Skip to content. | Skip to navigation

Personal tools


Complaint Arrow Questions or Comments:
You are here: Home / Water Quality / Total Maximum Daily Load Program / South Central Texas Streams: Evaluating Water Quality for Aquatic Life and Recreation

South Central Texas Streams: Evaluating Water Quality for Aquatic Life and Recreation

Completed assessment project that evaluated high bacteria and low dissolved-oxygen concentrations in several streams in south central Texas and determined whether TMDLs were required
photo of sampling in the Atascosa River
Sampling in the Atascosa River

Counties: Atascosa, Bandera, Bexar, Blanco, Comal, De Witt, Duval, Frio, Hays, Gonzales, Guadalupe, Karnes, Kendall, Kerr, La Salle, Live Oak, McMullen, Medina, Real, Travis, Uvalde, Webb, Wilson

Parameters: Bacteria, dissolved oxygen

Basins: Colorado River, Guadalupe River, Nueces River, San Antonio River

Segments: 1427, 1803A, 1803B, 1806A, 1815, 1906, 1908, 1913, 2104, 2107, 2113

Project Description

In 11 streams in south central Texas, water quality testing found elevated levels of fecal coliform bacteria and low concentrations of dissolved oxygen. In Phase I of this project, the TCEQ’s TMDL Program evaluated the impairments in those streams to determine whether it was necessary to develop TMDLs for any or all of the streams. In Phase II, TMDLs will be developed and implemented for five of the streams assessed.

Disease-causing bacteria from human and animal waste may threaten public health. People who swim or wade in the creek may be at risk. Oxygen, which dissolves in water, is essential for the survival of aquatic life. While the amount of dissolved oxygen in water fluctuates naturally, various human activities can cause unusually or chronically low levels of dissolved oxygen, which may harm fish and other aquatic organisms. The TCEQ is working with four river authorities and other regional stakeholders to develop a plan to restore the quality of the affected streams.

Phase 1 of the project involved targeted monitoring to collect more data and information on the extent and severity of the impacts on water quality in the project streams. The data has been anyalyzed, and the results are summarized below in the overview of Phase I.

In Phase II, the TCEQ carried out further assessment to determine appropriate strategies for four of the project water bodies—Elm Creek, Sandies Creek, the Atascosa River, and Mid Cibolo Creek. Data for the remaining six segments indicated that they were meeting their associated dissolved oxygen and bacteria criteria.

return to topReturn to top

Phase I—Overview, Documents, and Public Meetings

Phase I consisted of targeted monitoring and assessment to determine the extent and severity of the impairments, and to further characterize water quality, in order to determine if TMDLs were needed for the the project segments.

Phase I—Project Reports on Impairment Verification Monitoring

The documents provided below are PDFs.

return to topReturn to top

Phase I—Public Meeting Summaries

The TCEQ held public meetings in late 2003 and early 2004 to acquaint regional stakeholders with Phase I of the project. The documents from that meeting are provided below as PDFs.

return to topReturn to top

Phase II—Strategy Development

Based on the analyses of Phase I data, the TMDL Team carried out further assessment to determine the most appropriate management strategy for four of the streams.

return to topReturn to top

For More Information

Please e-mail us at, and mention the South Central Texas project in the subject line. Or call 512-239-6682.

return to topReturn to top

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