It’s never a good day when people lose their homes to a raging sea, whether they be summer beach houses or year-round residences.
Such is the case today on Plum Island, where half a dozen structures have been claimed by Mother Nature and up to 40 more are in jeopardy of further destruction.
The wind, waves and tides of the northwest Atlantic are relentless in their attack on Massachusetts’ fragile and vulnerable 1,500-mile shore.
Especially hard hit are the frontline defenses to the commonwealth’s coast — the 681 barrier beaches that make up almost a quarter of the Bay State shoreline. Plum Island is one of them.
These highly dynamic land forms migrate in response to sea level rise accelerated by global warming. The beaches are not disappearing, washing away or being destroyed, as the media so often claim, but are moving and reshaping themselves as they react to the forces of nature. The problem is when we build on those beaches and then attempt to stop them from moving beneath us.
Barrier beaches, such as Plum Island, generally consist of a narrow beach with the ocean before it, temporary wind- and wave-driven sand dunes in the middle, and a salt marsh, bay or harbor behind.
Together the beach, vegetated dunes, surrounding tidal flats and water comprise the barrier beach ecosystem. Left intact, these beaches provide storm buffers for both humans and wildlife that live in the uplands, marshes and embayments behind them.
A typical Massachusetts barrier beach tends to move landward. The strength of any barrier beach lies in its ability to roll over and re-establish itself as an ecological unit. This movement is generally caused by winter storm overwash, where waves carry sand from the ocean over the beach and through the dunes to the landward side of the barrier. Over time, if left unaltered, a barrier beach will respond to future storm overwash and rebuild itself at its new location, looking much as it did before the storm. In some areas, such as at the Cape Cod National Seashore, the rate of landward movement of barrier beaches can be as much as several feet per year.