NR 102.04 Note Note: For levels of public health significance for PFOA and PFOS, see s. NR 102.04 (8) (d) 1.

NR 102.04(2) (2) Revised uses and criteria. The following uses and criteria may be revised as new information or advancing technology indicate that revisions are in the public interest. Water used for hydropower and commercial shipping depends mainly on quantity, depth and elevation; consequently, no specific quality criteria for these uses have been prepared.

NR 102.04(3) (3) Fish and other aquatic life uses. All surface waters shall belong in one of the fish and other aquatic life subcategories described in this subsection. Only those use subcategories identified in pars. (a) to (c) shall be considered suitable for the protection and propagation of a balanced fish and other aquatic life community as provided in the federal water pollution control act amendments of 1972, P.L. 92-500; 33 USC 1251 et seq.

NR 102.04(3)(a) (a) Cold water communities. This subcategory includes surface waters capable of supporting a community of cold water fish and other aquatic life, or serving as a spawning area for cold water fish species. This subcategory includes, but is not restricted to, surface waters identified as trout water by the department of natural resources (Wisconsin Trout Streams, publication 6-3600 (80)).

NR 102.04(3)(b) (b) Warm water sport fish communities. This subcategory includes surface waters capable of supporting a community of warm water sport fish or serving as a spawning area for warm water sport fish.

NR 102.04(3)(c) (c) Warm water forage fish communities. This subcategory includes surface waters capable of supporting an abundant diverse community of forage fish and other aquatic life.

NR 102.04(3)(d) (d) Limited forage fish communities. (Intermediate surface waters). This subcategory includes surface waters of limited capacity and naturally poor water quality or habitat. These surface waters are capable of supporting only a limited community of forage fish and other aquatic life.

NR 102.04(3)(e) (e) Limited aquatic life. (Marginal surface waters). This subcategory includes surface waters of severely limited capacity and naturally poor water quality or habitat. These surface waters are capable of supporting only a limited community of aquatic life.

NR 102.04(4) (4) Criteria for fish and aquatic life. Except for natural conditions, all waters classified for fish and aquatic life shall meet the following criteria:

NR 102.04(4)(a) (a) Dissolved oxygen.

NR 102.04(4)(a)1. 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.

NR 102.04(4)(a)2. 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.

NR 102.04(4)(a)3. 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:

NR 102.04(4)(a)3.a. a. A minimum dissolved oxygen concentration of 6.0 mg/L at all times.

NR 102.04(4)(a)3.b. 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.

NR 102.04 Note 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.

NR 102.04(4)(a)3.c. 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.

NR 102.04(4)(a)4. 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.

NR 102.04(4)(a)5. 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:

NR 102.04(4)(a)5.a. 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.

NR 102.04(4)(a)5.b. 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.

NR 102.04 Note Note: Waterbodies described in subd. 5. are also known as altered waters.

NR 102.04(4)(a)6. 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.

NR 102.04(4)(a)7. 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.

NR 102.04(4)(am) (am) Oxythermal layer thickness for two-story fishery lakes.

NR 102.04(4)(am)1. 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:

NR 102.04(4)(am)1.a. a. For a two-story fishery lake with lake trout, 57°F or less.

NR 102.04(4)(am)1.b. b. For a two-story fishery lake with whitefish but not lake trout, 66°F or less.

NR 102.04(4)(am)1.c. 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.