Oak Bluffs Plots the Future With Rising Sea in Mind

There’s been a great deal of focus lately on the local effects of the rush by federal and state authorities to build big wind farms near the Vineyard to ameliorate climate change, but very little focus on the local effects of climate change itself.

Except in Oak Bluffs, where there is quiet work underway to prepare for the worst, including sea level rise that is expected to erase beachfront property as it is now known, and the potentially ruinous effects of extreme storms caused by climate change. And it’s all backed by a state grant.

But first consider for a minute what a three-foot rise in sea level would mean to the Vineyard. Much of downtown Vineyard Haven and Edgartown would be inundated. Likewise the Crystal Lake and Farm Pond areas of Oak Bluffs. Most of Lobsterville would be under water, along with a lot of land on the flat shores of the Great Ponds. Hines Point would be an island and the new drawbridge cut off. State Beach would be largely gone, as would the beachfront at Quansoo and elsewhere.

A three-foot rise in sea level over the next century is now the general consensus among climate scientists, but some predict much more.

Chris Seidel, the cartographer at the Martha’s Vineyard Commission, has mapped out how the Island’s shape would change if the waters came up three or six feet. It’s an arresting document.

Experts say the lead times on climate change mean actions must be taken soon to limit consequences decades hence. And some effects of climate change, like extreme weather, are expected to be manifest much sooner.

Ms. Seidel has also produced maps which plot the location of structures on the Island against so-called SLOSH (Sea, Lake and Overland Surges from Hurricanes) maps from the National Oceanic and Atmospheric Administration.

Her works shows that 3,200 buildings on the Vineyard sit on land which could be inundated by the storm surge of a category four hurricane. Even a category one storm would put almost 400 buildings at risk.

A category two storm would cut off all routes but one to the Martha’s Vineyard Hospital.

Factor in higher sea levels and more frequent, stronger storms, and the magnitude of the planning problem begins to come into focus.

And Oak Bluffs is the one Island town that is doing something about it.

Last year Oak Bluffs became one of eight pilot communities working with the state office of Coastal Zone Management’s Storm Smart Coast program. Next week the fruits of that collaboration will be presented to Oak Bluffs selectmen, and later, assuming no glitches, to the annual town meeting.

What they came up with sounds a bit dry: amendments to the town’s floodplain overlay districts bylaw. But it could provide a strong foundation for dealing with future sea level rise.

In a nutshell, the proposed changes seek to limit building in areas likely to be flooded. Landowners in the most at-risk areas (designated V and AO zones) would not be allowed to expand their homes and would need special permission even to make significant repairs. The owners of parcels which now have no structures on them would not be allowed to build.

Homeowners in less risky areas (the A zone) within the floodplain would need a special permit before they could extend or do other work.

In total, about 190 parcels of land will be immediately affected by the changes.

“Currently, there are 138 residential parcels with development currently on them, which have the majority of their land in the A zone,” said Oak Bluffs conservation agent Liz Durkee, who was the driving force behind the collaboration with Storm Smart.

In the more stringently-restricted zones, she said, there are currently 37 built parcels and 13 undeveloped lots.

The purpose of the exercise, Ms. Durkee said, is to get more clarity into the process and to begin preparing for a future of higher sea levels and worse storms. And the floodplain bylaw changes are one part of a bigger suite of measures, including beach replenishment and a major rethink of how the coast can be protected from erosion, aimed at protecting the town, its infrastructure and environment.

“We want to be at the forefront of developing proactive, science-based floodplain protection measures in light of what is already happening, which is climate change,” Ms. Durkee said, adding:

“We’re basing our project on an anticipated sea level rise of three feet before the end of the century. That was considered to be at the upper end of estimates only a couple of years ago, but now the science is saying that’s a conservative estimate.

“The ice is melting, the seawater is warming and expanding and rising faster than the experts anticipated. It’s really kind of frightening. The Storm Smart program is designed to help Oak Bluffs be prepared for the impacts.”

This will affect health, safety and emergency services, roads, bridges and other infrastructure, surface and groundwater quality, beaches and dunes, master planning.

“That’s why we’re updating our regulations — to minimize threats to public health and safety, increase the town’s capacity to bounce back after a storm by reducing damage to personal and public property, protect the economy by lowering clean-up costs, and preserve recreation areas and quality of life,” Ms. Durkee said.

Ms. Durkee said the bylaw changes would not be draconian for most landowners.

“The vast majority are not going to be affected at all,” she said.

“And most of the people who are affected are in the A zone. If they want to do things to their property or expand their building, they would have to go to the zoning board of appeals for a special permit.”

That would be simply to ensure any construction meets current federal and state codes for structural integrity in a flood zone.

“That protects the homeowners as well as public health and safety,” Ms. Durkee said.

And while she conceded people living in the V and AO zones would be much more restricted, she said: “Not a lot of properties are affected by this.”

In fact, most already are limited in what they can do.

Most, if not all, the unbuilt lots already are unbuildable under current state and town regulations.

“For example, some are on a barrier beach, and you can’t under wetlands laws build a structure on a barrier beach in this day and age,” Ms. Durkee said.

But while the immediate effects of the bylaw changes are relatively minor, they can be expected in the future to affect many more than the 190-odd properties now within the floodplain boundaries, simply because as sea level rises, the floodplain too increases in size.

“We have to base our information on current FEMA [the Federal Emergency Management Agency] maps, because that is what FEMA national flood insurance program uses, and the town,” Ms. Durkee said.

But those maps are at least 20 years old, she said, and need to be updated. More than a decade ago, FEMA began work on revising the maps which form the basis of its flood insurance, assuming a one to three-foot rise in sea level, and a consequent, equal increase in the height of flooding.

“Because of all the hurricanes and storm damage in the South in the past few years, FEMA has been concentrating on them,” she said. “Updating flood maps in this part of the world seems not to be a priority. As part of this program we want to get FEMA moving on our updated maps.”

Instead of waiting for that to happen, though, Oak Bluffs began its own assessment of the risk, based on its assessors maps and with Ms. Seidel’s help.

The recently released Island Plan prepared by the Martha’s Vineyard Commission advocates limits on construction in areas likely to be affected by sea level rise.

It also notes that the relative rise in sea level would be almost twice as great here as in most places around the globe, because the Island is actually subsiding at a rate roughly equal to the current rate of the waters’ rise.

So far, though, Oak Bluffs is the only town to have proposed significant steps. Ms. Durkee hopes the MVC and other towns will follow suit.

“All the Island towns have such a mishmash of regulations and overlays and different departments that look at things in different ways,” Ms. Durkee said. “We need to plan for these changes.

“If roads get eroded away, how are people going to get to the hospital? How are rescue personnel going to get to people? What do we do if houses on the shoreline get damaged, if beaches are disappearing?”

Public health and safety issues cross town lines.

The issues are complex, but as Ms. Durkee said, the essential concern is simple.

“When you live on an Island,” she said, “you have to be concerned that the sea is rising.”

 

This article appears in February 5, 2010.