Flood maps are being reevaluated

ADDISON COUNTY — For the first time since 1985, Addison County's official federal flood maps are being updated. This comes toward the end of statewide FEMA flood map reevaluations.

Unfortunately for those looking for relief from the recent highwater events, the new maps aren't expected to be completed until 2027.

The updates will not only reflect geographical changes since the 1980s, but also technological strides in the field of geography. Currently, the maps exist as PDFs online, but the next iteration will be digital and interactive.

Flood maps show how likely it is for an area to flood, which is important in land use planning and in flood insurance programs, according to Middlebury College Assistant Professor of Geography Joseph Holler.

"For land use planning, the flood risk map is often used to restrict development in high-risk areas," he said.

They're a tool meant for mitigation, rather than relief, according to Andrew L'Roe, Addison County Regional Planning Commission Emergency Management Planner.

"It's more on the front end," L'Roe said. "If there's a big flood or something, it's not like they go in and say, Oh, you were in or you're out. Like, it's, it's not an after-the-fact thing. It's definitely a planning device, and it's supposed to help us make better decisions," he said.

Holler enumerated three ways the current maps are inaccurate:

"First, extreme weather events are changing along with the changing baseline of a warming climate," he said.

"Second, the FIRM maps (Flood Insurance Rate Maps) represent the risk of flooding from inundation caused by rising seas, lakes, rivers and streams with a faulty assumption that river and stream channels do not change. In fact, much of the flood damage in Vermont is caused by stream bank erosion and stream or river channel migration. In other words, the shapes and paths of streams and rivers naturally change over time, and these changes can undermine housing and infrastructure.

"Third, the FIRM maps do not account for new land use change or development, or flood mitigation efforts over the past 30 years."

From a first-response perspective, security is compromised with inaccurate maps.

"It definitely increases our sort of insecurity as first responders … I would rather have less people to evacuate and have to worry about when there's big rains coming," Holler said.

Although the process is just beginning, L'Roe and Ned Swanberg, regional flood plain manager for the Department of Environmental Conservation, both said that for years their respective organizations have been urging the national organization to reevaluate Vermont's maps.

"We've been … advocating for updates for a while, because we knew they were out of date," L'Roe said.

In 2011, FEMA completed digitizing some Vermont counties' flood maps.

"The Vermont rivers program has been begging FEMA to come back and finish digitizing the rest of the state," said Swanberg.

Funding has been the source of a slow return since 1985. But, more recently, there's been more funding available and more data.

Swanberg said the program was not initiated with the assumption that 38 years would pass with no updates.

"In the original concept for the insurance program, they absolutely had the intention of having updated maps within each decade," he said.

"I think it is both unsurprising and unfortunate that the FIRMs have not been updated frequently," said Holler.

Their reevaluation coincidentally comes amid one of Vermont's most severe flooding events since Tropical Storm Irene in 2011. However, the new maps will not reflect this most recent event because data collection began prior to it.

CLIMATE CHANGE

Additionally, the maps do not reflect complications due to climate change.

"They're not adjusted for what seems to be happening with … global climate impacts. That simply is not part of the (FEMA) guidelines and specifications," Swanberg said.

"It's absolutely a problem," he added.

"What we really need to do is be thinking about the future and the future is, in many ways, becoming more and more unknowable, we're going to have probably a lot more drought, and a lot more floods … we need to be more careful. If we don't want our friends and family and communities to, you know, go through these kinds of disasters."

Is the FEMA program outdated?

"There's a lot of things that are out of date now," Swanberg said. "Yeah, we need real tools that will actually change development, guide development. And that's very difficult stuff to get, but real guidance about where are risks that are going forward? And how to create a sustainable outcome? The future that we're facing? Yeah, we don't have those yet."

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