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Stormwater Project: Oakman Boulevard
The Detroit Water and Sewerage Department (DWSD) is transforming a stretch of Oakman Boulevard with Green Stormwater Infrastructure (GSI) to reduce street flooding and basement backups. This is the city's largest investment to date in GSI. The two-year project, in the Aviation neighborhood, is between Joy Road and Tireman Avenue. It's features and benefits are:
- To reduce street and basement flooding in an area, not near the river, that has experienced massive flooding including during the 2014 and 2016 major rain events;
- A $8.6 million investment converting 10 medians into bioretention gardens to manage 37 million gallons of stormwater annually and keep some out of combined sewer system;
- A combined water and sewer systems project that includes water main and lead service line replacement
- Detroit-based Blaze Contracting to use Detroiters to perform at least 51% of work
“We made a commitment to the residents of the Aviation neighborhood that the City would take measures to help protect their homes,” said Mayor Mike Duggan. “What DWSD is doing here will use nature, instead of storm sewers, to manage huge amounts of stormwater to help reduce street flooding and basement backups.”
Duggan said the project also is an example of “Detroiters rebuilding Detroit.” Detroit-based Blaze Contracting is the primary contractor on the $8.6 million project. The contractor will be required to meet Mayor Duggan’s executive order that 51 percent of the hours worked during the project will be performed by Detroit residents. Failure by the contractor to meet this requirement will result in fines from the City of Detroit’s Civil Rights and Inclusion Office.
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 stormwater annually. The goal is to reduce street flooding and basement backups in the neighborhood. To residents and passersby, the bioretention practices DWSD will use on 10 medians will look like rain gardens, and will add further beauty to this historic neighborhood. The residents provided input during the design process with emphasis on the medians having passive features versus an active, park-like setting.
“We engaged the community in designing this project to ensure they would be comfortable with the natural features of the re-imagined medians that will manage stormwater,” said DWSD Deputy Director and Chief Engineer Palencia Mobley, P.E. “We have to protect the historic neighborhood by using innovation to reduce flooding. While this project will help the City of Detroit Water and Sewerage Department meet our National Pollution Discharge Elimination System permit – in our continual reduction of untreated combined sewage discharges during wet weather – what’s important to the residents is they will see a dramatic decrease in flooding during future rain events.”
What is green stormwater infrastructure?
The most common method to improve stormwater management is green stormwater infrastructure, or GSI. It replicates natural systems to reduce runoff volume, filter pollutants and cut down on flooding by slowing the movement of water into the City’s combined sewer system, thereby allowing it to soak and be absorbed into the ground. Reducing stormwater runoff with strategically placed GSI projects, such as a bioretention and bioswales, has the added benefit of reducing street flooding.
DWSD has installed 16 GSI projects in the past six years, which manage a total of 24.5 million gallons of stormwater annually. View the DWSD GSI projects, videos and manuals at www.detroitmi.gov/GSI. And, view a map of the more than 200 public and private GSI projects on the Detroit Stormwater Hub at www.detroitstormwater.org.
Bioretention to reduce flooding in the Aviation neighborhood
Bioretention features look similar to rain gardens on the surface, but underneath are designed and engineered to slowly soak up stormwater. The DWSD Oakman Blvd. project includes installing bioretention features on 10 medians in the project area. The conceptual bioretention designs shown in the map below reflect input from community residents during community meetings held in May and July 2017.
DWSD will install underground boxed-shaped chambers beneath eight of the bioretention areas in the median to temporarily store stormwater and slowly release it to the combined sewer system.
In some locations, DWSD is re-routing catch basin connections to the combined sewer lines to new storm sewer pipes that will flow into the GSI practices in the Oakman Blvd. median.
Water system upgrades
The project includes water system upgrades. DWSD will replace older water mains on Oakman Blvd. on both sides between Joy and Manor and between Joy and Appoline that are prone to breaks. The contractor will also dig up the water service line curbstop in front of each house to identify whether the line leading to the house is lead, galvanized or copper. Any existing lead or galvanized service lines will be replaced with copper pipe with owner/occupant permission.
Beginning in 2019, through its capital improvement program, DWSD began combining water and sewer upgrades to more efficiently use resources and reduce the multiple disruptions to the neighborhood, rather than projects taking place separately. This work is also coordinated in advance with other City departments and government agencies in order for streetscapes and road resurfacing, if planned, to be done in conjunction with the DWSD projects and vice versa. In the case of Oakman Blvd., the General Services Department’s Forestry Division has worked with DWSD to include removal or replacement of some unhealthy trees.
Community input began three years ago
DWSD had meetings with the community sharing design options for the GSI practices in the medians. The community gave feedback on trees, plantings, and other features during two meetings in 2017. An additional meeting was held in 2018 to show the preliminary designs based on their input. Following contractor selection and legislative approvals, the final pre-construction community meeting was held in February 2020 with DWSD and the contractor at Rippling Hope on Joy Road to share the project plans and construction timeline.
DWSD and the contractor will continue to conduct outreach with the community throughout the project including updates through door hangers, emails, and individual contact.
Capital improvement program funding the construction
Over the course of five years, which began in 2018, DWSD is investing $500 million in the city’s water and sewer systems. DWSD is able to make this investment by leveraging the $50 million annual lease payment for the regional water and sewer system operated by the Great Lakes Water Authority and improved operational efficiencies.
In May 2020, $100 million in bond proceeds for DWSD system improvements at less than 3% interest rate was secured. This is among the lowest 30-year borrowing rates achieved by the GLWA or DWSD. This was the final step to secure the full $500 million for the program.