NR 106.05(3)(a)(a) The discharge concentration of the substance for any day exceeds the limit of detection and exceeds the limitations based on either the acute toxicity criterion or secondary acute value for the substance as determined in s. NR 106.06 (3) where appropriate,

NR 106.05(3)(b)(b) The arithmetic average discharge concentration of the substance for any 4 consecutive days calculated as described in sub. (7) exceeds the limit of detection and exceeds the limitations based on either the chronic toxicity criterion or secondary chronic value for the substance as determined in s. NR 106.06 (4).

NR 106.05(3)(c)(c) The arithmetic average discharge concentration of the substance for any 30 consecutive days calculated as described in sub. (7) exceeds the limit of detection and exceeds any limitation based on the wildlife, human threshold, or human cancer criteria or secondary values, or taste and odor criteria for the substance as determined in s. NR 106.06 (4).

NR 106.05(4)(4) If at least 11 daily discharge concentrations of the substance are greater than the limit of detection and the requirements of sub. (3) do not result in the need for an effluent limitation, water quality based effluent limitations are necessary for a substance in a point source discharge if the upper 99th percentile of available discharge concentrations as calculated in sub. (5) meets any of the conditions specified in pars. (a) to (c).

NR 106.05(4)(a)(a) The upper 99th percentile of daily discharge concentrations of the substance exceeds the limitation based on either the acute toxicity criterion or the secondary acute value for the substance as determined in s. NR 106.06 (3).

NR 106.05(4)(b)(b) The upper 99th percentile of 4-day average discharge concentration of the substance exceeds the limitation based on either the chronic toxicity criterion or the secondary chronic value for the substance as determined in s. NR 106.06 (4), or

NR 106.05(4)(c)(c) The upper 99th percentile of 30-day average discharge concentration of the substance exceeds any limitation based on the wildlife, human threshold, or human cancer criteria or secondary value, or taste and odor criteria for the substance as determined in s. NR 106.06 (4).

NR 106.05(5)(5) This subsection shall be used to calculate upper 99th percentile values unless a probability distribution other than log normal is determined to be more appropriate and alternate methods to calculate the upper 99th percentile are available.

NR 106.05(5)(a)(a) When available daily discharge concentrations of the substance are not serially correlated and at least 11 concentrations are greater than the limit of detection, the upper 99th percentile of the daily average, the 4-day average and the 30-day average discharge concentrations may be calculated as follows:

NR 106.05(5)(b)(b) When the daily discharge concentrations of any substance are serially correlated, the serially correlated data may be adjusted using appropriate methods such as that presented in Appendix E of “Technical Support Document for Water Quality-based Toxics Control”, U.S. environmental protection agency, March 1991 (EPA/505/2-90-001). The equation presented in par. (a) may be used after adjustment of the serially correlated data.

NR 106.05(6)(6) If less than 11 daily discharge concentrations of the substance are greater than the limit of detection, and the requirements in sub. (3) do not result in an effluent limitation, water quality based effluent limitations are necessary for a substance in a point source discharge if the arithmetic average of available discharge concentrations as calculated in sub. (7) exceeds any value determined in par. (a) or (b):

NR 106.05(6)(a)(a) One fifth of the limitation based on the acute toxicity criterion or secondary acute value for the substance, as determined in s. NR 106.06 (3) where appropriate, or

NR 106.05(6)(b)(b) One fifth of any limitation based on chronic toxicity criteria or secondary chronic values or long-term impacts as determined in s. NR 106.06 (4).

NR 106.05(7)(7) The arithmetic average discharge concentration as used in subs. (3) and (6) shall be calculated using all available discharge data treated according to this subsection.

NR 106.05(7)(a)(a) If, in the judgment of the department, the analytical methods used to test for the substance represent acceptable methods, all values reported as less than the limit of detection shall be set equal to zero for calculation of the average concentration.

NR 106.05(7)(b)(b) If, in the judgment of the department, the analytical methods used to test for the substance do not represent the best acceptable methods, all values reported as less than the limit of detection shall be discarded from the data.

NR 106.05(8)(8) If representative discharge data are not available for a substance, the department may include water quality-based effluent limitations in a permit if, in the judgment of the department, water quality standards will be exceeded if the discharge of the substance is not limited.

NR 106.05(9)(9) Regardless of the results of the analysis conducted under this section, the department may, whenever determined necessary, require monitoring for any toxic or organoleptic substance.

NR 106.05 HistoryHistory: Cr. Register, February, 1989, No. 398, eff. 3-1-89; renum. (1) to be (1) (a), cr. (1) (b) and (c), am. (3) (a) to (c), (4) (a) to (c), (5) (b), (6) (a) and (b) and (8), Register, August, 1997, No. 500, eff. 9-1-97; CR 03-050: am. (5) (a) Register February 2004 No. 578, eff. 3-1-04; CR 09-123: am. (5) (a) Register July 2010 No. 655, eff. 8-1-10; CR 15-085: am. (1) (c), r. and recr. (8) Register August 2016 No. 728, eff. 9-1-16.

NR 106.06NR 106.06 Calculation of water quality based effluent limitations for toxic and organoleptic substances.

NR 106.06(1)(1) Basis for limitations.

NR 106.06(1)(a)(a) The department shall establish water quality based effluent limitations for point source dischargers whenever such limitations are necessary, as determined by any method in this section, to meet the applicable water quality standards, criteria and secondary values as determined in chs. NR 102 to 105.

NR 106.06(1)(b)1.1. Water quality based effluent limitations for toxic and organoleptic substances shall be determined to attain and maintain water quality standards and criteria or secondary values, specified in or determined according to procedures in ch. NR 105, at the point of discharge. Effluent limitations shall be established to protect downstream waters whenever the department has information to make the determinations.

NR 106.06(1)(b)2.2. For discharges to Green Bay that are north of 44° 32’ 30” north latitude, the cold water community criteria shall apply in effluent limit calculations. For discharges to Green Bay that are south of 44° 32’ 30” north latitude, effluent limitations shall be established in accordance with subd. 1.