Patrick Bayou: Assessing Toxic Substances and Temperature
County: Harris
Parameters: Copper, water toxicity, sediment toxicity, temperature
Basin: San Jacinto River
Segment: 1006A
- Project Overview (PDF)
- Background and Goals
- Project Status and Implementation
- Public Participation
- For More Information
Background and Goals
Water quality testing prior to 1999 found that Patrick Bayou might not be able to support a healthy aquatic community. Several conditions were found that exceeded criteria established to protect aquatic life and general uses of the water body:
- high average concentrations of dissolved copper
- water toxicity
- sediment toxicity
- high water temperatures
Patrick Bayou is a small tidal tributary of the Houston Ship Channel. The non-tidal portion of Patrick Bayou lies south of SH 225, is largely concrete lined, and serves as drainage for the City of Deer Park. Freshwater flow from the watershed is ephemeral. Immediately downstream (north) of SH 225, the first 1.3 km of the bayou flows through either concrete culverts or a gunite-lined channel. The bayou downstream of this point has earthen banks and a soft mud bottom. Most of the bayou north of SH 225 is tidally influenced to some degree. The bayou is affected by industrial and municipal wastewater discharges and by stormwater runoff from industrial and urban areas.
The goal of the project is to restore the quality of the bayou to conditions that will support a healthy aquatic community. The lead organization working with the TMDL Program is a consortium of permittees that discharge to Patrick Bayou. The member organizations are the City of Deer Park, Lubrizol, Oxy Vinyls, Praxair, Rohm and Haas Texas, and Shell Inc. Parsons Water & Infrastructure Inc. has performed technical work for the project.
Return to topProject Status and Implementation
Analyses of data collected through April 2001 indicate that water toxicity and dissolved copper no longer exceed water quality standards due to control actions previously implemented by dischargers. Those controls will continue, so no TMDL allocations to address water toxicity or dissolved copper will be prepared.
In September 2002, Patrick Bayou was added to the Superfund National Priority List. The federal Superfund program has begun to plan for remediation of sediment toxicity; the need for a TMDL will be addressed when Superfund information and plans are developed.
There are significant uncertainties and difficulties regarding future TMDL directions regarding water temperature and sediment toxicity. The major source of heated-water discharge has closed since the study, and bayou temperatures have not been observed to exceed the temperature criterion since then.
In addition, one interpretation of the federal Clean Water Act requires that regulation of thermal discharges should be based on whether water temperature is preventing the existence of a “balanced indigenous population” of aquatic organisms, rather than on simple water temperature measurements. The tidal portions of Patrick Bayou support abundant wildlife in the form of birds (such as ducks, shorebirds, roseate spoonbills, ospreys), turtles, and fish. Although benthic communities may be affected or limited, it is not clear why. Standard biometrics for estuarine benthic communities are not available as benchmarks for such determinations.
Current scientific techniques are unable to determine which of numerous chemicals or metals present in the sediment cause sediment toxicity in lab tests, nor can analytical techniques determine whether the primary limiting factors for benthic organisms are chemical, thermal, or natural (such as highly variable salinity and flow). It is not clear to what extent sediment chemistry reflects current discharges amenable to TMDL control, versus historical residue from 80 years of industrial production surrounding the bayou that might be more suitably addressed by remedial programs.
The TCEQ will continue to work towards resolution of water quality issues in Patrick Bayou. Temperature conditions will be monitored for some time to assess the effect of the closure of a major heat discharger. Progress of the Superfund project will also be monitored to determine if further action will be needed.
Public Participation
A named-member stakeholder group called the Patrick Bayou TMDL Community Participation Panel advised the TCEQ on this project.
The last planned meeting of the Public Participation Panel occurred on August 29, 2002. Records of the group's membership and meetings are available below.
For More Information
For additional information regarding this project, please contact Ron Stein at 512/239-6682. Or send an e-mail to tmdl@tceq.texas.gov, and mention the Patrick Bayou project in the subject line.
