Oso Bay and Oso Creek: A TMDL Project for Bacteria

County: Nueces
Parameter: Bacteria
Coastal Basins: Bays and Estuaries, Nueces–Rio Grande Coastal Basin
Segment: 2485, 2485A

Oso Creek

• Project Overview (PDF)
• Background and Goals
• TMDL
• Project Documents
• Public Participation
• For More Information

Background and Goals

Oso Bay is an enclosed, shallow body of water situated along the southern shore of Corpus Christi Bay, with a surface area of approximately seven square miles. The bay exchanges saltwater with Corpus Christi Bay and receives fresh water from Oso Creek, a stream whose flow is dominated by discharges subject to permit. Ecologically, Oso Bay provides habitat for many plants and animals, and plays an influential role in water purification and storm protection.

Water quality testing found that concentrations of bacteria are elevated in both the bay and the creek, which may pose a risk to people who swim or wade in them. 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.

In March 2006, the TCEQ separated development of the TMDLs for the bay and the creek, with the advice and consent of the stakeholder advisory group. The TMDLs will be drafted and processed as separate, related documents. The TCEQ adopted the Oso Bay TMDL on August 22, 2007 and the EPA approved it in June 2008.

At this time, additional studies of bacteria sources and quantities are underway in the Oso Creek watershed. TMDL development for the creek will proceed, as those studies provide sufficient information, in coordination with the Texas State Soil and Water Conservation Board.

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TMDL for Oso Bay

On August 22, 2007, the commission adopted a TMDL for Oso Bay. On June 6, 2008, the EPA approved the TMDL for bacteria in Oso Bay. The TMDL is part of the state's Water Quality Management Plan.

• One TMDL for Bacteria in Oso Bay, Segment Number 2485
• Response to Public Comment on the TMDL for Bacteria in Oso Bay

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Project Documents

Documents are provided in PDF.

• Oso Creek and Oso Bay Bacteria TMDL Model Report - 2006
• Oso Creek and Oso Bay Bacteria TMDL Model Report - 2005
• Map Showing Model Bacteria Loading and Land Use
• Water Quality and Biological Characterization of Oso Creek and Oso Bay, Corpus Christi, Texas

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Public Participation

An committee called the Oso Bay Watershed Advisory Group was established to advise the TCEQ on this project. The last planned meeting of the Advisory Group was in June 2008. The group may be reconvened if needed.

Records of the group's membership and meetings are provided below in PDF.

• June 2008
  • Meeting Summary
  • TMDL Project Update (TCEQ)
  • TMDL Project Update (CBBEP)
  • Ground Water Monitoring
  • Nonpoint Sources of Bacteria (TAMU-CC)
  • Nonpoint Sources of Bacteria (AgriLife)
• February 2007
  • Meeting Summary
  • Outline of Possible TMDLs And Implementation Plan
• May 2006
  • Meeting Summary
  • TMDL Project Update
  • Bacteria Loading Model
• January 2006
  • Meeting Summary
• August 2005
  • Meeting Summary
  • Numerical Modeling
  • Bacteria Monitoring
• June 2005
  • Meeting Summary
  • Numerical Modeling
  • Bacteria Monitoring
• January 2005
  • Meeting Summary
  • Draft List of Advisory Group Members
  • Public Participation in TMDL Projects
  • Overview of the TMDL Program
  • Historical Data Review
  • Bacteria Sampling Plan
  • Watershed Modeling

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For More Information

For additional information regarding this project, please send an e-mail to tmdl@tceq.texas.gov, and reference the Oso Bay and Oso Creek Bacteria project in the subject line. Or call the TCEQ project manager, Jason Leifester, at 512/239-6457.

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