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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Use of in-stream water quality measurements and geospatial parameters to predict consumer surfactant toxic units in the upper Trinity River watershed, Texas

Johnson, David Richard. Venables, Barney J., January 2008 (has links)
Thesis (M.S.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.
2

The North Texas Region and the Development of Water Resources in the Trinity River Basin of Texas, 1840-1998

Sparkman, Michael D. 08 1900 (has links)
This study focuses on the development of water resources in the Trinity River basin for navigation, flood control, water supply, recreation, and allied purposes. Special emphasis is given to the development of the upper Trinity River basin through the influence of community leaders in Dallas and Fort Worth. A desire harbored for generations by upper basin residents for creating a navigable waterway on the Trinity River coalesced in the twentieth century into a well organized movement for all facets of water resources development. Sources include correspondence, speeches, and promotional materials of civic leaders, politicians, and other citizens, as well as works by the United States Army Corps of Engineers.
3

Monitoring Watershed Health in the Upper Trinity River Basin, North Central Texas

Csekitz, Jill Diane 05 1900 (has links)
This study conducts watershed analysis using biological and geo-spatial techniques. Incorporating landscape features with biological attributes has been shown to be an effective method of monitoring environmental quality within watersheds. In situ biomonitoring using the Asiatic Clam, Corbicula fluminea, habitat suitability, and water quality data were evaluated for their potential to describe ecological conditions in agricultural and urban areas within the Upper Trinity River watershed. These data were analyzed with GIS to identify effects of land use on ecological conditions. C. fluminea downstream of point source effluents was effective detecting in-stream toxicity. Ambient toxicity appears to have improved in the Trinity, although urban influences limit aspects of aquatic life. No association between habitat quality and land use was identified.
4

Macroinvertebrate Community Structure as an Indicator of Watershed Health in the Upper Trinity River Basin, North Central Texas

Stephenson, Jaynie M. 05 1900 (has links)
This study describes macroinvertebrate community structure and assesses its potential in detecting point and non-point sources of disturbance associated with rural and urban areas in the Upper Trinity River Basin. Geospatial techniques were used to quantify landuse within the watershed in a GIS. At rural sites near the headwaters of the Trinity River, collector-gathering burrowers that are adapted to minimal flow comprised the majority of taxa. Destinies of taxa compositions at downstream sites increased and shifted toward psammophilic and rheophilic invertebrates, including primarily collector-filtering clingers, that are characteristic of shifting sand habitats in large prairie rivers. Benthic community structure generally benefited from point source impacts including wastewater treatment plant effluents that maintained higher flow. Community indices were negatively associated with forest landuse and positively associated with urban landuse. Partial CCA determined that flow and landuse contributed equally to species dispersions. Comparisons with historical biomonitoring studies in upper Trinity River Basin indicate improved watershed health.
5

Use of In-Stream Water Quality Measurements and Geospatial Parameters to Predict Consumer Surfactant Toxic Units in the Upper Trinity River Watershed, Texas

Johnson, David Richard 05 1900 (has links)
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.

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