Increasing Extreme Precipitation Events Heightens Flood Risk to Critical Infrastructure

Over the past few weeks, extreme precipitation events have occurred across the globe causing floods that have threatened human lives and critical infrastructure. As climate change increases the frequency of these events, critical infrastructure owners and operators should ensure their facilities are resilient to the growing flood risk.

In September alone, extreme precipitation events occurred in New England, southern Europe, Brazil, and Hong Kong, among others, which led to floods, human fatalities, and critical infrastructure impacts. The changing climate is almost certainly contributing to the increasing extreme rain events. As atmospheric and ocean temperatures heat up, storms and rain that cause flooding are likely to occur more frequently, since warmer water is more prone to evaporation, and warmer air can carry more water vapor. A study published in March found that since 2002, extreme precipitation events have been closely correlated with rising temperatures. Furthermore, the First Street Foundation recently reported larger parts of the U.S. can expect to experience “1-in-100 year flood” events, necessitating utilities plan for greater future flood impacts.

Highlighting the threat to critical infrastructure, a recent AP analysis found about one-third of wastewater facilities in the U.S. would be at risk of flooding if an extreme precipitation event hit their area today. And many drinking water utilites also likely face similar vulnerabilities as flood risks continue to grow.

In addition, dams are also increasingly at risk of failure during extreme precipitation events. In Leominster, Massachusetts, last week, the city got almost 11 inches of rain over several hours. At least two of the city’s 24 dams nearly failed, prompting the city to recommend residents evacuate before the threat subsided. Across New England there are 176 dams categorized as high-hazard structures that are in either poor or unsatisfactory condition. If these dams fail, they would pose a risk to people living downstream and critical infrastructure, such as water treatment plants. Relatedly, an AP investigation found in 2022 that the number of high-hazard dams was on the rise. To help increase your organization’s resilience to flooding, water and wastewater utilities are encouraged to read the EPA’s flooding resilience guide. Read more at the AP or at the Washington Post.