Detroit going green to help slow flooding
DETROIT » Massive amounts of green are being spent to find “green” ways to prevent basements, yards, streets and freeways in Detroit from flooding during heavy storms like one last month.
Of $100 million pumped each year into infrastructure upgrades for the city’s aging water and sewer systems, $10 million goes toward installing detention ponds, bioswales, rain gardens and permeable pavement. Called green stormwater infrastructure, the features hold and slowly release rainfall into sewers, lessening flooding that has plagued Detroit and other older cities for decades.
“It’s not the end-all-beall, but it is a type of intervention that reduces wet weather flows into the system or delays them,” cautioned Palencia Mobley, deputy director and chief engineer for Detroit’s Water and Sewerage Department.
City officials say 6 inches (15 centimeters) of rain that poured down in the area June 25-26 was the most at one time in 80 years. Like a funnel beneath a swiftly flowing faucet, the volume of water moved faster than it could be pumped out or pushed through sewers to water treatment plants.
Water pooled in streets and yards as debris clogged sewer grates. Untreated water pushed up through basement drains. Motorists were stranded on freeways. New vehicles in one auto plant lot were nearly submerged.
Democratic Gov. Gretchen Whitmer soon would declare a state of emergency for the city and surrounding Wayne County.
Near William M. Davis’ home in a west side neighborhood where Detroit’s water department recently installed sloping bioretention gardens in boulevard medians water rose in the basements. But Davis believes the $8.6 million project that was designed to manage more than 37 million gallons of stormwater each year helped lessen the flooding. Rain and snowmelt seep through the soil into box-shaped chambers that store the flow before releasing it into the sewer system.