Thanks to emergency preparedness and quick action by local and state officials, it appears that the Oroville Dam crisis has been averted, but communities across the country should consider this incident a wake-up call.

The Sacramento Bee reports that the flood-control manual for the Oroville Dam hadn’t been updated in nearly half a century and applied obsolete weather models. Experts say that structural failures were responsible for the crisis; however, this outdated document indicates that maintaining the dam likely wasn’t the biggest priority for local officials in Oroville. And they’re not alone.

Failing grade for dams in the U.S.

The 2017 Report Card for America’s Infrastructure issued by the American Society of Civil Engineers (ASCE) gives the 90,580 dams in the U.S. a failing letter grade of a D. The report found that the average age of dams in the country is 56 years old. By 2025, 70 percent of dams will be at least 50 years old.

Although many dams were built to protect areas of undeveloped agricultural land, increases in population and development have caused dams to age exponentially. According to the ASCE, nearly a third of all dams in the U.S. pose serious risks to their communities. In 2016, the number of high-hazard dams — those with the potential for the loss of human life — had grown to 15,500. Another 11,882 dams are classified as a “significant hazard,” meaning their failure would cause economic losses but not necessarily loss of life. At least 2,170 dams qualify as both high-hazard and deficient.

Part of the country’s aging infrastructure

Dams are active systems that, like a road or a bridge, need to be maintained, or they’ll fall into a dangerous state of disrepair. Given that the average age of a dam that fails is 62 years, many of our nation’s dams have an increasing likelihood of failing within the next decade if immediate preventative measures are not taken. Furthermore, the engineering and construction standards available when many of these dams were built don’t stand up to the increased prevalence of floods and earthquakes.