On many days, Apple Street looks like a picture postcard of New England. Oaks shade a time-worn stone wall, boat sheds loll behind granite outcrops. But during storms, this pretty lane only a few feet above sea level can turn into a moat, cutting off an emergency shortcut that ambulances count on when Essex’s main street floods several times per year.

Whether a short section of Apple Street should be raised – and its giant trees uprooted – has become a flash point in a broader debate stretching across the rocky Cape Ann peninsula north of Boston: how, exactly, to live with rising water.

Should the sewage treatment plant that overflows into the harbor during heavy rain be protected with a seawall or moved uphill? Which earthen berms should be removed to let marshes return and absorb future storms? And how to pay? The municipal math is unforgiving: As rising seas claim high-value waterfront homes, the property tax base erodes.

“There’s no starting gun on climate change adaptation – it’s already happening,” said Charles Waldheim, professor of landscape architecture and director of the Office for Urbanization at Harvard’s Graduate School of Design.

For the past five years, with local, state, and federal funding, Waldheim’s research group has been simulating a stress test on Cape Ann’s future. Collaborating with neighborhood groups and nonprofits, the team has modeled a Category 3 hurricane to see what breaks first, compared incipient sea-level rise to mid-century projections, and convened residents with wildly different backgrounds – retirees and fishermen, low-income immigrants and wealthy landowners – to discuss local capacity, collaborative decision-making, and visions for an uncertain future.

The point is not spectacle but evidence – to show how storm surge might slice through roads, strand neighborhoods, and strain the social ties people count on in crisis. The simulation surfaces secondary and tertiary impacts: the pump that fails, the clinic that closes when staff cannot cross town.

The researchers believe that resilience will be built from the bottom up, across overlapping jurisdictions. So the work links tangible fixes – wetland restoration, smarter siting – with the harder task of building trust across four towns that are together home to about 50,000 people: Essex, Gloucester, Manchester-by-the-Sea, and Rockport.

“Climate change doesn’t stop at a town boundary,” said Diane Davis, an advisor to the project and co-investigator on the Salata Institute’s Strengthening Communities climate research cluster.  

The Harvard team brings together the best-available science and lessons from elsewhere, but researchers insist their three-phase report is not a plan.

“Ultimately, decisions about the future of Cape Ann should be made on Cape Ann,” Waldheim said at a presentation of the final recommendations at Gloucester City Hall in late November.

The hard work is only just beginning, acknowledged Valerie Nelson, whose organization, The Cape Ann Climate Coalition, partnered with the Harvard team.

“We must learn lessons from the past about what we care about and what, for us, resilience and survival mean,” she added, because “there is absolutely no central plan.”

Holding back water, holding onto place

Tides now reach noticeably higher than during the 1970s and 1980s, when today’s working-age adults were kids. Beaches are washing away. Parking lots now routinely turn into ponds.

While seawalls may be a tempting fix, armoring coastlines with concrete can choke tidal ecosystems and upend a core aspect of Cape Ann’s identity: the maritime culture and fishing industry. Four-hundred-year-old Gloucester, the largest of the four towns, bills itself “America’s oldest seaport.”

Already, compared with a generation ago, there are fewer mussels in the mudflats and scarcer spawning grounds for the herring and eels that feed commercial stocks of cod, bluefish, and striped bass.

“Putting a seawall here would protect these houses,” said project leader Sarah Page, pointing at a map. “But it would destroy the marsh system, kill the clams that live there – and with them the fried-clam industry that is part of everyone’s cultural memory of Cape Ann.”

The Cape “has a variable hydrological condition that depends on water moving the way that it needs to move,” added Page, a lecturer in urban planning and design.

Restoring salt marshes can blunt the energy from a future storm, but that may mean retreating from some properties – an idea gaining traction with some state officials in Massachusetts and elsewhere. Building resilience to a wetter future demands trade-offs.

That’s a challenge facing the residents of Apple Street.

“Those trees are part of the identity of the street,” Page said of the oaks. “But so is the idea that an ambulance can get through in a storm.”

All perspectives expressed in the Harvard Climate Blog are those of the authors and not of Harvard University or the Salata Institute for Climate and Sustainability. Any errors are the authors’ own. The Harvard Climate Blog is edited by an interdisciplinary team of Harvard faculty.