104-9 Analyzing doline distribution in a karstic environment, and its relation to Escherichia coli contamination

Session: A Showcase of Undergraduate Research in Hydrogeology (Posters)

Presenting Author:

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Abstract:

Recent examinations into the water quality at Austin Peay State University’s farm have indicated the presence of Escherichia Coli or E. Coli. The farm is located in a karstic environment, making the groundwater in the area more prone to contamination. While E. Coli is generally not harmful to cattle, exposure can lead to gastrointestinal issues, dehydration, and even death in calves. While calves have access to treated water at the farm’s main building, it is essential that the calves have access to clean well water out in the field.

To project potential pathways for E. Coli to travel through, dolines in the region were plotted on a 1954 Clarksville, TN topographic map using GIS. Current aerial imaging was then paired with this map to see the distribution of the dolines and their expansion over time. Once the dolines were plotted, their short and long axes were measured to determine their geospatial orientation. Nearest neighbors were then assigned to each doline, so a Nearest Neighbor Index could be calculated. Based on preliminary results, the Nearest Neighbor Index for the region indicates that the dolines on the farm have a random distribution with instances of clustering. Results also indicate that some of the sinkholes have a preferred orientation in the NE-SW direction.

Future work on the farm will include water quality testing to determine the most probable number of  E. coli per 100 mL of water relative to precipitation data.  To investigate the effects of precipitation on E. Coli movement in this karstic environment, water samples will be collected in several locations around the farm during different weather conditions over a four-month period. Samples will be collected on a day before precipitation, during precipitation, and after the precipitation to see if there is any impact on the amount of E. Coli. In investigating this karstic environment, the goal is to determine potential pathways for E. Coli distribution by examining dolines in the region and water quality testing; ultimately ensuring a clean water supply for the cattle.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8803

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