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Long term forecast for Metro Detroit: More freeway flooding

Aug 17, 2016

Major stretches of highway throughout Metro Detroit were flooded out Tuesday morning, after heavy rainfall Monday night.

That’s likely a “new normal” people will just have to deal with going forward.

Both state and local transportation agencies acknowledge there have been more frequent, intense rainfall events in recent years—most notably the August 2014 storm that caused widespread damage.

And Southeast Michigan’s many recessed freeways are particularly vulnerable to heavy rainfall.

Pump houses that draw down the water are the historic answer. But many of the pumps are old, and prone to failure in heavy rainfall, says the Michigan Department of Transportation’s Jeff Cranson.

Cranson says MDOT might look to the private sector for help with that.

““While there’s nothing inked yet, that’s definitely the kind of innovative thing we’re looking at for pump houses--a way to stretch the money, make it go further. Let private industry absorb some of that risk if they want to,” Cranson said.

But otherwise, Cranson says there simply isn’t the money for a longer-term infrastructure plan.

“Figuring out that there is a long term trend, and there’s going to be more problems with the infrastructure because of weather events, is one thing,” Cranson said. “It does not necessarily translate into more money.”

MDOT and other agencies are partnering with some communities for roadside “green infrastructure” projects that help retain and slow the flow of water, says Carmine Palombo, deputy director of the Southeast Michigan Council of Governments (SEMCOG).

“We need to get everything working together, perhaps more green infrastructure working together with improved infrastructure, in order to try deal to deal with the situation,” Palombo said.

“It’s a priority, but it’s also a priority within the existing revenues that you have.”

In 2014, MDOT submitted a Climate Vulnerability Assessment to the federal government. It noted:

"Increased precipitation overall will create challenges by increasing or exacerbating road closures. The recent flooding events in Detroit caused significant road closures, and these can reasonably be expected to increase in number and duration in the future, potentially by a significant amount. MDOT and its partners in state and local governments may need to determine acceptable tolerance for road closures.

Similarly, the failure of pumping and stormwater systems should be monitored…Given the lack of adaptive capacity in existing urban infrastructure, pumping systems are an area where short term capital investment may be needed, especially since they were designed to handle 50-year extreme precipitation events for the present climate."