Metro Detroit has its share of old, hazardous dams

The news of massive flooding and evacuation in Midland this week after the breaching of two dams is shocking…. sort of. It was also entirely predictable.

That’s because Michigan has a dam problem.

The state had 1,059 regulated dams in 2018, according to data from the National Inventory of Dams. Most of those (996) are regulated by the state. The average age of all dams in Michigan is about 74 years, according to the data, and many have outlived their original purpose. The American Society of Civil Engineers gave Michigan’s dams a C- on its most 2018 infrastructure report card (better than the roads, storm drains and drinking water systems, which all got a D or worse.)

Dams by Hazard Rating in Metro Detroit

Source: National Dam Inventory

When the Edenville Dam in mid-Michigan failed to comply with Federal Energy Regulatory Commission requirements to build additional spillway capacity, federal regulators revoked its hydropower license and turned it over to the state. Michigan’s standards are laxer; the state only requires a dam to have the spillway capacity to route 50% of the probable maximum flood (MPF) whereas the feds require 100%.

Metro Detroit has 95 dams, the first of which was built in 1835 in Oakland County. The average age of dams in the three counties is 75 years.

Eighteen dams in the three-county region have a “High” hazard potential rating, meaning “failure or misoperation will probably cause loss of human life.” In Macomb County, the dams creating Stony Creek lake at Stony Creek Metropark are in that category. So are others on the Rouge and Huron Rivers.

Most of the dams are privately owned; in Wayne, Oakland, and Macomb County, just over half are owned by private owners, many by lake associations with a vested interest in maintaining lakefront property values and maintaining lake levels set by court orders.

Dams all over the nation are old and in need of repair. In Michigan, dams like the one in Edenville have become stranded assets that are too expensive to maintain even as they increasingly pose a safety risk. As climate change increases the frequency of large storms and flooding in Michigan, the threat of dam failure will loom ever larger. Expect more dam failures.

Meanwhile, conflicts between lakefront property owners who value their waterfronts, environmental advocates, and the realities of public safety make dam removal difficult. For dam owners who want to remove dams, finding the funding can be a challenge. They are an “expensive headache” at best, and a threat to life, limb, and property at worst.