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Climate change could leave millions of miles of US roads 'inoperable' in 30 years

Lately, maintaining roads in parts of the Florida Keys hasn't been easy. Sea water on the roads there is no longer uncommon, especially in the fall months, when the so-called “King Tides” rush in, right into neighborhoods.
Roads in coastal communities, as well as inland communities, may become inoperable within the next 30 years because of climate change-related flooding, due to either rising sea levels or additional rainfall.
A study by the First Street Foundation found the highest level of flooding threat lies with roads in coastal Louisiana and Florida (seen below), as well as inland counties like Johnson County, Kentucky and Logan County, West Virginia.
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KEY LARGO, Fla. — Where the ocean meets the land in Florida's southernmost county, the sea is both friend and foe.

“We're an island community,” said Rhonda Haag, chief resilience officer for Monroe County, Florida. “We have so many miles of shoreline where the tidal waters can readily come in.”

Monroe County is home to the Florida Keys, a series of islands stretching south of mainland Florida.

“We have over about 311 miles of local roads that the county maintains,” Haag said.

However, maintaining those roads hasn't been easy lately. Seawater on the roads there is no longer uncommon, especially in the fall months, when the so-called “King Tides” rush in, right into neighborhoods.

“We've been pumping it the last three or four days, so the water has gone down,” Haag said, motioning towards the remaining water on the road. “It's been known as a nuisance. But when it gets to that level of water and it's on for a tremendous period of time, it's no longer a nuisance. It's a real problem.”

The majority of roads there may become inoperable within the next two to three decades because of climate change-related flooding. Roads in the Florida Keys may be susceptible to rising seas, but they're hardly the only ones. It's not just roads in coastal communities that could be affected – those in inland communities could also be impacted by climate change.

“We've spent our entire time looking at flood risk,” said Matthew Eby, founder and executive director of the nonprofit First Street Foundation.

The foundation just released a multi-year, massive study, which examines how climate change will impact infrastructure in every county in the U.S., including roads.

“When we look at roads, we take 100-meter segments, so small chunks of roads across the entire country and we look at the elevation of that road and then the likelihood of water to actually pond on that road,” Eby said. “And if it's over six inches of water, that's the definition of an impassable road.”

They found the highest level of flooding threat lies with roads in coastal Louisiana and Florida, as well as inland counties like Johnson County, Kentucky and Logan County, West Virginia.

The cities considered “most at-risk” include New Orleans, Miami and Tampa.

Overall, their analysis shows that 23% of the nation's roads – about 2 million miles -- will be considered “inoperable” within 30 years because of flooding from either sea level rise or additional rainfall due to climate change.

“Events of the past are not the same as they are today, nor will they be in the future. And our sewer systems are not built to have all that water flow in all at once,” Eby said. “Now, the hard part is, how do you fix it, but not just for today? How do you fix it knowing what tomorrow is going to be like?”

It's what Rhonda Haag is confronting back in the Florida Keys.

“These are some really sticky questions that we're going to have to resolve here in the next year,” she said.

Elevating the roads there will cost $1.8 billion. It is money they, like other communities around the country, will need from federal and state governments and the people who live there.

“We're doing our planning. We're letting the community know what's coming,” Haag said. “We're very forthright about that and we're also very forthright in letting them know there is going to be some costs and you have to work together.”

For a look at the flood risk on your street, you can go to the interactive map at floodfactor.com and simply type in your address.