NR 106.58(1) (1) At the time of permit application, a permittee may submit the results of scientifically defensible technical approaches, such as calibrated models and verified mathematical water quality models developed or adapted for a particular water body, simplified modeling approaches as outlined in “WATER QUALITY ASSESSMENT” (EPA-600/6-82-004), or other dynamic methods to be utilized in developing water quality-based effluent limitations.

NR 106.58(2) (2) Data used to support the analyses conducted under sub. (1) shall be representative of the long-term characteristics of the receiving water and shall be collected in a manner consistent with requirements of ch. NR 219.

NR 106.58(3) (3) The department shall review the results of the analyses conducted under sub. (1) on a case-by-case basis and shall determine the water quality-based effluent limitations necessary to ensure that the applicable water quality standards specified in ch. NR 102 are maintained.

NR 106.58(4) (4) Effluent limitations approved under this section are in lieu of the procedures in s. NR 106.55 (5), (6), and (7), and are not modifications to the water quality criteria specified in ch. NR 102.

NR 106.58 History History: CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10.

NR 106.59 NR 106.59 Effluent limitations for temperature for permits issued to publicly or privately owned domestic sewage treatment works.

NR 106.59(1) (1) Applicability. This section applies to specific outfalls from permittees with discharges subject to ch. NR 210.

NR 106.59(2) (2) Definitions. In this section, the following definitions are applicable to terms used:

NR 106.59(2)(a) (a) “Dissipative cooling” means the cooling effects associated with heat loss to the ambient water, the atmosphere and the surrounding environment.

NR 106.59(2)(b) (b) “Estimated daily maximum effluent temperature” means the highest temperature expected in a calendar day based on an average of effluent temperatures available. Available data may be from at least two other POTWs within a 100 mile radius that utilize similar wastewater treatment technology and have a similar ratio of domestic to industrial waste stream composition, or representative data of the POTW.

NR 106.59(2)(c) (c) “Existing POTW outfall” means any discharge structure that has been included in a WPDES permit issued prior to October 1, 2010, that was used to convey wastewater effluent to a surface water and has not been re-located.

NR 106.59(2)(d) (d) “New POTW discharge” means any point source subject to ch. NR 210 that has not received a WPDES permit from the department prior to October 1, 2010 or a permitted outfall re-located to a new receiving water after October 1, 2010.

NR 106.59(2)(e) (e) “POTW” means all publicly operated treatment works and privately owned domestic sewage treatment works subject to ch. NR 210.

NR 106.59(2)(f) (f) “Re-located POTW outfall” means any point source outfall structure associated with a previously issued WPDES permit that is moved or constructed after October 1, 2010 to convey wastewater to the same receiving water where fish and other aquatic life are materially exposed to a modified thermal pollutant load.

NR 106.59 Note Note: The department considers an outfall to be re-located when an assemblage of fish and other aquatic life are subjected to a heat load that they were not exposed to previously. In determining whether a change in location is a re-located outfall, the department shall consider the distance of the changed location, the potential for the heat load to adversely impact resident organisms, and whether or not the applicable provisions of s. NR 102.05 (3) are satisfied.

NR 106.59(3) (3) Acute limitations for existing POTW outfalls.

NR 106.59(3)(a) (a) The department shall establish acute effluent temperature limitations for an existing POTW outfall to surface waters classified as limited aquatic life whenever the representative daily maximum effluent temperature is greater than the applicable water quality criterion specified in s. NR 102.245.

NR 106.59(3)(b) (b) The department shall establish acute effluent temperature limitations for an existing POTW outfall to surface waters classified as cold water, warm water sport fish, warm water forage fish, or limited forage fish whenever the representative daily maximum effluent temperature is greater than the applicable water quality criterion specified in s. NR 102.25 or determined under s. NR 102.27. The applicable acute water quality criterion shall be based on representative ambient temperature of the receiving stream determined as follows:

NR 106.59(3)(b)1. 1. Except as provided in subd. 2., the representative ambient temperature shall be equal to the ambient temperatures in s. NR 102.25 or approved under s. NR 102.26.

NR 106.59(3)(b)2. 2. Where the Qe of a permitted POTW is significantly greater than the Qs of the receiving stream immediately upstream of the POTW outfall, the representative ambient temperature may be equal to the daily maximum effluent temperature.

NR 106.59(3)(b)3. 3. The provisions of subd. 2. are not applicable to a permitted POTW with a discharge outfall that shares a mixing zone with an upstream discharger.

NR 106.59(4) (4) Sub-lethal limitations for existing POTW outfalls. Upon request by the POTW at the time of permit application, the department may account for dissipative cooling of a POTW effluent in determining the need for sub-lethal effluent limitations. The department shall establish sub-lethal effluent limitations for an existing POTW outfall whenever the department determines that the effluent has a reasonable potential to cause or contribute to an exceedance of the applicable sub-lethal criterion outside of a small area of mixing and cooling. In determining the need for sub-lethal effluent limitations, the department shall consider the cooling of the effluent through dissipation of heat to the environment to the extent that a POTW provides information to support such determination as set forth below.

NR 106.59(4)(a) (a) The POTW shall provide any of the following information to allow the department to determine whether or not sub-lethal criteria are exceeded outside a small area of mixing and cooling.

NR 106.59(4)(a)1. 1. A written description of the physical characteristics of the receiving water or outfall that encourage rapid dilution, diffusion, dispersion, or dissipation of heat.

NR 106.59(4)(a)2. 2. A written description of the presence or absence of other thermal loads to the receiving stream.

NR 106.59(4)(a)3. 3. The minimum and maximum effluent temperature for each calendar week for each permitted outfall over the past two years.

NR 106.59(4)(b) (b) In addition to the information submitted in par. (a), the POTW shall submit existing information it has collected, generated, reviewed, or received regarding the following site-specific conditions:

NR 106.59(4)(b)1. 1. Information regarding the biological quality of the animal and plant community of the receiving water including, but not limited to, species composition, richness, diversity, density, distribution, age structure, spawning incidence, and presence of any state or federally listed threatened or endangered species.

NR 106.59(4)(b)2. 2. Data concerning the physical characteristics of the receiving water or permitted outfalls that encourage rapid dilution, diffusion, dispersion, and/or dissipation of heat.