1. (a) Application. The antidegradation policy and implementation procedures set forth in this section shall apply to actions regulated under state and federal authority which would increase pollutant loads to the water in the state. Such actions include authorized wastewater discharges, waste load evaluations, and any other miscellaneous actions, such as those related to man-induced nonpoint sources of pollution, which may impact the water in the state.

2. (b) Antidegradation policy. In accordance with the Texas Water Code, §26.003, it is the policy of the commission that:

   1. (1) water quality sufficient to protect existing uses will be maintained. Categories of existing uses are the same as for designated uses, as defined in §307.7 of this title (relating to Site-specific Uses and Criteria);
   2. (2) no activities subject to regulatory action which would cause degradation of waters which exceed fishable/swimmable quality will be allowed unless it can be shown to the commission's satisfaction that the lowering of water quality is necessary for important economic or social development. Degradation is defined as a lowering of water quality to more than a de minimis extent, but not to the extent that an existing use is impaired. Water quality sufficient to protect existing uses will be maintained. Fishable/swimmable waters are defined as waters which have quality sufficient to support propagation of indigenous fish, shellfish, and wildlife and recreation in and on the water;
   3. (3) outstanding national resource waters are defined as high quality waters within or adjacent to national parks and wildlife refuges, state parks, wild and scenic rivers designated by law, and other designated areas of exceptional recreational or ecological significance. The quality of outstanding national resource waters will be maintained and protected;
   4. (4) authorized wastewater discharges or other activities will not result in the quality of any water being lowered below water quality standards without complying with federal and state laws applicable to water quality standards amendment;
   5. (5) anyone discharging wastewater which would constitute a new source of pollution or an increased source of pollution from any industrial, public, or private project or development will be required to provide a level of wastewater treatment consistent with the provisions of the Texas Water Code and the Clean Water Act (33 United States Code 1251 et seq.). As necessary, cost-effective and reasonable best management practices established through the Texas water quality management program shall be achieved for nonpoint sources of pollution;
   6. (6) application of antidegradation provisions shall not preclude the commission from establishing modified thermal discharge limitations consistent with the Clean Water Act, §316(a) (33 United States Code 1326).

3. (c) Antidegradation implementation procedures.

   1. (1) The commission staff will review any wastewater discharge permit application or amendment in accordance with permitting procedures described in the standards implementation procedures. This review will include a preliminary determination of the existing uses of the receiving water. These existing uses will be maintained and protected.
   2. (2) For proposed permit applications or amendments to discharge into waters exceeding fishable/swimmable quality, the commission staff will preliminarily determine if the discharge is expected to cause a degradation of water quality.
   3. (3) All pollutants which could cause degradation of waters which exceed fishable/swimmable quality will be considered in the evaluation of waste discharge permits. For dissolved oxygen, analyses of degradation will utilize the same critical conditions as are used for permit reviews and waste load evaluations. For other parameters, appropriate conditions may vary. Conditions for determining degradation will be commensurate with conditions for determining existing uses. The highest water quality sustained since November 28, 1975 (in accordance with EPA Standards Regulation, 40 Code of Federal Regulations Part 131) define baseline conditions for determinations of degradation.
   4. (4) When degradation of waters exceeding fishable/swimmable quality is anticipated, a statement that the antidegradation policy will be pertinent to the permit action will be included in the public notice for the said permit application or amendment. If no degradation is anticipated, the public notice will so state. The determination of existing use and the probability of degradation are issues upon which evidence can be introduced in permit hearings.
   5. (5) Interested parties will be given the opportunity to provide comments and additional information concerning the determination of existing uses, anticipated impacts of the discharge, baseline conditions, and necessity of the discharge for important economic or social development if degradation of water quality is expected. The commissioners will decide after full satisfaction of the intergovernmental coordination and public participation provisions of the continuing planning process if the economic or social development is important enough to allow the degradation.
   6. (6) Waste load evaluations conducted by the commission will adhere to the provisions of the antidegradation policy. If the waste load evaluation indicates that degradation of waters exceeding fishable/swimmable quality is expected, the public hearing notice will so state. The commission will not approve any waste load evaluation that would allow degradation of waters exceeding fishable/swimmable quality unless and until it has been demonstrated to the commission that the recommended lower water quality is necessary for important economic or social development. Permits which are consistent with an approved waste load evaluation under this antidegradation policy will not be separately subjected to the antidegradation provisions of this section unless the discharge may cause impacts on the receiving water which were not addressed by the waste load evaluation.
   7. (7) Additional implementation procedures for the antidegradation policy are described in the standards implementation procedures.

Source Note:The provisions of this §307.5 adopted to be effective July 10, 1991, 16 TexReg 3400; amended to be effective July 13, 1995, 20 TexReg 4701.