If sea level rise projections become reality and high tides a century from now resemble what today are major floods, the Aquarium Blue Line Station would likely be underwater while across the harbor the Spaulding Rehabilitation Hospital will be better prepared to weather frequent incursions of harbor water, according to Boston Harbor Association Executive Director Julie Wormser.

“By mid-century, every year the T’s going to have to deal with a foot and a half of seawater. By the end of the century it’s dealing more with five feet of seawater,” said Wormser, who said the Aquarium Station would need to be moved.

She said, “People have mentioned doing giant sea dams across our Boston Harbor Islands. I don’t know what that would do for all the money we spent on the cleanup, for one, but it also would sap all of our money to do anything else. What do you do with the water? You can’t keep back the tide?”

Officials from San Francisco, Louisiana and the Netherlands traveled to Dorchester’s JFK Library on Tuesday, carrying with them schematics and animations that depicted flooding scenarios that in the case of the Netherlands nearly swallowed the whole country, and discussed ways to reroute floodwaters and build large, protective sandbars.

In the Netherlands, parkland has been built to serve as temporary retaining ponds, or polders, during major floods; rivers have been reconfigured; and a city provided beach parking and reinforced the sand dunes at the same time by constructing an underground garage by the shore, said Royal Dutch Embassy Senior Economist Dale Morris.

“They get it. They get it. We don’t. It’s as simple as that,” said William Golden, executive director of the new National Institute for Coastal and Harbor Infrastructure, who said the impending sea level rise will be “the biggest business opportunity for engineering firms in this country.” He said, “The Dutch are coming over here and they’re eating your lunch.”

Boston does not face the altitudinal problems borne by much of the Netherlands and New Orleans, where substantial areas lie below sea level, however the sea level is projected to rise faster in Massachusetts Bay than the North Sea, where storms are less violent as well.

Much of Massachusetts has a hilly landscape and solid bedrock beneath, unlike southeastern Florida, which has little high ground to seek safety and sits on porous limestone, as Broward County official Jennifer Jurado described, saying water can rush up the Everglades flooding homes inland on the peninsula state.

The shape and makeup of Boston Harbor provides better protection from a massive storm surge than New York City, which was inundated with water when Super Storm Sandy’s landfall coincided with high tide a little more than a year ago.

“We located our state’s capital in a very, very good harbor. It doesn’t mean that the rest of Massachusetts doesn’t get hammered. So during Sandy while Boston was getting 2-foot waves, Scituate and Gloucester were getting 25-foot waves,” said Wormser.

“No one likes to hear it but the fact of the matter is we’re not going to be able to armor everywhere; we’re not going to be able to drain everywhere. There are going to need to be very real, hard choices about what areas we’re going to need to protect and what areas we are in fact going to have to walk away from,” said Scituate Selectman Richard Murray, who is a Boston University professor of oceanography. He said, “We’re not talking about next Thursday at 3:15 everybody’s going to get out.”

Murray said federal incentives for restrictive zoning should be used and areas should seek “managed retreat” from the sea, as was the case in the period since the Blizzard of 1978 when the roughly 50 homes on Peggotty Beach before the storm dwindled to 15 today, he said.

The talk took place at the presidential library, which sits on the harbor’s edge, next to UMass Boston, where a new academic building is also under construction. The talk also coincided with news of the devastation wrought late last week by Super Typhoon Haiyan’s path across the Philippines, which a few speakers referenced.

U.S. Housing and Urban Development Senior Advisor Josh Sawislak, who was a member of the President’s Hurricane Sandy Rebuilding Task Force, said, “We don’t know what the next storm will be like.”

Sawislak, who worked on the Big Dig project, said the task force recommended regional collaboration, fiscal sustainability, and efficacy when undertaking projects to handle rising seas and storms.
“Starting with recovery is the loser’s game,” Sawislak said.

The Spaulding Center has prepared for its perch near the harbor by putting electrical systems on the roof, keeping its vital program areas on the upper floors, while conference rooms occupy the bottom levels and the landscaping outside is well designed to handle flooding, Wormser said.

Massachusetts Water Resources Authority Advisory Board Executive Director Joe Favoloro said the Deer Island Waste Treatment Plant had been protected and built at enough elevation to keep it out of the surf, and said, “Most of the MWRA projects are not at a severe risk.”