Chapter NR 106

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.

NR 106.59(4)(b)3. 3. The minimum and maximum temperature of the receiving water upstream of all permitted outfalls for each calendar month over the past two years.

NR 106.59(4)(c) (c) In evaluating the potential for exceedance of sub-lethal criteria outside a small area of mixing and cooling, the department shall consider site-specific information including, but not limited to:

NR 106.59(4)(c)1. 1. The physical characteristics of the receiving water including those related to mixing, turbulence, diffusion, dilution, dispersion, and heat dissipation.

NR 106.59(4)(c)2. 2. The occurrence of other thermal mixing zones and their influence on the dissipative potential of the receiving water.

NR 106.59(4)(c)3. 3. The variability of effluent temperature from the POTW.

NR 106.59(4)(c)4. 4. The expected difference between the ambient receiving water temperature and the representative effluent temperature.

NR 106.59(4)(c)5. 5. The attainment status of the receiving water biological community in response to the discharge of heated effluent.\

NR 106.59(4)(c)6. 6. The potential impacts to state or federally listed threatened or endangered species.

NR 106.59 Note Note: The absence of information pertaining to subds. 1. to 6., shall not preclude a determination that a sub-lethal effluent limitation is not necessary.

NR 106.59(4)(d) (d) In addition to the requirements in pars. (a) and (b), the department reserves the right to request additional information from the POTW to support the request for consideration of dissipative cooling.

NR 106.59(4)(e) (e) If the department determines that a sub-lethal effluent limitation for temperature is not necessary, a specific request for comment on the department’s determination shall be included in the public notice for the proposed permit.

NR 106.59(5) (5) Acute limitations for new POTW discharges or re-located POTW outfalls.

NR 106.59(5)(a) (a) The department shall establish acute effluent temperature limitations for a new POTW discharge or re-located POTW outfall to a surface water classified as limited aquatic life whenever the estimated daily maximum effluent temperature is greater than the applicable water quality criterion specified in s. NR 102.245.

NR 106.59(5)(b) (b) The department shall establish acute effluent temperature limitations for a new POTW discharge or re-located POTW outfall to a surface water classified as cold water, warm water sport fish, warm water forage fish, or limited forage fish whenever the estimated 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 the ambient temperatures in s. NR 102.25 or approved under s. NR 102.26.

NR 106.59(6) (6) Sub-lethal limitations for new POTW discharges or re-located 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 a new POTW discharge or re-located POTW outfall whenever it is determined 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(6)(a) (a) The POTW shall provide any of the following information to allow the department to determine whether or not the sub-lethal criteria are exceeded outside of a small area of mixing and cooling:

NR 106.59(6)(a)1. 1. A written description of the physical characteristics of the receiving water or outfall that encourage rapid dilution, diffusion, dispersion, and dissipation of heat.

NR 106.59(6)(a)2. 2. A written description of the presence or absence of other thermal loads to the receiving water.

NR 106.59(6)(a)3. 3. The minimum and maximum known effluent temperature for each calendar week for each previously permitted outfall over the past two years.

NR 106.59(6)(a)4. 4. The maximum expected effluent temperature for each calendar month for each new outfall.

NR 106.59(6)(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(6)(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(6)(b)2. 2. Data concerning the physical characteristics of the receiving water or permitted or proposed outfalls that encourage rapid dilution, diffusion, dispersion, or dissipation of heat.

NR 106.59(6)(b)3. 3. The minimum and maximum temperatures of the receiving water upstream of all permitted or proposed outfalls for each calendar month over the past two years.

NR 106.59(6)(c) (c) In evaluating the potential for exceedance of sub-lethal criteria outside a small area of mixing and cooling, the department shall consider site-specific information including, but not limited to:

NR 106.59(6)(c)1. 1. The physical characteristics of the receiving water including those related to mixing, turbulence, diffusion, dilution, dispersion, and heat dissipation.

NR 106.59(6)(c)2. 2. The occurrence of other thermal mixing zones and their influence on the dissipative potential of the receiving water.

NR 106.59(6)(c)3. 3. The known or expected variability of effluent temperatures from the POTW.

NR 106.59(6)(c)4. 4. The known or expected difference between the ambient receiving water temperature and the representative effluent temperature.

NR 106.59(6)(c)5. 5. The attainment status of the receiving water biological community in response to the discharge of heated effluent.

NR 106.59(6)(c)6. 6. The potential impacts to state or federally listed threatened or endangered species.

NR 106.59 Note Note: The absence of information pertaining to subpars. 1-6 shall not preclude a determination that a sub-lethal effluent limitation is not necessary.

NR 106.59(6)(d) (d) In addition to the requirements of pars. (a) and (b), the department reserves the right to request additional information from the POTW to support the request for consideration of dissipative cooling.

NR 106.59(6)(e) (e) If the department determines that a sub-lethal effluent limitation is not necessary for a new POTW discharge or a re-located POTW outfall, a specific request for comment on the department’s determination shall be included in the public notice for the proposed permit.

NR 106.59(7) (7) Monitoring. WPDES permits issued in accordance with this section that include effluent temperature limitations shall include a requirement to monitor effluent temperatures on a weekly basis.

NR 106.59(8) (8) Permit reissuance.

NR 106.59(8)(a) (a) A POTW seeking reissuance of a permit in which the department did not include sub-lethal effluent limitations due to recognition of dissipative cooling may request continued consideration of dissipative cooling provided all of the following conditions are met:

NR 106.59(8)(a)1. 1. The request is received at the time of application for the permit reissuance.

NR 106.59(8)(a)2. 2. The POTW certifies, in writing, that there has been no substantive change in the operation of or loadings to the POTW relative to the information provided in the previous permit application under sub. (4) or (6).

NR 106.59(8)(a)3. 3. The POTW submits any new information generated during the current permit term and certifies, in writing, that the new information is consistent with information submitted with the previous permit application under sub. (4) or (6).

NR 106.59(8)(b) (b) If the department determines that the information provided in par. (a) is consistent with the information submitted with a previous permit application and that sub-lethal effluent limitations for temperature are not necessary, a specific request for comment on the department’s determination shall be included in the public notice for the proposed permit.

NR 106.59(8)(c) (c) If the department determines that the information provided in par. (a) is inconsistent with the information submitted with a previous permit application, the department shall establish sub-lethal effluent limitations when there is a reasonable potential for the discharge to cause or contribute to an exceedance of an applicable sub-lethal water quality criterion outside a small area of mixing and cooling.

NR 106.59 History History: CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10.

NR 106.60 NR 106.60 Effluent limitations for temperature for discharges from new facilities. Except as provided in subch. VI, new facilities issued a WPDES permit after October 1, 2010, shall be designed to meet applicable water quality-based effluent temperature limitations, as determined in this subchapter, on the effective date of the WPDES permit. The department may require a permittee to provide diffusers or other such devices to ensure rapid mixing of effluent into the water body receiving the discharge or may require a mixing zone analysis to demonstrate that the proposed mixing zone of the new POTW discharge will meet the mixing zone provisions of s. NR 102.05 (3).

NR 106.60 History History: CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10.

NR 106.61 NR 106.61 General permit.

NR 106.61(1) (1) A general permit issued by the department that contains effluent temperature limitations and monitoring requirements for discharges of non-contact cooling water, non-contact condensate, boiler water blowdown, and boiler bleedoff directly to surface water, to a storm sewer, or for discharges to the land surface, or to groundwater shall include all of the following conditions:

NR 106.61(1)(a) (a) Procedures to determine effluent temperature limitations for individual discharges covered by the general permit in accordance with the provisions of this subchapter. For each facility covered by the general permit, the department shall establish effluent temperature limitations for the facility directly in the general permit or in the general permit discharge authorization letter to the permittee.

NR 106.61(1)(b) (b) Discharges to wetlands shall be allowed if, when granting coverage, the department determines that the requirements of ch. NR 103 are met.

NR 106.61(1)(c) (c) Discharges shall not be allowed if the receiving waterbody is an outstanding resource water or an exceptional resource water, as specified in ss. NR 102.10 and 102.11, respectively.

NR 106.61(1)(d) (d) Discharges to the land surface, to the groundwater or to storm water ponds shall have a daily maximum effluent temperature limitation of 120oF, provided that the discharge does not have a reasonable potential to exceed temperature water quality standards in waters of the state downstream of the discharge location.

NR 106.61(1)(e) (e) Discharges shall not contain wastewater from industrial or commercial processes, other than those authorized in sub. (1).

NR 106.61(1)(f) (f) Discharge does not contain a water treatment additive including biocides. However, the department may approve in writing the use of water treatment additives that are not biocides.

NR 106.61(1)(g) (g) Discharge does not cause a safety hazard due to unsafe ice conditions in winter.

NR 106.61(1)(h) (h) The permittee shall be required to collect representative daily maximum effluent temperatures not less than once per month. Unless specified otherwise by the department when coverage is granted under the general permit, the permittee shall not be required to submit effluent temperature data collected under the monitoring provisions of the general permit issued under this section. Any effluent temperature data collected shall be retained by the permittee for the duration of the permit or 3 years after this information is collected, whichever is longer and shall be provided to the department upon request.

NR 106.61(2) (2) A general permit issued under this section may include any of the following conditions:

NR 106.61(2)(a) (a) Coverage under the general permit for discharges containing water treatment additives, except for biocides, provided all other requirements of this chapter are met.

NR 106.61(2)(b) (b) Provisions that account for the heat loss that occurs in a discharge to a storm sewer or other storm water conveyance channel assuming the heat loss occurs at a rate of 0.25 degree F per 100 feet of storm sewer or channel length. The effluent temperature limitations determined under this paragraph shall be established when the department grants coverage under this general permit.

NR 106.61(2)(c) (c) Provisions to allow the department to establish more stringent effluent temperature limitations as necessary to attain or maintain water quality standards in downstream or other adjacent waters. The effluent temperature limitations determined under this paragraph shall be established when the department grants coverage under the general permit.

NR 106.61(3) (3) A permittee granted coverage under the general permit authorized under this section shall be required to verify conformance with the conditions in sub. (1) whenever the permit coverage is renewed.

NR 106.61 History History: CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10.

NR 106.62 NR 106.62 Compliance schedules. The permittee shall attain compliance with the effluent limitations as soon as reasonably possible, but no later than the expiration date of the permit. When a permit is issued or reissued with effluent temperature limitations established using the procedures in this subchapter and representative effluent temperature data are available at the time of permit issuance or reissuance, the permit may contain a compliance schedule consistent with the provisions in s. NR 106.117 when either of the following conditions is met:

NR 106.62(1) (1) The permittee does not apply for an alternative effluent limitation under the provisions of subch. VI.

NR 106.62(2) (2) The permittee applies for an alternative effluent limitation under the provisions of subch. VI and, after reviewing the data and information provided with the application, the department determines that sufficient information to establish alternative effluent limitations for temperature is not available.

NR 106.62 History History: CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10; CR 15-085: am. (intro.) Register August 2016 No. 728, eff. 9-1-16.

subch. VI of ch. NR 106 Subchapter VI — Alternative Effluent Limitations for Temperature