Detroit banks on green infrastructure to rescue city from heavy rains

1 September 2016 by Kurt Kuban

Detroit has a water problem. Or, more correctly, it has a stormwater problem. Every time it rains, Detroit officials cross their fingers in hopes the city’s antiquated sewer system can handle the volume of stormwater that gets flushed into thousands of drains in parking lots and along city streets. In many cases, those drains are connected to sewer pipes that also carry sewage to the city’s wastewater treatment plant. When the system is overwhelmed with stormwater, which is happening with more frequency, the combined sewers end up discharging untreated sewage directly into local streams and rivers.

And during heavy rains, as residents have suffered through on at least three occasions this summer, basements also flood because they are hooked up to the same drains. These combined sewer overflows discharge billions of gallons of untreated sewage into the Great Lakes each year, are the prime source of pollution in the Rouge River and are one of the main factors in the algae blooms impacting Lake Erie.

To alleviate the problem, you might say the city is turning to a natural ally. Rather than build more and bigger (and more expensive) pipes to capture the stormwater, the city is looking to nature to help out.
Under the direction of Mayor Mike Duggan’s office, the city is focusing on green infrastructure projects, including the elimination of impervious ground surfaces that don’t allow water to soak through, and constructing bioswales (similar to large vegetated ditches), wetlands, rain gardens and other methods that allow rain and snowmelt to more naturally filter into the ground, rather than running off into city sewers.

….Instead of $1.2 billion for more pipes, the water department will spend approximately $50 million on green infrastructure projects in the Upper Rouge sewershed area, on the city’s far west side, where CSOs have plagued the Rouge River for years. Mobley said the city has until 2029 to complete the projects…..In fiscal year 2016, the city will spend $6.6 million on green infrastructure projects. Several have been completed, including the construction of four bioretention gardens on vacant lots in the Cody Rouge neighborhood, which was a collaborative effort with the University of Michigan. Stormwater is directed into these vegetated garden areas where it will percolate naturally into the ground. In essence, they act as natural wetlands. City officials say each of the gardens was designed to reduce stormwater runoff into local sewers by 300,000 gallons annually….

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