608-266-7055
Madison: Department of Natural Resources, 101 S. Webster St., Madison, WI 53707, Room G09
Green Bay: DNR Service Center, 2984 Shawano Ave, Green Bay WI 54313, Lake Michigan Room
Section 1 NR 102.01 (1) is amended to read:
NR 102.01 Purpose. (1) The purpose of this chapter is to establish, in conjunction with chs. NR 103 to 105, water quality standards for surface waters of the state pursuant to s. 281.15, Stats. This chapter describes the designated use categories for such waters and the water quality criteria necessary to support these uses. This chapter and chs. NR 103 to 105chapter, chs. NR 103 to 105, and 119 constitute the water quality standards for the surface waters of Wisconsin. Section 2. NR 102.06 (7) is amended to read:
NR 102.06 (7) Site-specific criteria. A criterion contained within this section may be modified by rule for a specific surface water segment or waterbody. A site-specific criterion may be adopted in place of the generally applicable criteria in this section where site-specific data and analysis using scientifically defensible methods and sound scientific rationale demonstrate a different criterion is protective of the designated use of the specific surface water segment or waterbody. Procedures for developing site-specific criteria for phosphorus are established in ch. NR 119. Section 3. NR 119 is created to read:
PHOSPHORUS SITE-SPECIFIC WATER QUALITY CRITERIA
NR 119.01 General. This chapter establishes standard protocols for developing site-specific water quality criteria for total phosphorus. A phosphorus site-specific criterion may be established to appropriately protect a waterbody’s designated uses when the applicable statewide total phosphorus criterion, as specified in s. NR 102.06, is determined by the department to be more or less stringent than necessary to protect the uses of the waterbody due to site-specific conditions. The requirements specified in s. 281.15 (1) and (2) (b) to (e), Stats., shall be met when developing a site-specific criterion under this chapter. Protection of a waterbody’s designated uses is evaluated using indicators of the ecosystem’s response to phosphorus and overall biotic integrity. After a phosphorus site-specific criterion is adopted, approved by the U.S. environmental protection agency, and takes effect, it becomes the applicable water quality criterion under s. 281.15, Stats., for the approved waterbody or segment. NR 119.02 Definitions. In this chapter the following definitions apply:
(1) “Biocriterion” means a surface water quality criterion under subch. III of ch. NR 102 that describes the structure and function of aquatic communities in a waterbody necessary to protect its designated aquatic life use. (2) “Clean Water Act” or “CWA” means the federal Clean Water Act of 1972 and amendments.
(3) “Designated uses” are the uses assigned to Wisconsin’s waterbodies as specified in s. NR 102.04. Note: Pursuant to the Clean Water Act, all of Wisconsin’s surface waters are assigned to the following use categories: aquatic life, recreation, public health and welfare, wildlife.
(4) “Less stringent SSC” means a site-specific phosphorus criterion that is established at a concentration higher than a waterbody’s statewide phosphorus criterion.
(5) “More stringent SSC” means a site-specific phosphorus criterion that is established at a concentration lower than a waterbody’s statewide phosphorus criterion.
(6) “Natural background phosphorus concentration” means the phosphorus concentration from natural sources, including forested and undeveloped lands, and from natural processes such as weathering and dissolution, that would exist in the absence of measurable impacts from human activity or influence.
(7) “Phosphorus response indicator” means an indicator and its thresholds, as specified in s. NR 102.07 (4) to (7), that characterize the condition or abundance of aquatic organisms that are responsive to phosphorus. (8) “Section 303(d) list” means a list of waters that do not attain water quality standards and require a total maximum daily load analysis, as specified in Section 303(d) of the Clean Water Act.
(9) “Site-specific criterion” or “SSC” means a phosphorus criterion applicable to a waterbody or segment that differs from the statewide phosphorus criterion due to specific conditions at the waterbody or segment, documented using data for the specific site or a similar reference site.
(10) “Statewide phosphorus criterion” means the statewide phosphorus surface water quality criterion specified in s. NR 102.06 that applies to a specific waterbody in absence of an adopted, approved, and effective site-specific criterion. (11) “Strahler stream order” is a numerical hierarchy of stream segments increasing from headwaters through downstream reaches.
(12) “Total maximum daily load” or “TMDL” has the meaning defined in s. NR 212.72 (11). (13) “U.S. EPA” means the United States environmental protection agency.
(14) “Weather-controlled ambient total phosphorus concentration” has the meaning defined in s. NR 102.06 (2) (k). (15) “WPDES permit” means a Wisconsin pollutant discharge elimination system permit issued by the department under ch. 283, Stats. NR 119.03 Less stringent SSC. A waterbody or segment may be eligible for an SSC that is less stringent than the statewide phosphorus criterion if the requestor demonstrates and the department determines that the designated uses of the waterbody and its affected downstream waters can be protected by a less stringent phosphorus criterion based on the analysis of site-specific data. For the department to approve a less stringent SSC, the SSC shall be developed using methods specified in ss. NR 119.05 to 119.06 and be protective of downstream uses as specified in s. NR 119.06 (6). The categories of waterbodies that may qualify for less stringent SSC include all of the following: (1) Biological metrics attained. A less stringent SSC may be appropriate for a waterbody that is not attaining its statewide phosphorus criterion if all of its phosphorus response indicators and biocriteria are attained.
(2) Biological metrics not attained. A less stringent SSC may be appropriate for a waterbody that is not attaining its statewide phosphorus criterion even if one or more of its phosphorus response indicators or biocriteria are not attained, provided a modeling analysis demonstrates that the phosphorus response indicators are expected to be attained if the waterbody’s phosphorus concentration is sufficiently reduced to attain a proposed SSC that is less stringent than the statewide phosphorus criterion.
Note: Certain reservoirs with a statewide phosphorus criterion of 30-40 ug/L may fit in this category. An example of this analysis is the modeling and analysis conducted for Petenwell and Castle Rock Lakes.
(3) High natural background phosphorus concentration. A less stringent SSC may be appropriate if a waterbody is not attaining the statewide phosphorus criterion because the natural background phosphorus concentration is higher than the statewide phosphorus criterion.
NR 119.04 More stringent SSC. A waterbody or segment is eligible for an SSC that is more stringent than the statewide phosphorus criterion if the requestor demonstrates and the department determines that the statewide phosphorus criterion is not sufficiently protective of the waterbody’s designated uses. A more stringent SSC may be appropriate if a waterbody is in one of the following categories:
(1) Biological metrics not attained. A more stringent SSC may be appropriate if a waterbody attains its statewide phosphorus criterion but does not attain one or more of its phosphorus response indicators or biocriteria. A more stringent SSC is not appropriate under this paragraph if a biocriterion or phosphorus response indicator is not attained due to reasons other than phosphorus.
Note: Because flowing waters may transport algae downstream from where it is produced, an SSC should only be established on the segment of the waterbody where the impairment is being generated. For example, if a river directly downstream of an impoundment attains its phosphorus criterion but receives high algae concentrations passed through from the impounded area, a more stringent SSC for the river segment downstream from the dam may not be appropriate since the source of the algae is upstream. Establishing an SSC downstream from the dam is not likely to achieve attainment of the phosphorus response indicator.
(2) Biological metrics attained. A more stringent SSC may be appropriate even if a waterbody attains its statewide phosphorus criterion, phosphorus response indicators, and biocriteria in cases when it is demonstrated that a more stringent SSC than the statewide phosphorus criterion is necessary to maintain attainment of any of these indicators and the level necessary can be demonstrated through modeling.
Note: Certain impounded flowing waters with a statewide phosphorus criterion of 100 ug/L may fit in this category.
NR 119.05 Methods for determining an SSC. An SSC shall be developed using one of the following methods:
(1) SSC based on ambient phosphorus concentration. For cases under s. NR 119.03 (1) when it is demonstrated that a less stringent SSC is appropriate because biological metrics are attained, the department may set the SSC at a concentration not to exceed a flowing water’s median ambient concentration, or a lake or reservoir’s mean ambient phosphorus concentration. If the weather-controlled ambient total phosphorus concentration can be determined for the waterbody, this value may be used as the ambient phosphorus concentration. Note: The SSC is set at the waterbody’s weather-controlled ambient phosphorus concentration because the long-term ambient concentration is deemed to be protective of designated uses if the waterbody attains its phosphorus response indicators and biocriteria at current concentrations.
(2) SSC derived through modeling. (a) Modeling analysis. If a statistical or modeling analysis demonstrates that attaining a phosphorus concentration higher or lower than the statewide phosphorus criterion will attain a waterbody’s suspended chlorophyll a phosphorus response indicators specified in s. NR 102.07 (4) (a) to (b) and (5), the department shall set the SSC at the modeled phosphorus concentration expected to attain the applicable indicators. The analysis shall be conducted following requirements specified in s. NR 119.06 (4) (b). Note: Modeling demonstrations are based only on suspended chlorophyll a phosphorus response indicators because existing modeling approaches cannot reliably predict responses of fish, aquatic insect, or aquatic plant communities to variation in phosphorus concentration.
(b) Use of natural background phosphorus concentrations. An SSC may be set no lower than a waterbody’s natural background phosphorus concentration if the background concentration can be determined. The natural background concentration may be estimated using the concentration for similar nearby waterbodies with minimal human impacts or other methods approved by the department. For natural lakes, the background concentration may be determined from a sediment core using paleolimnological methods.
Note: Natural background phosphorus concentrations can be inferred from diatoms deposited in the sediment prior to significant impacts from Euro-American settlement, circa 1850s but variable across the state.
(3) Alternative methods. An alternative method for setting an SSC may be used in cases that are outside of those described in ss. NR 119.03 to 119.04 or when methods in subs. (1) to (2) are not appropriate or feasible. An SSC based on an alternative method may be approved if the department and U.S. EPA determine that the SSC is protective of the designated uses of the waterbody and downstream waters under s. NR 119.06 (6). NR 119.06 Minimum requirements for an SSC submittal. Any person may request an SSC or the department may develop an SSC on its own initiative. The requestor is responsible for developing the proposed SSC, including conducting monitoring and modeling if needed. An SSC request submittal shall contain all of the following:
(1) SSC study area. Identification of all waterbodies and segments within the SSC study area. The SSC study area includes all waterbodies and segments for which monitoring data are needed to determine whether a proposed SSC would be protective of designated uses. The study area is determined as follows:
(a) For any SSC on an isolated waterbody such as a seepage lake, the isolated waterbody may comprise the entire SSC study area. At least one monitoring site within the waterbody is required.
(b) For a more stringent SSC on a flowing water system, a single waterbody or segment may comprise the SSC study area. In this case, at least one monitoring site within the waterbody is required. A larger study area may also be established.
(c) For a less stringent SSC on a flowing water system, the study area shall include monitoring sites on all of the following upstream and downstream waters:
1. A site upstream from the segment under consideration for an SSC.
2. At least one site within the segment under consideration for an SSC. This site shall be located downstream from any WPDES permitted dischargers present on the segment.
3. Downstream of the SSC segment, one site per Strahler stream order until the terminal waterbody defined in subd. 4 is reached.
4. At least one site within the study area’s terminal waterbody, which is the nearest downstream waterbody that has a statewide phosphorus criterion different from the statewide phosphorus criterion applicable to the proposed SSC segment. If no terminal waterbody is reached before the Mississippi River, the Mississippi River is the terminal waterbody.
Note: The combined sites listed in par. (c) should typically result in 6 or fewer sites. If more than one discharger is present, additional sampling sites may be needed.
(2) Applicable water quality standards. For each waterbody or segment identified in sub. (1), identification of all applicable designated uses under s. NR 102.04, phosphorus criteria under s. NR 102.06, phosphorus response indicators under s. NR 102.07 (4) to (7), and biocriteria under subch. III of ch. NR 102. (3) Monitoring. Sampling data for each of the study area monitoring sites specified in sub. (1). Data shall be collected following the department’s monitoring and quality assurance protocols for each metric. If additional relevant data are available beyond the minimum requirements specified in this section, such as more frequent data or a longer-term data record, they shall also be submitted and analyzed under sub. (4). Monitoring data requirements include all of the following:
(a) At least 2 years of total phosphorus data. Sampling frequency at each site shall comply with one of the following:
1. For lakes and reservoirs, a minimum of 12 phosphorus samples are required over a 2-year period. Collection of 12 samples requires 6 samples from June 1 to September 15 each year.
2. For flowing waters, a minimum of 12 phosphorus samples are required over a 2-year period. Collection of 12 samples requires monthly sampling from May to October each year.
3. For sites that are more variable than typical or that are close to the statewide phosphorus criterion, the department recommends more frequent sampling than the minimum. A requestor may consult with the department to determine if a higher sampling frequency is recommended.
(b) At least 2 years of data for each of the applicable phosphorus response indicators and biocriteria. For biological sampling, the department may approve sampling to be conducted by the requestor, conduct the sampling itself, or agree to a designee.
(c) Documentation of the monitoring protocols and quality assurance methods followed.
(d) Depending on site-specific circumstances, for the purposes of making an SSC determination, the department may require an additional number of samples, monitoring sites, or other chemical, biological, or physical metrics in addition to those specified in this section.
Note: The department’s monitoring protocols and standard operating procedures, including quality assurance protocols, and existing data housed by the department may be accessed through the department’s SWIMS database. Contact the department at DNRSWIMS@wisconsin.gov for access to the database. More information is available by contacting the department’s surface water monitoring section or on its surface water monitoring website at https://dnr.wi.gov/topic/SurfaceWater/monitoring.html. (4) analysis. Analysis of the data, including all of the following:
(a) An analysis of monitoring data following the department’s assessment protocols specified in ch. NR 102.52 to indicate current and historic attainment status of all water quality standards identified in sub. (2). This shall include identifying whether any waters are or have been on the section 303(d) list, and any trends observable over time. If any relevant water quality standard is not attained, evaluate whether there is a relationship between phosphorus and the non-attainment, and any other potential factors that may be causing the non-attainment. Note: The department’s surface water assessment protocols are found in guidance titled “Wisconsin Consolidated Assessment and Listing Methodology,” or WisCALM, which is available on the department’s surface water assessments website at https://dnr.wi.gov/topic/SurfaceWater/assessments.html. (b) A statistical or modeling analysis if needed to determine the appropriate SSC, as specified in s. NR 119.05 (2), and documentation of methods and results. The analysis shall demonstrate a clear link between phosphorus and attainment of a designated use, including characterization of the relationship between phosphorus and the applicable phosphorus response indicators. The analysis shall be based on or calibrated to data from the waterbody that are representative of the range of environmental variability that may influence the applicable phosphorus response indicators. For rivers that contain a reservoir, impounded flowing water, or natural drainage lake, the model may be based on attainment of the applicable chlorophyll a criterion specified in ch. NR 102.04 (6) (b), and a demonstration of attainment of the river phosphorus response indicator for chlorophyll a specified in ch. NR 102.06 (4) is not required. For rivers without a reservoir, impounded flowing water, or natural drainage lake, modeling shall include a demonstration that the phosphorus response indicator for chlorophyll a specified in ch. NR 102.06 (4) is expected to be attained. Note: The option for rivers with impounded flowing waters, reservoirs, or natural drainage lakes is provided because modeling chlorophyll a – phosphorus correlations is more cost-effective for these waters than modeling such correlations in rivers, and attaining the chlorophyll a targets for lakes, reservoirs, and impounded flowing waters should ensure that chlorophyll a targets are also met within the river.
