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Oso Creek: A Community Project to Protect Recreational Uses

A community project to protect recreational uses of the creek by reducing concentrations of bacteria in Oso Creek and in Oso Bay. The stakeholders have completed a total maximum daily load (TMDL) and are working on its implementation plan (I-Plan). Together, the TMDL and I-Plan are a road map for improving water quality.
photo of Oso Creek
Oso Creek

County: Nueces
Parameter: Bacteria
Coastal Basins: Bays and Estuaries, Nueces–Rio Grande Coastal Basin
Segment: 2485A
Assessment Unit (AU): 2485A_01

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Overview and Goals

Since 2002, water quality testing has found that concentrations of bacteria are elevated in Oso Creek, which may pose a risk to people who swim or wade in it. Swimming and wading are called “contact recreation” in the state’s standards for water quality; the term refers to all recreation in which people come in direct contact with the water. The goal of this project is to reduce bacteria concentrations to within acceptable risk levels for contact recreation.

The Oso Creek watershed is wholly contained within Nueces County in the Nueces-Rio Grande Coastal Basin. The creek is about 28 miles long. It flows south-easterly from near the western edge of Corpus Christi over flat to rolling terrain, emptying into Oso Bay. Economic activities in the area include oil and gas refining and production, agriculture, manufacturing, and tourism.

Since 2003, the TCEQ, the Texas State Soil and Water Conservation Board, and other agencies have conducted several studies of bacteria sources and quantities in the Oso Creek watershed. In 2013, based on results of those studies, the TCEQ began developing a total maximum daily load (TMDL) for the creek. A TMDL is like a budget for pollution—determining how much concentrations must be reduced to meet water quality standards. The Texas Institute for Applied Environmental ResearchExit the TCEQ completed technical tasks in support of TMDL development.

The TCEQ and area stakeholders also assessed the oyster waters use of Oso Bay and have completed a TMDL for bacteria in Oso Bay. The work done to improve Oso Creek should also improve conditions in Oso Bay.

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Get Involved

Staff from the Center for Coastal StudiesExit the TCEQ at Texas A&M University–Corpus Christi worked with stakeholders to develop a plan for watershed improvement. Public meetings about this project are open to everyone. See the For More Information section below to contact the TMDL Program about ways you could be involved.

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The commission adopted the TMDL on July 31, 2019. The EPA approved it on October 25, 2019, at which time it became part of the state's Water Quality Management Plan.

Updates to TMDLs

From time to time, it is necessary to revise TMDLs to account for changing conditions in the watershed, such as new or amended permits, or urban growth, or to correct oversights in the original TMDL report. Revisions to the load allocations in TMDLs are made via the state’s Water Quality Management Plan (WQMP), which is updated quarterly.

The WQMP provides projected effluent limits for use in planning and permitting activities under the Texas Pollutant Discharge Elimination System (TPDES). The TCEQ reviews all applications for new and amended permits for conformance with applicable portions of the WQMP, including adopted TMDLs.

Revisions to the TMDL are documented in the approved WQMP updates listed below.

Learn more about WQMP updates and about opportunities to comment on revisions to them.

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For More Information

Please send an e-mail to, and mention the Oso Creek Bacteria project in the subject line. Or call us at 512-239-6682.

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