Ruptured Edenville Dam in Michigan       Image: CNN via drone

The Edenville Dam failure in Michigan that caused thousands to evacuate put a spotlight on a problem that the American Society of Civil Engineers highlighted in 2017 when it gave our country a “D” for dam safety  — and this grade has not significantly improved in the last 20 years. According to the Association of State Dam Safety Officials that did an assessment in 2019, it would cost more than $70 billion to repair all the federal and non-federal dams in the United States that are in need of it, and the for just the high-risk dams, the cost exceeds $23 billion.  The New York Times reported last week that there are more than 91,000 dams across the country at risk due to climate change causing some regions to become wetter, and increasing the frequency of extreme storms as described in the 2018 Fourth National Climate Assessment.

Why This Matters:  When we think about the security risks to our nation, we need to start counting infrastructure failure due to climate change as one of the most troubling.  We spend hundreds of billions each year to protect our nation from the risk of terrorism and cyberwar and other security threats.  But the most immediate and also the most addressable threats could be the ones like these damn dams that we tend to ignore.  

Old Dams By the Numbers

The average age of dams in the United States is nearly 60 (meaning many are much older) and 15,500 are classified as having a high hazard potential, the Times reported.  Almost all the dams that have failed are less than 50 feet high and excessive rainfall has been the cause of most of these.  What the Fourth National Climate Assessment showed was that precipitation events are becoming wetter in two ways — both short but heavy rainstorms and also longer rain events that saturate the ground and rivers over time are causing the failures.  In fact, in the Michigan dam failure, the dam burst because the ground was saturated from many days of rain.   Older dams were designed to withstand the extreme weather of the past when the dam was built, which could be one hundred years ago, rather than the weather of the future.

The Fourth National Climate Assessment specifically called out the risks of dam failure, saying:

“Aging and deteriorating dams and levees also represent an increasing hazard when exposed to extreme or, in some cases, even moderate rainfall. Several recent heavy rainfall events have led to dam, levee, or critical infrastructure failures, including the Oroville emergency spillway in California in 2017, Missouri River levees in 2017, 50 dams in South Carolina in October 2015 and 25 more dams in the state in October 2016, and New Orleans levees in 2005 and 2015. The national exposure to this risk has not yet been fully assessed.”

Dam Removal Is Another Option

Not all dams can or should be repaired.  As we explained in January, removing legacy dams, which were first constructed dozens to more than a hundred years ago, is proving to be increasingly popular to restore river flows now that they are no longer serving any purpose for generating power or driving industrial uses.  According to the Times, there are about 2,000 dams in the Hudson River Estuary between New York City and Albany, N.Y. and there are thousands more across the country, many of which are totally obsolete and even dangerous to people — they can give way easily and some even have “recirculators” at the bottom of them that can pull people under if they happen to fall in or capsize when kayaking or canoeing.