The partial dam failure occurred after three days of heavy rainfall that caused the Minnesota River to reach its third-highest flood level since at least 1881. Brennan Dettman, a meteorologist with the National Weather Service in the Twin Cities, Minnesota, provided this information.
In the Mankato area, where the dam is situated, 7 to 8 inches of rain fell over the span of three days. Based on analysis by Kenny Blumenfeld, Senior Climatologist at the Minnesota Climate Division, the situation was dire. Blumenfeld’s analysis indicated that this level of heavy rain occurs approximately 0.5 to 2 percent of the time each year in southern Minnesota.
Bill McCormick, who headed Colorado’s dam safety program from 2011 to 2021, highlighted how extreme rainfall events are putting dams across the country under strain. “We are experiencing increasingly severe storms that are testing our aging infrastructure. Dams and spillways that previously didn’t face many storms annually are now encountering more frequent storms,” he noted. “These aging systems are facing heightened challenges.”
McCormick also pointed out that development in residential areas near dams has increased the risk factors, as people now live in regions previously designated for farmland. Dams constructed to protect agricultural areas are now safeguarding residential neighborhoods.
Hiba Baroud, an assistant professor of civil and environmental engineering at Vanderbilt University, emphasized the need for lawmakers to take proactive measures in strengthening dam infrastructure and prioritizing repairs following incidents like the partial failure of the Rapidan Dam. “To prevent such occurrences, it is essential to proactively assess all dams in the U.S., prepare for potential scenarios, and prioritize necessary repairs or upgrades,” she urged. “Simply reacting to major events as wake-up calls concerning specific dams is not sufficient.”
Source: www.nbcnews.com
