Two species — one to preserve, one to control — challenge dam removal
Ecosystem presents challenges to restoration of the Grand River.
LANSING — A proposed dam removal along the Grand River faces significant delays due to its potential to disrupt river ecosystems. The environmental risks involve the fate of two species: sea lampreys and snuffbox mussels.
The former needs to be kept out, while the latter needs to be protected.
The Sixth Street Dam in downtown Grand Rapids was installed in the mid-1800s to help ship milled logs downstream by controlling the water’s height and flow. It drowned the river’s naturally occurring rapids, allowing logs to float over them.
Eventually log transportation no longer relied on the river, but the dam remained.
Years of inadequate maintenance began to pose a hazard to kayakers and swimmers. In 2013, firefighters rescued two kayakers after they bumped against the dam and capsized. This and other accidents motivated city and state agencies to get the removal process going in earnest.
“This project has been going on for about eight years and has probably got a good eight years to go,” said Wendy Ogilvie, the director of environmental programs for the Grand Valley Metropolitan Council. The council is a regional governing body representing Allegan, Montcalm, Ionia, Ottawa, Barry and Kent counties.
One of the project coordinators working with Ogilvie, Matt Chapman, is the founder and head of Grand Rapids Whitewater. The nonprofit organization’s original mission was to restore the rapids for recreation, but it’s evolved into a “holistic river revitalization.”
“Recreation is certainly still a component of it, but much more of it is focused on making the river a better place for the animals and creatures that live in it as well as those of us that want to play on it,” Chapman said.
Lamprey are invasive parasites that attach themselves to fish like leeches and feed off the host’s blood and bodily fluids, killing them in the process. They could spread along rivers and tributaries without the dam to stop them.
“Removing the existing Sixth Street Dam would require a new structure to be built that would also stop sea lamprey,” said Jay Wesley, the Lake Michigan basin coordinator for the Department of Natural Resources.
“A sea lamprey infestation could be quite severe if they’re allowed to get past Grand Rapids,” he said.
Chapman said engineers hired by Grand Rapids Whitewater, working with the U.S. Fish and Wildlife Service and the Great Lakes Fishery Commission, intend to install an adjustable structure a mile upstream from the dam.
It would be raised when lampreys migrate and lowered when lampreys aren’t much of a threat, he said. That would allow native fish to pass.
Obermeyer Hydro Inc. is the manufacturer of this structure, Chapman said. They have installed similar adjustable structures across the country and around the world.
“The application of using Obermeyer adjustable gates for sea lamprey control is emerging and one we think will provide a range of benefits that include public safety and flood control improvements, sea lamprey control, natural river connectivity and enhanced recreational benefits,” Chapman said.
While the sea lamprey challenge was known from the outset, the discovery of endangered snuffbox mussels added another layer of complexity to an already intricate undertaking.
Ogilvie said, “The Grand River has always been known as a very good source of clams and mussels. But no one had really researched it that much; there just hadn’t been any interest just because there hadn’t been any construction plans on it.”
The snuffbox mussels were first noticed in the summer of 2011, when water was low enough that biologists from Central Michigan University and Grand Valley State University and DNR specialists could wade in it. A nearby highway renovation also helped reveal the presence of this endangered species.
Their mussel inventory revealed five living snuffbox mussels, kicking off conservation efforts to ensure the species wouldn’t be severely harmed by the dam removal. Grand Rapids Whitewater consulted with Heidi Dunn, an ecological consultant at Ecological Specialists Inc., on what to do.
“We’re going to go in and remove as many mussels as we can before they start their project, but you can’t get them all,” Dunn said.
Mussels are important for the Great Lakes and its tributaries due to their feeding habits. Attaching themselves to hard surfaces like rocks, they filter micro-organisms like plankton and are a natural water purification system. They also help support aquatic insects and fish species.
“These animals are aquatic animals — people tend to think of them as rocks because they’re kind of in the bottom and just kinda hard-shelled animals,” Dunn said. ”You have to keep them in water, you have to handle them properly, you have to mark them all, you have to move them to a suitable habitat.”
Dunn and other experts have found new habitat areas upstream, between Ionia and Grand Rapids, where the mussels can be relocated. Doing so requires divers to go in at the dam site and dig up as much as 6 inches of the river bottom as mussels tend to burrow.
Chapman and others declined to give a timeline for when actual removal work would begin. Project coordinators still are planning for many aspects of the venture, and Dunn hinted the mussel relocation might take around a year to complete.
Wesley said Grand Rapids isn’t the first Michigan city to deal with these environmental concerns.
The recent removal of the Lyons Dam on the Grand River ran up against mussel conservation problems, and Traverse City faced similar concerns of sea lamprey expansion with the removal of a dam from the Boardman River.
Such experience means the Sixth Street Dam project has a greater chance of success, removal experts said.