Skip to content. | Skip to navigation

Personal tools

Navigation

Questions or Comments:
tmdl@tceq.texas.gov
You are here: Home / Water Quality / Total Maximum Daily Load Program / Mission and Aransas Rivers, Tidal Portions: A Project to Protect Recreational Uses

Mission and Aransas Rivers, Tidal Portions: A Project to Protect Recreational Uses

A current TMDL project to keep recreation safe in tidal segments of the Mission and Aransas rivers by reducing bacteria levels.
scenic photo of Copano Bay from shore
Aransas River Tidal
Photo by Texas AgriLife

back arrow Back to TMDL Projects

Watershed Counties: Aransas, Bee, Goliad, Karnes, Refugio, and San Patricio
Parameter: Bacteria
Basin: San Antonio-Nueces Coastal
Segment: 2001, 2003

Background and Goals

High concentrations of bacteria are often found in the tidal portions of the Mission and Aransas Rivers. High concentrations of bacteria may indicate a health risk to people who swim or wade in the rivers—activities called “contact recreation” in the state’s standards for water quality.

Bacteria are commonly found in the intestines of warm-blooded organisms such as humans, livestock, cats, and dogs. These bacteria in water may indicate the presence of disease-causing microorganisms.

The goal of the project is to reduce bacteria levels to protect people who swim or wade in the rivers. The Texas Water Resources Institute (TWRI) Exit the TCEQ is coordinating development of the TMDLs and I-Plan.

return to top Return to top

Project History

The state and its partners collected and analyzed extensive amounts of data about the project watersheds from 2004 through 2010. While the TCEQ, the Texas State Soil and Water Conservation Board (TSSWCB), and stakeholders in the watershed evaluated the most appropriate strategy for reducing bacteria concentrations, agricultural producers voluntarily participated in educational activities aimed at better understanding the water quality issues and various methods for reducing the amount of bacteria that can wash off agricultural property and into waterways.

In 2011, stakeholders and the state agencies decided to develop TMDLs and an implementation plan for the watershed. The goal of a TMDL is to determine the amount (or load) of a pollutant that a body of water can receive and still support its designated uses. The allowable load is then allocated among the categories of sources within the watershed. Stakeholders work with the state to develop an implementation plan (I-Plan) with measures that reduce pollutant loads. 

Copano Bay, which is identified as having an impaired oyster waters use, was considered in the assessment stage of this project. Designation of the oyster waters impairment is based on a risk assessment by the Department of State Health Services (DSHS). These risk assessments are not based on concentrations of bacteria in the water; rather, they are based on certain risk factors such as the likelihood of high rainfall and runoff or the influx of sewage from failing or inefficient domestic treatment systems.

Concentrations of bacteria in the waters of the bay are within acceptable levels. Consequently, development of a bacteria TMDL for Copano Bay is not necessary, and would not be effective in reducing the risk assessed by the DSHS.

Get Involved

Project staff are informing the public about this project through a series of public meetings. The meetings are open to everyone.

In all its projects, the TCEQ seeks to gather opinion and information from people who represent government, permitted facilities, agriculture, business, environmental, and community and private interests in the watershed. The TWRI Exit the TCEQ is coordinating public participation in this project.

Educational Resources

See the Texas Water Resources Institute website for the Copano Bay Water Quality Education Project Exit the TCEQ, which provides information about educational programs and demonstrations for land and livestock owners. These programs and demonstrations are designed to increase awareness of water quality issues and best management practices for reducing bacteria in stormwater runoff.

Meeting Summaries and Presentations

Meeting summaries and presentations are in PDF.

return to top Return to top

Project Reports

return to top Return to top

For More Information

Please e-mail us at tmdl@tceq.texas.gov, and mention the Mission and Aransas Rivers project in the subject. Or call us at 512-239-6682. You may contact the TWRI project manager, Allen Berthold, at 979-845-2028 or taberthold@ag.tamu.edu.

return to top Return to top