This thesis is a contribution to the work of the Texas Environmental Observatory (TEO), which provides environmental information from the Greenbelt Corridor (GBC) of the Elm Fork of the Trinity River. The motivation of this research is to analyze the short-term water dynamic of soil in response to the substantial rainfall events that occurred in North Texas in 2007. Data collected during that year by a TEO soil and weather station located at the GBC includes precipitation, and soil moisture levels at various depths. In addition to these field measurements there is soil texture data obtained from lab experiments. By comparing existing water dynamic models, water balance equations were selected for the study as they reflect the water movement of the soil without complicated interrelation between parameters. Estimations of water flow between soil layers, infiltration rate, runoff, evapotranspiration, water potential, hydraulic conductivity, and field capacity are all obtained by direct and indirect methods. The response of the soil at field scale to rainfall event is interpreted in form of flow and change of soil moisture at each layer. Additionally, the analysis demonstrates that the accuracy of soil characteristic measurement is the main factor that effect physical description. Suggestions for model improvement are proposed. With the implementation of similar measurements over a watershed area, this study would help the understanding of basin-scale rainfall-runoff modeling.

The lower Trinity River in Texas flows 180 river kilometers from Livingston Dam to Trinity Bay. Like many sandy coastal rivers the lower Trinity is geomorphically active. Within this 180-km reach, the river exhibits three styles of channel geometry and kinematic behavior that have been characterized using aerial photographs spanning the past 60 years, as well as bathymetric surveys and field work completed over the past 5 years. The three channel zones are connected to spatial change in properties of the sediment transport field. The upstream zone is defined by channel-bed incision, relatively small and coarse-grained bars, and relatively low rates of lateral channel migration. These properties of the upstream zone are connected to the discharge of water with effectively no bed-material load from Livingston Dam. Eventually the channel flow scours enough sediment from the channel bed and sidewalls to reestablish the predicted transport capacity for sand in the river, marking the transition to the central zone. This zone is defined by the largest bars and channel bends with the highest rates of lateral migration that persist downstream until the transport of sand and gravel is influenced by the backwater hydraulics connected with the shoreline at Trinity Bay. This downstream river zone is characterized by very small point bars, the deepest flows at most discharges, and lower rates of channel migration. Studying the connections and transitions between these three river zones leads to a more complete understanding of the coevolution of river geometry and profile, channel kinematics, and downstream change in sediment transport in the coastal zone. / text

Thesis (M.S.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.

The Trinity River passes through the Dallas-Fort Worth metroplex receiving point and non-point source contaminant loadings. Lepomis spp. were collected at twelve sampling locations in the Trinity River in August 1987 and September 1988 and analyzed for organochlorine pesticides and heavy metals. Results from the study were compared to existing U.S. FDA action and tolerance levels, LC50s, and historical data. Various longitudinal trends and some concentration patterns were observed. Continual study of pesticide and metal body burdens in fish allow testing for trends, and thereby, lead to a better understanding of the distribution of contaminants in the Trinity River.

Surfactants are used in a wide assortment of "down-the-drain" consumer products, yet they are often discharged in wastewater treatment plant effluent into receiving water, potentially causing environmental harm. The objective of this project was to predict surfactant toxic units and in-stream nutrients in the upper Trinity River watershed. Surface and pore water samples were collected in late summer 2005. General chemistries and surfactant toxic units were calculated. GIS models of anthropogenic and natural factors were collected and analyzed according to subwatersheds. Multiple regression analyses using the Maximum R2 improvement method were performed to predict surfactant toxic units and in-stream nutrients using GIS and in-stream values. Both geospatial and in-stream parameters generated multiple regression models for surfactant surface and pore water toxic units, as well as in-stream nutrients, with high R2 values. Thus, GIS and in-stream parameter modeling have the potential to be reliable and inexpensive method of predicting surfactant toxic units and nutrient loading in the upper Trinity River watershed.

Edward C. Fritz was one of the most influential environmentalists in Texas history. Although he took a circuitous route to environmental activism, Fritz evolved into a powerful force fighting on behalf of Texan nature. Participating in substantial actions throughout the second half of the twentieth century, Fritz's contributions to environmental activism resulted in the successful preservation of thousands of acres and multiple wildlife species. Fritz parlayed his legal background into effective activism, beginning his career with a successful lobbying campaign for protection of Harris Hawks. He led the campaign to stop a decades old plan for canalization of the Trinity River. The creation of COST combined Fritz's environmental focus with the concerns of economic conservatives to prevent a billion dollar government funded project that would have significantly altered the river. Fritz then led a cadre who took over efforts to establish a preserve in the Big Thicket national forest. He oversaw the foundation of a protected area far larger than original expectations, capitalizing on the growing awareness of environmental issues in the 1970s. Fritz's interest in the Big Thicket led to a fight against the Forest Service's practice of clearcutting and its effect on Red Cockaded Woodpeckers. Through litigation and legislation, Fritz fostered a grassroots movement aimed at reforming management of the national forests, saw the establishment of the state's first wilderness, and saved the declining population of the woodpeckers. For his tireless approach and lifelong achievements, Fritz was given the title of "Father of Texas Conservation."

Archaeologically site catchment analysis produces valuable information regarding prehistoric subsistence strategies and social organization. Incorporating archaeological data into catchment analyses is an effective strategy to develop regional models of prehistoric site selection and settlement patterns. Digital access to data permits the incorporation of multiple layers of information into the process of synthesizing regional archaeology and interpreting corresponding spatial patterning. GIS software provides a means to integrate digital environmental and archaeological data into an effective tool. Resultant environmental archaeology maps facilitate interpretive analysis. To fulfill the objectives of this thesis, GIS software is employed to construct site catchment areas for archaeological sites and to implement multivariate statistical analyses of physical and biological attributes of catchments in correlation with assemblage data from sites. Guided by ecological, anthropological and geographical theories hypotheses testing evaluates patterns of prehistoric socio-economic behavior. Analytical results are summarized in a model of prehistoric settlement patterns in North Central Texas.

Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduction methods were used to characterize sediment toxicants. Sediment oxygen demand was also measured in resuspended and undisturbed bottom sediments through time. The Background Sediment Chemistry Approach and the Sediment Bioassay Approach were used to assess sediment quality. Sediment toxicity was observed in whole sediment bioassays using Chironomus tentans as the test species. A relationship between sediment contaminant concentration and toxicity was observed in approximately sixty percent of the sediments. Oxygen demand of resuspended sediments was elevated in sediments at two locations on the river. Oxygen demand of undisturbed sediments was elevated at one location on the river. Characterization of sediment toxicants was conducted using EDTA, pH, and carbon treatments and manipulations of the sediments. Aeration tests were also used to evaluate the contribution of volatile organic contaminants to observed toxicity.

The Trinity River flows through the Dallas-Ft. Worth Metroplex in north central Texas where it receives effluents from numerous point sources including seven large regional wastewater treatment facilities. Historically, the Trinity River has been impacted by massive wastewater loadings which often constitute > 80% of the total river discharge during low flow periods. Normally, high mass loadings correspond to the summer months, compounding the effects of a naturally stressful period, characterized by high temperatures and low dissolved oxygen concentrations. Samples from 12 stations were collected quarterly over an 18 month period from the Trinity River and two tributaries. Water samples were analyzed for a variety of water quality variables, including metals, priority pollutants, pesticides, and general water quality parameters. Water samples were also tested for acute and subchronic effects with several test species. Fish were collected at each station and assemblages were characterized using traditional classification techniques and the Index of Biotic Integrity. In addition, sediment samples were assessed for toxic effects which could have adversely impacted fish recruitment and in situ biomonitoring experiments were performed. Quantitative habitat characterization analyses were performed to gain additional information that could possibly explains differences in fish assemblage structure related to habitat variability. Data were analyzed using regression, univariate, multivariate, and descriptive statistical techniques and new approaches for analyzing impact assessment data were discussed. Results indicated that the most substantial impacts on fish assemblages were confined to a segment of the river where a sequence of point sources, in close proximity to each other, were overloading the river's capacity to sufficiently dilute and/or detoxify the effluent. Data also indicated the presence of episodic toxicity from nonpoint sources. In addition, toxic effects in sediment samples and differences in habitat were detected and may have contributed to measured differences among fish assemblages in the Trinity River.

The evolution of landscapes and seascapes in time is the result of the constant interaction between flows and topography. Flows change topography, which in turn change the flow. This feedback causes evolution processes to be highly non-linear and complex. When full analytical derivations of the co-evolution of topography and flow are not possible without oversimplifications, as is the case in river bends, recent large topographical datasets and modern computers allow for correlations between horizontal (planview) and cross-sectional geometry of channels. Numerical analysis in the Mississippi and Trinity rivers indicate that the type of correlation between river radius of curvature and bankfull channel width depends on the migration behavior of the river. In other cases, channel topography may only have a second-order effect on its own evolution, as is the case for fully depositional turbidity currents, and the evolution of aeolian field topography may only be a function of this topography. I show that in these situations, changes in topography may be decoupled from details of the flow field and modeled very easily with a good accuracy. / text