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Dallas and Tarrant Counties: A TMDL Project for Legacy Pollutants

A completed project to reduce legacy pollutant loads in streams and rivers in Dallas and Tarrant Counties. Together, the adopted TMDL and the approved I-Plan are the road map to improving water quality.

photo of Lake Worth
Lake Worth
Photograph courtesy of the Fort Worth Water Department

Counties: Dallas, Tarrant
Parameters: chlordane, DDT, DDD, DDE, dieldrin, heptachlor epoxide, and polychlorinated biphenyls (PCBs) in fish tissue
Basin: Trinity River
Segments: 0805, 0841, 0841A

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Background and Goals

Seven legacy pollutants were detected in fish tissues in portions of the Upper Trinity River, the Lower West Fork Trinity River, and Mountain Creek Lake, all in the Dallas area. Legacy pollutants are chemicals whose use has been banned or severely restricted, but which still remain in the environment. The pollutants involved include chlordane, DDT, DDD, DDE, dieldrin, heptachlor epoxide, and PCBs, most of which were once used as insecticides. The goal of this TMDL project is the reduction of concentrations of fish-tissue contaminants to levels that constitute an acceptable risk to consumers.

All the pollutants in the TMDL, with the exception of PCBs in Mountain Creek Lake, have been addressed. Legacy insecticides are no longer considered a risk to consumers of fish from these areas. The TCEQ contracted with DSHS to collect fish tissue samples in 2019. In August 2019, fish tissue samples were collected at various sites on the Upper Trinity river. Laboratory analysis is expected to occur in 2020, with a report reassessing the fish consumption risk in 2021.

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Adopted TMDLs

The TCEQ adopted these TMDLs on December 20, 2000. The EPA approved these TMDLs on June 27, 2001, at which time they became part of the state's Water Quality Management Plan.

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Implementation Plan

The TCEQ approved the Implementation Plan in August 2001.

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For More Information

Please e-mail us at and mention the Dallas and Tarrant Counties TMDL 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