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Developing the Targeted Assessment of Texas Surface Waters

Describes the process the TCEQ implemented in 2004 to meet requirements of the federal Clean Water Act for the assessment of Texas surface waters.

The 2004 Water Quality Inventory and 303(d) List was prepared using the targeted approach described here.

Contents of the Report

For 2004, the TCEQ conducted a targeted water quality assessment and submitted an integrated report to the United States Environmental Protection Agency (EPA). The 2004 report followed the format introduced with the 2002 Water Quality Inventory and §303(d) List.

The period of record for water quality data and information used in the 2004 Inventory and List was March 1, 1998 to February 28, 2003.

Following the 2004 submittal, the TCEQ convened a stakeholder workgroup to consider revisions to the existing assessment guidance. In 2006, the TCEQ will conduct a full assessment of state surface waters, implementing the new methodology.

The federal Clean Water Act (the Act) requires states to update the §305(b) Water Quality Inventory and the §303(d) List every two years. Section 305(b) of the Act requires states to report the extent to which water bodies attain designated water quality standards. Section 303(d) of the Act requires states to identify water bodies for which effluent limitations are not stringent enough to implement water quality standards.

Water Bodies and Criteria Targeted in the Assessment

The 2004 Water Quality Inventory and 303(d) List was developed using the 2000 Texas Surface Water Quality Standards adopted by the TCEQ. The status of standards attainment was evaluated according to the 2004 Guidance for Assessing Texas Surface and Finished Drinking Water Quality Data (PDF, August 15, 2003—help with PDF).

The following aspects of the current 2002 report were reviewed to prepare the 2004 report using the targeted approach:

  • The use-attainment status for any water body was reviewed at the request of an entity that demonstrated that the current listing status was inaccurate and submitted to the TCEQ a summary assessment prepared using recent data. New water bodies were also considered if an assessment demonstrated that the standards were not attained. Summary assessments with requests for changes in listing status were due to the TCEQ by July 18, 2003.
  • Primary concerns (where data were insufficient in 2002 and additional monitoring was scheduled) were reevaluated to identify water bodies that did not support the water quality standards. All areas of the water body were reassessed for the parameter of concern.
  • The collection of 24-hour dissolved-oxygen data is a priority for the TCEQ and data sets were evaluated for compliance with 24-hour average and minimum criteria.
  • The use-attainment status for any water body was reviewed at the request of the TCEQ Permits or Total Maximum Daily Load programs.
  • When special projects have been conducted and included a timely reassessment of water quality status as part of a TCEQ-approved work plan, the status of use attainment was reviewed.
  • Changes to shellfish harvesting (oyster waters) areas managed by the Texas Department of State Health Services (DSHS) were identified.
  • Changes to fish-consumption advisories issued by DSHS were identified.
  • Drinking-water sources with contamination resulting in exceedances of the maximum-contaminant levels for toxic substances were identified.