CHEBOYGAN ― The waters behind the Cheboygan Lock and Dam Complex rose more than six inches over 24 hours, with levels as of Tuesday morning hovering about 7.7 inches below the crest of the dam, putting the structure at greater risk.
Continued snowmelt and overnight rain have contributed to the levels rising over the past several days, most recently from 13.75 inches below the crest of the dam at 7 a.m. Monday morning to 7.7 inches Tuesday morning.
The increasing levels come as state and local officials continue to try to stem the rising water by increasing flow through and around the dam while also warning local residents to remain ready to evacuate.
Cheboygan dam reinforced with large sandbags
Mid-morning Tuesday, workers were operating a large crane in foggy weather beside the Cheboygan Lock and Dam Complex in an apparent attempt to reinforce a section of the dam.
The crane appeared to be placing bags of material northwest of the dam bays, between the dam and lock, an area the Michigan Department of Natural Resources said Monday that it is trying to protect from floodwater erosion.
The area between the lock and dam contains a grassy slope that the DNR hopes to protect from the worst of the flow should water begin to escape around the dam.
That side of the dam is more susceptible to erosion from the water, DNR senior engineer Michelle Crook said Monday, while the rocky slope southwest of the dam structure may weather any spillover better.
There was still steady traffic through the city’s downtown Tuesday morning, as well as a significant number of utility and state worker vehicles staging around the site.
Where the floodwater is coming from
The Michigan Department of Natural Resources said Monday that mitigation efforts have included the Monday early morning removal of six massive gates impeding flow through the dam bays and increased flow through a privately owned hydroelectric portion of the dam that had been idled since 2023.
Officials also have placed five pumps at the dam to move more water around it, removed an old wooden debris screen in front of the dam and placed hundreds of sandbags along areas of the dam that officials are hoping to protect.
Officials continue to work to increase capacity at the hydroelectric portion of the dam, bringing about 1,000 feet of industrial wire from Illinois to Cheboygan to fully open the hydroelectric station. Additional pumps and sandbags may also be added on Tuesday to increase flow, according to the DNR.
“We’re all working together to keep water flowing through the dam and to make sure that people are informed,” Jeremy Runstrom, emergency manager for Cheboygan County, said in a statement released by the DNR.
The water levels behind the dam are being exacerbated by the continued melting of snow and ice upstream and continued rain in the area. Michelle Crook, a DNR senior engineer, told The News Monday that the dam takes runoff and flow from a large geographic area.
“This is a huge, huge drainage basin,” Crook said of the amount of snowmelt and rain coalescing behind the dam. “It all comes through this area, from Black Lake, Mullet Lake, Burt Lake, all the way over to Crooked Lake. It’s almost to Lake Michigan.”
The Cheboygan Dam is a hydroelectric dam built in 1922, according to the National Dam Inventory maintained by the Federal Energy Regulatory Commission. It is a high-hazard dam, meaning it could cause destruction and potential loss of life if it were to fail. The dam was in “fair” condition when it was inspected in September 2022, according to the FERC inventory.
Crook said Monday that officials are trying to avoid water diverting to the northwest portion of the dam where water flow could erode a grassy slope between the dam structure and the lock.
Overnight rains poured more water into the already saturated area of Cheboygan on Tuesday morning, said Carole Yeck, executive director of the Cheboygan Area Chamber of Commerce. The water level behind the dam “did raise significantly,” she said.
Yeck said business owners and community members in the potential flood zone downstream of the dam should protect their valuable belongings and be ready to evacuate if water overtops the dam and surges downstream.
Yeck urged people to prepare but not panic. The potential flood zone is a narrow strip along the river between the dam and Lake Huron.
There is significant flooding in the areas surrounding Cheboygan, Yeck said. Some flooding is typical when snow and inland lake ice melt in the springtime, but the mid-March blizzard has amplified this year’s floods.
Residents on Black and Mullet lakes said the lake levels are higher than they’ve ever seen, Yeck said.
“The blizzard that we had a few weeks ago dropped so much at once that, with the warm temperatures, it’s that significant melt from spring warm-up that is all melting at one time that is really just surging into the waterways,” Yeck said.
This article originally appeared on The Detroit News: Cheboygan dam reinforced with sandbags as water rises. Will it hold?
Reporting by Beth LeBlanc and Carol Thompson, The Detroit News / The Detroit News
USA TODAY Network via Reuters Connect
