Could it happen here? That was the big question in the U.S. in the hours and days after a magnitude 9.0 earthquake and resulting tsunami crippled the Fukushima Daiichi nuclear power plant and destroyed the surrounding region. Most American worries focused on the integrity of our nation’s rapidly aging nuclear power plants, many of which are still churning through uranium long past the reactors’ original expected lifetimes. Fears were piqued again August 23 when a magnitude 5.8 temblor struck central Virginia, threatening power plants up and down the east coast. But a quieter danger lingers near many of our cities and towns. Tens of thousands of dams, many built before seismic engineering came of age, have the potential to release tsunami-like flash floods in the event of a seismic breach.
In 2009 the American Society of Civil Engineers released a survey of the state of infrastructure in the U.S. The group found that dams are, on average, in terrible disrepair. Of the more than 85,000 dams, more than 4,000 are unsafe or deficient, and nearly 1,800 of those are located where a breach would cause severe damage to life or property. With so many dams, it is hard to know where the gravest danger lies. The average budget for dam inspectors is distressingly low. For instance, Texas employs just seven inspectors to keep an eye on 7,400 dams, and in many states inspectors lack the authority to inspect private dams, including those built to hold back the chemical by-products of mining operations. A report by Switzerland’s Paul Scherrer Institute estimates that dams are the most potentially hazardous source of energy. A catastrophe at an average dam has the potential to kill 11,000 people. The second-most-hazardous energy source? Nuclear.