The natural erosional processes that inevitably shape Martha’s Vineyard are being sped up by increased climate change and sea level rise.
With significant amounts of beach being taken back by the sea each year, and with the Earth entering a period of more intense and frequent storm events, the question of proper coastal zone management is brought to the forefront of public awareness.
According to Ben Robinson, Martha’s Vineyard Commission member and part of the Island Climate Action Network, Islanders have “an uphill battle” to fight against the retreat from the coast.
Although living on Martha’s Vineyard tempers some of the changes we might see from climate change, Robinson said, the other side of the coin is that “our Island is shrinking.”
The truth is that the Vineyard is always shrinking, and it always will be — but the rate at which the coastlines are receding is multiplied by how often we experience strong weather events, and how rapidly the sea level rises.
For Robinson, addressing erosion is all about assessing the values of the Island, and determining how much time and money we are willing to put into nourishing and restoring the coastline. “Do we retreat human activity from certain areas and allow those coastal resources to move and change? Or do we intervene?” Robinson asked.
Certain areas of Martha’s Vineyard experience much more intense erosion than other places with low wave action.
The south shore of the Island is constantly battered by intense tidal forces, and that will never change. But Robinson said the rate of erosion in that area is such that the question remains — “Are we going to continue to protect this resource? If we are, how do we go about doing that in a way that makes the cost worthwhile?”
The same goes for the Tisbury waterfront district. Although that area is on the other end of the erosion spectrum, one major storm event could have serious consequences for the working waterfront.
Newly generated stormtide mapping has become a useful tool in anticipating weather events and flooding, but what happens when a storm rolls over the Island the likes of which we’ve never seen?
Based on predictions by the National Oceanic and Atmospheric Administration (NOAA), by 2050, up to $106 billion worth of coastal property will likely be below sea level (if we continue on the current path). According to the Environmental Defense Fund, climate change is creating heavier rainfall during storms, and more Category 4 and 5 storms will be seen as the temperature continues to rise.
As weather patterns become more extreme, the oscillation between intense heat waves and cold snaps increases in scale, which does not bode well for our coastline. “If you go from a period of drought to a period of heavy downpours, that’s when inland erosion becomes a real problem,” Robinson said.
Inland erosion occurs when the integrity of the soil structure is lost due to a lack of roots or plant matter holding the soil together.
There is an ongoing effort to create more agricultural land on Martha’s Vineyard, but if that means clearing old forest, Robinson wonders whether some of our developed land could be put to better use.
He referred to the 40 acres of land recently purchased next to Ernie Boch’s property by Morning Glory Farm. The farm is retaining 30 acres under conservation, and clearing 10 acres for agricultural purposes. “Great, we get to grow more food on the Island, but we are clearing all this old forest to do it. Is that really the right strategy?” he asked. “Have we really exhausted all the other options for farming here?”
Ecologist and Tisbury resident David R. Foster literally wrote the book on the Island’s ever-changing coastline, “A Meeting of Land and Sea: Nature and the Future of Martha’s Vineyard.”
He said his preferred approach to erosion is to interfere with the natural processes as little as possible, and instead try to look ahead and anticipate how the Island will look a year from now, five years from now, or 10 years from now.
“Our Island is going to continue to be shaped by erosional processes, even without sea level rise and climate change. But with the rise, and with more intense and frequent storms, that is going to be exacerbated,” Foster said. “My basic approach is that the Earth has been supporting us forever, and the best thing we can do is allow it to continue doing that. Basically, leave nature alone as much as possible, because nature itself has incredible resilience.”
By changing development practices and accommodating the receding coastline, Foster said, we can work with nature, instead of trying to divert away from an inescapable fate.
“The classic example is, you do a really good job of fighting erosion in one area, and it just transfers all that energy from the ocean into another place. You dredge sand from one area, and that area is now more vulnerable,” Foster said.
Unless Island planners can grapple with these inevitabilities, the task of managing beaches and low-lying areas over time will grow more costly and cumbersome. Eventually, Foster said, a time may come when it’s too late to be proactive, and emergency changes will need to be made to protect our way of life.
The Vineyard has been spared from the full brunt of several hurricanes and winter storms over the past few decades, but those events are growing more unpredictable. Foster says a powerful storm could decimate the Island — it’s just a matter of time. “The most extreme storm the Vineyard ever experienced was in 1635. It had stronger winds and higher surges than anything we have ever witnessed. It had a surge in Buzzards Bay of 20 feet,” Foster said.
Trustees of Reservations manages the 12 miles of barrier beach stretching from Norton Point to the tip of the gut in Cape Poge. This area sees a high degree of wave action, which means high rates of erosion.
As the tidal swells from the Atlantic Ocean continuously pummel the south shore of the Island, the areas directly inland are of particular concern.
Salt marshes sit at the border between beach and inland moraine, and those areas are having trouble keeping up with sea level rise, Trustees director for the Island Sam Hart said.
The Trustees are conducting a number of coastal resilience interventions at Norton Point and Wasque Point. The first is a full dune restoration at the entrance of Norton Point — The Trustees are replacing approximately 800 feet of dune (14,000 cubic yards of sand), and the town is removing the changing stalls at the end of Left Fork in order to extend the dune across where the pavement would be. The project is slated to be shovel-ready by the fall, at least for the Norton Point entrance work. The new dune will run all the way down to the Trustees gatehouse.
“That’s the most heavy-handed approach,” Hart said. “You can do that, or you can manage retreat.” He offered the idea of creating an Island sand bank, so that towns could store dredge materials and apply them as needed to coastal areas that are most vulnerable.
“In the Netherlands, they spend 2 percent of their GDP on dredging sand. They use huge sand engines and take sand from the bottom of the ocean and pile it up to maintain their coastline,” Hart said.
Further east, along Norton Point, The Trustees are planting dune grass and considering additional fencing to help build up the dune that has been overwashing.
Out at Wasque, where the erosion is most dramatic, the Trustees are doing what they can to manage retreat. When the barrier beach separating Katama Bay from the ocean breaches, Hart said, the water that flows through the coastal corridor of the dynamic saltwater estuary causes the bank to erode at one of the highest rates in the country.
To anticipate the inevitable retreat, The Trustees are relocating their upland trails at Wasque — moving them back farther away from the bluff.
Each intervention or management initiative involves a great deal of planning and consideration to determine whether it’s the right investment.
Along with oversand vehicle standards for The Trustees and restrictions for the public — which have been conducted ad hoc by the organization — Hart said they are working on codifying some of those methods, and implementing them in future projects.
“What that means is you might see more corridor fencing to protect the toe of the dune, and more efforts to keep vehicles from driving over the dune grass,” he said.
As an opulent Island community that cares about our natural landscape and ecology, Hart said, we can look at what our focuses are, and direct our efforts in a coordinated and thoughtful way: “We need to say to ourselves that we may be fighting a losing battle, but this is where our values lie. The beaches that The Trustees manage are certainly disappearing in places — the community is going to have a hard time digesting the fact that they eventually might not be able to access them anymore.”