DamsDo Two Failed Dams Foretell a Dire Future?
Climate change is increasing the frequency of extreme rainfall events and hence the risk for filling and overtopping dams, which is the predominant mechanism of dam failure. However, using climate change as a bogeyman for aging infrastructure failure is an unfortunate trend, since it takes attention away from an urgent and potentially fixable problem.
Two dams down last week, a few thousand more to go? It was a narrow escape for Michigan and luckily no one died. Altogether 10,000 people were evacuated and are presumably homeless at the moment. Further complicating matters is the ongoing disaster of COVID-19 and the challenges of having to evacuate while social distancing. What happened in Michigan shines a light on our aging and failing infrastructure. The question remains, will we do something now to fix it?
The 2018 National Climate Assessment report noted: “Aging and deteriorating dams and levees … 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 2016, and New Orleans levees in 2005 and 2015. The national exposure to this risk has not yet been fully assessed.” The failure of the Spencer dam in Nebraska in 2019, the failure of the two Michigan dams and the near failure of the dam near Roanoke, VA last week exemplify the concern. Still, dam failures are relatively rare, and hence despite their potentially catastrophic impacts, they seem to not get the attention that they deserve.
Climate change is increasing the frequency of extreme rainfall events and hence the risk for filling and overtopping dams, which is the predominant mechanism of dam failure. However, using climate change as a bogeyman for aging infrastructure failure is an unfortunate trend, since it takes attention away from an urgent and potentially fixable problem. The 2017 Oroville Dam Spillway failure that led to an evacuation of 200,000 people is a case in point. The wet conditions were anomalous, but not extreme. The flow over the spillway was merely 5 percent of what it was designed to handle. Known structural problems with the spillway were ignored for over a decade.
The projected maintenance costs were in the millions of dollars, and maintenance was deferred by state and federal officials, despite a formal study of the situation, warnings, and a Federal Energy Regulatory Commission hearing. The final repair bill was over $1.1 billion —about 10 times more than the cost of the dam’s construction when adjusted to 2018 dollars — and was passed on to the federal government. The city of Oroville filed
