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RULE §307.2Description of Standards

(a) Contents of the Texas Surface Water Quality Standards.

  (1) Section 307.1 of this title (relating to General Policy Statement) contains the general standards policy of the commission.

  (2) This section lists the major sections of the standards, defines basin classification categories, describes justifications for standards modifications, and provides the effective dates of the rules.

  (3) Section 307.3 of this title (relating to Definitions and Abbreviations) defines terms and abbreviations used in the standards.

  (4) Section 307.4 of this title (relating to General Criteria) lists the general criteria that are applicable to all surface waters of the state unless specifically excepted in §307.8 of this title (relating to Application of Standards) or §307.9 of this title (relating to Determination of Standards Attainment).

  (5) Section 307.5 of this title (relating to Antidegradation) describes the antidegradation policy and implementation procedures.

  (6) Section 307.6 of this title (relating to Toxic Materials) establishes criteria and control procedures for specific toxic substances and total toxicity.

  (7) Section 307.7 of this title (relating to Site-Specific Uses and Criteria) defines appropriate water uses and supporting criteria for site-specific standards.

  (8) Section 307.8 of this title sets forth conditions when portions of the standards do not apply - such as in mixing zones or below critical low-flows.

  (9) Section 307.9 of this title describes sampling and analytical procedures to determine standards attainment.

  (10) Section 307.10 of this title (relating to Appendices A - G) lists site-specific standards and supporting information for classified segments (Appendices A and C), water bodies that are sole-source surface drinking water supplies (Appendix B), site-specific uses and criteria for unclassified water bodies (Appendix D), site-specific toxic criteria that may be derived for any water in the state (Appendix E), chlorophyll a criteria for selected reservoirs (Appendix F), and site-specific recreational uses and criteria for unclassified water bodies (Appendix G). Specific appendices are as follows:

    (A) Appendix A - Site-specific Uses and Criteria for Classified Segments;

    (B) Appendix B - Sole-source Surface Drinking Water Supplies;

    (C) Appendix C - Segment Descriptions;

    (D) Appendix D - Site-specific Uses and Criteria for Unclassified Water Bodies;

    (E) Appendix E - Site-specific Toxic Criteria;

    (F) Appendix F - Site-specific Nutrient Criteria for Selected Reservoirs; and

    (G) Appendix G - Site-specific Recreational Uses and Criteria for Unclassified Water Bodies.

(b) Applicability. The Texas Surface Water Quality Standards apply to surface waters in the state - including wetlands.

(c) Classification of surface waters. The major surface waters of the state are classified as segments for purposes of water quality management and designation of site-specific standards. Classified segments are aggregated by basin, and basins are categorized as follows:

  (1) River basin waters. Surface inland waters comprising the major rivers and their tributaries, including listed impounded waters and the tidal portion of rivers to the extent that they are confined in channels.

  (2) Coastal basin waters. Surface inland waters, including listed impounded waters but exclusive of paragraph (1) of this subsection, discharging, flowing, or otherwise communicating with bays or the gulf, including the tidal portion of streams to the extent that they are confined in channels.

  (3) Bay waters. All tidal waters, exclusive of those included in river basin waters, coastal basin waters, and gulf waters.

  (4) Gulf waters. Waters that are not included in or do not form a part of any bay or estuary but that are a part of the open waters of the Gulf of Mexico to the limit of the state's jurisdiction.

(d) Modification of standards.

  (1) The commission reserves the right to amend these standards following the completion of special studies.

  (2) Any errors in water quality standards resulting from clerical errors or errors in data may be corrected by the commission through amendment of the affected standards. Water quality standards not affected by such clerical errors or errors in data remain valid until changed by the commission.

  (3) The narrative provisions, presumed uses, designated uses, and numerical criteria of the Texas Surface Water Quality Standards may be amended for a specific water body to account for local conditions. A site-specific standard is an explicit amendment to this chapter, and adoption of a site-specific standard requires the procedures for public notice and hearing established under the Texas Water Code, §26.024 and §26.025. An amendment that establishes a site-specific standard requires a use-attainability analysis that demonstrates that reasonably attainable water-quality related uses are protected. Upon adoption, site-specific amendments to the standards will be listed in §307.10 of this title.

  (4) Factors that may justify the development of site-specific standards are described in §307.4 and §§307.6 - 307.8 of this title.

  (5) Temporary variance. When scientific information indicates that a site-specific standards amendment is justified, the commission may allow a corresponding temporary variance to the water quality standards in a permit for a discharge of wastewater or stormwater.

    (A) A temporary variance is only applicable to an existing permitted discharge.

    (B) A permittee may apply for a temporary variance prior to or during the permit application process. The temporary variance request must be included in a public notice during the permit application process. An opportunity for public comment is provided, and the request may be considered in any public hearing on the permit application.

    (C) A temporary variance for a Texas Pollutant Discharge Elimination System permit also requires review and approval by the United States Environmental Protection Agency (EPA) during the permitting process.

    (D) The permit must contain effluent limitations that protect existing uses and preclude degradation of existing water quality, and the term of the permit must not exceed three years. Effluent limitations that are needed to meet the existing standards are listed in the permit and are effective immediately as final permit effluent limitations in the succeeding permit, unless the permittee fulfills the requirements of the conditions for the variance in the permit.

    (E) When the permittee has complied with the terms of the conditions in the temporary variance, then the succeeding permit may include a permit schedule to meet standards in accordance with subsection (f) of this section. The succeeding permit may also extend the temporary variance in accordance with subsection (f) of this section in order to allow additional time for a site-specific standard to be adopted in this chapter. This extension can be approved by the commission only after a site-specific study that supports a standards change is completed and the commission agrees the completed study supports a change in the applicable standard(s).

    (F) Site-specific standards that are developed under a temporary variance must be expeditiously proposed and publicly considered for adoption at the earliest opportunity.

(e) Standards implementation procedures. Provisions for implementing the water quality standards are described in a document entitled Procedures to Implement the Texas Surface Water Quality Standards (RG-194) as amended and approved by the Texas Commission on Environmental Quality and EPA.

(f) Permit schedules to meet standards. Upon permit amendment or permit renewal, the commission may establish interim effluent limitations to allow a permittee time to modify effluent quality in order to attain final effluent limitations. The duration of any interim effluent limitations may not be longer than three years from the effective date of the permit issuance, except in accordance with a temporary variance as described in subsection (d)(5) of this section.

(g) Temporary standards. Where a criterion or designated use is not attained and cannot be attained for one or more of the reasons listed in 40 Code of Federal Regulations (CFR) §131.10(g), or to facilitate restoration or reconfiguration activities that preclude the attainment of the designated use or criterion, then a temporary standard for specific water bodies or permittees may be adopted in §307.10 of this title as an alternative to changing uses.

  (1) A temporary standard identifies the interim numerical criteria or use that applies during the existence of the temporary standard. When a temporary standard is adopted for permittees or water bodies, the temporary standard must be expressed as one of the following:

    (A) The interim effluent condition that reflects the greatest pollutant reduction achievable;

    (B) Or if no additional feasible pollutant control technology can be identified, the interim effluent condition that reflects the greatest pollutant reduction achievable with the pollutant control technologies installed at the time the temporary standard is adopted, and implementation of a remediation plan as specified in the Procedures to Implement the Texas Surface Water Quality Standards (RG-194); or

    (C) The highest attainable interim criterion.

  (2) A temporary standard must be adopted in accordance with the provisions of subsection (d)(3) of this section. Once adopted by the commission and approved by EPA, a temporary standard is the applicable standard for the purposes of developing wastewater discharge permit limits and issuing certifications specified in the federal Clean Water Act, §401 and Chapter 279 of this title (relating to Water Quality Certification).

  (3) Specific reasons and additional procedures for justifying a temporary standard are provided in the Procedures to Implement the Texas Surface Water Quality Standards (RG-194). A temporary standard must identify the water body or permittee to which the temporary standard applies. A temporary standard does not exempt any discharge from compliance with applicable technology-based effluent limits.

  (4) A temporary standard must be reevaluated every five years at a minimum, which may be conducted through the permit process or a triennial review of the Texas Surface Water Quality Standards. If the reevaluation is not submitted to EPA within 30 days of completion, subsequent federal Clean Water Act activities will be evaluated using the applicable existing underlying water quality standards.

  (5) The term of a temporary standard is expressed as an interval of time from the date of EPA approval or a specific date cited in the temporary standard. If the continuance of a temporary standard is sufficiently justified, it can be renewed during revisions of the Texas Surface Water Quality Standards. When a temporary standard expires, subsequent discharge permits are issued to meet the applicable existing water quality standards.

  (6) A temporary standard must preclude the degradation of existing water quality unless degradation is necessary to facilitate restoration or reconfiguration activities as specified in this section.

(h) Effective date of standards. Except as provided in 40 CFR §131.21 (EPA review and approval of water quality standards), this chapter becomes effective 20 days after the date the chapter is filed in the Office of the Secretary of State. As to actions covered by 40 CFR §131.21, the rules become effective upon approval by EPA.

(i) Effect of conflict or invalidity of rule.

  (1) If any provision of this chapter or its application to any person or circumstances is held invalid, the invalidity does not affect other provisions or applications of the provisions contained in this chapter that can be given effect without the invalid provision or application, and to this end the provisions of this chapter are severable.

  (2) To the extent of any irreconcilable conflict between provisions of this chapter and other rules of the commission, the provisions of this chapter supersede.

Source Note: The provisions of this §307.2 adopted to be effective July 10, 1991, 16 TexReg 3400; amended to be effective July 13, 1995, 20 TexReg 4701; amended to be effective August 17, 2000, 25 TexReg 7722; amended to be effective July 22, 2010, 35 TexReg 6294; amended to be effective March 6, 2014, 39 TexReg 1450; amended to be effective March 1, 2018, 43 TexReg 1102; amended to be effective September 29, 2022, 47 TexReg 6216

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