The department first determined the site-specific characteristics of LCO and the set of stressors that underly the need for a site-specific phosphorus criterion. The department then developed a model based on over thirty years of extensive data from LCO to predict how whitefish habitat would respond to a range of phosphorus concentrations in the lake. This analytical approach allowed the department to examine the effect of phosphorus on oxythermal habitat. It demonstrated that the current phosphorus criterion of 15 µg/L is not protective of whitefish in LCO and that a lower phosphorus criterion is necessary to provide more oxythermal habitat for whitefish in the East Basin. The department’s analysis confirmed that a phosphorus criterion of 10 µg/L is appropriate and necessary to increase survival during the most stressful warm periods. This phosphorus concentration will likely preserve at least some depth of oxythermal habitat for whitefish with a dissolved oxygen concentration of at least 3 mg/L and temperature of not more than 18.9°C in 4 out of 5 years. Further, the analysis demonstrated that a criterion of 10 µg/L is not more stringent than reasonably necessary for attaining that protection, as concentrations above this point would not provide sufficient habitat. Achieving a criterion of 10 µg/L would also improve habitat conditions for cisco.
While the analysis indicates that phosphorus reduction alone will not result in optimal oxythermal habitat for whitefish, reduced phosphorus levels can increase the likelihood of survival during the most stressful warm periods for most years. Due to other factors influencing the lake (such as temperature), fish kills are still likely to occur in some years with more severe weather conditions.
10. Analysis and Supporting Documents Used to Determine the Effect on Small Business or in Preparation of an Economic Impact Report: The department does not anticipate any compliance costs related to this rule, because there are currently no point source dischargers within the lake’s watershed. The phosphorus loads in the LCO watershed are all from nonpoint sources (forested or agricultural lands, cranberry bogs and septic systems at private residences), which are not under the department’s regulatory authority. Because the department’s authority does not extend to these sources, there will be no regulatorily required reductions of phosphorus discharges and consequently no fiscal impacts from promulgating a site-specific criterion. Any new point source discharger to LCO would be permitted to discharge based on a limit that is calculated to achieve the site-specific phosphorus criteria.
If the proposed site-specific criterion is promulgated, follow-up phosphorus reduction efforts within the watershed would continue to be voluntary on the part of any nonpoint sources. The community has been proactive in seeking voluntary reductions; however, phosphorus levels continue to increase.
The lake is already on the impaired waters list for dissolved oxygen impacts. If a criterion of 10 µg/L total phosphorus is promulgated, the lake will also be listed as impaired for phosphorus until such time the criterion of 10 µg/L is attained. Listing status does not have a direct economic effect on stakeholders. Even if a TMDL analysis or other pollutant reduction plan is developed based on a more stringent phosphorus site-specific criterion of 10 µg/L, there will be no regulatorily required reductions of phosphorus for current sources of phosphorus under such a plan because all of the current phosphorus sources are nonpoint sources.
Although an impairment listing will not result in regulatory requirements or costs, it increases the potential for local entities to secure grant funding from the department or other sources. The department provides $2.3 to 3.3 million annually to local communities to address lake and watershed issues through its Surface Water Grants program. These grants can fund a wide variety of water quality and restoration activities, which can be used to enable further voluntary efforts to address this issue.
11. Effect on Small Business (initial regulatory flexibility analysis): The department has determined the rule will have no fiscal impact on small businesses. Promulgation of a site-specific criterion for the lake will not impose additional pollution reduction requirements for Wisconsin Pollutant Discharge Elimination System (WPDES) permittees or nonpoint sources. Small businesses within the watershed could take voluntary measures to reduce phosphorus inputs to the lake with or without a phosphorus site-specific criterion for the lake.
12. Agency Contact Person:
Kristi Minahan, Wisconsin Department of Natural Resources, Bureau of Water Quality WY/3, P.O. Box 7921, Madison, WI 53707-7921; Kristi.Minahan@Wisconsin.gov, 608-266-7055 13. Place where comments are to be submitted and deadline for submission:
A comment period was held from December 5, 2022 to January 30, 2023 with a public hearing on January 23, 2023.
RULE TEXT
Section 1 NR 102.06 (7) (a) (Note) and (b) 4. are created to read:
NR 102.06 (7) (a) Note: Assessment procedures for site-specific phosphorus criteria are the same as those for statewide phosphorus criteria under s. NR 102.07, unless otherwise specified. (b) 4. For Lac Courte Oreilles, a stratified two-story fishery lake, the total phosphorus criterion is 10 ug/L. Attainment of the criterion is determined by taking samples within 2 meters of the surface at the deepest points of the lake’s two-story fishery basins: East, Central, and West Basins. If the criterion is not attained at any one of the 3 deep points, then the lake as a whole, including the bays, is not attaining the criterion.
Section 2. Effective Date. This rule takes effect on the first day of the month following publication in the Wisconsin Administrative Register as provided in s. 227.22 (2) (intro.), Stats. Section 3. Board adoption. This rule was approved and adopted by the State of Wisconsin Natural Resources Board on June 28, 2023.
