Hennepin Marsh, located in the Detroit River’s Trenton Channel, runs along Michigan’s Grosse Ile west shoreline. This Detroit River Area of Concern (AOC) site was experiencing degradation of its island shoals, wetlands, and emergent coastal shoreline caused by river currents, wave action, winter ice flow and boat and freighter traffic. This degradation threatens the important habitat comprised of marshes and submergent areas and productive wetlands containing rushes and submergent macrophyte plants. These types of marshes and wetlands provide important habitat for fish, shore birds, waterfowl, turtles, and amphibians and the shallow warm water is critical for fish nesting. Therefore, this project was identified as being integral in the restoration and protection of coastal wetland habitat within the Detroit River system.

Friends of the Detroit River hired ECT to provide the feasibility study, investigation, design, permitting, monitoring, and construction oversight for the restoration. The design included the stabilization and lengthening of two existing island shoals that had been significantly eroded and mostly under water. Limestone rock was used as a base and native planting and fallen trees were incorporated to enhance habitat for fish and pollinators, birds, reptiles, and amphibians. When completed, the shoals will provide more than 1,000 linear feet of protection between the navigation channel and the marsh. Habitat structures were integrated to further enhance the environment for critical fish and wildlife species.

The project is being completed under Great Lakes Restoration Initiative (GLRI) funding from National Oceanic and Atmospheric Administration (NOAA) via a partnership grant awarded to the Friends of the Detroit River.