PART 131--WATER QUALITY STANDARDS Subpart A--General Provisions Sec. 131.1 Scope. 131.2 Purpose. 131.3 Definitions. 131.4 State authority. 131.5 EPA authority. 131.6 Minimum requirements for water quality standards submission. 131.7 Dispute resolution mechanism. 131.8 Requirements for Indian Tribes to be treated as States for purposes of water quality standards. Subpart B--Establishment of Water Quality Standards 131.10 Designation of uses. 131.11 Criteria. 131.12 Antidegradation policy. 131.13 General policies. Subpart C--Procedures for Review and Revision of Water Quality Standards 131.20 State review and revision of water quality standards. 131.21 EPA review and approval of water quality standards. 131.22 EPA promulgation of water quality standards. Subpart D--Federally Promulgated Water Quality Standards 131.31 Arizona. 131.33--131.34 [Reserved] 131.35 Colville Confederated Tribes Indian Reservation. Authority: Clean Water Act, Pub. L. 92 - 500, as amended: 33 U.S.C. 1251 et seq. Source: 48 FR 51405, Nov. 8, 1983, unless otherwise noted. Subpart A--General Provisions 131.1 Scope. This part describes the requirements and procedures for developing, reviewing, revising and approving water quality standards by the States as authorized by section 303(c) of the Clean Water Act. The reporting or recordkeeping (information) provisions in this rule were approved by the Office of Management and Budget under 3504(b) of the Paperwork Reduction Act of 1980, U.S.C. 3501 et seq. (Approval number 2040 - 0049). 131.2 Purpose. A water quality standard defines the water quality goals of a water body, or portion thereof, by designating the use or uses to be made of the water and by setting criteria necessary to protect the uses. States adopt water quality standards to protect public health or welfare, enhance the quality of water and serve the purposes of the Clean Water Act (the Act). ``Serve the purposes of the Act'' (as defined in sections 101(a)(2) and 303(c) of the Act) means that water quality standards should, wherever attainable, provide water quality for the protection and propagation of fish, shellfish and wildlife and for recreation in and on the water and take into consideration their use and value of public water supplies, propagation of fish, shellfish, and wildlife, recreation in and on the water, and agricultural, industrial, and other purposes including navigation. Such standards serve the dual purposes of establishing the water quality goals for a specific water body and serve as the regulatory basis for the establishment of water-quality-based treatment controls and strategies beyond the technology-based levels of treatment required by sections 301(b) and 306 of the Act. 131.3 Definitions. (a) The Act means the Clean Water Act (Pub. L. 92 - 500, as amended (33 U.S.C. 1251 et seq.)). (b) Criteria are elements of State water quality standards, expressed as constituent concentrations, levels, or narrative statements, representing a quality of water that supports a particular use. When criteria are met, water quality will generally protect the designated use. (c) Section 304(a) criteria are developed by EPA under authority of section 304(a) of the Act based on the latest scientific information on the relationship that the effect of a constituent concentration has on particular aquatic species and/or human health. This information is issued periodically to the States as guidance for use in developing criteria. (d) Toxic pollutants are those pollutants listed by the Administrator under section 307(a) of the Act. (e) Existing uses are those uses actually attained in the water body on or after November 28, 1975, whether or not they are included in the water quality standards. (f) Designated uses are those uses specified in water quality standards for each water body or segment whether or not they are being attained. (g) Use attainability analysis is a structured scientific assessment of the factors affecting the attainment of the use which may include physical, chemical, biological, and economic factors as described in 131.10(g). (h) Water quality limited segment means any segment where it is known that water quality does not meet applicable water quality standards, and/or is not expected to meet applicable water quality standards, even after the application of the technology-bases effluent limitations required by sections 301(b) and 306 of the Act. (i) Water quality standards are provisions of State or Federal law which consist of a designated use or uses for the waters of the United States and water quality criteria for such waters based upon such uses. Water quality standards are to protect the public health or welfare, enhance the quality of water and serve the purposes of the Act. (j) States include: The 50 States, the District of Columbia, Guam, the Commonwealth of Puerto Rico, Virgin Islands, American Samoa, the Trust Territory of the Pacific Islands, the Commonwealth of the Northern Mariana Islands, and Indian Tribes that EPA determines qualify for treatment as States for purposes of water quality standards. (k) Federal Indian Reservation, Indian Reservation, or Reservation means all land within the limits of any Indian reservation under the jurisdiction of the United States Government, notwithstanding the issuance of any patent, and including rights-of-way running through the reservation.'' (l) Indian Tribe or Tribe means any Indian Tribe, band, group, or community recognized by the Secretary of the Interior and exercising governmental authority over a Federal Indian reservation. [48 FR 51405, Nov. 8, 1983, as amended at 56 FR 64893, Dec. 12, 1991] 131.4 State authority. (a) States (as defined in 131.3) are responsible for reviewing, establishing, and revising water quality standards. As recognized by section 510 of the Clean Water Act, States may develop water quality standards more stringent than required by this regulation. Consistent with section 101(g) and 518(a) of the Clean Water Act, water quality standards shall not be construed to supersede or abrogate rights to quantities of water. (b) States (as defined in 131.3) may issue certifications pursuant to the requirements of Clean Water Act section 401. Revisions adopted by States shall be applicable for use in issuing State certifications consistent with the provisions of 131.21(c). (c) Where EPA determines that a Tribe qualifies for treatment as a State for purposes of water quality standards, the Tribe likewise qualifies for treatment as a State for purposes of certifications conducted under Clean Water Act section 401. [56 FR 64893, Dec. 12, 1991] 131.5 EPA authority. (a) Under section 303(c) of the Act, EPA is to review and to approve or disapprove State-adopted water quality standards. The review involves a determination of: (1) Whether the State has adopted water uses which are consistent with the requirements of the Clean Water Act; (2) Whether the State has adopted criteria that protect the designated water uses; (3) Whether the State has followed its legal procedures for revising or adopting standards; (4) Whether the State standards which do not include the uses specified in section 101(a)(2) of the Act are based upon appropriate technical and scientific data and analyses, and (5) Whether the State submission meets the requirements included in 131.6 of this part. If EPA determines that State water quality standards are consistent with the factors listed in paragraphs (a) through (e) of this section, EPA approves the standards. EPA must disapprove the State water quality standards and promulgate Federal standards under section 303(c)(4) of the Act, if State adopted standards are not consistent with the factors listed in paragraphs (a) through (e) of this section. EPA may also promulgate a new or revised standard where necessary to meet the requirements of the Act. (b) Section 401 of the Clean Water Act authorizes EPA to issue certifications pursuant to the requirements of section 401 in any case where a State or interstate agency has no authority for issuing such certifications. [48 FR 51405, Nov. 8, 1983, as amended at 56 FR 64894, Dec. 12, 1991] 131.6 Minimum requirements for water quality standards submission. The following elements must be included in each State's water quality standards submitted to EPA for review: (a) Use designations consistent with the provisions of sections 101(a)(2) and 303(c)(2) of the Act. (b) Methods used and analyses conducted to support water quality standards revisions. (c) Water quality criteria sufficient to protect the designated uses. (d) An antidegradation policy consistent with 131.12. (e) Certification by the State Attorney General or other appropriate legal authority within the State that the water quality standards were duly adopted pursuant to State law. (f) General information which will aid the Agency in determining the adequacy of the scientific basis of the standards which do not include the uses specified in section 101(a)(2) of the Act as well as information on general policies applicable to State standards which may affect their application and implementation. 131.7 Dispute resolution mechanism. (a) Where disputes between States and Indian Tribes arise as a result of differing water quality standards on common bodies of water, the lead EPA Regional Administrator, as determined based upon OMB circular A - 105, shall be responsible for acting in accordance with the provisions of this section. (b) The Regional Administrator shall attempt to resolve such disputes where: (1) The difference in water quality standards results in unreasonable consequences; (2) The dispute is between a State (as defined in 131.3(j) but exclusive of all Indian Tribes) and a Tribe which EPA has determined qualifies to be treated as a State for purposes of water quality standards; (3) A reasonable effort to resolve the dispute without EPA involvement has been made; (4) The requested relief is consistent with the provisions of the Clean Water Act and other relevant law; (5) The differing State and Tribal water quality standards have been adopted pursuant to State and Tribal law and approved by EPA; and (6) A valid written request has been submitted by either the Tribe or the State. (c) Either a State or a Tribe may request EPA to resolve any dispute which satisfies the criteria of paragraph (b) of this section. Written requests for EPA involvement should be submitted to the lead Regional Administrator and must include: (1) A concise statement of the unreasonable consequences that are alleged to have arisen because of differing water quality standards; (2) A concise description of the actions which have been taken to resolve the dispute without EPA involvement; (3) A concise indication of the water quality standards provision which has resulted in the alleged unreasonable consequences; (4) Factual data to support the alleged unreasonable consequences; and (5) A statement of the relief sought from the alleged unreasonable consequences. (d) Where, in the Regional Administrator's judgment, EPA involvement is appropriate based on the factors of paragraph (b) of this section, the Regional Administrator shall, within 30 days, notify the parties in writing that he/she is initiating an EPA dispute resolution action and solicit their written response. The Regional Administrator shall also make reasonable efforts to ensure that other interested individuals or groups have notice of this action. Such efforts shall include but not be limited to the following: (1) Written notice to responsible Tribal and State Agencies, and other affected Federal agencies, (2) Notice to the specific individual or entity that is alleging that an unreasonable consequence is resulting from differing standards having been adopted on a common body of water, (3) Public notice in local newspapers, radio, and television, as appropriate, (4) Publication in trade journal newsletters, and (5) Other means as appropriate. (e) If in accordance with applicable State and Tribal law an Indian Tribe and State have entered into an agreement that resolves the dispute or establishes a mechanism for resolving a dispute, EPA shall defer to this agreement where it is consistent with the Clean Water Act and where it has been approved by EPA. (f) EPA dispute resolution actions shall be consistent with one or a combination of the following options: (1) Mediation. The Regional Administrator may appoint a mediator to mediate the dispute. Mediators shall be EPA employees, employees from other Federal agencies, or other individuals with appropriate qualifications. (i) Where the State and Tribe agree to participate in the dispute resolution process, mediation with the intent to establish Tribal-State agreements, consistent with Clean Water Act section 518(d), shall normally be pursued as a first effort. (ii) Mediators shall act as neutral facilitators whose function is to encourage communication and negotiation between all parties to the dispute. (iii) Mediators may establish advisory panels, to consist in part of representatives from the affected parties, to study the problem and recommend an appropriate solution. (iv) The procedure and schedule for mediation of individual disputes shall be determined by the mediator in consultation with the parties. (v) If formal public hearings are held in connection with the actions taken under this paragraph, Agency requirements at 40 CFR 25.5 shall be followed. (2) Arbitration. Where the parties to the dispute agree to participate in the dispute resolution process, the Regional Administrator may appoint an arbitrator or arbitration panel to arbitrate the dispute. Arbitrators and panel members shall be EPA employees, employees from other Federal agencies, or other individuals with appropriate qualifications. The Regional administrator shall select as arbitrators and arbitration panel members individuals who are agreeable to all parties, are knowledgeable concerning the requirements of the water quality standards program, have a basic understanding of the political and economic interests of Tribes and States involved, and are expected to fulfill the duties fairly and impartially. (i) The arbitrator or arbitration panel shall conduct one or more private or public meetings with the parties and actively solicit information pertaining to the effects of differing water quality permit requirements on upstream and downstream dischargers, comparative risks to public health and the environment, economic impacts, present and historical water uses, the quality of the waters subject to such standards, and other factors relevant to the dispute, such as whether proposed water quality criteria are more stringent than necessary to support designated uses, more stringent than natural background water quality or whether designated uses are reasonable given natural background water quality. (ii) Following consideration of relevant factors as defined in paragraph (f)(2)(i) of this section, the arbitrator or arbitration panel shall have the authority and responsibility to provide all parties and the Regional Administrator with a written recommendation for resolution of the dispute. Arbitration panel recommendations shall, in general, be reached by majority vote. However, where the parties agree to binding arbitration, or where required by the Regional Administrator, recommendations of such arbitration panels may be unanimous decisions. Where binding or non-binding arbitration panels cannot reach a unanimous recommendation after a reasonable period of time, the Regional Administrator may direct the panel to issue a non-binding decision by majority vote. (iii) The arbitrator or arbitration panel members may consult with EPA's Office of General Counsel on legal issues, but otherwise shall have no ex parte communications pertaining to the dispute. Federal employees who are arbitrators or arbitration panel members shall be neutral and shall not be predisposed for or against the position of any disputing party based on any Federal Trust responsibilities which their employers may have with respect to the Tribe. In addition, arbitrators or arbitration panel members who are Federal employees shall act independently from the normal hierarchy within their agency. (iv) The parties are not obligated to abide by the arbitrator's or arbitration panel's recommendation unless they voluntarily entered into a binding agreement to do so. (v) If a party to the dispute believes that the arbitrator or arbitration panel has recommended an action contrary to or inconsistent with the Clean Water Act, the party may appeal the arbitrator's recommendation to the Regional Administrator. The request for appeal must be in writing and must include a description of the statutory basis for altering the arbitrator's recommendation. (vi) The procedure and schedule for arbitration of individual disputes shall be determined by the arbitrator or arbitration panel in consultation with parties. (vii) If formal public hearings are held in connection with the actions taken under this paragraph, Agency requirements at 40 CFR 25.5 shall be followed. (3) Dispute resolution default procedure. Where one or more parties (as defined in paragraph (g) of this section) refuse to participate in either the mediation or arbitration dispute resolution processes, the Regional Administrator may appoint a single official or panel to review available information pertaining to the dispute and to issue a written recommendation for resolving the dispute. Review officials shall be EPA employees, employees from other Federal agencies, or other individuals with appropriate qualifications. Review panels shall include appropriate members to be selected by the Regional Administrator in consultation with the participating parties. Recommendations of such review officials or panels shall, to the extent possible given the lack of participation by one or more parties, be reached in a manner identical to that for arbitration of disputes specified in paragraphs (f)(2)(i) through (f)(2)(vii) of this section. (g) Definitions. For the purposes of this section: (1) Dispute Resolution Mechanism means the EPA mechanism established pursuant to the requirements of Clean Water Act section 518(e) for resolving unreasonable consequences that arise as a result of differing water quality standards that may be set by States and Indian Tribes located on common bodies of water. (2) Parties to a State-Tribal dispute include the State and the Tribe and may, at the discretion of the Regional Administrator, include an NPDES permittee, citizen, citizen group, or other affected entity. [56 FR 64894, Dec. 12, 1991] 131.8 Requirements for Indian Tribes to be treated as States for purposes of water quality standards. (a) The Regional Administrator, as determined based on OMB Circular A - 105, may treat an Indian Tribe as a State for purposes of the water quality standards program if the Tribe meets the following criteria: (1) The Indian Tribe is recognized by the Secretary of the Interior and meets the definitions in 131.3 (k) and (l), (2) The Indian Tribe has a governing body carrying out substantial governmental duties and powers, (3) The water quality standards program to be administered by the Indian Tribe pertains to the management and protection of water resources which are within the borders of the Indian reservation and held by the Indian Tribe, within the borders of the Indian reservation and held by the United States in trust for Indians, within the borders of the Indian reservation and held by a member of the Indian Tribe if such property interest is subject to a trust restriction on alienation, or otherwise within the borders of the Indian reservation, and (4) The Indian Tribe is reasonably expected to be capable, in the Regional Administrator's judgment, of carrying out the functions of an effective water quality standards program in a manner consistent with the terms and purposes of the Act and applicable regulations. (b) Requests by Indian Tribes for treatment as States for purposes of water quality standards should be submitted to the lead EPA Regional Administrator. The application shall include the following information: (1) A statement that the Tribe is recognized by the Secretary of the Interior. (2) A descriptive statement demonstrating that the Tribal governing body is currently carrying out substantial governmental duties and powers over a defined area. The statement shall: (i) Describe the form of the Tribal government; (ii) Describe the types of governmental functions currently performed by the Tribal governing body such as, but not limited to, the exercise of police powers affecting (or relating to) the health, safety, and welfare of the affected population, taxation, and the exercise of the power of eminent domain; and (iii) Identify the source of the Tribal government's authority to carry out the governmental functions currently being performed. (3) A descriptive statement of the Indian Tribe's authority to regulate water quality. The statement shall include: (i) A map or legal description of the area over which the Indian Tribe asserts authority to regulate surface water quality; (ii) A statement by the Tribe's legal counsel (or equivalent official) which describes the basis for the Tribes assertion of authority; (iii) A copy of all documents such as Tribal constitutions, by-laws, charters, executive orders, codes, ordinances, and/or resolutions which support the Tribe's assertion of authority; and (iv) An identification of the surface waters for which the Tribe proposes to establish water quality standards. (4) A narrative statement describing the capability of the Indian Tribe to administer an effective water quality standards program. The narrative statement shall include: (i) A description of the Indian Tribe's previous management experience including, but not limited to, the administration of programs and services authorized by the Indian Self-Determination and Education Assistance Act (25 U.S.C. 450 et seq.), the Indian Mineral Development Act (25 U.S.C. 2101 et seq.), or the Indian Sanitation Facility Construction Activity Act (42 U.S.C. 2004a); (ii) A list of existing environmental or public health programs administered by the Tribal governing body and copies of related Tribal laws, policies, and regulations; (iii) A description of the entity (or entities) which exercise the executive, legislative, and judicial functions of the Tribal government; (iv) A description of the existing, or proposed, agency of the Indian Tribe which will assume primary responsibility for establishing, reviewing, implementing and revising water quality standards; (v) A description of the technical and administrative capabilities of the staff to administer and manage an effective water quality standards program or a plan which proposes how the Tribe will acquire additional administrative and technical expertise. The plan must address how the Tribe will obtain the funds to acquire the administrative and technical expertise. (5) Additional documentation required by the Regional Administrator which, in the judgment of the Regional Administrator, is necessary to support a Tribal request for treatment as a State. (6) Where the Tribe has previously qualified for treatment as a State under a Clean Water Act or Safe Drinking Water Act program, the Tribe need only provide the required information which has not been submitted in a previous treatment as a State application. (c) Procedure for processing an Indian Tribe's application for treatment as a State. (1) The Regional Administrator shall process an application of an Indian Tribe for treatment as a State submitted pursuant to 131.8(b) in a timely manner. He shall promptly notify the Indian Tribe of receipt of the application. (2) Within 30 days after receipt of the Indian Tribe's application for treatment as a State, the Regional Administrator shall provide appropriate notice. Notice shall: (i) Include information on the substance and basis of the Tribe's assertion of authority to regulate the quality of reservation waters; and (ii) Be provided to all appropriate governmental entities. (3) The Regional Administrator shall provide 30 days for comments to be submitted on the Tribal application. Comments shall be limited to the Tribe's assertion of authority. (4) If a Tribe's asserted authority is subject to a competing or conflicting claim, the Regional Administrator, after consultation with the Secretary of the Interior, or his designee, and in consideration of other comments received, shall determine whether the Tribe has adequately demonstrated that it meets the requirements of 131.8(a)(3). (5) Where the Regional Administrator determines that a Tribe meets the requirements of this section, he shall promptly provide written notification to the Indian Tribe that the Tribe has qualified to be treated as a State for purposes of water quality standards and that the Tribe may initiate the formulation and adoption of water quality standards approvable under this part. [56 FR 64895, Dec. 12, 1991] Subpart B--Establishment of Water Quality Standards 131.10 Designation of uses. (a) Each State must specify appropriate water uses to be achieved and protected. The classification of the waters of the State must take into consideration the use and value of water for public water supplies, protection and propagation of fish, shellfish and wildlife, recreation in and on the water, agricultural, industrial, and other purposes including navigation. In no case shall a State adopt waste transport or waste assimilation as a designated use for any waters of the United States. (b) In designating uses of a water body and the appropriate criteria for those uses, the State shall take into consideration the water quality standards of downstream waters and shall ensure that its water quality standards provide for the attainment and maintenance of the water quality standards of downstream waters. (c) States may adopt sub-categories of a use and set the appropriate criteria to reflect varying needs of such sub-categories of uses, for instance, to differentiate between cold water and warm water fisheries. (d) At a minimum, uses are deemed attainable if they can be achieved by the imposition of effluent limits required under sections 301(b) and 306 of the Act and cost-effective and reasonable best management practices for nonpoint source control. (e) Prior to adding or removing any use, or establishing sub-categories of a use, the State shall provide notice and an opportunity for a public hearing under 131.20(b) of this regulation. (f) States may adopt seasonal uses as an alternative to reclassifying a water body or segment thereof to uses requiring less stringent water quality criteria. If seasonal uses are adopted, water quality criteria should be adjusted to reflect the seasonal uses, however, such criteria shall not preclude the attainment and maintenance of a more protective use in another season. (g) States may remove a designated use which is not an existing use, as defined in 131.3, or establish sub-categories of a use if the State can demonstrate that attaining the designated use is not feasible because: (1) Naturally occurring pollutant concentrations prevent the attainment of the use; or (2) Natural, ephemeral, intermittent or low flow conditions or water levels prevent the attainment of the use, unless these conditions may be compensated for by the discharge of sufficient volume of effluent discharges without violating State water conservation requirements to enable uses to be met; or (3) Human caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place; or (4) Dams, diversions or other types of hydrologic modifications preclude the attainment of the use, and it is not feasible to restore the water body to its original condition or to operate such modification in a way that would result in the attainment of the use; or (5) Physical conditions related to the natural features of the water body, such as the lack of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic life protection uses; or (6) Controls more stringent than those required by sections 301(b) and 306 of the Act would result in substantial and widespread economic and social impact. (h) States may not remove designated uses if: (1) They are existing uses, as defined in 131.3, unless a use requiring more stringent criteria is added; or (2) Such uses will be attained by implementing effluent limits required under sections 301(b) and 306 of the Act and by implementing cost-effective and reasonable best management practices for nonpoint source control. (i) Where existing water quality standards specify designated uses less than those which are presently being attained, the State shall revise its standards to reflect the uses actually being attained. (j) A State must conduct a use attainability analysis as described in 131.3(g) whenever: (1) The State designates or has designated uses that do not include the uses specified in section 101(a)(2) of the Act, or (2) The State wishes to remove a designated use that is specified in section 101(a)(2) of the Act or to adopt subcategories of uses specified in section 101(a)(2) of the Act which require less stringent criteria. (k) A State is not required to conduct a use attainability analysis under this regulation whenever designating uses which include those specified in section 101(a)(2) of the Act. 131.11 Criteria. (a) Inclusion of pollutants: (1) States must adopt those water quality criteria that protect the designated use. Such criteria must be based on sound scientific rationale and must contain sufficient parameters or constituents to protect the designated use. For waters with multiple use designations, the criteria shall support the most sensitive use. (2) Toxic pollutants. States must review water quality data and information on discharges to identify specific water bodies where toxic pollutants may be adversely affecting water quality or the attainment of the designated water use or where the levels of toxic pollutants are at a level to warrant concern and must adopt criteria for such toxic pollutants applicable to the water body sufficient to protect the designated use. Where a State adopts narrative criteria for toxic pollutants to protect designated uses, the State must provide information identifying the method by which the State intends to regulate point source discharges of toxic pollutants on water quality limited segments based on such narrative criteria. Such information may be included as part of the standards or may be included in documents generated by the State in response to the Water Quality Planning and Management Regulations (40 CFR part 35). (b) Form of criteria: In establishing criteria, States should: (1) Establish numerical values based on: (i) 304(a) Guidance; or (ii) 304(a) Guidance modified to reflect site-specific conditions; or (iii) Other scientifically defensible methods; (2) Establish narrative criteria or criteria based upon biomonitoring methods where numerical criteria cannot be established or to supplement numerical criteria. 131.12 Antidegradation policy. (a) The State shall develop and adopt a statewide antidegradation policy and identify the methods for implementing such policy pursuant to this subpart. The antidegradation policy and implementation methods shall, at a minimum, be consistent with the following: (1) Existing instream water uses and the level of water quality necessary to protect the existing uses shall be maintained and protected. (2) Where the quality of the waters exceed levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on the water, that quality shall be maintained and protected unless the State finds, after full satisfaction of the intergovernmental coordination and public participation provisions of the State's continuing planning process, that allowing lower water quality is necessary to accommodate important economic or social development in the area in which the waters are located. In allowing such degradation or lower water quality, the State shall assure water quality adequate to protect existing uses fully. Further, the State shall assure that there shall be achieved the highest statutory and regulatory requirements for all new and existing point sources and all cost-effective and reasonable best management practices for nonpoint source control. (3) Where high quality waters constitute an outstanding National resource, such as waters of National and State parks and wildlife refuges and waters of exceptional recreational or ecological significance, that water quality shall be maintained and protected. (4) In those cases where potential water quality impairment associated with a thermal discharge is involved, the antidegradation policy and implementing method shall be consistent with section 316 of the Act. 131.13 General policies. States may, at their discretion, include in their State standards, policies generally affecting their application and implementation, such as mixing zones, low flows and variances. Such policies are subject to EPA review and approval. Subpart C--Procedures for Review and Revision of Water Quality Standards 131.20 State review and revision of water quality standards. (a) State review. The State shall from time to time, but at least once every three years, hold public hearings for the purpose of reviewing applicable water quality standards and, as appropriate, modifying and adopting standards. Any water body segment with water quality standards that do not include the uses specified in section 101(a)(2) of the Act shall be re-examined every three years to determine if any new information has become available. If such new information indicates that the uses specified in section 101(a)(2) of the Act are attainable, the State shall revise its standards accordingly. Procedures States establish for identifying and reviewing water bodies for review should be incorporated into their Continuing Planning Process. (b) Public participation. The State shall hold a public hearing for the purpose of reviewing water quality standards, in accordance with provisions of State law, EPA's water quality management regulation (40 CFR 130.3(b)(6)) and public participation regulation (40 CFR part 25). The proposed water quality standards revision and supporting analyses shall be made available to the public prior to the hearing. (c) Submittal to EPA. The State shall submit the results of the review, any supporting analysis for the use attainability analysis, the methodologies used for site-specific criteria development, any general policies applicable to water quality standards and any revisions of the standards to the Regional Administrator for review and approval, within 30 days of the final State action to adopt and certify the revised standard, or if no revisions are made as a result of the review, within 30 days of the completion of the review. 131.21 EPA review and approval of water quality standards. (a) After the State submits its officially adopted revisions, the Regional Administrator shall either: (1) Notify the State within 60 days that the revisions are approved, or (2) Notify the State within 90 days that the revisions are disapproved. Such notification of disapproval shall specify the changes needed to assure compliance with the requirements of the Act and this regulation, and shall explain why the State standard is not in compliance with such requirements. Any new or revised State standard must be accompanied by some type of supporting analysis. (b) The Regional Administrator's approval or disapproval of a State water quality standard shall be based on the requirements of the Act as described in 131.5, and 131.6. (c) A State water quality standard remains in effect, even though disapproved by EPA, until the State revises it or EPA promulgates a rule that supersedes the State water quality standard. (d) EPA shall, at least annually, publish in the Federal Register a notice of approvals under this section. 131.22 EPA promulgation of water quality standards. (a) If the State does not adopt the changes specified by the Regional Administrator within 90 days after notification of the Regional Administrator's disapproval, the Administrator shall promptly propose and promulgate such standard. (b) The Administrator may also propose and promulgate a regulation, applicable to one or more States, setting forth a new or revised standard upon determining such a standard is necessary to meet the requirements of the Act. (c) In promulgating water quality standards, the Administrator is subject to the same policies, procedures, analyses, and public participation requirements established for States in these regulations. Subpart D--Federally Promulgated Water Quality Standards 131.31 Arizona. (a) Article 6, part 2 is amended as follows: (1) Reg. 6 - 2 - 6.11 shall read: Reg. 6 - 2 - 6.11 Nutrient Standards. A. The mean annual total phosphate and mean annual total nitrate concentrations of the following waters shall not exceed the values given below nor shall the total phosphate or total nitrate concentrations of more than 10 percent of the samples in any year exceed the 90 percent values given below. Unless otherwise specified, indicated values also apply to tributaries to the named waters. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Mean 90 pct annual value 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Total phosphates Total nitrates as as PO4mg/ NO3mg/ l l 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 1. Colorado River from Utah border to Willow Beach (main stem)................. 0.04 - 0.06 4 - 7 2. Colorado River from Willow Beach to Parker Dam (main stem)................... 0.06 - 0.10 5 3. Colorado River from Parker Dam to Imperial Dam (main stem)................. 0.08 - 0.12 5 - 7 4. Colorado River from Imperial Dam to Morelos Dam (main stem).................. 0.10 - 0.10 5 - 7 5. Gila River from New Mexico border to San Carlos Reservoir (excluding San Carlos Reservoir)........................ 0.50 - 0.80 ................ 6. Gila River from San Carlos Reservoir to Ashurst Hayden Dam (including San Carlos Reservoir)............................... 0.30 - 0.50 ................ 7. San Pedro River........................ 0.30 - 0.50 ................ 8. Verde River (except Granite Creek)..... 0.20 - 0.30 ................ 9. Salt River above Roosevelt Lake........ 0.20 - 0.30 ................ 10. Santa Cruz River from international boundary near Nogales to Sahuarita....... 0.50 - 0.80 ................ 11. Little Colorado River above Lyman Reservoir................................ 0.30 - 0.50 ................ 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 B. The above standards are intended to protect the beneficial uses of the named waters. Because regulation of nitrates and phosphates alone may not be adequate to protect waters from eutrophication, no substance shall be added to any surface water which produces aquatic growth to the extent that such growths create a public nuisance or interference with beneficial uses of the water defined and designated in Reg. 6 - 2 - 6.5. (2) Reg. 6 - 2 - 6.10 Subparts A and B are amended to include Reg. 6 - 2 - 6.11 in series with Regs. 6 - 2 - 6.6, 6 - 2 - 6.7 and 6 - 2 - 6.8. (Sec. 303, Federal Water Pollution Control Act, as amended, 33 U.S.C. 1313, 86 Stat. 816 et seq., Pub. L. 92 - 500; Clean Water Act, Pub. L. 92 - 500, as amended; 33 U.S.C. 1251 et seq.) [41 FR 25000, June 22, 1976; 41 FR 48737, Nov. 5, 1976. Redesignated and amended at 42 FR 56740, Oct. 28, 1977. Further redesignated and amended at 48 FR 51408, Nov. 8, 1983] 131.33--131.34 [Reserved] 131.35 Colville Confederated Tribes Indian Reservation. The water quality standards applicable to the waters within the Colville Indian Reservation, located in the State of Washington. (a) Background. (1) It is the purpose of these Federal water quality standards to prescribe minimum water quality requirements for the surface waters located within the exterior boundaries of the Colville Indian Reservation to ensure compliance with section 303(c) of the Clean Water Act. (2) The Colville Confederated Tribes have a primary interest in the protection, control, conservation, and utilization of the water resources of the Colville Indian Reservation. Water quality standards have been enacted into tribal law by the Colville Business Council of the Confederated Tribes of the Colville Reservation, as the Colville Water Quality Standards Act, CTC Title 33 (Resolution No. 1984 - 526 (August 6, 1984) as amended by Resolution No. 1985 - 20 (January 18, 1985)). (b) Territory Covered. The provisions of these water quality standards shall apply to all surface waters within the exterior boundaries of the Colville Indian Reservation. (c) Applicability, Administration and Amendment. (1) The water quality standards in this section shall be used by the Regional Administrator for establishing any water quality based National Pollutant Discharge Elimination System Permit (NPDES) for point sources on the Colville Confederated Tribes Reservation. (2) In conjunction with the issuance of section 402 or section 404 permits, the Regional Administrator may designate mixing zones in the waters of the United States on the reservation on a case-by-case basis. The size of such mixing zones and the in-zone water quality in such mixing zones shall be consistent with the applicable procedures and guidelines in EPA's Water Quality Standards Handbook and the Technical Support Document for Water Quality Based Toxics Control. (3) Amendments to the section at the request of the Tribe shall proceed in the following manner. (i) The requested amendment shall first be duly approved by the Confederated Tribes of the Colville Reservation (and so certified by the Tribes Legal Counsel) and submitted to the Regional Administrator. (ii) The requested amendment shall be reviewed by EPA (and by the State of Washington, if the action would affect a boundary water). (iii) If deemed in compliance with the Clean Water Act, EPA will propose and promulgate an appropriate change to this section. (4) Amendment of this section at EPA's initiative will follow consultation with the Tribe and other appropriate entities. Such amendments will then follow normal EPA rulemaking procedures. (5) All other applicable provisions of this part 131 shall apply on the Colville Confederated Tribes Reservation. Special attention should be paid to 131.6, 131.10, 131.11 and 131.20 for any amendment to these standards to be initiated by the Tribe. (6) All numeric criteria contained in this section apply at all in-stream flow rates greater than or equal to the flow rate calculated as the minimum 7-consecutive day average flow with a recurrence frequency of once in ten years (7Q10); narrative criteria (131.35(e)(3)) apply regardless of flow. The 7Q10 low flow shall be calculated using methods recommended by the U.S. Geological Survey. (d) Definitions. (1) Acute toxicity means a deleterious response (e.g., mortality, disorientation, immobilization) to a stimulus observed in 96 hours or less. (2) Background conditions means the biological, chemical, and physical conditions of a water body, upstream from the point or non-point source discharge under consideration. Background sampling location in an enforcement action will be upstream from the point of discharge, but not upstream from other inflows. If several discharges to any water body exist, and an enforcement action is being taken for possible violations to the standards, background sampling will be undertaken immediately upstream from each discharge. (3) Ceremonial and Religious water use means activities involving traditional Native American spiritual practices which involve, among other things, primary (direct) contact with water. (4) Chronic Toxicity means the lowest concentration of a constituent causing observable effects (i.e., considering lethality, growth, reduced reproduction, etc.) over a relatively long period of time, usually a 28-day test period for small fish test species. (5) Council or Tribal Council means the Colville Business Council of the Colville Confederated Tribes. (6) Geometric mean means the nth root of a product of n factors. (7) Mean retention time means the time obtained by dividing a reservoir's mean annual minimum total storage by the non-zero 30-day, ten-year low-flow from the reservoir. (8) Mixing Zone or dilution zone means a limited area or volume of water where initial dilution of a discharge takes place; and where numeric water quality criteria can be exceeded but acutely toxic conditions are prevented from occurring. (9) pH means the negative logarithm of the hydrogen ion concentration. (10) Primary contact recreation means activities where a person would have direct contact with water to the point of complete submergence, including but not limited to skin diving, swimming, and water skiing. (11) Regional Administrator means the Administrator of EPA's Region X. (12) Reservation means all land within the limits of the Colville Indian Reservation, established on July 2, 1872 by Executive Order, presently containing 1,389,000 acres more or less, and under the jurisdiction of the United States government, notwithstanding the issuance of any patent, and including rights-of-way running through the reservation. (13) Secondary contact recreation means activities where a person's water contact would be limited to the extent that bacterial infections of eyes, ears, respiratory, or digestive systems or urogenital areas would normally be avoided (such as wading or fishing). (14) Surface water means all water above the surface of the ground within the exterior boundaries of the Colville Indian Reservation including but not limited to lakes, ponds, reservoirs, artificial impoundments, streams, rivers, springs, seeps and wetlands. (15) Temperature means water temperature expressed in Centigrade degrees (C). (16) Total dissolved solids (TDS) means the total filterable residue that passes through a standard glass fiber filter disk and remains after evaporation and drying to a constant weight at 180 degrees C. it is considered to be a measure of the dissolved salt content of the water. (17) Toxicity means acute and/or chronic toxicity. (18) Tribe or Tribes means the Colville Confederated Tribes. (19) Turbidity means the clarity of water expressed as nephelometric turbidity units (NTU) and measured with a calibrated turbidimeter. (20) Wildlife habitat means the waters and surrounding land areas of the Reservation used by fish, other aquatic life and wildlife at any stage of their life history or activity. (e) General considerations. The following general guidelines shall apply to the water quality standards and classifications set forth in the use designation Sections. (1) Classification boundaries. At the boundary between waters of different classifications, the water quality standards for the higher classification shall prevail. (2) Antidegradation policy. This antidegradation policy shall be applicable to all surface waters of the Reservation. (i) Existing in-stream water uses and the level of water quality necessary to protect the existing uses shall be maintained and protected. (ii) Where the quality of the waters exceeds levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on the water, that quality shall be maintained and protected unless the Regional Administrator finds, after full satisfaction of the inter-governmental coordination and public participation provisions of the Tribes' continuing planning process, that allowing lower water quality is necessary to accommodate important economic or social development in the area in which the waters are located. In allowing such degradation or lower water quality, the Regional Administrator shall assure water quality adequate to protect existing uses fully. Further, the Regional Administrator shall assure that there shall be achieved the highest statutory and regulatory requirements for all new and existing point sources and all cost-effective and reasonable best management practices for nonpoint source control. (iii) Where high quality waters are identified as constituting an outstanding national or reservation resource, such as waters within areas designated as unique water quality management areas and waters otherwise of exceptional recreational or ecological significance, and are designated as special resource waters, that water quality shall be maintained and protected. (iv) In those cases where potential water quality impairment associated with a thermal discharge is involved, this antidegradation policy's implementing method shall be consistent with section 316 of the Clean Water Act. (3) Aesthetic qualities. All waters within the Reservation, including those within mixing zones, shall be free from substances, attributable to wastewater discharges or other pollutant sources, that: (i) Settle to form objectionable deposits; (ii) Float as debris, scum, oil, or other matter forming nuisances; (iii) Produce objectionable color, odor, taste, or turbidity; (iv) Cause injury to, are toxic to, or produce adverse physiological responses in humans, animals, or plants; or (v) produce undesirable or nuisance aquatic life. (4) Analytical methods. (i) The analytical testing methods used to measure or otherwise evaluate compliance with water quality standards shall to the extent practicable, be in accordance with the ``Guidelines Establishing Test Procedures for the Analysis of Pollutants'' (40 CFR part 136). When a testing method is not available for a particular substance, the most recent edition of ``Standard Methods for the Examination of Water and Wastewater'' (published by the American Public Health Association, American Water Works Association, and the Water Pollution Control Federation) and other or superseding methods published and/or approved by EPA shall be used. (f) General water use and criteria classes. The following criteria shall apply to the various classes of surface waters on the Colville Indian Reservation: (1) Class I (Extraordinary)--(i) Designated uses. The designated uses include, but are not limited to, the following: (A) Water supply (domestic, industrial, agricultural). (B) Stock watering. (C) Fish and shellfish: Salmonid migration, rearing, spawning, and harvesting; other fish migration, rearing, spawning, and harvesting. (D) Wildlife habitat. (E) Ceremonial and religious water use. (F) Recreation (primary contact recreation, sport fishing, boating and aesthetic enjoyment). (G) Commerce and navigation. (ii) Water quality criteria. (A) Bacteriological Criteria. The geometric mean of the enterococci bacteria densities in samples taken over a 30 day period shall not exceed 8 per 100 milliliters, nor shall any single sample exceed an enterococci density of 35 per 100 milliliters. These limits are calculated as the geometric mean of the collected samples approximately equally spaced over a thirty day period. (B) Dissolved oxygen--The dissolved oxygen shall exceed 9.5 mg/l. (C) Total dissolved gas--concentrations shall not exceed 110 percent of the saturation value for gases at the existing atmospheric and hydrostatic pressures at any point of sample collection. (D) Temperature--shall not exceed 16.0 degrees C due to human activities. Temperature increases shall not, at any time, exceed t=23/(T+5). (1) When natural conditions exceed 16.0 degrees C, no temperature increase will be allowed which will raise the receiving water by greater than 0.3 degrees C. (2) For purposes hereof, ``t'' represents the permissive temperature change across the dilution zone; and ``T'' represents the highest existing temperature in this water classification outside of any dilution zone. (3) Provided that temperature increase resulting from nonpoint source activities shall not exceed 2.8 degrees C, and the maximum water temperature shall not exceed 10.3 degrees C. (E) pH shall be within the range of 6.5 to 8.5 with a human-caused variation of less than 0.2 units. (F) Turbidity shall not exceed 5 NTU over background turbidity when the background turbidity is 50 NTU or less, or have more than a 10 percent increase in turbidity when the background turbidity is more than 50 NTU. (G) Toxic, radioactive, nonconventional, or deleterious material concentrations shall be less than those of public health significance, or which may cause acute or chronic toxic conditions to the aquatic biota, or which may adversely affect designated water uses. (2) Class II (Excellent).--(i) Designated uses. The designated uses include but are not limited to, the following: (A) Water supply (domestic, industrial, agricultural). (B) Stock watering. (C) Fish and shellfish: Salmonid migration, rearing, spawning, and harvesting; other fish migration, rearing, spawning, and harvesting; crayfish rearing, spawning, and harvesting. (D) Wildlife habitat. (E) Ceremonial and religious water use. (F) Recreation (primary contact recreation, sport fishing, boating and aesthetic enjoyment). (G) Commerce and navigation. (ii) Water quality criteria. (A) Bacteriological Criteria--The geometric mean of the enterococci bacteria densities in samples taken over a 30 day period shall not exceed 16/100 ml, nor shall any single sample exceed an enterococci density of 75 per 100 milliliters. These limits are calculated as the geometric mean of the collected samples approximately equally spaced over a thirty day period. (B) Dissolved oxygen--The dissolved oxygen shall exceed 8.0 mg/l. (C) Total dissolved gas--concentrations shall not exceed 110 percent of the saturation value for gases at the existing atmospheric and hydrostatic pressures at any point of sample collection. (D) Temperature-shall not exceed 18.0 degrees C due to human activities. Temperature increases shall not, at any time, exceed t=28/(T+7). (1) When natural conditions exceed 18 degrees C no temperature increase will be allowed which will raise the receiving water temperature by greater than 0.3 degrees C. (2) For purposes hereof, ``t'' represents the permissive temperature change across the dilution zone; and ``T'' represents the highest existing temperature in this water classification outside of any dilution zone. (3) Provided that temperature increase resulting from non-point source activities shall not exceed 2.8 degrees C, and the maximum water temperature shall not exceed 18.3 degrees C. (E) pH shall be within the range of 6.5 to 8.5 with a human-caused variation of less than 0.5 units. (F) Turbidity shall not exceed 5 NTU over background turbidity when the background turbidity is 50 NTU or less, or have more than a 10 percent increase in turbidity when the background turbidity is more than 50 NTU. (G) Toxic, radioactive, nonconventional, or deleterious material concentrations shall be less than those of public health significance, or which may cause acute or chronic toxic conditions to the aquatic biota, or which may adversely affect designated water uses. (3) Class III (Good).--(i) Designated uses. The designated uses include but are not limited to, the following: (A) Water supply (industrial, agricultural). (B) Stock watering. (C) Fish and shellfish: Salmonid migration, rearing, spawning, and harvesting; other fish migration, rearing, spawning, and harvesting; crayfish rearing, spawning, and harvesting. (D) Wildlife habitat. (E) Recreation (secondary contact recreation, sport fishing, boating and aesthetic enjoyment). (F) Commerce and navigation. (ii) Water quality criteria. (A) Bacteriological Criteria--The geometric mean of the enterococci bacteria densities in samples taken over a 30 day period shall not exceed 33/100 ml, nor shall any single sample exceed an enterococci density of 150 per 100 milliliters. These limits are calculated as the geometric mean of the collected samples approximately equally spaced over a thirty day period. (B) Dissolved oxygen. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Other Early life life stages\1\\,\\2\ stages 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 7 day mean............................................ 9.5 (6.5) \3\NA 1 day minimum\4\...................................... 8.0 (5.0) 6.5 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 \1\These are water column concentrations recommended to achieve the required intergravel dissolved oxygen concentrations shown in parentheses. The 3 mg/L differential is discussed in the dissolved oxygen criteria document (EPA 440/ 5 - 86 - 003, April 1986). For species that have early life stages exposed directly to the water column, the figures in parentheses apply. \2\Includes all embryonic and larval stages and all juvenile forms to 30-days following hatching. \3\NA (not applicable) \4\All minima should be considered as instantaneous concentrations to be achieved at all times. (C) Total dissolved gas concentrations shall not exceed 110 percent of the saturation value for gases at the existing atmospheric and hydrostatic pressures at any point of sample collection. (D) Temperature shall not exceed 21.0 degrees C due to human activities. Temperature increases shall not, at any time, exceed t=34/(T+9). (1) When natural conditions exceed 21.0 degrees C no temperature increase will be allowed which will raise the receiving water temperature by greater than 0.3 degrees C. (2) For purposes hereof, ``t'' represents the permissive temperature change across the dilution zone; and ``T'' represents the highest existing temperature in this water classification outside of any dilution zone. (3) Provided that temperature increase resulting from nonpoint source activities shall not exceed 2.8 degrees C, and the maximum water temperature shall not exceed 21.3 degrees C. (E) pH shall be within the range of 6.5 to 8.5 with a human-caused variation of less than 0.5 units. (F) Turbidity shall not exceed 10 NTU over background turbidity when the background turbidity is 50 NTU or less, or have more than a 20 percent increase in turbidity when the background turbidity is more than 50 NTU. (G) Toxic, radioactive, nonconventional, or deleterious material concentrations shall be less than those of public health significance, or which may cause acute or chronic toxic conditions to the aquatic biota, or which may adversely affect designated water uses. (4) Class IV (Fair)--(i) Designated uses. The designated uses include but are not limited to, the following: (A) Water supply (industrial). (B) Stock watering. (C) Fish (salmonid and other fish migration). (D) Recreation (secondary contact recreation, sport fishing, boating and aesthetic enjoyment). (E) Commerce and navigation. (ii) Water quality criteria. (A) Dissolved oxygen. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 During periods of During salmonid all other and other time fish periods migration 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 30 day mean........................................... 6.5 5.5 7 day mean............................................ \1\NA \1\NA 7 day mean minimum.................................... 5.0 4.0 1 day minimum\2\...................................... 4.0 3.0 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 \1\NA (not applicable). \2\All minima should be considered as instantaneous concentrations to be achieved at all times. (B) Total dissolved gas--concentrations shall not exceed 110 percent of the saturation value for gases at the existing atmospheric and hydrostatic pressures at any point of sample collection. (C) Temperature shall not exceed 22.0 degrees C due to human activities. Temperature increases shall not, at any time, exceed t=20/(T+2). (1) When natural conditions exceed 22.0 degrees C, no temperature increase will be allowed which will raise the receiving water temperature by greater than 0.3 degrees C. (2) For purposes hereof, ``t'' represents the permissive temperature change across the dilution zone; and ``T'' represents the highest existing temperature in this water classification outside of any dilution zone. (D) pH shall be within the range of 6.5 to 9.0 with a human-caused variation of less than 0.5 units. (E) Turbidity shall not exceed 10 NTU over background turbidity when the background turbidity is 50 NTU or less, or have more than a 20 percent increase in turbidity when the background turbidity is more than 50 NTU. (F) Toxic, radioactive, nonconventional, or deleterious material concentrations shall be less than those of public health significance, or which may cause acute or chronic toxic conditions to the aquatic biota, or which may adversely affect designated water uses. (5) Lake Class--(i) Designated uses. The designated uses include but are not limited to, the following: (A) Water supply (domestic, industrial, agricultural). (B) Stock watering. (C) Fish and shellfish: Salmonid migration, rearing, spawning, and harvesting; other fish migration, rearing, spawning, and harvesting; crayfish rearing, spawning, and harvesting. (D) Wildlife habitat. (E) Ceremonial and religious water use. (F) Recreation (primary contact recreation, sport fishing, boating and aesthetic enjoyment). (G) Commerce and navigation. (ii) Water quality criteria. (A) Bacteriological Criteria. The geometric mean of the enterococci bacteria densities in samples taken over a 30 day period shall not exceed 33/100 ml, nor shall any single sample exceed an enterococci density of 150 per 100 milliliters. These limits are calculated as the geometric mean of the collected samples approximately equally spaced over a thirty day period. (B) Dissolved oxygen--no measurable decrease from natural conditions. (C) Total dissolved gas concentrations shall not exceed 110 percent of the saturation value for gases at the existing atmospheric and hydrostatic pressures at any point of sample collection. (D) Temperature--no measurable change from natural conditions. (E) pH--no measurable change from natural conditions. (F) Turbidity shall not exceed 5 NTU over natural conditions. (G) Toxic, radioactive, nonconventional, or deleterious material concentrations shall be less than those which may affect public health, the natural aquatic environment, or the desirability of the water for any use. (6) Special Resource Water Class (SRW)--(i) General characteristics. These are fresh or saline waters which comprise a special and unique resource to the Reservation. Water quality of this class will be varied and unique as determined by the Regional Administrator in cooperation with the Tribes. (ii) Designated uses. The designated uses include, but are not limited to, the following: (A) Wildlife habitat. (B) Natural foodchain maintenance. (iii) Water quality criteria. (A) Enterococci bacteria densities shall not exceed natural conditions. (B) Dissolved oxygen--shall not show any measurable decrease from natural conditions. (C) Total dissolved gas shall not vary from natural conditions. (D) Temperature--shall not show any measurable change from natural conditions. (E) pH shall not show any measurable change from natural conditions. (F) Settleable solids shall not show any change from natural conditions. (G) Turbidity shall not exceed 5 NTU over natural conditions. (H) Toxic, radioactive, or deleterious material concentrations shall not exceed those found under natural conditions. (g) General Classifications. General classifications applying to various surface waterbodies not specifically classified under 131.35(h) are as follows: (1) All surface waters that are tributaries to Class I waters are classified Class I, unless otherwise classified. (2) Except for those specifically classified otherwise, all lakes with existing average concentrations less than 2000 mg/L TDS and their feeder streams on the Colville Indian Reservation are classified as Lake Class and Class I, respectively. (3) All lakes on the Colville Indian Reservation with existing average concentrations of TDS equal to or exceeding 2000 mg/L and their feeder streams are classified as Lake Class and Class I respectively unless specifically classified otherwise. (4) All reservoirs with a mean detention time of greater than 15 days are classified Lake Class. (5) All reservoirs with a mean detention time of 15 days or less are classified the same as the river section in which they are located. (6) All reservoirs established on pre-existing lakes are classified as Lake Class. (7) All wetlands are assigned to the Special Resource Water Class. (8) All other waters not specifically assigned to a classification of the reservation are classified as Class II. (h) Specific Classifications. Specific classifications for surface waters of the Colville Indian Reservation are as follows: (1) Streams: Alice Creek....................... Class III Anderson Creek.................... Class III Armstrong Creek................... Class III Barnaby Creek..................... Class II Bear Creek........................ Class III Beaver Dam Creek.................. Class II Bridge Creek...................... Class II Brush Creek....................... Class III Buckhorn Creek.................... Class III Cache Creek....................... Class III Canteen Creek..................... Class I Capoose Creek..................... Class III Cobbs Creek....................... Class III Columbia River from Chief Joseph ...................................... Dam to Wells Dam. Columbia River from northern ...................................... Reservation boundary to Grand Coulee Dam (Roosevelt Lake). Columbia River from Grand Coulee ...................................... Dam to Chief Joseph Dam. Cook Creek........................ Class I Cooper Creek...................... Class III Cornstalk Creek................... Class III Cougar Creek...................... Class I Coyote Creek...................... Class II Deerhorn Creek.................... Class III Dick Creek........................ Class III Dry Creek......................... Class I Empire Creek...................... Class III Faye Creek........................ Class I Forty Mile Creek.................. Class III Gibson Creek...................... Class I Gold Creek........................ Class II Granite Creek..................... Class II Grizzly Creek..................... Class III Haley Creek....................... Class III Hall Creek........................ Class II Hall Creek, West Fork............. Class I Iron Creek........................ Class III Jack Creek........................ Class III Jerred Creek...................... Class I Joe Moses Creek................... Class III John Tom Creek.................... Class III Jones Creek....................... Class I Kartar Creek...................... Class III Kincaid Creek..................... Class III King Creek........................ Class III Klondyke Creek.................... Class I Lime Creek........................ Class III Little Jim Creek.................. Class III Little Nespelem................... Class II Louie Creek....................... Class III Lynx Creek........................ Class II Manila Creek...................... Class III McAllister Creek.................. Class III Meadow Creek...................... Class III Mill Creek........................ Class II Mission Creek..................... Class III Nespelem River.................... Class II Nez Perce Creek................... Class III Nine Mile Creek................... Class II Nineteen Mile Creek............... Class III No Name Creek..................... Class II North Nanamkin Creek.............. Class III North Star Creek.................. Class III Okanogan River from Reservation Class II north boundary to Columbia River. Olds Creek........................ Class I Omak Creek........................ Class II Onion Creek....................... Class II Parmenter Creek................... Class III Peel Creek........................ Class III Peter Dan Creek................... Class III Rock Creek........................ Class I San Poil River.................... Class I Sanpoil, River West Fork.......... Class II Seventeen Mile Creek.............. Class III Silver Creek...................... Class III Sitdown Creek..................... Class III Six Mile Creek.................... Class III South Nanamkin Creek.............. Class III Spring Creek...................... Class III Stapaloop Creek................... Class III Stepstone Creek................... Class III Stranger Creek.................... Class II Strawberry Creek.................. Class III Swimptkin Creek................... Class III Three Forks Creek................. Class I Three Mile Creek.................. Class III Thirteen Mile Creek............... Class II Thirty Mile Creek................. Class II Trail Creek....................... Class III Twentyfive Mile Creek............. Class III Twentyone Mile Creek.............. Class III Twentythree Mile Creek............ Class III Wannacot Creek.................... Class III Wells Creek....................... Class I Whitelaw Creek.................... Class III Wilmont Creek..................... Class II (2) Lakes: Apex Lake......................... LC Big Goose Lake.................... LC Bourgeau Lake..................... LC Buffalo Lake...................... LC Cody Lake......................... LC Crawfish Lakes.................... LC Camille Lake...................... LC Elbow Lake........................ LC Fish Lake......................... LC Gold Lake......................... LC Great Western Lake................ LC Johnson Lake...................... LC LaFleur Lake...................... LC Little Goose Lake................. LC Little Owhi Lake.................. LC McGinnis Lake..................... LC Nicholas Lake..................... LC Omak Lake......................... SRW Owhi Lake......................... SRW Penley Lake....................... SRW Rebecca Lake...................... LC Round Lake........................ LC Simpson Lake...................... LC Soap Lake......................... LC Sugar Lake........................ LC Summit Lake....................... LC Twin Lakes........................ SRW [54 FR 28625, July 6, 1989]