Date of Award

Summer 8-5-2023

Degree Type


Degree Name

Master of Science - Environmental Sciences


Environmental Science

First Advisor

Dr. Matthew McBroom

Second Advisor

Dr. Yanli Zhang

Third Advisor

Dr. Yuhui Weng


In 2004, bacteria and nutrient sampling on the Attoyac Bayou Watershed discovered elevated concentrations of E. coli on five of the main channels key tributary streams. The Attoyac Bayou was then listed on the Texas 303d list of impaired waterbodies and further research was conducted to identify the main sources of contamination in the waterbody. In 2016, the Attoyac Bayou Watershed Plan (WPP) was developed to implement best management practices (BMPs) that would decrease bacteria and nutrient concentrations in the watershed. Educational outreach programs, on-site-sewage facility repair, and livestock management were some of the strategies suggested by the protection plan that sought to decrease bacteria across the watershed. Monthly water quality sampling on five sampling locations across the watershed has been conducted from 2010 to 2022 to monitor changes in water quality and quantity. Data from 2010 to 2022 were separated into pre-implementation plan and post-implementation plan periods in order to determine the effectiveness of these strategies in lowering bacteria and nutrient concentrations. E. coli concentrations currently remain elevated above the primary contact standard of 126 CFU/100mL when data from all five sampling sites are compared. On a per site basis, there was no significant change in E. coli concentrations in four of the five sampling sites. Concentrations at the fifth sampling location, Waffelow Creek, increased significantly. Waffelow Creek also had the greatest increase in the frequency of E. coli concentrations violating the standard of 126 cfu/100ml, with 53% of samples violating the standard during the pre-WPP period and 86.5% of samples violating the standard in the post-WPP period. Continued water quality monitoring is required in order to more accurately assess the efficacy of the Watershed Protection Plan and address potential sources of contamination from Waffelow Creek across time and weather conditions. Due to higher post-WPP period streamflow rates, annual mass loading of E. coli increased significantly in the post-WPP period on the three largest sub-watersheds (Attoyac, Big Iron Ore Creek, and Naconiche Creek) indicating that additional monitoring is warranted for these watersheds as well.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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