The Friends of the Detroit River and Michigan Department of Natural Resources are working together to improve fish habitat and recreational opportunities around Lake Okonoka on Belle Isle Park in Detroit. The Lake Okonoka Habitat Restoration project is designed to restore the lake’s natural connections to the Detroit River and Blue Heron Lagoon to enhance fish spawning and nursery habitat, expand recreational access, and improve water quality in the lake. The restored aquatic and upland habitat would be another step towards removing an “Area of Concern” designation for the Detroit River under the 1987 Great Lakes Water Quality Agreement between the U.S. and Canadian governments.

Working with prime consultant, SmithGroup, Wade Trim designed a 58-foot, single-span, box-beam, concrete deck bridge over the new channel that connects to the lagoon upstream. Previously, a weir structure controlled water flow between the lagoon and lake. The bridge will carry three lanes of one-way traffic and includes a 7-foot-wide bike lane and 12-foot-wide sidewalk. Clearance is provided underneath for canoeists and kayakers.

The downstream connection back to the river is designed as a 10-foot-square, 56-foot-long, precast box culvert. We completed hydraulic studies to ensure the bridge and culvert could handle 100-year flows. The culvert was situated with a low under-clearance to keep canoeists and kayakers within the Belle Isle Waterway System.

Funded primarily by a Great Lakes Restoration Initiative grant administered by the National Oceanic and Atmospheric Administration, the Lake Okonoka restorative work and the bridge are complete. The culvert work will be completed after record Detroit River water levels subside.