Detroit to test innovative 'blue infrastructure' project

Detroit is about to find out whether an innovative landscape concept known as "blue infrastructure" actually works to save taxpayers big money.

Blue infrastructure refers to the practice of diverting rainwater and snowmelt from the city's combined sewer and stormwater system into ponds, fields and other more natural settings. By keeping water out of the sewer system, the city in theory could save hundreds of millions of dollars by not having to invest in more big-pipe gray infrastructure to treat the mix of sewage and storm runoff.

To test that idea, the city is working out details of a pilot project on the far east side in the Jefferson Village area. There, local grocer Sam Yaldo of the Parkway Foods store gets a bill from the Detroit Water & Sewerage Department each month for more than $8,000 to deal with the drainage of rainwater off his parking lot, which now flows into nearby sewers.

The city's Water & Sewerage Department began charging commercial landowners a monthly drainage fee in 2013 to cover the cost of cleaning up water that runs off impervious roofs, parking lots and other hard surfaces into the city's sewers, where it mixes with sanitary waste and must be cleaned before discharge into the river.

If the diversion of rainwater to a nearby man-made wetlands is successful, that would eliminate that charge, making Yaldo's business more profitable. Done citywide, blue infrastructure could save business owners millions each year and make doing business in the city that much more likely.

"That's pretty substantial, and it literally can put him out of business," Waymon Guillebeaux, executive vice president at the Detroit Economic Growth Corp., said of the monthly drainage charge that the DWSD began charging property owners like Yaldo. "It is a huge problem for the City of Detroit, not only to attract new businesses to the city but to retain what's there. The goal is how do we fix this problem citywide."

In late April, the city's Economic Development Corp., a quasi-public body, approved spending $162,000 to hire the Detroit-based Giffels Webster Engineers to "investigate and explore possible measures" to divert the rainwater and snowmelt from Yaldo's parking lot to a more natural setting a block or two away.

That most likely will mean funneling the water off the parking lot into a nearby vacant field where the water would pass through a natural filtration system as in a wetlands and eventually be discharged to the Detroit River. Keeping some or all of the water out of the sewer and stormwater system would save a huge amount of money since the water wouldn't need to be cleaned up before discharge into the river, or at least not as much as is needed today.

Normally, rain and melting snow pick up dirt and debris from parking lots, streets and other paved surfaces and carry it into the sewers. In recent decades, the city has built filtration plants at great expense to clean up the watery mess before discharging it into the river.

Scott Clein, a Giffels Webster engineer who heads the project, estimated that Yaldo's business would still face a yearly maintenance charge of about $10,000 if the pilot project works, but that would be only about 10% of what he pays now for the discharge fee.

It is by no means a simple problem to solve. Multiple licenses and approvals would be needed from a variety of agencies, including the city itself, the U.S. Environmental Protection Agency and others. But there is great enthusiasm among experts for trying the experiment.

Blue infrastructure is a key recommendation of the Detroit Future City visionary framework and has been much talked about in recent years, but nothing of this magnitude has been done so far in Detroit.

To date, blue infrastructure in metro Detroit has meant the creation of porous parking lots and so-called "green alleys" that allow rain and snowmelt to filter down into the ground beneath instead of running off into sewers.

All such blue-infrastructure systems mimic the natural setting that Europeans found when they first arrived in Detroit three centuries ago. Detroit's natural network of streams, ponds and fields dealt with rain and snow until a growing city paved over nearly every surface.

Clein, head of the Giffels Webster office in Detroit, said the Jefferson Village project is not likely to involve a huge retention pond but rather a series of modest man-made wetlands, rain gardens and other small systems.

"Instead of just making a big old pond, where you get algae problems, bugs, a big fence around it, we work through forms of wetland factors that allow us to put parks and paths and other things in the land and still use it and still provide value," he said.

A final plan is expected to be ready in a few months, but it was unclear when construction of the system could begin or what would be the ultimate cost.

John Gallagher is a reporter for the Detroit Free Press.