2004 Texas Water Quality Inventory and 303(d) List

This report describes the status of the state’s waters, as required by Sections 305(b) and 303(d) of the federal Clean Water Act. It summarizes the status of the state’s surface waters, including concerns for public health, fitness for use by aquatic species and other wildlife, and specific pollutants and their possible sources.

• Site Map of 2004 documents
• Overview of the Texas Water Quality Inventory and List (PDF) (Help with PDF)
  How surface waters are assessed, highlights of the results of the 2004 assessment, and information about the actions the TCEQ is taking to improve the quality of waters on the 303(d) List.
• Developing the Targeted Assessment
• Summary of the 2004 Texas Water Quality Inventory and 303(d) List
• Trophic Classification of Texas Reservoirs
• 2004 Texas 303(d) List and Status and Category of All Waters
• 2004 Assessments of Individual Water Bodies
• Summary Lists
• Public Comment and Participation

2004 Guidance for Assessing Texas Surface and Finished Drinking Water Quality Data

• 2004 Guidance for Assessing Texas Surface and Finished Drinking Water Quality Data (PDF, August 15, 2003) (Help with PDF)

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

New in the 2004 Guidance

In 2002, the TCEQ specified a minimum number of samples for assessment. Support of designated uses in the water quality standards was assessed with a minimum of 10 samples, and concerns were identified with a minimum of four samples. For assessments that depend on the frequency of exceedances of a criterion to identify nonsupport of a use, a threshold number of exceedances was required. At the minimum sample set of ten samples, two or three exceedances, depending on the parameter, were required in order for the water body to be identified as partially supporting or not supporting the use.

For the 2004 assessment, the TCEQ has identified water bodies with small data sets as partially supporting or not supporting designated uses, without regard for sample size, provided they meet the threshold number of exceedances and are otherwise representative. This change in assessment procedure was implemented due to the certainty that small data sets that already have the threshold number of exceedances will demonstrate partial or nonsupport of uses once more samples are collected to reach a total sample size of 10.