Date of Award
Master of Public Health (MPH)
INTRODUCTION: Beaver Dam Analogs (BDAs) have been installed along Mill Creek to help improve water quality. As a feeder creek into the impaired creek Nancy Creek, it would be beneficial to improve water quality in Mill Creek. Nancy creek is listed on Georgia’s 303(d) list as an impaired stream. The EPA classifies a stream as impaired if the E. coli levels are consistently over 2.1 Log10/100mL, among other standards.
AIM: Compare the level of E. coli in the water before the beaver dam analogs were installed to the level of E. coli in the water after the beaver dam analogs were installed. In addition, the spatial difference of E. coli levels was also investigated.
METHODS: Fifteen water samples were collected each week from the same sites that were marked by stakes on the bank of the creek. The water samples were then processed through membrane filtration. The filter was plated on BioRad RAPID'E. coli 2™ medium and incubated at 37 degrees Celsius for 18 – 24 hours. Once the plates were removed, the colonies were counted. The data was collected from March 2018 to April 2021.
RESULTS: A One-Way ANOVA test was conducted on the data through the program GraphPad Prism 8. When comparing the dates over time it showed that the E. coli levels did differ significantly over time. This adds evidence that the beaver dam analogs (BDAs) do impact the E. coli levels. However, while the ANOVA test showed a significant difference the majority of the data was over the EPA's water quality limit of 2.1 Log10/100mL. Another One-Way ANOVA was run spatially (site-to-site), and it was found that there was no significant difference in the E. coli levels between the fifteen sites.
DISCUSSION: Overall, the data showed that the beaver dam analogs were not effective in improving E. coli levels of Mill Creek. While there was a significant difference between the E. coli levels between dates, there were data points above the EPA's limit of 2.1 Log10/100mL. While the beaver dam analogs did not improve water quality, they also did not decrease water quality. Therefore, the beaver dam analogs had relatively no change on Mill Creek's water quality.
Daniel, Jordan, "Temporal and Spatial Evaluation of the Relationship between Beaver Dam Analogs (BDAs) and E. coli Levels." Thesis, Georgia State University, 2021.
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