America’s aging dams are a disaster waiting to happen

This story was originally appeared on Inside Climate News and part of it is Climate Desk Collaboration.

Minnesota’s Centennial Rapidan Dam made national headlines last week when its partial failure destroyed a home and forced county officials The shop next door was demolishedYet, it’s one of hundreds of dams across the Upper Midwest that are in similar or worse condition, according to an analysis of federal data by Inside Climate News.

The incident occurred amid days of historic flooding in the Midwest that has left two people dead and several others injured. Broke records in at least 10 placesThe report highlights the growing threat climate change poses to the nation’s aging infrastructure, as extreme weather becomes more common and severe.

State and federal officials have been warning for years that the nation’s roughly 92,000 dams — many of which were built in the early 1900s — are being overly impacted by extreme weather, particularly in the Midwest. Fifth National Climate AssessmentA survey released last year found that annual rainfall across much of the Midwest increased by 5 to 15 percent over the previous decade in the decade leading up to 2021. About 30 dams in the Midwest have failed or nearly failed since 2018, the assessment said.

Most of America’s dams are over 60 years old, leading to complications such as sediment buildup. This is what happened at Rapidan Dam, about 90 miles southwest of the Twin Cities. Too much sediment caused water to flow around the dam’s western side, eroding much of the land.

The National Inventory of Dams, a database managed by the Army Corps of Engineers, classifies the 114-year-old Rapidan as having a “critical” hazard potential while it is in “poor” condition. The hazard potential indicates how much a dam failure could threaten human life or damage property, with “critical” indicating moderate risk and “high” indicating high risk.

An Inside Climate News analysis of that database found that about 4,100 dams across the country are in poor or unsatisfactory condition and pose a potential threat to human life or property. In Minnesota, Wisconsin and Michigan, about 200 dams are in poor condition, and 13 are in poor condition and pose a “high” threat if any of them breaks.

“A high-risk dam means that if it fails it could result in the loss of human life or significant property damage,” said Erin McCombs, regional conservation director for a nonprofit called American Rivers. “Dams that are high-risk and in poor condition are disasters that can and should be avoided.”

Of the 13 high-hazard dams listed in poor condition in Minnesota, Wisconsin and Michigan, eight dam owners responding to questions from Inside Climate News said their dams pose no immediate threat to the public and are inspected frequently, some as often as weekly. The owners of the other five dams located in Michigan — Portage Plant Dam, Menasha Dam, Manistique Peppers Dam, Cornwall Creek Dam and Little Black River Structure B — did not respond.

Repair, replace or remove?

Many of the country’s ailing dams are no longer useful for purposes such as preventing floods or generating power. As dams reach the end of their lives and their licences expire, their owners will have to decide whether to repair them, replace them or remove them altogether.

Congress allocates around Rs 1,000 crore $3 billion for dam-related projects in the Infrastructure Investment and Jobs Act signed into law in 2021. Dam repairs can often be too costly for cities and small towns, especially in the long run. Some owners say replacing or removing dams may be the best option, and while it may cost more upfront, the savings over time make it worthwhile.