T154 Characterization of Karst Aquifers Using Chemical, Biological, and Hydrogeological Data

Tuesday, 17 October 2023
8:00 AM - 12:00 PM
310 / 311

GEOCHEMICAL CHANGES IN GROUNDWATER SEEN FOLLOWING A LAKE-DRAINING SINKHOLE EVENT IN NORTH FLORIDA, USA

Paper number: T154-3
Program: Technical Sessions
Time: 8:25 AM – 8:40 AM

Authors

  • Ming Ye Presenting Author
    Florida State University, Tallahassee, FL
  • Kyle Compare
    Florida State University, Tallahassee, FL

Abstract

The karst environments of Florida experience rapid groundwater-surface water interactions through surface water flow through sinkholes. A particular case highlighting this process is a lake dry-down event, in which a lake periodically drains into a karst aquifer through sinkholes within the lakebed. These events have been recorded throughout Florida, but are particularly common within the lakes surrounding Tallahassee, with 11 dry-downs having occurred in three different lakes over the past five years. With this rapid influx of surface water into the karst aquifer, there are questions concerning the impacts of these events on groundwater geochemistry. This research examines the chemical impacts of multiple dry-downs of Lake Jackson, which is located in Tallahassee, FL., on groundwater collected 10 miles downgradient of the lake. Daily groundwater sampling of the well has shown distinct shifts in groundwater chemistry, leading to changes in the hydrofacies of the groundwater, following the dry-downs. In this research, we explain the chemical changes through two processes of (1) dilution of carbonate rich waters within the karst aquifer and (2) the chemical weathering of the siliciclastic confining unit as the lake water flows through the sinkhole into the aquifer. Chronical impacts of the dry-down events on aquatic ecosystem have not been studied.

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

doi: 10.1130/abs/2023AM-390645

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.