St Louis River Estuary: The stories and the science

21st Avenue West Restoration Site

Where have all the plants gone? By restoring the sediment and creating shallow habitat, natural resource managers hope wetland vegetation will return to 21st Avenue West, and with it, bugs, fish and birds.

At the base of the Blatnik Bridge, the 21st Ave West restoration site is a complex of open water flats and shallow sheltered bays impaired by historical industrial activities. The 350-acre site is in part of the estuary that receives effluent from the Western Lake Superior Sanitary District (WLSSD) Treatment Plant. The adjacent land is bordered by the Canadian National Ore Docks, numerous industries, and Rice's Point, a popular public boat access.

Although degraded, this site has the ability to provide productive spawning, nursery and foraging areas for both prey fish (minnows) and game fish, including walleye, muskellunge, lake sturgeon, smallmouth bass, bluegill and black crappie. An aquatic habitat restoration project is underway to provide a diversity of depths needed for various types of water plants to grow. This will be accomplished through the beneficial reuse of dredged materials; these materials are being placed along the shoreline and within the river bed. The shallower water depths will also help reduce wind fetch and provide shelter to the bay. As more vegetation grows, the animals and bugs that live in the sediment will thrive and the site will be enhanced for fish habitat, recreational anglers and outdoor enthusiasts.

What is happening now?

The dredging activity you see in the harbor is moving sediment from the shipping channel to create shallow habitat in the restoration site. Work on this pilot project began in summer 2013 and full design implementation is expected in 2016. The goal is to complete the movement of all the material by 2018. It will take time for the site to recover and thrive, and results will be analyzed.

Unique site characteristics

  • Two creeks, Miller and Coffee, discharge at the northernmost point of the site. Both creeks receive runoff from highly urbanized watersheds, with the headwaters of Miller Creek draining Duluth's largest commercial shopping area. The streams contribute large amounts of sediment to this small bay, and the City of Duluth dredges the sediment on a regular basis to protect culverts under the I-35 freeway.
  • The 21st Avenue West Restoration Site is the location of the WLSSD outfall, where an average of 43 million gallons per day of treated wastewater enters the bay. Restoration project planners will need to ensure that constructed habitat features (shoals, islands) don't interfere with the flow of this outfall.
  • The North Channel, (a deepwater channel associated with dredging) bisects the site and extends into the federal navigation channel. There is also a deep rectangular depression to the southwest of Interstate Island.
  • Interstate Island is a Wildlife Management Area created from dredged materials years ago and is maintained to be free of woody vegetation to provide nesting habitat for the common tern, a threatened species in Minnesota and endangered species in Wisconsin, albeit with significant competition from ring-billed gulls. In 2015, the island will receive clean sand to enhance lost nesting area for threatened bird species. This is part of an additional Minnesota Department of Natural Resources wildlife restoration project.

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