St Croix Flowage Critical Habitat Designation This is a summary of the St Croix Flowage Critical Habitat Designation Reort, prepared by Alex Smith, Northern Region Critical Habitat Coordinator for the DNR. An increase in shoreline development over the past 30 years has changed lake ecosystems affecting habitat and water quality. The Critical Habitat Designation program includes formal designations of areas considered important to fish and wildlife.
There are three categories:
- sensitive areas
- public rights features
- resource protection areas
The designations serve four primary purposes:
- Resource protection through science based regulatory review.
- Community-based resource protection through community education, planning, and zoning.
- A guide to land trusts and individuals acquiring land and conservation easements.
- A mechanism to track long-term changes in these habitats.
General Lakewide Recommendations
Permanent Land Protection. Tools include: land acquisition, conservatin easements, and mutual covenants. Much of the Flowage is already in County ownership.
Shoreland Restoration. Leave natural shorelines undisturbed in accordance with local shoreland zoning rules. If the shoreline buffer does not exist or is disturbed, it should be replanted with native vegetation.
Runoff Control. Tools include rainwater gardens, rain barrels, infiltration pits and trenches, grass swales.
Septic Systems. Inspect and maintain septic systems to prevent excess nutrient addition while protecting present water quality conditions.
In-Lake Habitat Protection. The Flowage contains many areas where boat traffic is directed to protect safety and habitat. In general, native aquatic plants should not be actively managed (no raking, herbicide use, or mechanized removal), and will require a permit for manual removal and chemical control.
Specific Lakewide Recommendations
Management actions recommended for all of the St Croix Flowage include protecting Ceratophyllum echinatum (Spiny hornwort), a rare aquatic plant species found throughout the Flowage. Continue to aggressively manage the isolated Eurasian water milfoil population and monitor other aquatic invasive species.
Specific Site Recommendations
Management actions are specific to the site ans supersede general lakewide recommendations if explicitly stated. One area on the St Croix Flowage is designated as Critical Habitat for a total of 3596 acres (see Tables 1 and 2).
It is classified as Sensitive Areas for submerged aquatic plants, rushes, emergent and floating leaf aquatic plants, and extensive reparian wetlands. St Croix Flowage Critical Habitat Area 1 The St Croix Flowage Critical Habitat Area is designated a Sensitive Area because of its Submerged Aquatic Vegetation Important to Fish and Wildlife Habitat, Emergent and Floating Leaf Vegetation, Bulrush Beds, and Extensive Riparian Wetland. It is 3596 acres in size which includes most of the Flowage and the extensive riparian wetland areas that adjoin the Flowage (see map below).
Management RecommendationsDo not actively manage aquatic plants with the exception of continued control of Eurasian Water Milfoil. Monitor curlyleaf pondweed. Continue watercraft inspection projects at public landings to ensure AIS are not transferred into or from the Flowage. Buffers and overhanging vegetation, bog fringe and floating, emergent and submersed aquatic plants should be left alone. Do not remove rush beds. Place piers outside of rushes, or where possible, extend thepiers beyond the rushes for boat mooring. Extensive wild rice beds are located in this area and because of their importance as wildlife habitat and seasonal use by several fish species should be left undisturbed. Table 3 shows the inventory of aquatic plants in the St Croix Flowage Critical Habitat Area.