Upper Coast Oyster Waters: A TMDL Project for Bacteria
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Oyster Harvesting in the
Gulf of Mexico |
Counties: Brazoria, Chambers, Galveston, Harris
Parameter: Bacteria in Oyster Waters
Basins: Neches-Trinity Coastal, Trinity River, San Jacinto River, and San Jacinto–Brazos Coastal, Bays and Estuaries
Segments: 2421, 2422, 2423, 2424, 2432, 2439
- Project Overview
- Background and Goals
- Adopted TMDLs
- Implementation Plan
- Public Participation and Meetings
- For More Information
Background and Goals
Bacteria concentrations are sometimes elevated in six bays in the Houston–Galveston area. Restricted areas are closed to the harvesting of shellfish for direct marketing. Microorganisms from human and animal waste may contaminate oysters and other shellfish, making them unsafe to eat, especially since some shellfish are eaten raw.
The use of coastal waters for harvesting shellfish —called the “oyster waters use” in the state’s standards for surface water quality—is the most commonly impaired use among Texas bay and gulf waters. The affected segments are Upper Galveston Bay (Segment 2421), Trinity Bay (Segment 2422), East Bay (Segment 2423), West Bay (Segment 2424), Chocolate Bay (Segment 2432), Lower Galveston Bay (Segment 2439).
Assessment of the oyster waters use is conducted by the Seafood Safety Division of the Texas Department of State Health Services (DSHS). The DSHS is responsible for monitoring and classifying shellfish harvest areas into four categories for harvesting — approved, conditionally approved, restricted, or prohibited. These classifications are published as maps on the DSHS website 
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The goal of this TMDL project is to improve water quality so that the oyster beds are routinely safe for harvesting. Analysis indicates that isolated zones of high bacteria concentrations occur in isolated areas near shorelines, rather than occurring chronically throughout the bays. Because the exceedances are confined to discrete areas, bay-wide reductions can be achieved by targeting each isolated zone.
Return to topAdopted TMDLs
On August 20, 2008, the commission adopted the TMDLs below. On February 4, 2009, the EPA approved these TMDLs, at which time they became part of the state’s Water Quality Management Plan.
- Six Total Maximum Daily Loads for Bacteria in Waters of the Upper Gulf Coast, Segments 2421, 2422, 2423, 2424, 2432, and 2439
- Response to Public Comment on the TMDLs
The reductions of bacteria loads were determined using a concentration-based approach, which compares water quality to both median and the 90th percentile criteria.
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 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.
- April 2009, Appendix V, page 21
- July 2009, Appendix V, page 12
- October 2009, Appendix III, page 15
- October 2010, Appendix III, page 14
Learn more about WQMP updates and about opportunities to comment on revisions to them.
Implementation Plan
An I-Plan describes the steps that the TCEQ and partners will take to achieve the pollutant reductions identified in the TMDL report. The Galveston Bay Foundation (GBF) is managing the development of the I-Plan to ensure that local partners and stakeholders are a part of the process.
Work groups were formed at a public meeting on February 24, 2010. These work groups are meeting monthly to develop sections of the I-Plan.
For additional information about the work group meetings or to become a stakeholder, visit the Galveston Bay Foundation website.
Public Participation and Meetings
The TCEQ is working with existing forums in the watershed to inform the public about the project and work together with stakeholders on an I-Plan to improve conditions in the watershed.
Next Meeting
Wednesday, January 18, 2012
5:30-7:30 p.m.
Armand Bayou Nature Center
Education Center
8500 Bay Area Boulevard
Pasadena, Texas 77507
We will discuss the various management measures being proposed, as well as ways you can help prevent bacteria from entering our waterways. We will have representatives from each stakeholder group present to address your concerns and listen to your feedback on this project.
Summaries of Meetings during TMDL Development
- November 2011 Meeting
- February 2010 Meeting
-February 28, Clear Lake
- Presentation: Overview of the TMDL
- Presentation: Overview of the IPlan Process
- June 2008 Meetings
- June 9, Clear Lake; June 11, Hankamer- Presentation: Overview of the Project
- February 2008 Meetings
- February 27, Hankamer; February 28, Clear Lake; February 29, Galveston
- Presentation: TMDL Process
- Presentation: DSHS Overview of Oyster Waters and Classification Zones
- Presentation: Project Overview - Upper Coast Oyster Water TMDL for Bacteria
- Handout: Reductions Necessary to Meet 90th Percentile Criteria
- Handout: Announcement for April 2008 Storm Water Workshop
1905 Map of Galveston Bay:
This 1905 map of Galveston Bay (9.9 MB) was originally produced by the Corps of Engineers. An old paper copy was scanned to produce digital images; that was the only known copy of this map. The file posted here was made by combining two overlapping partial images, merging to a single image, adjusting color to reduce yellowed effect of original, trimmed, and reduced to 4000 x 4000 pixel density to make a smaller but readable image. Larger format (6848 x 9584 pixels) files are available in TIF and JPG format, but require additional work to merge pieces or color correct the image. Contact the TCEQ TMDL program if the original files are desired.
For More Information
Please e-mail us at tmdl@tceq.texas.gov, and reference the Upper Coast Oyster Waters TMDL in the subject line. Or call us at 512-239-6682.
