Chapter NR 217

NR 217.13 Note Note: Section 283.84, Stats., establishes requirements for pollutant trades.

NR 217.13 History History: CR 10-035: cr. Register November 2010 No. 659, eff. 12-1-10; CR 19-094: am. (2) (d) Register September 2022 No. 801, eff. 10-1-22; correction in (2) (d) made under s. 35.17, Stats., Register September 2022 No. 801.

NR 217.14 NR 217.14 Expression of limitations.

NR 217.14(1) (1) General.

NR 217.14(1)(a) (a) Water quality based effluent limitations, when required pursuant to s. NR 217.15, shall be expressed in a discharge permit as a concentration. A mass limit shall also be included in a permit for discharges of phosphorus to any of the following receiving or downstream waters:

NR 217.14(1)(a)1. 1. A lake or reservoir;

NR 217.14(1)(a)2. 2. An outstanding or exceptional resource water, as designated in ss. NR 102.10 and 102.11;

NR 217.14(1)(a)3. 3. A phosphorus impaired water; or

NR 217.14(1)(a)4. 4. A surface water that has an approved TMDL for phosphorus.

NR 217.14(1)(b) (b) The department may establish mass limitations in permits for any other discharges of phosphorus if a concentration limit for phosphorus is included in the permit, and where an increase in phosphorus load is likely to result in adverse effects on water quality in the receiving water or downstream water.

NR 217.14(1)(c) (c) For discharges to lakes, the department shall also include an annual mass limit for phosphorus in the permit.

NR 217.14(1)(d) (d) If there is a US EPA approved TMDL for the receiving water, the department shall include a mass limit expressed in the manner consistent with the requirements of the TMDL. As provided in s. NR 217.16, this TMDL based mass limit may be included in the permit in addition to, or in lieu of the mass limit established pursuant to this section.

NR 217.14 Note Note: In accordance with s. 283.84, Stats., the department may approve the use of phosphorus trading as a means for a point source to achieve compliance with the water quality based effluent limitation, including a TMDL based limitation. The trade shall be incorporated into the terms of the WPDES permit for the point source and must be approved by the department prior to implementation.

NR 217.14(2) (2) Concentration based limitations. Concentration effluent limitations calculated under s. NR 217.13 shall be expressed as a monthly average in permits, except for concentrations of less than or equal to 0.3 mg/L for which limitations may be expressed as six-month averages. If a concentration limitation expressed as a six-month average is included in a permit, a monthly average concentration limitation equal to three times the water based effluent limitation calculated under s. NR 217.13 shall also be included in the permit.

NR 217.14(3) (3) Mass based limitations. Concentration effluent limitations calculated under s. NR 217.13 shall be converted into mass effluent limitations using the effluent flow identified in s. NR 217.13 and an appropriate conversion factor, and expressed as a monthly average in the permit, except for concentration based limitations of less than or equal to 0.3 mg/L for which mass limitations may be expressed as six-month averages.

NR 217.14 History History: CR 10-035: cr. Register November 2010 No. 659, eff. 12-1-10; CR 15-085: am. (2), (3) Register August 2016 No. 728, eff. 9-1-16.

NR 217.15 NR 217.15 Determination of necessity for water quality based effluent limitations for phosphorus.

NR 217.15(1) (1) 

NR 217.15(1)(a) (a) General. The department shall include a water quality based effluent limitation for phosphorus in a permit whenever the discharge or discharges from a point source or point sources contain phosphorus at concentrations or loadings which will cause, has the reasonable potential to cause or contribute to, an exceedance of the water quality standards in s. NR 102.06 in either the receiving water or downstream waters. The department shall use the procedures in this section to make this determination.

NR 217.15(1)(b) (b) Permittees with existing phosphorus limitations. If a permittee has a technology based phosphorus limitation in a permit that is less restrictive than a water quality based effluent limitation for phosphorus calculated pursuant to s. NR 217.13, then the department shall include the water quality based effluent limitation in the permit.

NR 217.15(1)(c) (c) Permittees without existing phosphorus limitations. If a permittee discharges phosphorus, but does not have a technology based limitation for phosphorus in its permit, the department shall use the procedures in this paragraph to determine whether a discharge will cause, has the reasonable potential to cause or contribute to an exceedance of the phosphorus water quality criterion in s. NR 102.06 in the receiving or downstream waters, and whether to include a water quality based effluent limit for phosphorus in the WPDES permit.

NR 217.15(1)(c)1. 1. Using at least 11 daily discharge concentrations of phosphorus, if the upper 99th percentile of the 30 day average discharge concentration of phosphorus exceeds the potential phosphorus limitation calculated under s. NR 217.13, then the water quality based effluent limitation for phosphorus shall be included in the WPDES permit. If the upper 99th percentile of the 30 day average discharge concentration of phosphorus is less than the potential phosphorus limitation calculated under s. NR 217.13, then a water quality based effluent limitation for phosphorus is not required in the WPDES permit. The upper 99th percentile of available discharge concentrations shall be calculated pursuant to s. NR 106.05 (5).

NR 217.15(1)(c)2. 2. If 11 daily discharge concentrations of phosphorus are not available for a permittee, then a water quality based effluent limitation for phosphorus shall be included in the permit when the mean of available effluent concentrations is greater than one-fifth of the limit.

NR 217.15(1)(c)3. 3. If no phosphorus effluent data is available for an existing permittee, the department may require phosphorus sampling as part of a permit application for reissuance to determine whether a water quality based effluent limit is necessary in the WPDES permit under par. (a), or the department may use effluent data information from similar point sources to make the determination under par. (a).

NR 217.15 Note Note: The department will develop guidance regarding the administration of this section to ensure that permitted discharges with a reasonable potential to cause or contribute to exceedances of the applicable phosphorus water quality criterion in s. NR 102.06 are identified.

NR 217.15(1)(d) (d) Sampling. Prior to permit reissuance, a permittee discharging any phosphorus shall collect effluent samples of phosphorus at a frequency specified by the department in the permit application for reissuance.

NR 217.15(1)(e) (e) New dischargers. The department shall include a water quality based phosphorus limitation in a permit for a new discharger if the department determines the new discharger will discharge phosphorus at concentrations or loadings which may cause or contribute to exceedances of the water quality criteria in s. NR 102.06 in either the receiving water or downstream waters. To estimate the amount of phosphorus discharged by a new discharger, the department may consider projected discharge information from the permit applicant and phosphorus discharge information from similar sources.

NR 217.15(2) (2) If the department determines a water quality based effluent limitation is not necessary in a permit based on the procedures in this section, the department may still require monitoring for phosphorus discharges.

NR 217.15 History History: CR 10-035: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (1) (c) 1. made under s. 13.92 (4) (b) 7., Stats., Register November 2010 No. 659.

NR 217.16 NR 217.16 Relationship of WQBELs and TMDL based limitations.

NR 217.16(1) (1) In addition to a water quality based effluent limitation calculated pursuant to s. NR 217.13, the department may derive a water quality based effluent limitation for phosphorus consistent with the wasteload allocation and assumptions of a US EPA approved TMDL that is designed to achieve water quality standards in ch. NR 102. This TMDL based limitation may be included in a permit in addition to, or in lieu of, the water quality based limitation calculated under s. NR 217.13. When deciding whether to use a TMDL based limit as a substitute for the limitation calculated under s. NR 217.13, the department shall consider the following factors:

NR 217.16(1)(a) (a) The degree to which nonpoint sources contribute phosphorus to the impaired water;

NR 217.16(1)(b) (b) Whether waters upstream of the impaired waters are meeting the phosphorus criteria; and

NR 217.16(1)(c) (c) Whether waters downstream of the impaired water are meeting the phosphorus criteria.

NR 217.16(2) (2) If the phosphorus limitation based on an approved TMDL is less stringent than the water quality based effluent limitation calculated in s. NR 217.13, the department may include the TMDL based limit in lieu of the limit calculated in s. NR 217.13 if the limit calculated under s. NR 217.13 has not yet taken effect. If the department includes the TMDL based limitation for phosphorus in the WPDES permit in lieu of the limit calculated in s. NR 217.13, the TMDL based limit may remain in the permit for up to two permit terms to allow time for implementation of the TMDL, or the implementation period specified in the TMDL, whichever is less. The department may include a schedule of compliance to achieve a TMDL based limit if the department determines a schedule of compliance is necessary. If after two permit terms, the department determines the nonpoint source load allocation has not been substantially reduced, the department may impose the more stringent water quality based effluent limitation calculated under s. NR 217.13, or may include the TMDL based limitation for an additional permit term if the department determines there will be significant nonpoint source load reductions within the upcoming permit term. If the department decides to remove a TMDL based phosphorus limit from a permit and instead include a more stringent water quality based phosphorus limit in the permit calculated under s. NR 217.13, the department may provide a schedule of compliance for the more stringent limit if the department determines additional time is needed for the permittee to comply with the revised limit. Such schedules shall require compliance as soon as possible, but in no case no more than five years from the date that the permit is reissued or modified to include the revised effluent limitations.

NR 217.16(3) (3) If a phosphorus water quality based limit calculated under s. NR 217.13 has already taken effect in a permit, the department may replace the limit with a less stringent TMDL based limit, if allowed pursuant to antidegradation procedures in ch. NR 207.

NR 217.16 Note Note: The TMDL based limitation may be less stringent than the water quality based effluent limitation calculated under s. NR 217.13 in cases where nonpoint sources are the significant phosphorus sources responsible for the impairment.

NR 217.16(4) (4) If the phosphorus limitation based on an approved TMDL is more stringent than the water quality based effluent limitation calculated under s. NR 217.13, the department shall include the more stringent TMDL based limitation in the WPDES permit.

NR 217.16 History History: CR 10-035: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 217.17 NR 217.17 Schedules of compliance.

NR 217.17(1) (1) General.

NR 217.17(1)(a) (a) Except as provided in sub. (4), the department may provide a schedule of compliance for a water quality based phosphorus limitation in a WPDES permit, where based on available information the department finds that:

NR 217.17(1)(a)1. 1. The schedule of compliance will lead to compliance with the water quality based effluent limitation as soon as possible; and

NR 217.17(1)(a)2. 2. The schedule of compliance is appropriate and necessary because the permittee cannot immediately achieve compliance with the water quality based effluent limitation based on existing operation of its treatment system.

NR 217.17 Note Note: Before any compliance schedule is established in a permit pursuant to this subchapter, the department must make the finding in par. (a).

NR 217.17(1)(b) (b) In determining whether a compliance schedule is appropriate and determining the length of the compliance schedule, the department shall consider all of the following factors:

NR 217.17(1)(b)1. 1. Whether there is any need for modifications to the treatment facilities, operations or measures to meet the water quality based effluent limitation, and if so, how long it will take to implement the modifications. If the department determines that a permittee only needs to make operational changes to achieve compliance with a limitation, the compliance schedule shall be as brief as possible and only allow time for operational start-up adjustments.

NR 217.17(1)(b)2. 2. The amount of time the discharger has already had to meet the water quality based effluent limitation under prior permits.

NR 217.17(1)(b)3. 3. The extent to which the discharger has made good faith efforts to comply with the water quality based effluent limitation and other requirements in prior permits, if applicable.

NR 217.17(1)(b)4. 4. The extent to which the phosphorus removal process technologies have been developed and proven to be effective.

NR 217.17(1)(c) (c) In determining whether a compliance schedule is appropriate and determining the length of the compliance schedule, the department may also consider any of the following factors:

NR 217.17(1)(c)1. 1. Whether there is a need to acquire a substantial amount of property to accommodate the needed modifications; and

NR 217.17(1)(c)2. 2. Whether there is a need to develop an extensive financing plan and obtain financing for the proposed treatment plant upgrade.

NR 217.17 Note Note: A compliance schedule may be provided for a water quality based effluent limit for phosphorus calculated under s. NR 217.13 and a TMDL based limit for phosphorus.

NR 217.17(2) (2) Maximum compliance schedule period. Except for situations where filtration or a similar phosphorus removal process is required, any compliance schedule established by the department under sub. (1) may not exceed seven years from the date a permit was first modified or reissued to include a water quality based phosphorus limit calculated under s. NR 217.13. Where compliance with the water quality based phosphorus limit requires the construction of filtration or a similar phosphorus removal process, the department may grant a schedule of compliance not to exceed nine years from the date that the permit is first reissued or modified to include effluent limitations developed under provisions of this subchapter. In cases where a compliance schedule extends beyond five years, the department may revise the schedule at reissuance or pursuant to a permit modification.

NR 217.17(3) (3) requirements, limitations, dates, and reporting. When granting a schedule of compliance, the department shall include, as conditions of the permit, the following:

NR 217.17(3)(a) (a) Dates for achievement of interim requirements. The time between interim dates may not exceed one year.

NR 217.17(3)(b) (b) A sequence of actions or operations that may include, as appropriate, but are not limited to:

NR 217.17(3)(b)1. 1. Development and implementation of a phosphorus discharge optimization plan for the current operation.

NR 217.17(3)(b)2. 2. Preparation of preliminary and final designs for new or modified treatment technology.

NR 217.17(3)(b)3. 3. Initiation and completion of construction.

NR 217.17(3)(c) (c) Interim effluent limitations representing good management and operation for similar treatment processes based on performance of other wastewater treatment facilities that will lead to compliance with the final water quality based effluent limitation.

NR 217.17(3)(d) (d) A requirement that no later than 30 days following each interim date and the final date of compliance, the permittee shall notify the department in writing of its compliance or non-compliance with the interim or final requirements, including submittal of progress reports. If any interim requirement will take more than one year to complete, the permit shall also include a projected completion date for the interim requirement.

NR 217.17(3)(e) (e) The final water quality based effluent limit for phosphorus calculated pursuant to s. NR 217.13 shall be included in the permit even if the limit is not effective during the permit term. The department may revise the final limit at permit reissuance or pursuant to a permit modification.

NR 217.17(3)(f) (f) If the permittee chooses to engage in pollutant trading as a means to achieve compliance with interim limitation or final water quality based effluent limitations, then the terms and conditions related to the trade shall be incorporated into the permit.

NR 217.17(4) (4) New dischargers. Any new discharger may not receive a compliance schedule to achieve compliance with a phosphorus water quality based effluent limitation.

NR 217.17 History History: CR 10-035: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 217.18 NR 217.18 Watershed adaptive management option.

NR 217.18(1) (1) General. The adaptive management option is a strategy to achieve the phosphorus water quality criteria in s. NR 102.06 in the most economically efficient manner, and as soon as possible, taking into consideration the contributions of phosphorus from point and nonpoint sources in a watershed.

NR 217.18(2) (2) Application. If requested by the permittee in the permit application for reissuance and if approved by the department, the permittee may implement a watershed adaptive management approach under this section as a means to achieve compliance with the phosphorus water quality standards in s. NR 102.06. The department may approve and authorize the adaptive management option in this section only if the permittee demonstrates and the department concurs that all of the following conditions are met:

NR 217.18(2)(a) (a) The exceedance of the applicable phosphorus criterion in s. NR 102.06 is caused by phosphorus contributions from both point sources and nonpoint sources.

NR 217.18(2)(b) (b) Either the sum of the nonpoint sources and the permitted municipal separate storm sewer system contribution of phosphorus to the receiving water is at least 50 percent of a total contribution within the watershed of the receiving water where the applicable phosphorus criterion in s. NR 102.06 is exceeded; or the permittee demonstrates that the applicable phosphorus criterion cannot be met in the watershed without the control of phosphorus from nonpoint sources.

NR 217.18(2)(c) (c) Documentation that the proposed water quality based effluent limit in the applicant’s permit will require filtration or other equivalent treatment technology to achieve compliance.

NR 217.18(2)(d) (d) The permittee has submitted an adaptive management plan that identifies specific actions to be implemented that will achieve compliance with the applicable phosphorus criterion in s. NR 102.06 through verifiable reductions of phosphorus from point and nonpoint sources in the watershed. At a minimum, the plan shall include the following:

NR 217.18(2)(d)1. 1. An analysis of the levels of phosphorus in the permittee’s effluent and significant sources of point and nonpoint phosphorus loadings in the watershed.

NR 217.18(2)(d)2. 2. Goals and measures for determining whether the actions identified in the plan are effective in achieving compliance with the applicable phosphorus criterion in s. NR 102.06.

NR 217.18(2)(d)3. 3. Identification of any anticipated partners that will assist in implementing the phosphorus reductions to achieve compliance with the applicable phosphorus criterion in s. NR 102.06, including the partner’s level of support for the plan.

NR 217.18(2)(d)4. 4. A demonstration that the permittee has the ability to fund and implement the plan either individually, or in conjunction with other permittees and nonpoint sources, or other partners, including municipal and county governments, in the watershed. Plans should include any contracts reflecting commitments by partners to implement applicable actions.

NR 217.18(3) (3) Permit terms and conditions. If the department determines that the permittee has provided all necessary information and the conditions in sub. (2) have been met, it may issue a permit that includes watershed adaptive management actions to achieve compliance with the applicable phosphorus criterion in s. NR 102.06 on a schedule approved by the department. At a minimum, the permit shall include the following:

NR 217.18(3)(a) (a) Monitoring in the receiving water at locations and times established in the permit to assess phosphorus loading and to document progress toward achieving the applicable phosphorus criterion in s. NR 102.06. The department shall also require permittees to monitor, record and report the mass and concentration of phosphorus in the effluent at an appropriate frequency specified by the department in the permit.

NR 217.18(3)(b) (b) Requirements to design and implement the actions identified in the permittee’s approved adaptive management plan in accordance with the goals and measures identified in the plan and any compliance schedule included in the permit.

NR 217.18(3)(c) (c) Requirements to optimize the permittee’s treatment system to control phosphorus.

NR 217.18(3)(d) (d) Reporting procedures and deadlines for all monitoring, assessment and data gathering requirements in the plan. Permittees shall be required to file and the department will review an annual report that identifies implementation of actions in the plan that were completed the previous year, and that documents any progress in achieving the goals and measures in the adaptive management plan. Adjustment or corrections, to the extent that they are needed, will be incorporated into the permit via permit modification procedures.

NR 217.18(3)(e) (e) Numerical effluent limitations as follows:

NR 217.18(3)(e)1. 1. All permits issued under the adaptive management option in this section shall include water quality based effluent limitations calculated consistent with the federal water pollution control act, 33 USC 1251 to 1387, that are established according to s. NR 217.13 or a US EPA approved TMDL. These limitations shall take effect in accordance with the timeframe established in this paragraph, or pursuant to par. (g) if the adaptive management option is terminated.

NR 217.18(3)(e)2. 2. In the first permit reissuance term following approval by the department under sub. (2), the initial interim effluent limitation shall be no higher than 0.6 mg/L of total phosphorus expressed as a six-month average. An effluent limit not to exceed 1.0 mg/L of total phosphorus expressed as a monthly average shall also be included in the permit. The department may allow the permittee a compliance schedule that may not exceed five years if necessary to meet this interim limitation.

NR 217.18(3)(e)3. 3. If the permittee has met all of the requirements of its previous permit, but the monitoring data of the receiving water indicate that the applicable phosphorus water quality criterion in s. NR 102.06 has not been met by the time the first permit issued under the adaptive management option expires, the department may issue a subsequent adaptive management permit. The subsequent permit shall include an interim effluent limitation of no higher than 0.5 mg/L expressed as a six-month average. An effluent limit not to exceed 1.0 mg/L of total phosphorus expressed as a monthly average shall also be included in the permit. The subsequent permit shall also include an updated adaptive management plan to achieve the phosphorus water quality criterion in s. NR 102.06. The department may allow the permittee a compliance schedule that may not exceed five years if necessary to meet this interim limitation.

NR 217.18(3)(e)4. 4. If by the expiration of the second permit issued under the adaptive management option, monitoring data collected for the receiving water indicate that the applicable phosphorus criterion under s. NR 102.06 has not been met, the department shall require compliance with a water quality based effluent limitation for phosphorus calculated under s. NR 217.13 or a US EPA approved TMDL. The department may allow the permittee a compliance schedule that may not exceed five years if necessary to meet this limitation.

NR 217.18(3)(f) (f) A statement that failure to implement any of the terms or conditions established under pars. (a) through (e) above, is a violation of the permit.