NR 212.73(3)(d)(d) TMDLs shall include wasteload allocations for point sources and load allocations for nonpoint sources such that the sum of the allocations is not greater than the loading capacity of the water for the pollutants addressed by the TMDL, minus the sum of natural background loads, the reserve capacity and, if specified, an explicit margin of safety. Allocations shall meet the following requirements:

NR 212.73(3)(d)2.2. If allocations in the TMDL are expressed as a concentration, the TMDL shall also indicate the flows, including effluent flows, assumed in the analyses.

NR 212.73(3)(d)3.3. If multiple EPA-approved TMDLs are prepared for impaired waters, and the TMDLs include allocations for the same pollutant for one or more of the same sources, then the applicable allocations that are protective of both immediate and downstream segments shall be used for TMDL implementation, including permitting.

NR 212.73(3)(d)5.5. Natural background loads may be accounted for in a TMDL through an allocation to a single category or through individual allocations to applicable sources of natural background loads.

NR 212.73(3)(d)6.6. Nonpoint sources may be accounted for in a TMDL through an allocation to a single category or through individual load allocations to various nonpoint sources.

NR 212.73(3)(d)7.7. Point source dischargers covered through individual permits shall be assigned individual waste load allocations. Point source dischargers covered through general permits may be accounted for through an allocation to a single category or through individual wasteload allocations.

NR 212.73(3)(e)(e) TMDLs shall include a margin of safety sufficient to account for technical uncertainties in establishing the TMDL and shall describe the manner in which the margin of safety is determined and incorporated into the TMDL. The margin of safety may be provided explicitly by leaving a portion of the loading capacity unallocated, implicitly by using conservative modeling assumptions to establish wasteload allocations and load allocations, or a combination thereof. If a portion of the loading capacity is left unallocated to provide a margin of safety, the amount left unallocated shall be documented. If conservative modeling assumptions are relied on to provide a margin of safety, the specific assumptions providing the margin of safety shall be described.

NR 212.73(3)(f)(f) A portion of the TMDL may be allocated to a reserve capacity to account for new or increased discharges, or other sources not allocated in the TMDL. When such reserve allocations are not included in a TMDL, any increased loadings of the pollutant for which the TMDL was developed that are due to a new or expanded discharge may not be allowed unless the TMDL is revised to include an allocation for the new or expanded discharge or the new or expanded discharge is offset by a reduction of the pollutant in the watershed covered by the TMDL.

NR 212.73(4)(4) Monitoring data. Monitoring data shall be collected to support the development of the TMDL and track implementation of a TMDL. Monitoring data shall be used for all of the following:

NR 212.73(4)(a)(a) To demonstrate progress towards achieving water quality standards such as quantifying pollutant reductions made through implementation of the TMDL and evaluating the effectiveness of controls being used to implement the TMDL.

NR 212.73(4)(b)(b) To validate the assumptions and scientific analysis used to establish the TMDL or revise the TMDL, if necessary.

NR 212.73(5)(5) Reasonable assurance. A TMDL, implementation plan for a TMDL, or remediation plan shall provide reasonable assurances that water quality standards will be attained within a reasonable timeframe. Determining the reasonable period of time in which water quality standards will be met is a case-specific determination considering a number of factors including, but not limited to: receiving water characteristics including persistence, behavior, and ubiquity of pollutants of concern; the types of remedial activities necessary; and available regulatory and non-regulatory controls.

NR 212.74NR 212.74 Developing TMDLs for nearshore and open waters of the Great Lakes. This section describes requirements for deriving TMDLs for waters of the Great Lakes system as defined in s. NR 102.22 (5) and inland lakes within the Great Lakes system with no appreciable flow relative to their volumes. This section applies to TMDLs for all pollutants excluding the following: alkalinity, ammonia, bacteria, biochemical oxygen demand, chlorine, color, dissolved oxygen, dissolved solids, pH, phosphorus, salinity, temperature, total and suspended solids, turbidity, and whole effluent toxicity. In addition to the requirements specified in s. NR 212.73, TMDLs in this section shall also meet all of the following:

NR 212.74(1)(1) TMDLs shall reflect, when appropriate and when sufficient data are available, contributions to the water column from sediments inside and outside of any applicable mixing zones. TMDLs shall be sufficiently stringent so as to prevent accumulation of the pollutant of concern in sediments to levels injurious to designated or existing uses, human health, wildlife, and aquatic life.

NR 212.74(3)(3) TMDLs shall reflect, when appropriate and when sufficient data are available, background concentrations of pollutants stemming from atmospheric deposition, sediment release or resuspension, or as a result of chemical reactions.

NR 212.75NR 212.75 Developing TMDLs for Great Lakes systems tributaries and connecting channels. This section describes conditions for deriving TMDLs for tributaries and connecting channels of the Great Lakes system as defined in s. NR 102.12 (1) that exhibit appreciable flows relative to their volumes. This section applies to TMDLs for all pollutants excluding the following: alkalinity, ammonia, bacteria, biochemical oxygen demand, chlorine, color, dissolved oxygen, dissolved solids, pH, phosphorus, salinity, temperature, total and suspended solids, turbidity, and whole effluent toxicity. In addition to the requirements specified in s. NR 212.73, TMDLs in this section shall also meet all of the following:

NR 212.75(1)(1) TMDLs shall reflect, when appropriate and when sufficient data are available, contributions to the water column from sediments inside and outside of any applicable mixing zones. TMDLs shall be sufficiently stringent so as to prevent accumulation of the pollutant of concern in sediments to levels injurious to designated or existing uses, human health, wildlife, and aquatic life.

NR 212.75(3)(3) TMDLs shall reflect, when appropriate and when sufficient data are available, background concentrations of pollutants stemming from atmospheric deposition, sediment release or resuspension, or as a result of chemical reactions.

NR 212.75(4)(4) Design flows shall be used unless data exist to demonstrate that an alternative stream design flow is appropriate for stream-specific and pollutant-specific conditions. For purposes of calculating a TMDL, the stream design flows shall be all of the following:

NR 212.75(4)(a)(a) The 7-day, 10-year stream design flow (7Q10), or the 4-day, 3-year biologically-based stream design flow for chronic aquatic life criteria or values.