Muskegon River flooding reshapes habitat, stresses dams

BIG RAPIDS – The Muskegon River’s surge past 15 feet during recent flooding, heavy rains and melted snow left behind damaged infrastructure, debris piles and eroded riverbanks across Mecosta, Osceola, Lake and Newaygo counties, but environmental experts say the ecological effects will likely include both disruption and renewal.

The flooding, driven largely by heavy rainfall, pushed communities into emergency response and long-term recovery efforts as roads, parks and riverfront infrastructure were damaged or submerged. 

Environmental officials and watershed experts said the event highlighted vulnerabilities in aging dams and riverbank stability while reshaping habitat and transporting sediment.

Jeff Johnston, public information officer for the Michigan Department of Environment, Great Lakes, and Energy, said flooding can create widespread environmental and public health risks.

“Floodwaters can pick up and transport pollutants, sediment, toxic materials, and other contaminants that can impact the environment, personal safety, and public health,” he said.

Johnston said flooding can damage wastewater treatment systems, septic systems and drinking water wells while reducing access to safe water and utilities. He also said recent events underscore concerns surrounding Michigan’s aging dam infrastructure.

“Because extreme weather and high waters can strain Michigan’s thousands of dams, recent events make clear that the state needs stronger tools supporting dam safety,” Johnston said.

Johnston pointed to proposed legislation, House Bill 5485, which he said would expand oversight and inspection requirements for regulated dams across the state.

Although no dam failures occurred within the Muskegon River watershed during the flooding, officials said many structures experienced stress from the high water.

Paul Haan, executive director of the Muskegon River Watershed Assembly, said sedimentation represented one of the most significant ecological impacts.

“With the high water, we did see a number of bank failures,” Haan said. “Every time the bank fails, it releases a lot of sand, dirt, soil and other sediment into the river.”

Haan said excess sediment can cover spawning gravel and alter river hydrology – the study of the movement, distribution, and dynamics of water within river channels and their surrounding basins.

“The real opportunity there is to mitigate that for future high-water events by paying attention to bank health and the stability of our banks in the watershed,” Haan said.

He said infrastructure along the river also suffered stress during the flood event, particularly older dams and water-control structures.

“We were very fortunate during this event,” Haan said. “We didn’t see any dam failures in our watershed, but we did see everything from small to large dams experience some impact from the stress of the high water.”

Haan said litter and debris scattered throughout the watershed created another challenge for communities and volunteers.

“Typically, there’s not necessarily a government agency that’s going to swoop down and take care of those,” Haan said. “So that’s really up to local communities, volunteers and local folks to address.”

Haan described the debris as a form of “nonpoint source pollution” caused by floodwaters carrying away items from across the watershed rather than illegal dumping by any one person.

“It came from people’s lawns getting flooded and their kids’ toys floating away,” Haan said. “It’s a very diffused problem, so it requires a very diffused solution — many hands.”

He said debris ranging from household trash to refrigerators washed downstream into the river system during the flooding. The Watershed Assembly is using its annual Trash Bash cleanup effort and an online reporting form to connect volunteers with cleanup locations.

Despite the damage, Haan said the flooding also produced ecological benefits in healthier sections of the watershed.

“I think where rivers have healthy banks and healthy natural function, when we get these high-water events it does help with sediment transport,” Haan said.

Haan added some stretches of river saw natural gravel and coarse stone substrate exposed after the floodwaters receded, creating conditions beneficial to aquatic ecosystems.

He also said large amounts of wood swept into tributaries and river channels could improve habitat complexity for fish and wildlife.

Haan said woody debris can create habitat for native species and game fish while reintroducing natural river features reduced during the region’s historic logging era.

“Particularly those who live along some of the tributaries and smaller rivers might be inclined to want to pull this wood out,” Haan said. “There are some exceptions where you might have a large jam that creates a hydrologic issue, like in Newaygo where they just released some debris off a bridge abutment on a train crossing. That’s necessary. But most of this is actually very, very good for rivers.”

He said the event demonstrated the importance of maintaining healthy riparian zones along riverbanks and investing in aging infrastructure before failures occur.

Michigan Department of Natural Resources fisheries biologist Mark Tonello said the flooding is not expected to cause major long-term damage to fish populations in the Muskegon River watershed.

“Our fish have lived in these rivers,” Tonello said. “Especially the native species like smallmouth bass and walleye, and they can handle the high water.”

Tonello said the timing of the flood likely prevented greater disruption because many fish species had not yet entered spawning season.

“If it were later, like when the smallmouth bass were trying to spawn, then that could have been a problem,” Tonello said.

He said some fish may have become stranded in flooded wooded areas, but he described those incidents as isolated and minor.

Tonello said the most noticeable changes for anglers may come from alterations to the river itself rather than declines in fish populations.

“It probably reshaped the river some,” Tonello said. “Some areas that were previously good fishing spots, deeper holes, those might have changed.”

Tonello said the Muskegon River remains a relatively stable environment for native fish despite periodic flooding events.

“I really don’t think we’re going to see a lot of noticeable impacts on the fisheries populations,” Tonello said.

Haan said the flooding ultimately altered the river in ways both destructive and natural.

“Nature likes a mess,” he said. “It likes diversity. It likes complexity.”