Thermally Sensitive Areas are areas within a watershed that drain to an existing or proposed Cold Water Community or Class I, II, or III Trout Stream, as designated by the Wisconsin Department of Natural Resources. These streams are capable of supporting cold water fish and other aquatic life.
The Dane County Ordinance Chapter 14: Manure Management, Erosion Control and Stormwater Management requires provisions to reduce the temperature of runoff for development sites located within a Thermally Sensitive Area. To determine if your site is located within this area, use the Land & Water Viewer online mapping application (link below) to view your parcel, Thermally Sensitive Areas, and Cold Water Communities under Map Layers. The viewer webpage contains tutorials and help guides.
If your development site is located within a Thermally Sensitive Area, the ordinance states that a stormwater plan required under the ordinance does not have to meet thermal reduction requirements if the applicant can justify that practices are not necessary because there will be no post-development runoff temperature increase. Models must be approved by the Dane County Water Resource Engineering Division Manager. Contact Jeremy Balousek at firstname.lastname@example.org with questions.
One model that has been approved for estimating thermal impacts is the Temperature Urban Runoff Model (TURM) developed by the University of Wisconsin and the Dane County Land & Water Resources Department.