The department’s guidance for assessing waterbodies, Wisconsin Consolidated Assessment and Listing Methodology guidance or WisCALM, has additional detail on recommended goals and methods for biological assessment thresholds (both numeric and narrative). WisCALM guidance has been used by the department for years to prepare the biennial surface water quality report required under 33 USC 1315 that is submitted to U.S. EPA. It will continue to be used and updated every two years in preparation for the biennial report, and any updates to the guidance are subject to a separate public notice and comment period. As WisCALM is updated over time, existing biological metrics such as those for fish and aquatic insects may be revised to reflect the most recent science and public input. If any new biological metrics are included in WisCALM in the future, waterbodies would then be assessed for attainment of the new biological metric as well. However, the proposed numeric assessment thresholds, once established in rule, may only be revised through future rulemaking.
Under any biological assessment thresholds—narrative or numeric--a waterbody that is determined to be biologically degraded (listed as having “observed effects”) and for which a pollutant is identified as the cause of the degradation may be subject to future pollutant reduction measures that could entail a cost. However, permitted dischargers would only be fiscally impacted if a site-specific criterion (SSC) more stringent than the pollutant’s statewide criterion was developed by rule and approved by U.S. EPA. Development of such SSC through rulemaking is already allowable under existing authority.Narrative biological assessment thresholds. This section establishes narrative biological assessment thresholds that describe the biological quality goals for a surface water’s aquatic life community, and provides a general outline of the procedures currently being used by the department to assess biological quality. As such, there is no economic impact expected from the creation of this section. WisCALM guidance recommendations will be used in interpreting narrative thresholds—for instance for fish and aquatic insect assessments that are not codified—but as guidance these recommendations are non-binding and subject to change.
Numeric biological assessment thresholds for lakes, reservoirs, and impounded flowing waters.
Aquatic plant numeric assessment thresholds. Aquatic plant numeric thresholds established in this rule identify lakes or reservoirs in which the plant community has been degraded due to a variety of disturbance factors. This metric was added in response to stakeholder preferences to include numeric thresholds. As a biological assessment threshold, this metric would not affect permit limits. As with other biological thresholds, if a lake is not attaining these thresholds it would be listed as having “observed effects” on the section 303(d) list.
Algae (chlorophyll a) numeric assessment thresholds to determine attainment of Recreation and Aquatic Life uses. These numeric thresholds apply to lakes, reservoirs and impounded flowing waters and are the same as algae levels already considered by the department to assess water quality for the biennial report to U.S. EPA and used to list a waterbody as impaired when its uses are adversely affected. The department’s analysis shows that, once attained, the existing statewide phosphorus criteria will be protective of the proposed chlorophyll a assessment thresholds in most waterbodies. The department does not intend to require chlorophyll a monitoring of discharges, and there are no permit implementation procedures associated with the chlorophyll a standard included in this rule package. The only way a more stringent phosphorus limit would be derived based on an exceedance of a chlorophyll a assessment threshold is if a more-stringent phosphorus SSC was developed by the department through rulemaking and approved by U.S. EPA. Any potential costs associated with a more stringent SSC would be evaluated as part of that rulemaking process. The establishment of chlorophyll a assessment thresholds does not provide any new authority for developing SSC; that avenue is already available where algae levels are a concern. For these reasons, the department does not expect an additional economic impact based on this change. 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:
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)(6d), and (9) 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) “Biocriterion” means a surface water quality criterion under subch. III that describes the structure and function of aquatic communities in a waterbody necessary to protect its designated aquatic life use. “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.
(6d)(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). (9) “U.S. EPA” means the United States environmental protection agency.
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, a minimum dissolved oxygen concentration of 5 mg/L at all times.
b. For any other community, a minimum dissolved oxygen concentration of 3 mg/L at all times.
Note: Waterbodies described in subd. 5 are also known as altered warmwater or altered macroinvertebrate 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 impairmentattainment 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 and shall be listed on the section 303 (d) list. 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) and (Note) and (g) areis created to read:
NR 102.04 (4) (f) Chlorophyll a. 1. ‘Criteria.’ a. Mean suspended chlorophyll a concentrations in lakes and reservoirs other than stratified two-story fishery lakes shall not exceed 27 ug/L.
b. Mean suspended chlorophyll a concentrations in stratified two-story fishery lakes shall not exceed 8 ug/L.
2. ‘Assessment.’ Data requirements are the same as those specified in s. NR 102.07 (1) (a) 1., except that the sampling period for chlorophyll a is July 15 to September 15. To determine attainment of the chlorophyll a criterion under subd. 1., the department shall compare the waterbody’s mean suspended chlorophyll a concentration during the sampling period to the criterion, using the confidence interval approach described under s. NR 102.52 (2) (b) to (c) to determine if additional samples are needed. Note: The aquatic life chlorophyll a criteria do not apply to streams, rivers, or impounded flowing waters, as they were established based on lake trophic status levels.
(g)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) and biocriteria described in subch. III.
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 102.04 (6) (b), Table B, (Note 1), and (Note 2) are created to read:
[Note to LRB: NR 102.04 (6) (a) and Table A are created in Board Order WY-17-15.]
NR 102.04 (6) (b) Frequency of moderate algae levels. 1. ‘Criteria.’ A moderate algae level is defined as a chlorophyll a concentration of 20 ug/L or greater. Lakes, reservoirs, and impounded flowing waters shall not exceed the frequency of moderate algae levels specified in Table B during the summer sampling period.
Table B
Recreational use criteria for frequency of moderate algae levels
Waterbody Type1 | Subcategory | Criteria for frequency of moderate algae levels |
Lakes, Reservoirs, Impounded Flowing Waters (includes cold and warm) | Impounded flowing water, Unstratified drainage, Unstratified seepage | Does not exceed 20 ug/L chlorophyll a for more than 30% of days during the summer sampling period2 |
| Stratified drainage, Stratified seepage | Does not exceed 20 ug/L chlorophyll a for more than 5% of days during the summer sampling period2 |
| Stratified two-story fishery | |
