In this June 24, 2021 photo, a workman walks by an electrical substation in Bath that flooded in 2015, causing a major power outage. Credit: Troy R. Bennett / BDN

Flooding caused by more frequent and intense storms threatens broad swaths of Maine’s critical infrastructure, roads, homes, social services and businesses over the next 30 years, a national study released Monday found.

Warming seas and atmospheric temperatures are both creating stronger storms in the southern U.S. that are dropping more rain and moving further north, including inland in Maine, according to the study by First Street Foundation, a New York City nonprofit that studies flood risk. The study covers all 50 states and estimates the risk of waters so high they render infrastructure unusable and roads no longer passable.

While Maine is not as much at risk as states severely affected by hurricanes, including Louisiana and Florida, almost one-quarter of the state’s infrastructure facilities, including utilities, hospitals and emergency services, are already at risk of disabling floods. That risk will increase over the coming decades and stretch beyond coastal and riverside cities to smaller towns along streams that do not experience major overflows now, the study found.

“It doesn’t surprise me that the flood risk is going to be increasing,” Peter Slovinsky, a Maine state marine geologist, said. “We’re probably going to have more periods of drought punctuated by higher periods of rain falling in shorter amounts of time.”

The new data come as a bipartisan $1 trillion infrastructure package that would be partially directed toward rebuilding America’s deteriorating roads and bridges and funding climate plans and broadband initiatives is stalled in Washington amid debate over a larger Democratic spending plan.

“New England has a much higher risk of flooding than we’d think, and part of that has to do with the changing environment and the standards to which infrastructure was built,” Jeremy Porter, head of research for First Street, said.

The northeast tends to have older infrastructure. Maine’s bridges, for example, are in worse condition than almost every other state in the U.S., with nearly 13 percent of the state’s inventory in poor condition, according to Federal Highway Administration data.

The Maine cities and towns most susceptible to major flooding include Gardiner, Yarmouth, Bath, Rockland, Bangor, Skowhegan and Old Town, which all have 50 percent or higher risk of infrastructure flooding now, more than double the state average. Those numbers will rise several percentage points by 2051, according to the study.

In Gardiner, all critical infrastructure, including utilities, wastewater treatment and emergency services, are already at risk of being hobbled by floods, as are half of commercial buildings, according to the study. The city has had floods before, often caused by ice dams in the Kennebec River and others by storms. North Windham, which is not known for major flooding even though it is on the Pleasant River, has a 33 percent risk of infrastructure flooding.

Brewer already faces a risk of 32 percent of its roads becoming impassable with flooding, and 20 percent of its properties are at significant risk of flooding. Almost one-third of Oxford County’s roads could become impassable from flooding now, and more than 40 percent of the infrastructure is at risk.

The devastation from Hurricane Ida in late August showed that the nation’s infrastructure is not built to a standard that protects against the level of flood risk even now, let alone how those risks will grow over the next 30 years as the climate changes, said Matthew Eby, executive director of First Street, said.

“You’d expect critical infrastructure to be at the lowest level of risk because you would think that we build it to avoid any operational failure,” he said.

Nationally, 25 percent of all critical infrastructure in the country is at risk of becoming inoperable today, while 23 percent of road segments are at risk of becoming impassable, the study said. Some 20 percent of commercial properties are at risk today, 17 percent of social buildings including government and education could be flooded and 14 percent of residential properties are at risk for floods.

Those numbers all will rise over the next 30 years, the study found. Now, 12.4 million residential properties are at risk, and that is expected to rise by 1.4 million by 2051. The 36,ooo critical infrastructure facilities at risk from flooding now will add another 2,000 facilities over the next three decades.

The foundation used data to create its flooding model from the National Oceanic and Atmospheric Association, the Federal Emergency Management Agency and other federal sources and collaborated with 80 researchers and hydrologists, including those at Columbia University and the Massachusetts Institute of Technology. First Street has published the data, which can be looked up by zip code, for public access on its interactive website.  

While Maine towns may be aware of their existing flood risk, they may not know how vulnerable they may be in the future, Slovinsky said.

Kaylee Collin (right) and Spencer Stone walk through water along North Avenue in Camp Ellis in Saco, Maine, on Sunday, March 4, 2018, the third day in a row of flooding. Credit: Gregory Rec / Portland Press Herald via AP

“Some of the smaller streams that have not flooded in the past might start flooding,” he said.

Maine is laying plans to cope with flooding. The state’s four-year climate action plan released in December 2020 requires a statewide infrastructure vulnerability assessment, including transportation, water, energy and communications, to be completed by 2023 as well as developing design standards for resilience in infrastructure projects. Every $1 invested in pre-disaster risk reduction avoids $6 in disaster damages, according to the plan, which quoted National Institute of Building Sciences data.

Eby said the 25 percent risk to infrastructure nationwide is “absolutely crazy” and will be costly.

“It means that over a 30-year period, which is the period of some mortgages, there is a 25 percent chance that it could be flooded,” he said. “That’s something we need to address.”