SECTION 10. NR 205.067 is created to read:
NR 205.067 Reasonable potential for water quality based effluent limitations. (1) GENERAL. (a) The department shall include an effluent limitation for a pollutant in a WPDES permit when the department determines that the discharge of the pollutant causes, has the reasonable potential to cause, or contributes to an excursion above the allowable ambient concentration of a numeric water quality criterion in chs. NR 102 to 104 in the receiving water or a downstream water. Note: Downstream water includes downstream waterbodies in other states or tribal waters that have EPA approved standards under 40 CFR 130. (b) Limitations must control all pollutants or pollutant parameters, including conventional, nonconventional, and toxic pollutants, that the department determines are or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any water quality standard in chs. NR 102 to 104, including narrative criteria for water quality. (2) FACTORS TO CONSIDER. When determining under sub. (1) or (4) whether a pollutant discharged causes, has the reasonable potential to cause, or contributes to an exceedance of a numeric or narrative water quality standard, the department shall consider all of the following factors:
(a) Existing controls on the discharge.
(b) Controls on the pollutant discharged by nonpoint source pollution in the watershed.
(c) The variability of the pollutant or parameter in the effluent discharged.
(d) Sensitivity of species to toxicity testing when evaluating whole effluent toxicity as defined in s. NR 106.03 (14). (e) Dilution of the effluent in the receiving water.
(3) WATER QUALITY BASED EFFLUENT LIMITATIONS. If the department determines a limitation is necessary under this section, the limitation shall:
(a) Be consistent with a total maximum daily load as defined in s. NR 217.11 (7) if a total maximum daily load has been approved by the EPA for the receiving waterbody. (b) Ensure achievement of a level of water quality derived from, and in compliance with, the applicable water quality standard.
(4) IN ABSENCE OF NUMERIC WATER QUALITY CRITERIA. (a) When a chemical pollutant, for which a numeric water quality criterion does not exist, is present in an effluent at a concentration that causes, has the reasonable potential to cause, or contributes to an excursion above a narrative criterion within an applicable water quality standard, effluent limits shall be established using one or more of the following options:
1. Establish effluent limits using a calculated numeric water quality criterion for the pollutant that the department demonstrates will attain and maintain applicable narrative water quality criteria and will fully protect the designated use. Such a criterion may be derived using data for a proposed criterion or other relevant information such as EPA’s Water Quality Standards Handbook, risk assessment data, exposure data, information about the pollutant from the Food and Drug Administration, and current EPA criteria documents.
2. Establish effluent limits on a case-by-case basis, using EPA’s water quality criteria, published under 33 USC 1314(a), supplemented when necessary by other relevant information. 3. Establish effluent limits on an indicator parameter for the pollutant of concern, provided that all of the following are true:
a. The permit identifies which pollutants are intended to be controlled by the use of the effluent limitation.
b. The fact sheet sets forth the basis for the limit, including a finding that compliance with the effluent limit of the indicator parameter will result in controls on the pollutant of concern that are sufficient to attain and maintain applicable water quality standards.
c. The permit requires all effluent and ambient monitoring necessary to show that, during the term of the permit, the limit on the indicator parameter continues to attain and maintain applicable water quality standards.
d. The permit contains a reopener clause allowing the department to modify or revoke and reissue the permit if the limits on the indicator parameter no longer attain and maintain applicable water quality standards.
(b) If there is reasonable potential under par. (a) to exceed a narrative criterion and if required under s. NR 106.08, a limitation for whole effluent toxicity shall be included in the permit. Note: Limitations and procedures for whole effluent toxicity are established in subch. II of ch. NR 106. (5) LIMIT CONTINUATION. If a permit includes a water quality based effluent limitation for a pollutant because the limitation is required under this section or is required under the procedures in another chapter, the water quality based effluent limitation for the pollutant shall be included in a subsequently reissued permit if all of the following apply:
(a) Treatment or pollutant control measures were added to comply with the water quality based effluent limitation for the pollutant and the water quality based effluent limitation took effect in a prior permit.
(b) The facility has the ability to alter or suspend the treatment or pollutant control measures for the pollutant to the degree that there is continued reasonable potential to exceed the applicable standard.
(6) EXCEPTION. Subsections (1) to (4) do not apply to pollutants or limitations that are subject to the procedures in chs. NR 106 or 217. SECTION 11. NR 205.10 is created to read:
NR 205.10 Best management practices. Best management practices to control or abate the discharge of pollutants shall be included in a WPDES permit issued by the department in all of the following cases:
(1) When the permit is authorized under section 33 USC 1314(e) for the control of toxic pollutants and hazardous substances from ancillary industrial activities. (2) When numeric effluent limitations are infeasible.
(3) When the practices are reasonably necessary to achieve effluent limitations and standards or to carry out the purposes and intent of ch. 283, Stats. Note: Chapters NR 216 and 243 also include regulations requiring best management practices for WPDES permittees for control of stormwater discharges and concentrated animal feeding operations (CAFOs). SECTION 12. NR 205.14 is created to read:
NR 205.14 Schedules of compliance. A WPDES permit may, when appropriate, include a schedule of compliance leading to compliance with permit limitations. Any schedule of compliance for water quality based effluent limitations for phosphorus shall be consistent with all of the requirements in s. NR 217.17. Any other schedule of compliance included in a permit shall be consistent with all of the requirements in s. NR 106.117.
SECTION 13. NR 207 Chapter (title) is amended to read:
WATER QUALITY ANTIDEGRADATION AND ANTIBACKSLIDING
SECTION 14. NR 207 Subchapter I (title), inserted before NR 207.01, is created to read:
SUBCHAPTER I
ANTIDEGRADATION
SECTION 15. NR 207.01 is amended to read:
NR 207.01 Purpose and applicability. (1) PURPOSE. The purpose of this chaptersubchapter is to establish implementation procedures for the antidegradation policy in s. NR 102.05 (1) (a). This chaptersubchapter sets procedures applicable to proposed new or increased discharges to outstanding resource waters, exceptional resource waters, Great Lakes system waters, fish and aquatic life waters, and waters listed in tables 3 through 8 in ss. NR 104.05 to 104.10. (2) APPLICABILITY. This chaptersubchapter applies to any person proposing to increase an existing discharge or create a new discharge to the surface waters of the state.
SECTION 16. NR 207 Subchapter II, inserted after NR 207.05, is created to read:
SUBCHAPTER II
ANTIBACKSLIDING
NR 207.10 Purpose and applicability. (1) PURPOSE. The purpose of this subchapter is to establish antibacksliding requirements for the WPDES permit program.
(2) APPLICABILITY. This subchapter applies to any permittee that requests in a WPDES permit modification or reissuance application an increased or less stringent limitation that limits the discharge of a pollutant to a surface water. This subchapter does not apply to a request for an increased limitation that limits the discharge of a pollutant to groundwater. This subchapter is not applicable when the department increases a limitation that has not yet taken effect in a WPDES permit.
NR 207.11 Definitions. In addition to the definitions in ch. NR 205, the following definitions apply to this subchapter: (1) “Best professional judgment limitation” means technology based effluent limitations established on a case-by-case basis by the permit drafter when there are no applicable promulgated effluent guidelines for the category of discharge. These limitations are established under s. NR 220.21 and 33 USC 1342(a)(1)B of the Clean Water Act. (2) “Effluent limitation guidelines” or “effluent guideline standard” or “ELGs” means guidelines for establishing technology based limitations under 33 USC 1313(b) including, but not limited to, guidelines for best practicable technology, best conventional pollutant control technology, best available technology, and new source performance standards. (3) “State Technology Based Treatment Standard” means a technology based treatment standard promulgated by the state that is not an ELG.
Note: The Department’s state statutory authority for establishing technology based guidelines and standards is found in ss. 283.11, 283.13, 283.19, and 283.21, Stats. An example of a state treatment technology based standard is a standard promulgated under s. 283.11 (3) or (4), Stats. NR 207.12 Antibacksliding. (1) GENERAL. Except as provided in this section, effluent limitations or standards in a reissued, revoked and reissued, or modified permit shall be at least as stringent as the effective effluent limitations or standards in the previous permit. If one of the exceptions in subs. (2) to (4) is satisfied to relax or backslide a limitation, the limitation may only be made less stringent if both of the following apply:
(a) The less stringent limitation is at least as stringent as required by applicable effluent limitation guidelines.
(b) The less stringent limitation complies with state water quality standards, including the antidegradation requirements in subch. I.
(2) RELAXING A BEST PROFESSIONAL JUDGMENT LIMITATION. Best professional judgment limitations established under s. NR 220.21 (1) that have taken effect in a permit may be made less stringent in a reissued, revoked and reissued, or modified permit if the requirements of sub. (1) (a) and (b) are satisfied and one or more of the following apply: (a) Material and substantial alterations or additions to the permitted facility occurred after the best professional judgment limitation was initially imposed in the permit, which justify the application of a less stringent effluent limitation,
(b) New information is available that was not available at the time of permit issuance and that would have justified the application of a less stringent effluent limitation at the time of permit issuance. New information under this paragraph does not include revised regulations, guidance, or test methods.
(c) The department determines that technical mistakes or mistaken interpretations of law were made when the best professional judgment limitation was initially imposed in the permit.
(d) A less stringent effluent limitation is necessary because of events over which the permittee has no control and for which there is no reasonably available remedy.
(e) The permittee has received department approval for any of the following:
1. A modified technology based limitation under s. 283.13 (3), Stats. 2. An extended compliance schedule under s 283.13 (6), Stats.
3. A modified technology based limitation under a fundamentally different factors variance under ss. NR 220.30 to 220.33. 4. An alternate thermal effluent limitation under s. 283.17 (1), Stats. (f) The permittee has installed the treatment facilities required to meet the effluent limitations in the previous permit and has properly operated and maintained the facilities, but has nevertheless been unable to achieve the best professional judgment limitations. In such a case, the effluent limitation in the reissued, revoked and reissued, or modified permit may be relaxed to reflect the level of pollutant control actually achieved. However, in no case may the limitation be less stringent than applicable effluent guidelines in effect at the time of reissuance or modification.
