The Detroit Water and Sewerage Department (DWSD) provided a demonstration and revealed all the completed bioretention gardens in 10 boulevard medians.
This project is the city’s largest-ever single investment in green storm water infrastructure to reduce neighborhood flooding and basement backups, reported the city. The $8.6-million project on Oakman Boulevard in the Aviation neighborhood redirects rain and snowmelt from the street into the bioretention gardens.
According to the press release, Mayor Mike Duggan made a commitment to the Aviation residents after they experienced significant flooding following heavy rains in August 2014. More than five years later, construction began in May 2020, following design work and community meetings led by DWSD.
DWSD staff used a fire hydrant to demonstrate the project. Large amounts of water were flushed onto the street, which quickly flowed into the catch basins and curb cuts. The catch basins are now tied into the bioretention gardens in the medians. As the water entered the bioretention area it quickly infiltrated the plants and ground and flowed into drains to be retained, then slowly flowed to the Water Resource Recovery Facility (treatment plant). The project is not intended to hold water above ground, rather it moves through swiftly.
“More than five years in the making, the Oakman project demonstrates how we can transform existing infrastructure, in this case, boulevard medians, to improve storm water management, reduce street flooding and basement backups and further reduce combined sewer overflows during major rain events,” said Palencia Mobley, P.E., DWSD deputy director and chief engineer. “And, due to the storm sewer tie-ins we did underground as part of this project, it not only helps homes on Oakman Boulevard, it also benefits residents on nearby streets.”
The Oakman project has been designed to take advantage of the medians on the boulevard between Joy and Tireman to manage 37.3 million gallons of storm water annually. The goal is to reduce street flooding and basement backups in the neighborhood.
DWSD installed underground boxed-shaped chambers beneath eight of the bioretention areas in the median to temporarily store storm water and slowly release it to the combined sewer system. In some locations, DWSD re-routed catch basin connections to the combined sewer lines to new storm sewer pipes that flow into the green stormwater infrastructure (GSI) practices in the Oakman Blvd. median.
DWSD chose Detroit-based contractor, Blaze Contracting to undertake the project. DWSD had meetings with the community sharing design options for the GSI practices in the medians.
Blaze holds the contract an additional two years to maintain the plantings and surrounding landscaping. After that, DWSD will issue a request for proposals and select a contractor for project maintenance and landscaping after 2023 and beyond.
