The New York Times notes that although no one died in last week’s flooding of Midland due to dam failures, thousands were evacuated, homes and businesses were inundated, and floodwaters spilled into a chemical plant and Superfund site. They continue that little has been done to address the looming national hazard of aging dams like those that failed in Michigan.
In November 2019, The Associated Press reported that 19 dams in Michigan, including the first of the dams to breach, were in unsatisfactory condition and presented high hazards, meaning their failure can cause loss of life. The events of last week should not have come as a surprise, and it is only a matter of time before a catastrophic dam collapse will occur somewhere in the United States. The combination of aging and poorly maintained dams and extreme, climate-caused flooding presents potentially deadly risks for people downstream.
…In Michigan, Gov. Gretchen Whitmer said experts characterized the flooding that led to the recent dam failures as a 500-year event — something that would have a one in 500 chance of occurring in any given year. If we consider dams in the eight-state Great Lakes region older than 60 years (most have a design life of 50 years) that are in counties with a population larger than 500,000, 317 dams are classified as having a high potential for hazard in a failure. The chances of one or more of these dams experiencing a 500- or 1,000-year flooding event in a year would be 47 percent and 27 percent — which strikes us as pretty high.
The Great Lakes region exhibits approximately 10-year cycles of rainfall and is currently near record high levels. Extreme rainfalls are happening much more frequently in the region than in the past 100 years. What is being done to prepare for potential flooding and dam failures?
The state and the federal government have multiple offices that assess dam safety. What we lack is an overall strategy to fix the problem and the requisite financial resources. Rehabilitating dams with high hazard potential will cost an estimated $3 billion for federal impoundments and another $19 billion for nonfederal ones — a cost that vastly exceeds current spending.
We need a real plan and real money, and we need them soon.
Ann took this back in 2011. View more in her Flickr.