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Atascosa River: Evaluating the Aquatic Life and Recreational Uses

A current project to evaluate concentrations of dissolved oxygen and bacteria in the Atascosa River in South Central Texas

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photo of kicknet sampling in the Atascosa River
Atascosa River
Counties: Atascosa, Bexar, Frio, Karnes, Live Oak, McMullen, Medina, Wilson
Parameters: Bacteria and Dissolved Oxygen
Basin: Nueces River
Segment: 2107

Background and Goals

In the Atascosa River in south central Texas, water quality testing found elevated levels of bacteria and low concentrations of dissolved oxygen. The TCEQ is working with the Nueces River Authority Exit the TCEQ site and other stakeholders to develop a plan to address these conditions.

High concentrations of bacteria may indicate a health risk to people who swim or wade in the rivers—activities referred as “contact recreation” in the state’s Standards for surface water quality. Dissolved oxygen is essential for the survival of aquatic life, and so is used to indicate whether conditions support the “aquatic life use” in the Standards

In 2009, proposed revisions to the state’s recreational use standard prompted the re-evaluation of the Atascosa River TMDL project, which had been underway since fall 2004. Work on the TMDL has been suspended until a survey and analysis of recreational uses of the river can be completed. The agency decided to evaluate the aquatic life use at the same time to gain a fuller understanding of the biological and flow conditions for the entire stream.

Using protocols developed by the TCEQ’s Water Quality Standards Group, the TMDL Team is managing a study to support both an aquatic life use attainability analysis (ALUAA) and a recreational use attainability analysis (RUAA) on the entire length of the Atascosa River. UAAs are comprehensive examinations of the physical, chemical, and biological factors that determine whether a particular use is attainable in a specific area of a water body.

Depending on the results of these UAAs, the recreational and aquatic life use standards may be modified. If the Standards Team finds the current standards to be appropriate, the TCEQ will consider development of TMDLs for Segment 2107.

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Public Participation

The TCEQ is informing stakeholders about this project at public meetings and in print and electronic media. Meetings about the project are open to everyone.

Meeting Summaries

Documents linked from this page are provided in PDF unless otherwise indicated.

Meetings Related to UAA Development

Meetings Related to TMDL Development

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Project Documents

Final reports from the 2004 assessment to determine the extent and severity of impairments to the recreational and aquatic life uses of the river.

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For More Information

Please e-mail us at tmdl@tceq.texas.gov and reference the Atascosa River in the subject line. Or call Dania Grundmann at 512-239-6682.

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Document Actions
Public Comment Requested

On proposed drafts of three TMDLs and their implementation plan for the Carters Creek Watershed. The public comment period ends at midnight, May 28, 2012.