1,059 Dams In MI; Their Average Age 74 Years; Average Rating Of 91,000 US Dams - "D" From ASCE
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The 91,000 dams in the U.S. earned a “D” for safety in a 2017 report from the American Society of Civil Engineers. The ASCE estimated the cost of fixing up the dams whose failure would threaten lives at roughly $45 billion, and the cost of fixing all aging dams at over $64 billion.
In Michigan, which is under a state of emergency after the two dam breaches, the average age of the state’s total 1,059 dams is 74 years old, older than the typical 50-year designed life span. Just over 170 of those dams are labeled as high hazard potential — meaning a collapse will result in a loss of life. “The combination of aging infrastructure, older design guidelines and an increasing probability of extreme events from global warming is increasing the overall risk of these events,” said Noah Diffenbaugh, a Stanford University climate scientist.
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Regarding the two dams that broke on Tuesday, the Edenville Dam that was built in 1924 was rated in unsatisfactory condition in 2018 by the state. And the Sanford Dam that was built a year later was rated in fair condition.
Federal regulators since 2014 were warning the Edenville Dam’s owner, Boyce Hydro Power, that the dam could not handle a “probable” heavy flooding event. The Federal Energy Regulatory Commission eventually revoked the dam’s license in 2018 due to a failure to increase the dam’s spillway capacity to safely allow flood water to pass through.
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https://www.cnbc.com/2020/05/21/more-dams-will-collapse-as-aging-infrastructure-cant-keep-up-with-climate-change.html