Restoring a highly degraded and altered river is a complex process that requires the need to balance multiple objectives. A key goal of this project has always been to improve the environmental and ecological conditions of the the Grand River in Grand Rapids from what we see today.
Revitalizing the Grand River will improve the river ecosystem by:
- Restoring a more natural river flow thereby introducing more oxygen into the water to improve habitat for spawning fish and their eggs, increase beneficial microbial, insect, and mussel activity, and enhancing the overall health of the river
- Exposing the remaining prehistoric bedrock rapids currently drowned out by the Sixth Street dam which is likely the historic spawning ground for Lake Sturgeon
- Increasing and diversifying habitat for sport fish and other desirable fish species
- Providing habitat for the twenty-seven species of mussels discovered in the project area, including federally endangered and state-threatened species
- Maintaining protection against upstream migration of invasive species like Sea Lamprey
Sea Lamprey Control: A Top Priority
Widespread consensus exists that the 6th Street Dam should be removed, which would allow for the realization of the many benefits “Restore the Rapids” would bring. The removal of the dam poses opportunities for better connectivity and better sea lamprey control. To complement the 6th Street Dam Removal, and to improve sea lamprey control on the river, an “Adjustable Hydraulic Structure” (AHS) will be constructed about a mile upstream of the existing 6th Street Dam prior to the removal of the existing dam. The AHS structure is designed to ensure that sea lampreys do not migrate upstream of the City of Grand Rapids.
The AHS will represent a state-of-the-art structure, engineered for multiple purposes, though the primary purpose will remain sea lamprey control. The AHS combines inflatable crest and velocity barrier technology to block the upstream migration of invasive species. The structure is the result of large-scale collaboration among the Grand Rapids Whitewater, the Great Lakes Fishery Commission, the U.S. Army Corps of Engineers, Obermeyer Hydro Inc, the City of Grand Rapids, and many others. Once constructed, the City of Grand Rapids will own and operate the AHS, though the Great Lakes Fishery Commission will remain responsible for sea lamprey control.
Federally Endangered Mussels: Snuffbox Mussels
The Grand River historically supported a diverse freshwater mussel community, and at least 29 species have been reported from the lower Grand River. Many of the environmental changes such as logging, urbanization, and impoundment of the floodplain vegetation have changed local hydrological conditions that have negatively effected freshwater mussel species. The lower Grand River still supports 26 of the 29 species that historically occurred in the lower river, including the federally endangered E. triquetra, also known as the Snuffbox Mussel, as well as an additional 10 species listed as endangered, threatened, species of special concern, or species of greatest conservation need in Michigan.