Firn, Heather B.S., Southern Connecticut State University, 2009 M.S., Southern Connecticut State University, 2013

Characterization of an Urban Watershed: The Case

for Rowlett Creek Watershed Impaired by Bacteria

and Nutrient Concerns

Advisor: Professor Wenjie Sun

Master of Science conferred May, 15, 2021

Thesis completed April, 27, 2021

Water quality and its relationship with urbanization is one of many nationwide environmental concerns. Rowlett Creek is located in an urban watershed in the Dallas-Fort Worth Metroplex. Since 2014, it has been listed by the Texas Commission on Environmental Quality as impaired for bacteria and as a screening limit concern for nitrate. Water quality samples were collected and analyzed for several parameters including flow, Escherichia coli (E. coli), total suspended solids (TSS), nitrate (NO3-), nitrite (NO2-), total Kjeldahl nitrogen (TKN), ammonia as Nitrogen (NH3), total phosphorus (TP), pH, specific conductivity, dissolved oxygen (DO), and temperature. Load duration curves were developed to identify non-point source and point source pollutant concerns. The influence of land cover on water quality was also investigated. Analyzation of this watershed showed that E.coli, Nitrate + Nitrite, and TSS are non-point source concerns. Low flows indicate pollutants stem from point source and potentially non-point source. High flow conditions, Moist conditions, and Mid-range conditions are a source of non-point pollutants. Land cover between Rowlett Creek headwaters and outlet to Lake Ray Hubbard impacts pollutant concentration in the watershed, increasing flow and concentrations per acre. Best management practices are needed for all flow conditions. Green infrastructure, such as rain gardens and bioretention areas, is an implementation strategy to mitigate non-point source pollutants during rainfall events. Public outreach and education as a pollutant mitigation strategy are needed for all flow conditions, specifically low flows, to change human practices. Wastewater effluent into Rowlett Creek also needs to be further investigated.

Degree Date

Spring 5-15-2021

Document Type


Degree Name



Civil and Environmental Engineering


Wenjie Sun

Second Advisor

Fouad Jaber

Subject Area

Civil Engineering

Number of Pages




Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License