A regional water utility in Michigan is getting federal help to determine how to best mitigate increasing flood risks. The Great Lakes Water Authority, whose wastewater system serves 2.8 million residents in southeast Michigan, has teamed up with the U.S. Army Corps of Engineers to conduct a multi-year survey meant to reduce flooding caused by climate change and aging infrastructure.
The project has been years in the making. Historic flooding in 2021 prompted the water authority to start looking at what other large cities have done to reduce damage from floods, CEO Suzanne Coffey said.
“We want to reduce the frequency and intensity of flooding, surface flooding and basement backups in the region,” she said. The authority’s stormwater systems can handle 3.5” of rainfall in 24 hours, she said. Between June 25 and 26, 2021, some parts of southeast Michigan received up to eight inches.
As a result, President Joe Biden issued a presidential declaration of disaster for Wayne and Washtenaw counties.
“We know that we're seeing very, very severe storms,” Coffey said. “We know that we're seeing repetitive damage to structures. These types of things are what we look at and say, ‘okay, do we need to do something different?’”
Climate change has fueled extreme weather events, which can include increased precipitation. In areas like southeast Michigan that have lots of impervious surfaces, that means more rainwater flowing into wastewater systems in a shorter amount of time.
Solutions will involve ways to direct excessive rainfall elsewhere, such as an additional pipe or a retention basin. Using green infrastructure to divert water across the landscape, rather than into a storm sewer, is also an option, Coffey said.
The survey will take at least three years to complete, she said. When it's done, the Corps will submit a report to Congress outlining its findings and recommendations.
The water authority is already working on projects to strengthen its system, Coffey said.
“We are continuing to do all that we're doing to make our system resilient,” she said. “This is about what's next.”
