Excellent article from Jack Clarke who spoke at our Firehouse event: BEACHES ON THE MOVE JACK CLARKE 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 the Plum Island where structures have been claimed by mother nature and 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, and 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 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. Any artificial alteration of a migrating barrier beach, however, can result in the interruption of the barriers equilibrium and can cause excessive beach erosion during severe winter storms. Oftentimes, the response to beach overwash, shoreline retreat, and flooding is to try to armor the beach with seawalls and other hard structures in an attempt to protect the beach and any buildings constructed on it. Unfortunately, these alterations, along with bulldozing of beach-front sand or so-called beach-scrapping, and the placement of rocks and boulders do not protect the beach, but instead place it at greater risk. These attempts to “stabilize” the beach interrupt natural beach-building processes, retard dune growth, and acerbate erosion of the beach itself and adjacent areas. These understandable yet futile and self-defeating responses can provide a false sense of security. At Plum Island, we have a situation that includes a highly dynamic barrier beach, residential and infrastructure development in the middle of the barrier, old stone groins at the water’s edge that interrupt sand that would naturally flow to and nourish the beach, a nearby Merrimack River stone jetty that robs additional sediment from the system, increased sea level rise with accelerated beach erosion, more frequent and severe nor’easters and super storms, and human attempts to hold the beach in place. This all results in a barrier beach whose ability to protect what is behind it greatly compromised and severely diminished. Fortunately, Massachusetts prepared for these types of situations following the Blizzard of ’78. Along with a Governor’s Executive Order that prohibits public investments in barrier beach development, coastal standards were established to ensure the natural functioning of beaches and dunes and limit their future development. These policies, however, are only as good as their compliance. It is thus up to the state’s environmental agencies to avoid future crises, such as we see at Plum Island, and enforce the law in a tough, fair and compassionate manner. Jack Clarke, a Gloucester resident, was chairman of the Massachusetts Barrier Beach Task Force in the Weld Administration, is a gubernatorial appointee to the Massachusetts Coastal Erosion Commission, is director of public policy and government relations for Mass Audubon.
Posted on: Wed, 12 Nov 2014 20:47:26 +0000
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