Antidegradation policy

Antidegradation policy. (1) General. The entirety of this section constitutes the antidegradation policy, which is a narrative water quality standard. No high quality waters of the state shall be lowered in quality unless it has been demonstrated that all of the conditions of the policy in this section and the implementation procedures under subch. I of ch. NR 207 and ch. NR 216 have been met. (2) Definitions. In this section and subch. I of ch. NR 207 : (a) “Assimilative capacity” means the difference between the water quality criterion for a parameter identified under this chapter or ch. NR 105 and the existing level of that parameter in a surface water. (b) “High quality waters” means any of the following waters: 1. Outstanding national resource waters as described under 40 CFR Part 132 , Appendix E, II. A. 2. Outstanding resource waters as listed under s. NR 102.10 . 3. Exceptional resource waters as listed under s. NR 102.11 . 4. All other surface waters where water quality is better than a water quality standard for an existing or designated use, as determined by the department on a parameter-by-parameter basis. A water is high quality for a specific parameter if it has assimilative capacity for that parameter. Waters may not be excluded from being considered high quality based solely on permit violations, unlawful discharges from nonpoint sources, or spills that cause non-attainment of water quality criteria under chs. NR 102 to 105 . (c) “Non-high quality waters” means any of the following: 1. Waters designated as limited aquatic life or limited forage fish under ch. NR 104 . 2. Waters without assimilative capacity, including any of the following: a. Waters that are not attaining the water quality criteria for the parameter of concern, including those listed on the section 303 (d) list as not attaining the applicable criterion or for which the department determines there is water quality data indicating that the water is not attaining the applicable criterion. b. Waters that have background concentrations equal to the water quality criteria for the parameter of concern. c. Unidirectional flow waters where the waterway immediately upstream from the proposed new or increased discharge has an upstream low flow of zero, as defined for toxics in s. NR 106.06 (3) (bm) and (4) (c) , for total phosphorus in s. NR 217.13 (2) (b) , and for temperature in s. NR 106.53 (1) . In this case, the non-high quality water extends until such point where there is available assimilative capacity. (3) Maintain existing uses. Existing uses and the level of water quality necessary to protect the existing uses shall be maintained and protected from degradation. If a surface water is listed on the section 303 (d) list as not attaining a water quality criterion for a specific parameter or the department has data showing that it is not attaining a water quality criterion for a parameter, there shall be no lowering of water quality with respect to the concentration, level, or loading of a parameter that is causing the impairment unless it is allocated as part of the reserve capacity or wasteload allocation under a U.S. EPA-approved TMDL or as allowed under s. NR 217.13 (8) . Wetland water quality standards under s. NR 103.03 shall be maintained. (4) High quality waters listed by waterbody type. The water quality in high quality waters described under sub. (2) (b) 1. to 3. shall be maintained and protected, with no lowering of water quality, except as specified for certain proposed discharges to exceptional resource waters under s. NR 207.031 (6) (b) . (5) Other high quality waters. For other high quality waters with assimilative capacity identified on a parameter-by-parameter basis under sub. (2) (b) 4. , water quality shall be maintained and protected from degradation unless the department finds, after intergovernmental coordination and public participation provisions of the continuing planning process described under ch. NR 121 , that all of the following are met: (a) After an analysis of alternatives, a lowering of water quality is necessary to accommodate important economic or social development in the area of the affected waters. (b) The resulting water quality will be adequate to fully protect existing uses of the water. (c) Statutory and regulatory requirements for all new and existing point sources under ch. 283 , Stats., and relevant requirements for regulated nonpoint sources under s. 281.16 , Stats., and ch. NR 151 , are being achieved. (6) Great Lakes system waters. As specified under s. NR 102.12 , Great Lakes system waters are to be protected from the impacts of bioaccumulative chemicals of concern, as defined under s. NR 105.03 (9) , by avoiding or limiting to the maximum extent practicable increases in these substances. (7) Thermal discharges. In those cases where potential water quality impairment associated with a thermal discharge is involved, the antidegradation policy and implementing procedure shall be consistent with section 316 (a) of the Clean Water Act, 33 USC 1326 (a).