How safe are Metro Detroit’s dams? We broke down...

How safe are Metro Detroit’s dams? We broke down the data

It shouldn’t have been a surprise when two dams in mid-Michigan dams failed on May 19th—they are two of hundreds of dams across Michigan that have “high” hazard potential ratings from the National Dam Inventory, meaning that “failure or misoperation… will probably cause loss of human life.”

Dam safety—like the safety of much of our infrastructure—has been overlooked for decades nationwide. Metro Detroit is no exception. As Midland recovers, Planet Detroit decided to take a look at the dams in our backyard. 

Metro Detroit has 95 dams, 35 of which are rated “high” or “significant” hazard. The hazard rating reflects the amount of damage that a dam would incur if the dam failed. ‘High’ hazard means that failure will result in loss of life and severe ecological damage, ‘significant’ means possible loss of life and moderate ecological damage. 

Most (64 percent) of Metro Detroit’s dams are situated in Oakland County. There are no dams within the city of Detroit. But Wayne County has the greatest number of “high-hazard” dams—57 percent of its dams. That is a larger percentage than Oakland (11 percent) or Macomb (17 percent) combined. 

Metro Detroit’s dams are about 16 years older than the national average.  The nationwide average age of dams is 56 years, making Metro Detroit’s oldest dam is nearly three times the national average. 

Built in 1829, the region’s oldest dam—the Lake Orion Dam on Paint Creek—is also the second-oldest dam in Michigan. But it will soon be the oldest as the Pucker Street Dam in Lagrange is set to be removed later this year.  In 2017, the Lake Orion Dam underwent emergency repairs. Like most dams in Metro Detroit, the Paint Creek Dam is locally owned by the Village of Lake Orion. 

Fifty-two percent of Metro Detroit’s dams are privately-owned and are used mostly for recreation purposes. It’s not surprising to see such a large percentage of smaller privately owned dams—according to FEMA, 56.4 percent of dams nationwide are privately owned. Generally, only very large dams are federally owned. 

In a press conference on May 22, Governor Gretchen Whitmer said that she personally doesn’t believe that dams, and other critical infrastructure, should be privately owned. This was said in relation to the fact that the dams that failed in Mid Michigan were privately owned by Boyce Hydro. 

“We can talk about the merits of whether or not private companies should own critical infrastructure or not—I don’t think that they should,” Whitmer said.

The eight largest dam owners in Metro Detroit

Owner NameNumber of Dams
Oakland County Drain Commissioner16
Michigan DNR Parks & Recreation12
Michigan DNR Wildlife4
Huron-Clinton Metro Authority4
City Of Novi4
Wayne County Department Of Public Services3
Village Of Milford2
Wayne County Airport Authority2

One public dam operator, The Huron-Clinton Metroparks, owns 3 high-hazard dams: the upper and lower Stony Lake Dams and the Flat Rock Dam. They say the dams are inspected by the state at the request of the Metroparks.

“The dams are all up to date on inspections,” Danielle Mauter, Their Chief of Marketing and Communications, wrote in an email. ”The Metroparks writes and submits the emergency action plans for each dam to the county emergency managers and the State for their review and approval of the plans, and each of these dams has an approved emergency action plan in place.”

Emergency action plans are required by the state for high and significant hazard dams. They breakdown specify who will be contacted in the event of a failure, the downstream impacts of a dam failure, and the actions being taken to resolve the issue. These plans are resubmitted each time the dam goes through a state-required inspection—which mandated is every three years. 

At these inspections, dams are rated on condition as well. In Metro Detroit, there are 6 dams in poor condition. The Edenville Dam which failed was rated poor condition.

Poor Condition Dams In Metro Detroit

NameOwnerRiverHazard Potential
Erity DamVillage of Beverly HillsRiver RougeLow
Vhay Lake DamVhay Lake POAAmy DrainLow
Upper Straits DamOakland County Drain CommissionerUpper Straits Lake OutletLow
Haven Hill Lake DamMichigan DNR Parks & RecreationCedar CreekLow
Holly DamVillage of HollyShiawassee RiverSignificant
Bevins Lake DamOakland County Drain CommissionerPatterson Holly DrainLow

Not all inspections occur tri-yearly. The Oakland County’s Water Resource Commissioner manages 33 dams to maintain state-regulated lake levels throughout the county. In addition to dam inspections from structural engineers every three years, county staff check Oakland County dams weekly, according to OCWR engineer Steven Korth.

“We visit the dams anywhere between one and three times a week, just depending on the weather and things like that,” Korth told Planet Detroit. ”They basically take a look to see if there are any problems just on an eyeball-type inspection because they’re out there so often, to see if anything changed. And that’s year-round.”

Planet Detroit was able to identify two locations from the Federal Toxic Release Inventory that are downstream of high hazard dams in Metro Detroit. Flat Rock Metal Inc. is downstream of several dams, the closest being the Flat Rock Dam on the Huron River. The United States Gypsum Company is downstream of several dams that feed into the Clinton River. We found no Superfund sites directly downstream from a dam, however, several Superfund sites are located near the floodplain of the Clinton River. Moreover, 76 of Metro Detroit’s dams are within 5 miles of a city

Regular maintenance is the key to dam safety. Korth says that the Oakland County’s Water Resource Commissioner office is happy to share its expertise and recommend resources to private dam owners in the area—ranging from engineering consultants to assist with repairs to divers to inspect large dams. More than anything, Korth sees regular dam monitoring as the most important aspect of ensuring dam safety. 

“The critical step is that we’re out there on a regular basis once to several times a week, so that we can keep an eye on everything that’s going on”