A residential neighborhood built a half-century ago 3 miles inland from the Portland waterfront will soon be part of a federally designated flood zone, a shock to homeowners who weren’t even aware of the tiny creek that now threatens their property values and family budgets.

The homes at issue are clustered on Alden Circle, Wayside Road and the north side of Brighton Avenue, an area of mid-20th century housing developments straddling the boundaries between the city’s Rosemont, Deering Center and Nason’s Corner neighborhoods. At first glance it appears to be as high and dry as any place in the city, 2 miles from Back Cove or the tidal flats at the head of the Fore River with no river in sight.

Hidden under a canopy of trees and shrubs at the edge of the neighborhood, however, is a modest creek that flows out of sight and mind of commuters passing over it on Brighton Avenue and homeowners living even a few hundred yards from its banks. And as the Federal Emergency Management Agency has reassessed flood risks nationwide in light of global warming and improved mapping technologies, the agency has concluded Capisic Brook will overflow and flood much of the neighborhood at least once a century, prompting one city official to suggest homeowners put their houses on stilts.

“We were certainly surprised when we got the postcard from the city informing us,” says Daniel Calles, whose family lives in a four-bedroom house built on Alden Circle in 1958. “We were aware of Capisic Pond, but we hadn’t even heard of Capisic Brook.”

The new FEMA maps are based on improved mapping technology and, in some areas, the impact of climate change, which is expected to bring increased precipitation and flooding events to Maine.

Other neighborhoods in Maine also are finding themselves in designated flood zones as maps are gradually updated nationwide. But those are typically in low-lying coastal areas where the residents are more aware of the increasing flood risks caused by climate change and rising sea levels.

Olivia Saucier, right, and Christina Strubbe look out over a culvert on the Capisic Stream in Portland last month. The new flood designation requires homeowners with federally backed mortgages to purchase flood insurance, with quotes ranging from $700 to $5,000 annually. Brianna Soukup/Staff Photographer

Chris Markesich, a risk analyst at the agency’s regional office in Boston, said the changes at Alden Circle were the result of improved topographic mapping conducted via Light Detection and Range (or LiDAR), which has a 2-foot contour elevation interval and is more accurate than what was used for the original 1986 map, which relied on 20-foot contours.

Homeowners who never thought they were at risk are now scrambling to price flood insurance and to hire surveyors to better determine the risks to their homes. In the months since they learned FEMA’s analysis of the risk was accurate, they’ve also discovered neighborhoods that find themselves in their situation have almost nowhere to turn to for help in adapting to the unexpected surprise.

“Similar to how property owners are responsible for assessing and mitigating the risk of fire to their property and creating an emergency plan in the event a fire occurs, protecting and preparing for the eventuality of a flood is ultimately the responsibility of private property owners,” city spokeswoman Jessica Grondin said via email.

Residents surprised by the map change initially sought information and assistance from the city, but say they soon discovered the staff had little time to help. They didn’t receive responses to a four-page set of questions sent to the city April 1st until mid-September and it became clear any assistance would be limited to helping contract a surveyor to provide the detailed calculations of how each home would be affected by the 100-year flood level.

Olivia Saucier listens to her neighbor Lois Winter talk about her flood insurance on their street, Alden Circle, in Portland. Many houses on their street and other homes around Capisic Stream are now considered to be in a flood plain. Brianna Soukup/Staff Photographer

“I think it’s sad when people in our group say the people in the city government are too overworked and stressed and underpaid to deal with more than one lone request at a time from us,” says Christina Strubbe, who expects her basement would flood in the 100-year event.

The map updates affecting Alden Circle are expected to go into effect in the spring of 2023.

Being included in a federal flood zone map – which comprises land that can be expected to be flooded at least once in a century – means a property’s owner must get flood insurance if they have a federally backed mortgage. The majority of home mortgages fall into this category, including those insured by the Federal Housing Administration, guaranteed by the Veterans Administration or U.S. Department of Agriculture, or held by Fannie Mae and Freddie Mac, government-sponsored companies that buy mortgages from private lenders.

The cost of that insurance varies based on the provider and on how much of a building lies below the base flood level on the FEMA map.

Alden Circle residents say they’ve seen quotes ranging from $700 to $5,000 a year for their homes, most which are one of three models built here by the original developers, the Minat Corporation, between 1958 and 1964. The higher figures often exceed their annual property tax bill. The real estate site Zillow currently estimates the values of all the affected homes at between $300,000 and $500,000.

The Federal Emergency management Agency has concluded that Capisic Brook, just off Brighton Avenue in Portland, will overflow and flood much of the Alden Circle neighborhood at least once a century. Brianna Soukup/Staff Photographer

Many have a larger concern about how being in a designated flood zone will affect their homes’ resale value, and about the long-term future of a neighborhood where residents typically stay for decades and go on nightly dog walks together.

“Maybe it’s putting a tragic spin on it, but what will this do for the vibrancy of the neighborhood over time,” says Olivia Saucier, who bought here in 2016. “We’ve lived in different countries and in many parts of the U.S. and have never been in a neighborhood like this where people really know each other.”

The Alden Circle area appears to be far and away the largest residential zone in the coastal counties of Maine to unexpectedly find itself inside FEMA’s new round of flood zone maps, which replace those from the 1980s and early 1990s, when climate change wasn’t yet part of the public discourse and mappers relied on low resolution geographic contour data from paper maps. There are larger inhabited areas under greater threats – a swath of downtown Machias and strips of vulnerable waterfronts from Saco to Stonington, for instance – but most of those are places that expected to be in harm’s way. Most of Alden Circle’s homeowners had no idea.

Olivia Saucier holds a map of her neighborhood that shows the flood zone. Brianna Soukup/Staff Photographer

“The good news is that Maine has been fairly prudent in our flood plain development compared to what happens nationally, but there are going to be some surprises and disruptions,” says David Reidmiller, director of the climate center at the Gulf of Maine Research Institute in Portland, which assists coastal communities in adapting to a warmer world. The Portland waterfront itself, he notes, is relatively protected from the worst aspects of coastal storms, and most of it is several feet above sea level, providing buffering for storm-driven flood surges and rising seas.

Some inland property owners have gotten good news in recent years, as FEMA has rolled out new flood zone maps largely on a county-by-county basis. For example, the removal of dams on the Penobscot and lower Kennebec rivers also eliminated the lake-like impoundment areas behind them, lowering river levels and shrinking the flood zones.

“It’s really a mixed bag,” said Sue Baker, the state’s national flood insurance program coordinator, who is based at the Department of Agriculture, Conservation and Forestry. “There are a whole lot of coastal communities where buildings are being drawn into the new flood zones, but in inland communities they’re being taken out of them.”

Lois Winter, a retired conservation biologist who lives on Alden Circle, questions the methodology federal officials used in their decision to expand the floodplain for Capisic Brook. Brianna Soukup/Staff Photographer

Cumberland and York counties are the last in coastal Maine to receive their revised FEMA flood zone maps, which have been finalized in recent years in most communities further east. 

Alden Circle-area residents first learned of the new flood zone in 2017 and believed the boundaries must have been an error and would be overturned. But a review by the City of Portland conducted late last year concluded FEMA was right: Capisic Brook would, in a 100-year flood event, create a lake behind the large culverts under Brighton Avenue and nearby Lucas Street that would inundate most properties on Alden Circle and adjacent Wayside Road, as well as part or all of another dozen on Brighton Ave.

The property owners first realized the threat was real during a March 23 virtual meeting with city officials, during which city engineer Gerard Remsen delivered a sobering assessment: Residents should buy flood insurance and consider raising their homes on 10-foot stilts. Engineering an infrastructure solution would be impossibly expensive for the city, he noted.

City officials say it would cost more than $110 million to widen the culverts sufficiently to deal with the 100-year event, a project that would require converting the culverts to bridges and reconstructing a 2-mile-long section of Brighton Avenue. Thirty homes would have to be demolished to make it happen. Nor is it possible to create a detention area for the floodwaters as there isn’t enough undeveloped land in that section of the watershed to do so.

While no one appears to be taking the advice about stilts, the warnings have prompted homeowners here to seek help from the city to secure surveys of all the properties in the neighborhood to tell them how a flood would affect their properties. At least one, concerned about delays, hired one herself.

Lois Winter, a retired conservation biologist for the U.S. Fish & Wildlife Service who lives on Alden Circle, says she has a lot of questions about the methodology and data FEMA used in its decision to expand the floodplain for Capisic Brook, which runs along the southern edge of her backyard.

But she also has a pretty good idea what the 100-year flood will look like.

When Winter had her house surveyed for flood insurance, the surveyor concluded that the basement would flood but her living areas would remain above water.

Winter also was living here in October 1996, when southern Maine experienced a storm that dumped nearly 15 inches of rain on Portland, left Route 302 underwater in Westbrook and damaged 2,500 homes in southern Maine.

The U.S. Geological Survey later reported the flood levels at three nearby waterways, including Capisic Brook where it goes under Brighton Avenue, exceeded what was then the expected 500-year flood level.

While some residents nearest to the brook experienced flooding, many did not.

Lois Winter points out where the water would come up to her home in a “100-year flood” on their street, Alden Circle, in Portland. Brianna Soukup/Staff Photographe

Winter said that storm brought Capisic Brook up to the edge of her foundation.

“It was a 500-plus-year flood event,” she recalls. “But the sump pump was operational and we had zero water in the basement.”

Winter wondered why, if a 500-year flood event presented no real threat to her home, a 100-year one is now expected to be about as bad.

The person who analyzed the 1996 flood, Gregory J. Stewart – now the U.S. Geological Survey’s associate director for hydrologic monitoring throughout New England – said he didn’t know the specifics of the new survey, but that even a few small changes in infrastructure can dramatically change the way a heavy rainfall event plays out in a watershed.

“Sometimes a small change to culverts or bridges or dams can result in a very big change in water surface flood elevation,” Stewart said. Add to that the improved mapping of the floodplain, and it’s not so surprising that the maps for a 100-year event may have changed substantially in an area upstream from two culverts and a dam, he said.