Section NR 106.56 - Establishment of water quality-based effluent limitations for temperature in WPDES permits(1) GENERAL. The department shall use the methods in this section to determine the need to establish water quality-based effluent temperature limitations in a permit.(2) REASONABLE POTENTIAL TO EXCEED AN ACUTE EFFLUENT LIMITATION. An acute water quality-based effluent limitation for temperature shall be established in a WPDES permit for each month in which the representative daily maximum effluent temperature for that month exceeds the acute water quality-based effluent limitation determined in s. NR 106.55. The representative daily maximum effluent temperature used in this subsection shall be the greater of the following: (a) The highest recorded representative daily maximum effluent temperature as measured or determined according to s. NR 106.54(1).(b) The projected 99th percentile of all representative daily maximum effluent temperatures as measured or determined according to s. NR 106.54(1).(3) REASONABLE POTENTIAL TO EXCEED A SUB-LETHAL EFFLUENT LIMITATION. A sub-lethal water quality-based effluent limitation for temperature shall be established in a WPDES permit for each month in which the representative weekly average effluent temperature for that month exceeds the sub-lethal water quality-based effluent limitation calculated in s. NR 106.55. The representative weekly average effluent temperature used in this subsection shall be the greater of the following: (a) The highest weekly average effluent temperature for the month as measured or determined according to s. NR 106.54(2).(b) The projected 99th percentile of all representative weekly average effluent temperatures for the month as measured or determined according to s. NR 106.54(2).(4) REASONABLE POTENTIAL TO EXCEED A LIMITED AQUATIC LIFE EFFLUENT LIMITATION. A daily maximum effluent temperature limitation of 86°F shall be established in a WPDES permit for each month in which the representative daily maximum effluent temperature exceeds 86°F for discharges to limited aquatic life waters not classified as a wastewater effluent channel according to s. NR 104.02(1), storm sewers or as a wetland regulated under ch. NR 103.(5) REASONABLE POTENTIAL TO EXCEED A WASTEWATER EFFLUENT CHANNEL EFFLUENT LIMITATION. A daily maximum effluent temperature limitation of 120°F shall be established in a WPDES permit for each month in which the representative daily maximum effluent temperature exceeds 120°F for discharges to a wastewater effluent channel, as classified in s. NR 104.02(1).(6) REASONABLE POTENTIAL TO EXCEED A STORM SEWER EFFLUENT LIMITATION. A daily maximum effluent temperature limitation greater than 120°F shall be established in a WPDES permit for a discharge to a storm sewer for each month in which the representative daily maximum effluent temperature exceeds the limitation determined according to the procedure in s. NR 106.55(5).(7) REASONABLE POTENTIAL TO EXCEED A WETLAND EFFLUENT LIMITATION. A daily maximum or weekly average effluent temperature limitation shall be established in a WPDES permit for each month in which the representative daily maximum or weekly average effluent temperature, respectively, exceeds the limits for a discharge to a wetland determined according to the provisions in s. NR 106.55(4).(8) REASONABLE POTENTIAL TO EXCEED LIMITATIONS FOR THE PROTECTION OF PUBLIC HEALTH AND WELFARE. A daily maximum effluent temperature limitation of 120°F shall be established in a WPDES permit for each month in which the representative daily maximum effluent temperature exceeds 120°F, unless the permittee demonstrates to the satisfaction of the department that the heated effluent is not discharged in a manner that will cause a potential for scalding of humans.(9) LIMITATIONS TO PROTECT DOWNSTREAM WATERS. Whenever the department determines that more stringent effluent temperature limitations than those established according to subs. (1) through (6) are necessary to attain or maintain water quality standards in downstream or other adjacent waters and the representative daily maximum or weekly average effluent temperatures exceed the limitations, then more stringent effluent temperature limitations shall be established in a WPDES permit.(10) LIMITATIONS TO PROTECT FOR COLD SHOCK. The department shall determine on a case-by-case basis if any additional conditions are necessary in a WPDES permit to protect against cold shock and in accordance with the standard specified in s. NR 102.28. Provisions under this subsection shall be in addition to the water quality-based effluent temperature limitations determined under this section.(11) LIMITATIONS TO PROTECT FOR RATE OF TEMPERATURE CHANGE. The department shall determine on a case-by-case basis if any conditions are necessary in a WPDES permit to protect against detrimental health or reproductive effects to fish and aquatic life caused by excessive rates of temperature change.(12) REPRESENTATIVE DATA UNAVAILABLE. Whenever after October 1, 2010, the department issues or reissues a permit to a discharger for which representative effluent temperature data as described in s. NR 106.54 is not available, the following requirements shall be included in the issued or reissued permit: (a) Monitoring to obtain representative effluent temperature as described in s. NR 106.54. Monitoring shall be required for a period of not less than one year. When effluent temperatures in any month are highly variable, monitoring for 2 years may be required. If the facility only operates during certain portions of the year, representative effluent temperature shall be measured during the period of operation.(b) Water quality-based effluent temperature limitations determined under applicable methods described in s. NR 106.55 and as determined necessary under any applicable provision of this section. Compliance with the limitations shall be attained as soon as reasonably possible, but no later than the expiration date of the permit. The department may modify the permit at any time during the permit term and establish a compliance date to attain effluent temperature limitations sooner than the expiration date of the permit.(c) If, after the data collection required under par. (a), it is determined that an effluent temperature limitation is not necessary under any applicable provision of this section, the water quality-based effluent temperature limitations in the permit may not be effective. A condition shall be included in the permit that invalidates any effluent temperature limitations and the compliance schedule in the permit. Continued monitoring of effluent temperature may be required.(13) MONITORING. The department shall establish on a case-by-case basis the monitoring and reporting frequency for temperature in a WPDES permit.(14) LIMITATIONS IN PERMITS. Effluent temperature limitations of 86°F, 120°F or greater than 120°F determined necessary under subs. (4) to (7) shall be expressed in permits as daily maximum effluent temperature limitations. (a) Acute effluent temperature limitations determined necessary under this section shall be expressed in permits as daily maximum effluent temperature limitations.(b) Sub-lethal effluent temperature limitations determined necessary under this section shall be expressed in permits as weekly average effluent temperature limitations.(c) In all cases, monitoring data collected for purposes of reporting and determining compliance shall be representative effluent temperature data as described in s. NR 106.54.Wis. Admin. Code Department of Natural Resources § NR 106.56
CR 07-111: cr. Register September 2010 No. 657, eff. 10-1-10.