Editor’s note: This story was reported by students in the University of Connecticut’s environmental journalism class, led by Professor Christine Woodside, an environmental writer and former Day reporter/editor. Students who contributed to this story are Sara Bedigian, Robbie Hetzer, Ketel Nkuili, Sandra Maina, Paris Phillips, Blessing Reynolds, Alicia Rodriguez-Monge, Kirk Ross, Dan Stark, and Anna Zimmermann.

Groton ― To get a sense of how rising seas and more intense rainstorms could change life on the coast, consider how Hurricane Sandy landed on the tiny waterfront Groton-New London Airport in late October 2012.

The runways flooded, and the airport could not operate for two days. Instrument flights ― with only the assistance of instruments in poor visibility ― and night flights halted for many more days because the runway lights had to dry out.

Weather and climate records, and the Intergovernmental Panel on Climate Change, are documenting that heavy storms and a steadily rising sea level are inundating roads with more frequency than a few decades ago.

Groton-New London Airport is situated just 5 to 6 feet above sea level, nestled at the edge of Baker Cove and the Poquonnock River mouth, hosting about 50,000 private and government planes each year.

About a mile away, South Road, one of the two roads leading to the airport, flooded on Jan. 13 after heavy rains fell overnight.

Two days before that rainstorm, first lady Jill Biden landed here in a 737 to visit the crew of the submarine USS Delaware (SSN-791).

Airport officials have confirmed that they will include a study of flood risks when they begin work on updating a report that looks at all airport operations in Connecticut every several years.

“We’re going to try to get it into plan this year,” said Bob Bruno, the director of planning, engineering, and environmental services for the Connecticut Airport Authority (CAA), which manages this airport and five others, including Bradley International Airport in Windsor Locks.

“That’s our goal,” he said during a phone interview. “It will take some time, but we anticipate it within the next year or two.” And Bruno acknowledged that “sea level rise could potentially affect operations at the airport in the future.”

The airport authority maintained in interviews this spring that Groton-New London’s 5,000- and 4,000-foot-long asphalt runways have not flooded in the last two years, which were years of normal rainfall in the area. Bruno said the airport monitors its runways and parking lots and is aware of ocean trends and flood risks.

John Moody, director of general aviation for the CAA, said in an interview at the airport that the airport’s runways are crowned ― the asphalt is higher in the center than at the edges, to shed and drain water, like highways.

Bruno said the airport parking lot is more likely to flood first because it is located on slightly lower ground than the runways.

The runways are technically four runways, because each span can handle two-way plane traffic. These runways end less than 100 feet from the shoreline.

Climate and storm trends show the sea in southeastern Connecticut has been rising steadily and is projected to rise between 13 and 18 inches above the 1994-2014 baseline level by 2050, according to the Intergovernmental Panel on Climate Change.

In 2019 UConn Marine Sciences Professor James O’Donnell, whose expertise is ocean processes, recommended that the state plan for up to 20 inches of rise by 2050. The recommendation he gave through UConn’s Connecticut Institute for Resilience and Climate Adaptation (CIRCA) is used in planning for state development projects.

“Note that this is the upper bound of what is likely,” O’Donnell said in an email. “If you are building a road or a treatment plant, then that is prudent. The best guess is about half of that, but then there is a 50% chance that it will be higher.”

Groton-New London Airport and surrounding coastline shown in a 2022 satellite image

Researchers at UConn say Connecticut’s coastal communities should plan for a 20-inch rise in sea levels (outlined in blue) by 2050

The scenarios worsen when storms add to higher sea levels. This shows the impact of a 10-year flood on top of a 20-inch sea level rise. (A 10-year flood event is a flood that has a 10% chance of occuring in any given year.)

A 30-year flood event would leave virtually all of the runway areas at the Groton-New London Airport under water.

A 100-year flood event, which has a 1% chance of occuring in any given year, would look something like this.

Flood-prone area

The last Groton-New London Airport Master Plan in 2013 updated a 1999 plan, looking at the airport’s future demands and financial analyses. The document noted that Groton-New London Airport lies within a “100-year floodplain,” which means that in any given year, this area has a 1% chance of flooding.

Another way a property owner might define a 100-year floodplain is “those areas have at least a one-in-four chance of flooding during a 30-year mortgage,” FEMA reports on its flood map website.

The plan noted the airport is located entirely within a coastal flood hazard area, and that part of the parking lot floods during major storms. Some parts of the plan were updated in 2017, and the document is on schedule for its next update this year, Bruno of the CAA confirmed.

The old plan said the safety areas at the end of the runways had sometimes flooded during hurricanes or other storms. Tower Road, one of the roads to the airport, floods in major rain during high tide.

Federal government flood maps confirm that the entirety of the Groton-New London Airport is vulnerable to flooding.

According to the maps, each area highlighted in light blue represents land that exceeds a 1% chance of experiencing a flood each year. The Federal Emergency Management Agency creates these maps to monitor these areas of land, which are considered to be at a “high risk” of annual flooding.

The frequency and intensity of storms in the region has been increasing for many years.

Although rainfall varies tremendously from year to year in Connecticut, the overall trend the last century has been toward a wetter state. Flooding near the coast is worst when sea-level and tides meet big rainfalls.

High rainfalls have been dramatic in the last five years: in 2019, more than 54 inches fell on the airport, according to the National Weather Service data from that site. This was almost 15 inches above the 39-year “normal” amount the service expects. But there have been low-rain years too, such as 2014, when just over 18 inches fell all year at the airport.

Connecticut’s developed coastline is at risk for high tide flooding, which will impact roads, homes, businesses, and other infrastructure.

Sunny Wescott, chief meteorologist of the Homeland Security Cybersecurity and Infrastructure Security Agency, wrote in a report last year that “research predicts that the 21st century’s tropical cyclones will likely occur over a wider range of latitudes than has been the case on Earth for the last 3 million years.”

“This means that more tropical cyclones such as tropical storms and hurricanes will extend further north,” University of Connecticut Sea Grant ecologist Julianna Barrett said, “and more storms may impact New England.”

CIRCA’s Connecticut Physical Climate Science Assessment Report (PCSAR), published in 2019 by six UConn scientists, found that, since 1980, the intensity of individual storms in Connecticut has increased. It also reported that the state has been getting more days with 1 inch or more of precipitation at a time, more days with heavy rain, and higher daily precipitation totals.

The report compares changes in precipitation to the increase in greenhouse gases in the atmosphere. It said that precipitation’s intensity in individual storms will increase while the frequency of rainstorms will decrease. This combination is predicted to increase both flooding risks and drought risks.

Groton’s resilience efforts

The Town of Groton has spent many years assessing the impacts of climate change and is now focusing on drafting strategies to enhance its resilience. The town hired a sustainability and resiliency manager about a year ago whose sole focus is the rising sea level and flooding issues and ways to resolve them.

Concerns about rising sea levels and extreme weather events have prompted proactive measures to safeguard against potential disasters.

Groton officials are prioritizing coastal flooding, stormwater management, and heat resilience to keep residents safe.

The town is working on structural improvements like backflow preventers, creating flood response plans and other measures to handle the changing landscape, collaborating with CIRCA.

Jonathan Reiner, director of the town’s Office of Planning and Development Services, said Groton received a $200,000 state grant to safeguard the downtown Mystic area from rising water. In the summer, the town will start working on a five- to 10-year climate action plan. The town has also received grants for studying the use of permeable pavements that allow rainwater to seep into the ground instead of rushing into waterways.

A look at Logan Airport’s flood risks

A larger waterfront airport has been dealing with the specter of flooding, too. Boston Logan International Airport, bordered by Boston Harbor, is also susceptible to sea level rise. According to the National Park Service, the sea level in Boston Harbor has risen 10 inches since the start of the Industrial Revolution and is estimated to rise another 2 to 4 feet by the end of 2100.

The Massachusetts Port Authority, which oversees Logan, began the Massport Resiliency Program in 2013 to prepare for the impacts of climate change.

The program created a design guide for “floodproofing,” most recently revised in 2018. It is supposed to minimize flood and property damage and protect passengers, occupants and workers.

The guide explained the resilience initiative was created as South Boston faces an increase in flooding hazards caused by storms and rising sea levels as a result of climate change. It was launched after the impacts of the Hurricanes Sandy and Irene and winter storm Nemo.

Massport hired Kleinfelder Northeast to perform a “Disaster and Infrastructure Resiliency Planning Study” to focus on the risks associated with climate change, specifically coastal flooding.

The city of Boston is also working on ways to reduce flooding risk along the East Boston waterfront.

About the maps

The Connecticut Institute for Resilience and Climate Adaptation at the University of Connecticut has recommended that planners anticipate a 20-inch sea level rise in Long Island Sound by 2020. The projection uses National Oceanic and Atmospheric Administration data modified to include the effects of local oceanographic conditions and land movement, as well as more recent data and models.

CIRCA researchers also modeled storm surge water levels. The models were calibrated to account for the “complexity of Connecticut’s geology and landscapes.” A 10-year flood event has a 10% chance of occurring in any given year. A 100-year storm has a 1% chance of occurring.

You can find more information at circa.uconn.edu.