Geological Society of America

T178 Karst Hydrology and Hydrogeology (Posters)

Tuesday, 17 October 2023
8:00 AM - 5:30 PM
Hall B

COMPARISON OF ELECTRICAL CONDUCTIVITY AND TEMPERATURE DATASETS ALONG A KARST SINK-RISE FLOW SYSTEM TO INFER FLOW DYNAMICS

Paper number: T178-7
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Esther Lam Presenting Author
Wheaton College, Wheaton, IL
Matthew Covington
University of Arkansas - Fayetteville, Fayetteville, AR
Megan Noble
Department of Earth and Environmental Science, Wheaton, IL
Andrew Luhmann
Department of Earth and Environmental Science, Wheaton, IL
Han Byul Woo
New Mexico Institute of Mining and Technology, Socorro, NM
Jacob A. Gochenour
New Mexico Institute of Mining and Technology, Socorro, NM
Susan Bilek
New Mexico Institute of Mining and Technology, Socorro, NM
Ronni Grapenthin
University of Alaska, Fairbanks, Fairbanks, AK
Jonathan B. Martin
University of Florida, Gainesville, FL
Madison Flint
University of Florida, Gainesville, FL

Abstract

Karst aquifers are important water resources and facilitate rapid groundwater flow through conduits. Electrical conductivity and temperature are two parameters which can be used to infer aquifer flow dynamics. We collected a three-year dataset from the Santa Fe River Sink-Rise system, where water from the Santa Fe River sinks underground upon encountering a swallet at River Sink, flows through conduits that are ~20 m in diameter and ~30 m below the surface, periodically reemerges at karst windows, and eventually discharges at River Rise. Our dataset includes water level, electrical conductivity, and temperature that were collected every 2 to 4 minutes at River Sink, River Rise, and five intermediate karst windows. We identified distinctive features (maxima or minima) in the electrical conductivity and temperature datasets and use them as a proxy for travel time by comparing the times they appear at upstream and downstream monitoring locations. We tracked 85 distinctive temperature events and 78 electrical conductivity events. Very few of the distinctive electrical conductivity features at River Sink correspond to the same times as the distinctive temperature features, making it difficult to compare travel times calculated from individual events of the two datasets. However, we found an inverse relationship between travel time from electrical conductivity or temperature and River Sink discharge (temperature produced a stronger relationship), and the relationships indicate that temperature has longer travel times than conductivity. Electrical conductivity and temperature events at the karst window Hawg Sink showed unique characteristics when compared to records at other surface water monitoring locations, suggesting that this site is more diluted by water from other flow paths beyond the water that enters River Sink. We also use the inverse relationships to assist cross correlations of longer windows of data to assess how travel times for electrical conductivity and temperature vary throughout hydrograph rising limbs, peaks, and recessions to infer mixing dynamics during aquifer recharge events.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-395595

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