SWWD’s Trout Brook Project was awarded Project of the Year at the 2023 Minnesota Watersheds Annual Conference.
Trout Brook is a cold water stream in Denmark Township, Washington County tributary to Lake St. Croix. The stream is fed by a 5500 acre watershed made up primarily of forest and agricultural lands. In the 1800s and early 1900s, the Trout Brook watershed was heavily impacted by logging resulting in mass erosion which buried lower Trout Brook in 10-15 feet of sand. The stream has been working to reestablish itself ever since, cutting down through the legacy sand deposits. Today, lower Trout Brook flows through Afton State Park and the Afton Alps Ski Area. Prior to restoration Trout Brook suffered from excessive bank erosion, dumped massive amounts of sediment and excess nutrients into Lake St. Croix, and provided little habitat value.
SWWD and its partners; including MnDNR, Vail Corp, and Great River Greening, are now completing the third and final phase of restoration of lower Trout Brook. Phase I included in stream habitat structures in upper portions of Afton State Park. Phase II included construction of a new re-meandered channel at Afton Alps Ski Area, abandonment of a straightened section of the old stream, and replacement of one of two sets of perched culverts that blocked fish migration. Phase III, currently wrapping up, constructed a second re-meander in Afton State Park, additional in stream habitat and stabilization structures in Afton Ski Area, and replacement of the second set of perched culverts. Funding has come from several sources including; Lessard Sams Outdoor Heritage Council, Lower St. Croix 1W1P, and local funding. Additionally, MnDNR provided extensive staff time for data gathering, assisting with design, and construction observation. Vail Corp donated conservation easements covering the entirety of the stream and floodplain area through the Ski Area providing for public access. Funding was saved by using volunteer planting events hosted by Great River Greening and salvaging a box culvert from a previous project.
Together, restoration of Trout Brook is expected to reduce loading of sediment and phosphorus to the St. Croix by over tons/yr and 200 lbs/yr respectively and achieve TMDL allocations for Trout Brook in the St. Croix TMDL. Additionally, since work began, Trout Brook has seen an influx of trout migrating from other streams along the St. Croix River. Prior to work, MnDNR fisheries staff found only a few trout in total throughout the stream. Following just the second phase of restoration work, fish were surveyed at rates ranging from 150-1,100 fish per mile. MnDNR will continue to manage the trout population going forward. Trout Brook is now designated as a Trout Stream.
