrier Group (Mississippian), especially the Hillsdale and Sinks Grove Limestones.

For the present study, a series of qualitative dye tracer tests were conducted in order to help redefine the Scott Hollow groundwater basin and establish hydrologic connections between the surface and subsurface, in conjunction with a water quality analysis. The dye trace utilized multiple dyes, including Sodium Fluorescein, Rhodamine WT, and Eosin, which were monitored using activated charcoal detectors. The water quality analysis was preformed monthly for the duration of one year. Nitrates and total coliform counts were analyzed to determine if surface agriculture practices have a direct impact on the cave environment below.

Based on dye tracer test results in this complex karst setting, groundwater flow appears to be strongly influenced by the local structure and stratigraphy. On a small scale, three dyes were injected in the main entrance sink within close proximity to one another and were detected in two separate sections of Scott Hollow Cave. On a larger scale, tracer tests conducted in the eastern section of the groundwater basin appear to be flowing toward the south, wrapping around the nose of the plunging Sinks Grove Anticline, and then flowing to the north. Another dye trace conducted in this area yielded even more complex results. Dye was detected at a spring fed stream outside of the proposed groundwater basin and in Scott Hollow Cave, therefore extending the eastern boundary.

Water quality results varied throughout the cave. Surface water coming from areas with high intensities of cattle and row crops contained higher nitrates and total coliform counts with values ranging from 4 to 47mg/L. These results were also compared to local total precipitation rates. During drier periods, nitrates and coliform values were substantially lower, versus times when precipitation was high, indicating that seasonal variations do influence water quality as well.