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Clear Fork Trinity River: Evaluating Water Quality for Aquatic Life

A completed project to evaluate the attainability of the presumed aquatic life use for the Clear Fork of the Trinity River

photo of the Clear Fork of the Trinity River

Clear Fork of the Trinity River

Counties: Parker, Tarrant
Parameter: Dissolved oxygen
River Basin: Trinity
Segments: 0831, 0832

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Background and Goals

This project focused on the two uppermost river segments of the Clear Fork Trinity River: Clear Fork Trinity above Lake Weatherford (Segment 0833) and Clear Fork Trinity below Lake Weatherford (Segment 0831). Both watersheds were predominantly rural; however, rapidly increasing urban populations were changing the landscape of this watershed.

Water quality assessment indicated that concentrations of dissolved oxygen in those segments of the river were not optimal for supporting aquatic life. However, data and information about the river suggested that the water quality standards for the segments might not be appropriate. Some criteria for evaluating attainability of the uses in specific water bodies are presumed if there are insufficient data to formulate site-specific criteria. The upper segments of the Clear Fork Trinity River had a presumed aquatic life standard.

The TMDL Program conducted a project to study the causes of low dissolved oxygen in the stream and to evaluate whether the agency should develop a total maximum daily load (TMDL) or a use attainability analysis (UAA).

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This project was a collaborative effort involving the TCEQ, the Texas Institute for Applied Environmental Research, the Trinity River Authority, and the Tarrant Regional Water District. To involve area stakeholders in the project, the TMDL Program worked with an existing stakeholder forum, the Trinity River Basin Steering Committee created by the Texas Clean Rivers Program. The steering committee includes representatives from state and federal agencies, cities, industries, citizen groups, local governments, universities, water districts, agriculture groups, and other water user groups.

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The final project report, Technical Use Attainability Analysis, Clear Fork Trinity River (Stream Segments 0831 and 0833), was submitted in April 2003 by the Texas Institute for Applied Environmental Research (TIAER). The TCEQ Water Quality Standards program reviewed TIAER’s report. They found that the UAA demonstrated the need for changes to the aquatic life use and/or the dissolved oxygen criteria for the streams. These changes were proposed in the 2010 update to the Texas Surface Water Quality Standards, which the commission adopted on June 30, 2010. The TCEQ then submitted the 2010 Standards to the U.S. EPA for their review and approval. In June 2011, the EPA approved revisions to the site-specific standards for both segments. See more about the 2010 Texas Surface Water Quality Standards.

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These documents are provided in PDF.

Final Report:

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For More Information

Please e-mail us at, and mention the Clear Fork Trinity River project in the subject line. Or call us at 512-239-6682 and ask for the Standards Team or the TMDL Team.

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communities working together taking care of our rivers, lakes, and bays