T182 Karst Environments: Problems, Management, Human Impact, and Environmental Sustainability (Posters)

Tuesday, 2 November 2010
8:00 AM - 6:00 PM
Hall D

PHYSICAL AND CHEMICAL CHARACTERIZATION OF THE REDMOND CREEK KARST AQUIFER, SOUTHEAST KENTUCKY

Paper number: T182-20
Program: Technical Sessions
Time: 8:00 AM – 6:00 PM

Authors

Abstract

Redmond Creek is a sinking stream within the karst of the Cumberland Plateau in the Otter Creek watershed of the Upper Cumberland River and is often noted as Kentucky’s largest sinkhole. Undifferentiated Quaternary alluvium of unknown thickness blankets the floor of the sinkhole and mantles much of the underlying karst between Redmond Creek Cave to the south and Natural Bridge Caverns at the downstream terminus of the sink. In all, 15 km of passage within 8 caves have been surveyed in Redmond Creek. Storm events, both documented and undocumented, have a profound impact upon the hydrogeology of this karst aquifer. This yearlong study, now underway, seeks to understand the dynamics of groundwater flow in this aquifer. In particular, we are monitoring the seasonal and short-term fluctuations of physical hydrology, ion chemistry, and isotope geochemistry of waters that enter and emerge from this late Mississippian carbonate aquifer.

In this abstract, we present preliminary data that indicates variability in specific conductance (SpC), dissolved oxygen (DO), pH, total alkalinity (Alk), temperature (T), and water level between the input and output of the aquifer and within individual storm events. Specifically, data collected every fifteen minutes from a YSI piezometer (Level Scout) and datasonde (600 XLM) at the input and output demonstrate an expected drop in pH, SpC, and DO with a corresponding rise in T following storm events recorded on a Onset HOBO microstation. Supplemental data collected every two weeks at both sites using an YSI 556 MPS and HACH Alk titrations clearly distinguish between the chemistry of the input and the output to the aquifer. For example, during our summer measurements, average values of pH, SpC, and Alk are greater at the output, 7.8, 230 μS/cm, and 82 mg/L, compared to the input, 7.1, 50 μS/cm, and 13 mg/L. In contrast, average values of T and DO are lower at the output, 14.2 °C and 11.5 mg/L, compared to the input, 16.0 °C and 9.5 mg/L.