NR 102.06(7)(b)2. 2. For Petenwell Lake, the total phosphorus criterion is 53 ug/L.

NR 102.06(7)(b)3. 3. For Lake Wisconsin, the total phosphorus criterion is 47 ug/L.

NR 102.06(7)(b)4. 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.

NR 102.06 Note Note: Reservoirs, two-story fishery lakes and water bodies with high natural background phosphorus concentrations are the most appropriate water bodies for site-specific criteria.

NR 102.06 History History: Cr. Register, July, 1975, No. 235, eff. 8-1-75; am. Register, October, 1986, No. 370, eff. 11-1-86; renum. from NR 102.04, Register, February, 1989, No. 398, eff. 3-1-89; am. Register, November, 1992, No. 443, eff. 12-1-92; CR 10-035: r. and recr. Register November 2010 No. 659, eff. 12-1-10; renumbering of (2) (fm) made under s. 13.92 (4) (b) 1., Stats., Register November 2010 No. 659; CR 19-083: am. (4) (intro.), renum. (7) to (7) (a), cr. (7) (b) Register May 2020 No. 773, eff. 6-1-20; CR 10-093: am. (7) (a) Register September 2022 No. 801, eff. 10-1-22; CR 19-094: am. (1), (2) (intro.), renum. (2) (a), (f), (fm), (g), (i), (j) to NR 102.03 (1o), (4s), (6e), (6m), (6s), (7m) and, as renumbered, am. (6m), (6s), r. and recr. (3) (title), renum. (4) (c) to (3) (c) and am. Register September 2022 No. 801, eff. 10-1-22; CR 22-082: cr. (7) (b) 4. Register January 2024 No. 817, eff. 2-1-24.

NR 102.07 NR 102.07 Assessing phosphorus concentration.

NR 102.07(1) (1) Data requirements.

NR 102.07(1)(a) (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.

NR 102.07 Note Note: Reservoirs, multi-lobed lakes, or very large lakes may need more than one sampling station to assess the lake.

NR 102.07(1)(b) (b) Flowing waters. The total phosphorus criteria specified in s. NR 102.06 (3) apply to samples taken from the main channel near the area with greatest flow. For assessment purposes samples shall, whenever possible, be taken at least once per month for 6 months during the sampling period of May 1 to October 31. The department shall calculate the median total phosphorus concentration for a stream, river, or impounded flowing water using at least one year of data from the sampling period.

NR 102.07(1)(c) (c) Assessment timeframe for lakes, reservoirs and flowing waters.

NR 102.07(1)(c)1. 1. In this paragraph, “weather-controlled total phosphorus concentration” means a waterbody’s mean or median total phosphorus concentration during the applicable assessment period, estimated from measured data while controlling for weather variability using a method such as the department’s Phosphorus Mixed Effects Regression calculation method.

NR 102.07(1)(c)2. 2. All representative data from the most recent 5 years shall be used for assessments, but data from the most recent 10 years may be used if representative of current conditions. If fewer than the recommended number of samples in par. (a) or (b) are available, the department may be able to make an assessment determination on a case-by-case basis. The department may calculate a site’s weather-controlled total phosphorus concentration to correct for weather variability and use this value to make an assessment determination in place of the mean or median calculated under par. (a) or (b).

NR 102.07 Note Note: A mean total phosphorus concentration is used for lakes or reservoirs; a median concentration is used for streams, rivers, or impounded flowing waters. Total phosphorus data may be submitted and weather-controlled concentrations can be obtained by contacting the department at [e-mail] for access to the department’s SWIMS database. The statistical computer programming script to run the Phosphorus Mixed Effects Regression calculation can be obtained through the department’s Water Evaluation Section by contacting the department’s call center at 1-888-WDNRINFo (1-888-936-7463) or using options provided on its website at https://dnr.wi.gov/contact/.

NR 102.07 Note Note: The procedures in pars. (b) to (c) are also used for determining upstream concentrations of phosphorus under s. NR 217.13 (2) (d) for purposes of calculating a water-quality based effluent limit for a Wisconsin pollutant discharge elimination system (WPDES) permit.

NR 102.07(2) (2) Exceedance determination. The department shall compare the mean or median calculated under sub. (1) to the waterbody’s applicable total phosphorus criterion specified in s. NR 102.06 to determine whether the waterbody is exceeding the criterion. To determine whether additional data are needed to make an attainment decision for section 303 (d) listing purposes, the department shall apply the confidence interval approach in s. NR 102.52 (2) (b) to (c). If application of those methods indicates that the waterbody is exceeding the phosphorus criterion, the department shall propose to include the waterbody on the section 303 (d) list as impaired for total phosphorus unless the department determines the waterbody is not exhibiting a biological response to phosphorus as specified in s. NR 102.60.

NR 102.07 History History: CR 19-094: cr. Register September 2022 No. 801, eff. 10-1-22.

NR 102.10 NR 102.10 Outstanding resource waters.

NR 102.10(1) (1) The following surface waters are designated as outstanding resource waters:

NR 102.10(1)(a) (a) National wild and scenic rivers. All rivers designated under the national wild and scenic rivers act, as amended, 16 USC 1271 to 1287, except those portions flowing through Indian reservations, including:

NR 102.10(1)(a)1. 1. St. Croix river between the northern boundary of the Hudson city limits and the St. Croix flowage dam in Douglas county except that the portion of the St. Croix river from the northern boundary of the St. Croix Falls city limits to a distance one mile below the STH 243 bridge at Osceola shall be classified exceptional resource waters under s. NR 102.11.

NR 102.10(1)(a)2. 2. Namekagon river between its confluence with the St. Croix river and the outlet of Lake Namekagon in Bayfield county.

NR 102.10(1)(b) (b) State wild and scenic rivers. All state wild and scenic rivers designated under s. 30.26, Stats., including:

NR 102.10(1)(b)1. 1. Pike river and its headwater branches in Marinette county.

NR 102.10(1)(b)2. 2. Pine river and its headwater branches in Florence and Forest counties.

NR 102.10(1)(b)3. 3. Popple River and its headwater branches in Florence and Forest counties.

NR 102.10(1)(b)4. 4. The portion of the Brunsweiler River (Martin Hanson Wild River) from the point in Ashland County at which it leaves T44N R4W S22 QSW QQSW downstream to the point at which it crosses the boundary of the Chequamegon-Nicolet National Forest at T45N R4W S22 QNW.

NR 102.10(1)(b)5. 5. Portions of the Totagatic River in Bayfield, Sawyer, Washburn, Douglas, and Burnett Counties as described in the following table:

SEG 1: From the outlet of Totogatic Lake located in Bayfield County to the upstream end of Nelson Lake at the southern edge of the walleye spawning refuge located in Sawyer County.