As Ann Arbor’s $9.4 million flood mitigation/nonmotorized trail tunnels near completion, city transportation manager Eli Cooper recalls how they came together. Passing a meeting in City Hall, he heard stormwater and floodplain programs coordinator Jerry Hancock talking about tunneling under the Amtrak railroad line.

Hancock’s people wanted to reduce flooding along Depot St. But Cooper had his own motive for getting under the tracks: as the city developed its parks and pathways along the river, more people were taking a dangerous and illegal shortcut across the tracks to reach them.

It “started out as just a stormwater project,” explains Hancock. Allen Creek normally flows through an underground pipe on the west side of downtown. But in heavy rains, the pipe backs up and the creek emerges–“like Dracula,” an Observer writer once wrote–to flow overland toward the Huron.

Just past Depot St., though, it was stopped by the raised railroad berm. In anything more than a “two-year storm”–one that has a 50 percent chance of happening in any given year–“Allen Creek backed up in the system and caused flooding in the streets,” says Hancock.

Hancock’s group was looking at ways to get that water under the tracks. Cooper suggested combining their project with his search for a safe pedestrian crossing.

Hancock agreed–“and once they were together, they each helped each other out,” he says. “The pedestrian thing wouldn’t have been talked about if it weren’t for the stormwater part, and the stormwater part wouldn’t have looked as attractive to the public if it didn’t have the pedestrian part.”

Cooper had a cuter way of putting it, likening the pairing to a Reese’s Peanut Butter Cup: “By putting two good things together, we created something that was even better.”

Not that it was easy. “I first put it down to paper in 2006,” Hancock says. “It’s taken fourteen years to actually accomplish it.”

Though the tunnels were built simultaneously–two for water, one for walkers and bicyclists–they were paid for separately. “It’s symbiotic,” says Hancock. “They helped each other, but the grant money from one is not contributing to the other.”

A breakthrough came in 2014. “There was a flood in the Dearborn/Detroit area,” Hancock remembers. “There was a federal disaster declaration … and when there are declarations, it opens up grant money for mitigation in a different pot.”

The Michigan State Police handle those grants for FEMA, but “when they went through the application process, they didn’t get enough applications to use all the money,” Hancock says. So they “actually contacted me, and said, ‘Hey, you know this project you’ve been telling us about for years? Do you think you could put together an application quick and get it in?'”

He did, and the grant brought the “Allen Creek Berm Opening Project” to life.

“Shutting down the railroad–that decision doesn’t get made lightly–or often,” Cooper says. But in May, trains were halted for a day and a half. In a carefully choreographed process, the tracks were lifted, a trench cut, precast concrete sections placed to form the three tunnels, and the track bed and rails replaced–all in time for the Chicago Amtrak train’s evening arrival.

The entire project cost more than $9 million, including $3.7 million from FEMA, $970,000 from the Michigan Department of Transportation, $300,000 from the Michigan Department of Natural Resources, $315,000 from the Southeast Michigan Council of Governments, and $4.1 million from the city–$2.9 million from stormwater funds and $1.2 million from alternative transportation funds.

Depot St. will still flood, but less often, and when it does, the water won’t spread as widely, or get as deep. Some buildings will no longer be in the floodplain, “so they’ll no longer have to pay flood insurance,” Hancock says, “which will be a savings for them, and also there won’t be building restrictions because of that.” Even those that are still in the floodplain and the floodway–the most dangerous area, because water moves there–will “have reduced risk because of lower flood elevation,” he adds. “Instead of flooding, say, eight feet up the building, it will only flood like three feet up the building.”

“To me, I think there’s just really great upside for the city and the entire area,” says Mike Martin of First Martin commercial real estate. The company’s headquarters will still be in the floodway, but be at less risk. Casey’s Tavern, which First Martin owns, will come out of the floodplain entirely. And though the construction disrupted the parking for their 201 Depot office building, Martin points out a Covid silver lining: with most everyone working from home, “this was the year” to do it.

“I can’t wait to ride my bike along the river, get a coffee, meet friends,” says Douglas Allen, who manages five of his family’s properties along N. Main. “The more people can be close to the river, the more people will appreciate it and want to protect it and want to keep it clean.” Two of their buildings will come out of the floodplain.

The recently approved $100 million Broadway Park West redevelopment at the former DTE site on Broadway will also benefit. “We’ve eliminated some of the flood risk,” says Hancock, and “the pedestrian tunnel … gives people much easier access to downtown.”

But while Hancock is working to mitigate floods, he’s also asking city council to set tougher rules for building in their path. The current ordinance requires that occupied areas be elevated above a “100-year flood” (which has a 1-percent chance of occurring in any year). Hancock wants to make that a 500-year flood, or .2 percent annual chance.

That’s what Broadway Park West will do. “I don’t really like to advocate for building in the floodplain,” Hancock says. “That said, the developer and their design team did a good job of addressing my comments and going above the current codes.”

“When I told them we were working on this code change … they just went ahead and elevated all of the buildings.”

See earlier article about the project here.