The purpose of this problem was to determine the cause of tastes and odors in the Breckenridge water supply and to isolate and culture the organisms responsible for the offensive chemicals.

The purpose of this investigation is to compare the dissolved and suspended organic material in Lake Dallas to that coming into the lake through Pecan Creek.

Nutrients are of critical concern in water quality assessment. The development of empirical models to estimate mean nutrient concentrations, based on satellite derived land use, could aid water resource managers. Models using land use acreages outperformed those using percentages, and discrete urban land uses were superior to lumped urban. Regressions of the combinations of two, three and four of the eight possible land use variables were investigated. Sensitivity analyses, with one stream deleted each series, identified robust combinations of variables at each level. Although uncertainty exists regarding the final regression coefficients, five of the six actual measured nitrate and total phosphorus mean concentrations were within the 95 percent confidence limits.

Copano Bay currently exceeds fecal coliform Texas Surface Water Quality Standards for oyster water use. Aransas and Mission River Tidals currently exceed enterococci water quality standards for contact recreation use. The fecal coliform Copano Bay Bacterial Loadings Model will be used to support the TCEQ Total Maximum Daily Load (TMDL) program to develop the TMDLs for the three impaired water segments. The objectives of this research are to identify the major bacterial sources in the Copano Bay watershed, to calculate the total bacterial loadings (i.e., the TMDLs) from these sources, and to estimate the load reductions needed to bring each of the impaired segments into compliance with water quality standards. The potential bacterial sources that were considered in the model were wastewater treatment plants (WWTPs), waterbirds, livestock, failing septic systems, and other non-point sources that originate from different types of land uses (e.g., urban, forest, etc.). This thesis presents an analysis of the existing bacterial monitoring dataset for fecal coliform, including spatial and statistical analysis of the bacterial monitoring data, an estimation of fecal coliform loadings (the input into the models), including non-point and point source calculations, and a description of bacterial transport of fecal coliform from the sources in the watersheds, rivers, and Copano Bay using the model, including explanations for how the model parameters were determined. The main assumptions used in the model were that the fecal coliform bacteria decay (first-order reaction rate) in watersheds and along streams and channels, and Copano Bay is divided up into four Continuous Flow, Stirred Tank Reactors (CFSTRs). The results of the research include the modeled median fecal coliform concentrations throughout the watershed, the impact of different bacterial sources on each of the water segments in Copano Bay watershed, and the load reductions needed (and from what sources) to meet fecal coliform water quality standards. Cattle were determined (based on model results) to be the largest fecal coliform contributor of fecal coliform in Copano Bay. / text

The purpose of this study was to determine the chemical content of Denton County's (Texas) water. Based on the analysis of the three samples, the water of Denton County is classed as poor for irrigation.

The purpose of this investigation is to determine the suspended organic matter and the total phosphorus in the waters of Lake Dallas and to evaluate these findings. Since organic matter floating in lakes is largely comprised of minute plants, animals, and detritus derived from animals and plants, the fertilizing effect of phosphorus must be considered as an integral part of this problem.

Since Pecan Creek receives sewage wastes from an obviously inadequate disposal system, it seemed possible that it could receive pathogenic bacteria. The fact that these might be present in numbers sufficient to cause epidemics, provided the proper natural vectors were present, stimulated an interest in and the pursuance of this study.

The purpose of this investigation is to determine the suspended organic matter and the total phosphorus in the waters of Lake Dallas and to evaluate these findings. Since organic matter floating in lakes is largely composed of minute plants, animals, and detritus derived from animals and plants, the fertilizing effect of phosphorus must be considered as an integral part of this problem.

The Texas Stream Team (TST) is one of an increasing number of citizen science water monitoring programs throughout the US which have been continuously collecting surface water quality data under quality assurance protocols for decades. Volunteer monitoring efforts have generated monitoring datasets that are long-term, continuous, and cover a large geographic area - characteristics shown to be valuable for scientists and professional agencies. However, citizen science data has been of limited use to researchers due to concerns about the accuracy of data collected by volunteers, and the decades of water quality monitoring data collected by TST volunteers is not widely used, if at all. A growing body of studies have attempted to address accuracy concerns by comparing volunteer data to professional data, but this has rarely been done with large-scale, existing datasets like those collected by TST. This study assesses the accuracy of the volunteer water quality data collected across the state of Texas by the TST citizen science program between 1992-2017 by comparing it to professional data from corresponding stations during the same time period, as well as comparing existing and experimental data from a local TST partner agency. The results indicate that even large-scale, existing volunteer and professional data with unpaired samples that may have been taken months apart can show statewide agreement of 80% for all parameters (DO = 77%, pH = 79%, conductivity = 85%) over the 38 years of sampling included in the analyses, across all locations. The local case study using paired datasets for which a greater number of factors were controlled for show an even higher agreement between volunteers and professionals (DO = 91%, pH = 87%, conductivity = 100%) and show no significant difference between experimental and existing sampling data. The results from this study indicate that TST has been collecting water sampling data for decades that is comparable to professional data and provides compelling evidence for researchers and managers to better utilize TST's and other large-scale monitoring datasets already in existence from similar citizen science water monitoring programs across the country.

The purpose of this study was to use the Global Water Stormwater Sampler SS201 to characterize the urban runoff in Pecan Creek. Location of the samplers was influenced by land use and ease of installation. Determination of the constituents for analysis was modeled after those used in the NPDES permit for seven cities within the Dallas/Ft.Worth metroplex. Some metals, notably cadmium and arsenic, exceeded the U.S. EPA's MCL's. Statistical analysis revealed first flush samples to be significantly more concentrated than composite samples. Minimum discharge loadings were found to be significantly lower than maximum discharge loadings. Additionally there were significant differences of specific constituents between station locations and storm events.