Under its new policy to solicit public comment on draft guidance documents before they are finalized, the Wisconsin Department of Natural Resources (WDNR) has opened a 21 day public comment period on its draft "TMDL Development and Implementation Guidance: Integrating the WPDES and Impaired Waters Programs, Edition No. 2" (draft Guidance).

The public comment period closes on March 22, 2013.

A Total Maximum Daily Load (TMDL) sets the allowable amount of pollutant load to an impaired water body and then allocates that allowable load between the point and nonpoint sources, with a small margin of safety set aside. The load allocated to the point sources is then incorporated into their Wisconsin Pollutant Discharge Elimination System (WPDES) Permits. For more information about TMDLs, visit the WDNR website.

The draft Guidance instructs WDNR permit drafters how to translate and incorporate the TMDL requirements into the WPDES permits. Because the assumptions and goals of each TMDL are tailored to the specific water body, one size does not fit all. The draft Guidance uses four approved TMDLs to illustrate the process with sample effluent limitation calculations based on the assumptions and goals for each:

a. Lower Fox River TMDL

b. Rock River TMDL

c. Lake St. Croix TMDL

d. Tainter Lake and Lake Menomin (Red Cedar River) TMDL

If your facility holds a WPDES Permit, whether or not it is covered by one of these four or any other approved TMDL, the Guidance will apply if/when a TMDL is finalized for the water body to which your facility discharges.

To review the draft Guidance, click here.

To submit comments on the draft Guidance, click here.

To review WDNR’s new policy and/or to subscribe to emails announcing when new guidance is available for comment, click here.