Phosphorus assessment procedures using biological metrics. These sections clarify the protocols currently used by the department to assess attainment of the phosphorus criteria, and add a component that allows a waterbody’s biological response to phosphorus, or lack thereof, to be taken into account before listing it as impaired for phosphorus. This will provide the benefit of keeping a small number of waters off the impaired waters list that have healthy biological communities, but which may have periodic exceedances of the phosphorus statewide criterion. It would not add additional waters to the impaired waters list. No costs are associated with this portion of the rule.
Dissolved oxygen criteria for Aquatic Life. Revisions to the dissolved oxygen section are minimal and help clarify which criteria apply to different waterbody types. These have no expected economic impact. The addition of oxythermal criteria for two-story fisheries is useful in assessing the health of the fishery but is not expected to have an economic impact, as there are no dischargers with individual Wisconsin Pollutant Discharge Elimination System (WPDES) permits on or upstream of two-story fishery lakes. If a waterbody is not attaining this criterion, the department may recommend a study to determine the reason for non-attainment and what restoration actions may be appropriate.
NR 217 calculation of upstream background phosphorus concentrations. The department does not anticipate an economic impact from this revision. Currently, the two methods yield very similar results and alignment of the calculation methods is not expected to have an impact. For a small number of facilities it is possible that this would change the upstream phosphorus concentration used and the resulting calculated limit, but this minor change would not necessitate different treatment types, and economic impacts are not expected.
Definitions. Because the clarifications to definitions are not expected to change the waterbodies included in the categories, only clarify existing interpretation of these terms, no economic impact is expected.
10. Effect on Small Business (initial regulatory flexibility analysis): As discussed above, this rule is not expected to incur additional costs for small businesses.
11. Agency Contact Person: Kristi Minahan, Wisconsin Department of Natural Resources, Bureau of Water Quality WY/3, P.O. Box 7921, Madison, WI 53707-7921;
12. Place where comments are to be submitted and deadline for submission:
The initial comment period was held from July to September, 2019 with a public hearing on September 12, 2019. After that initial comment period, Board Order WY-23-13 was adopted by the Board at its December 2019 meeting. After approval by the governor, the rule was submitted for legislative review on December 23, 2019. The Assembly Committee on Forestry, Parks, and Outdoor Recreation held a hearing on February 4, 2020, and received comments. The rule was subsequently recalled by the department from legislative committees on February 28, 2020 to make germane modifications in response to these comments. The modifications changed the term “biocriteria” to “biological assessment thresholds” and relocated biological thresholds from the surface water criteria section of chapter NR 102 to a subchapter titled “Waterbody Assessments and Reporting.” The purpose of these changes is to further clarify that biological assessments differ from water quality criteria in that the assessments are not used to derive discharge permit effluent limits. Additionally, aquatic plant numeric thresholds for lakes and reservoirs were added to the code to address stakeholder preferences for inclusion of numeric thresholds. This Board Order reflects these germane modifications.
A second public comment period was recently held pertaining to the germane modifications contained in the rule. This second comment period ran from September 7 to November 1, 2021 and a hearing was held on October 25, 2021.
RULE TEXT
Section 1 NR 102.03 (intro.) is amended to read:
NR 102.03 Definitions. In this chapter, the following definitions are applicable to terms usedapply:
Section 2 NR 102.03 (1c), (1e), (1g), (1i), (1k), (1m), (1q), (1v), and (6) are created to read:
NR 102.03 (1c) “Benthic” means relating to the ecological zone at the bottom of a body of water, including the sediment surface and subsurface layers.
(1e) “Biological assessment threshold” means a numeric value or condition description used to measure the quality of a waterbody’s biological community and to determine attainment of its designated uses.
(1g) “Chlorophyll a” means a green pigment present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis.
(1i) “Clean Water Act” means the federal Clean Water Act of 1972 and amendments.
(1k) “Confidence interval” means a range within which the true value of a parameter is likely to occur, with a specified level of confidence.
(1m) “Diatom” means a common and diverse group of unicellular algae of the phylum Chrysophyta, having cell walls containing silica.
(1q) “Impounded flowing water” means a waterbody impounded by a constructed outlet structure on a river or stream that is not a reservoir as defined in sub. (4m).
(1v) “Macrophyte” means an aquatic plant large enough to be seen without the use of a microscope.
(6) “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 under section 303 (d) of the Clean Water Act, 33 USC 1313 (d). Section 3 NR 102.04 (4) (a) is repealed and recreated to read:
NR 102.04 (4) (a) Dissolved oxygen. 1. For streams, rivers, and impounded flowing waters, dissolved oxygen criteria apply to samples taken from the main channel near the area with greatest flow. For lakes or reservoirs, the dissolved oxygen criteria in this paragraph apply to the epilimnion of stratified lakes and to all but the deepest one meter of the water column of unstratified lakes.
2. Except as provided in subds. 3. to 7. and par. (am), surface waters shall attain a minimum dissolved oxygen concentration of 5 mg/L at all times.
3. A waterbody classified by the department as a trout class I or II water under s. NR 1.02 (7), a cold water community that is not a two-story fishery lake covered under par. (am), or a great lakes tributary used by salmonids for spawning during the period of habitation, shall attain all of the following: a. A minimum dissolved oxygen concentration of 6.0 mg/L at all times.
b. A minimum dissolved oxygen concentration of 7.0 mg/L when cold water fish are spawning through fry emergence from their redds, or gravel nests.
Note: The period from spawning through fry emergence from their gravel nests is approximately mid-October through April, but varies depending on water temperature and location in the state.
c. Dissolved oxygen concentrations and diurnal patterns may not be altered from natural background levels to such an extent that cold water populations are adversely affected.
4. A waterbody classified by the department as trout class III under s. NR 1.02 (7) shall attain a minimum dissolved oxygen concentration of 6.0 mg/L at all times. 5. A waterbody for which a use attainability analysis under 40 CFR 131.10 (g) (1) to (6) demonstrates that its otherwise applicable designated use category is unattainable shall attain the following: a. For a coldwater community with an approved use attainability analysis that redesignates it as warmwater, a minimum dissolved oxygen concentration of 5 mg/L at all times.
b. For any other community except those under subd. 7., a minimum dissolved oxygen concentration of 3 mg/L at all times to protect aquatic life
Note: Waterbodies described in subd. 5 are also known as altered waters.
6. A waterbody designated by the department as limited forage fish shall attain a minimum dissolved oxygen concentration of 3 mg/L at all times.
7. A waterbody designated by the department as limited aquatic life or wetlands, or classified as diffuse surface waters or wastewater effluent channels shall attain a minimum dissolved oxygen concentration of 1 mg/L at all times when water is present.
Section 4 NR 102.04 (4) (am) is created to read:
NR 102.04 (4) (am) Oxythermal layer thickness for two-story fishery lakes. 1. ‘Criteria.’ A two-story fishery lake shall maintain, during its period of summer stratification, an oxythermal layer of at least 1 meter in thickness that maintains both a dissolved oxygen concentration of at least 6 mg/L and a maximum temperature of the following:
a. For a two-story fishery lake with lake trout, 57° F or less.
b. For a two-story fishery lake with whitefish but not lake trout, 66° F or less.
c. For a two-story fishery lake with cisco but not whitefish or lake trout, or that the department manages for brook, brown, or rainbow trout, 73°F or less.
d. For a two-story fishery lake with multiple coldwater fish species, the applicable criterion under subd. 1. a. to c. is that for the lake’s species requiring the lowest temperature.
2. ‘Assessment.’ a. The monitoring period for the criteria under subd. 1. is June 1 to September 15. When monitoring for assessment purposes, depth profiles of temperature and dissolved oxygen shall, whenever possible, be taken in increments of 1 meter or less near the deepest part of the lake, at least monthly July to September. Samples taken outside this time frame but during summer stratification may also be used to determine assessment.
Note: Reservoirs, multi-lobed lakes, or very large lakes may need more than one sampling station to assess the lake.
b. If at any time during a lake’s summer stratification the applicable criterion in subd. 1. is not met, that year is an exceedance year. At least 2 years of data are needed to make an attainment determination. If any 2 or more years within the most recent 5-year period are exceedance years, the lake is not attaining the water quality criterion. If insufficient data are available from the most recent 5-year period, data from up to 10 years may be used if representative of current conditions.
Section 5 NR 102.04 (4) (b) is repealed.
Section 6 NR 102.04 (4) (d) is amended to read:
NR 102.04 (4) (d) OtherToxic substances. Unauthorized concentrations of substances are not permitted that alone or in combination with other materials present are toxic to fish or other aquatic life. Surface waters shall meet the acute and chronic criteria as set forth in or developed pursuant to ss. NR 105.05 and 105.06. Surface waters shall meet the criteria which correspond to the appropriate fish and aquatic life subcategory for the surface water, except as provided in s. NR 104.02 (3). Section 7 NR 102.04 (4) (f) is created to read:
NR 102.04 (4) (f) Other criteria. Surface waters shall meet all other criteria that correspond to the appropriate aquatic life subcategory for the surface water, including narrative criteria specified in sub. (1).
Section 8 NR 102.04 (5) (b) is amended to read:
NR 102.04 (5) (b) Exceptions. Whenever the department determines, in accordance with the procedures specified in s. NR 210.06 (3), that wastewater disinfection is not required to protect recreational uses, the criteria specified in par. (a)sub. (6) (a) and in chs. NR 103 and 104 do not apply. Section 9. NR 102.06 (1) and (2) (intro.) are amended to read:
NR 102.06 (1) General. This section identifies the water quality criteria for total phosphorus that shall be met in surface waters. Assessment procedures for waterbodies are specified in ss. NR 102.07 and 102.60. (2) Definitions. In this section, the following definitions apply:
Section 10. NR 102.06 (2) (a), (f), (fm), and (j) are renumbered 102.03 (1o), (4s), as affected by CR 21-083, (6e), and (7m). [Note to LRB: A separate rule package, CR 21-083, creates a definition for s. NR 102.03 (4e) and (4m), which affects the numbering of definition (4s) renumbered under this Section.] Section 11. NR 102.06 (2) (g) and (2) (i) are renumbered 102.03 (6m) and (6s) and amended to read:
NR 102.03 (6m) “Stratified lake or reservoir” means a lake or reservoir where either of sufficient field data demonstrate that the lake is dimictic or, in absence of sufficient field data, the following equationsequation results in a value of greater than 3.8:
Maximum Depth (meters) — 0.1
Log10Lake Area (hectares)
Maximum Depth (feet)* 0.305 — 0.1
Log10Lake Area (acres) * 0.405
(6s) “Stratified two-story fishery lake” means a stratified lake which has supported a cold water fishery in its lower depths within the last 50 yearsor “two-story fishery lake” means a lake greater than 5 acres in size that is typically stratified in the summer, with the potential for an oxygenated hypolimnion, that has documentation at any time since 1975 of a population of cold water fish species such as cisco, whitefish, or trout that is sustained through natural reproduction or long-term active stocking with year-to-year survival.
Section 12. NR 102.03 (6s) (Note) is created to read:
NR 102.03 (6s) Note: A list of two-story fishery lakes that contain naturally reproducing lake trout, whitefish, or cisco, or are stocked and managed by the department for brook, brown, rainbow, or lake trout, is available on the department’s designated uses website at https://dnr.wi.gov/topic/SurfaceWater/usedesignations.html. Section 13. NR 102.06 (3) (title) is repealed and recreated to read:
NR 102.06 (3) (title) Rivers, streams, and impounded flowing waters.
Section 14. NR 102.06 (4) (c) is renumbered 102.06 (3) (c) and amended to read:
NR 102.06 (3) (c) Waters impounded on rivers or streams that don’t meet the definition of reservoir in this sectionAn impounded flowing water shall meet the river andor stream criterion in sub. (3)par. (a) or (b) that applies to the primary stream or river entering the impounded water.
Section 15. NR 102.06 (7) (Note 2) is repealed.
Section 16. NR 102.07 is created to read:
NR 102.07 Assessing phosphorus concentration. (1) Data requirements. (a) Lakes and reservoirs. The total phosphorus criteria specified in s. NR 102.06 (4) apply to samples taken near a lake or reservoir’s deepest point, within 2 meters of the surface. For assessment purposes samples shall, whenever possible, be taken at least once per month for 3 months during the sampling period of June 1 to September 15. The department shall calculate a lake or reservoir’s arithmetic mean total phosphorus concentration using at least 2 years of data from the sampling period. Note: Reservoirs, multi-lobed lakes, or very large lakes may need more than one sampling station to assess the lake.
