How Shoreline Science Guides Northeast Coastal Parks After Hurricane Sandy

By Minh Phan, National Park Service.

NPS.

On a summer day at Herring Cove Beach, Cape Cod National Seashore, beachgoers buy cold drinks at the concession stand and rinse off sand at the showers, probably without noticing that the buildings are modular. As rising seas worsen storm surges and erosion, the National Park Service can move them further inland and extend their life.

Coastal parks have long been living laboratories for scientists studying how storms, erosion and longshore drift change the coast and the structures along it. With so many buildings on the edge of land and sea, the Park Service is redesigning or relocating boardwalks and buildings to keep people's favourite summer places open. Hurricane Sandy underlined the need for this science to plan for an uncertain future.

The tools

Hurricane Sandy recovery funding made it possible to study the shorelines the storm hit, in some places comparing them before and after.

• GPS surveys capture snapshots of where the coast lies, and precise surveys now record both the position and the height of the shoreline, so researchers can estimate the volumes of sand protecting what lies inland.
• Jet skis and amphibious vehicles gather data on the underwater terrain that drives coastal change.
• Aircraft and laser scanners provide high-resolution data showing in detail how the sea washes away and rebuilds dunes and other landforms.

Together they tell planners how fast a beach is moving and where facilities can safely go.

Gateway: a road built to wash away

Eight million people use Gateway National Recreation Area, camping at Floyd Bennett Field, sunbathing at Jacob Riis Park and exploring New York City's history. The park uses shoreline science to set priorities for natural and cultural resources, maintenance and visitor experience. In 2012 Hurricane Sandy destroyed a beach access road on the ocean side near Fort Tilden. Because the road matters to residents and is an emergency evacuation route, the Park Service is rebuilding Shore Road sustainably: clay topped with shells, natural materials that will do less harm when future storms wash them away — and that cost less than repaving.

Chincoteague: moving the beach

Shoreline research at Assateague Island National Seashore also helped nearby Chincoteague National Wildlife Refuge in Virginia. The recreational beach and parking area near Toms Cove, on an exposed narrow strip of land, changes by sixty feet a year from storm surge and flooding, and repairs have cost several million dollars since 2003. Guided by research showing which parts of the refuge are less exposed to wind and waves, managers decided to move the parking lot 1.5 miles north to a more stable, protected site.

Fire Island: letting nature work

Managing the coastal features themselves is a different challenge, because the Park Service's job can mean protecting the natural processes that shape the shore. Hurricane Sandy's surge and waves opened three breaches — channels between ocean and bay — in the barrier islands off Long Island's South Shore. One lies in the Otis Pike Fire Island High Dune Wilderness, a federally designated wilderness at Fire Island National Seashore.

The park had wanted to learn how such natural breaches affect the land and water around them, and the 2012 breach gave the Park Service and its partners a chance to watch a new one form and move. Carried by the natural flow of sand around the island, it migrated westward until 2013, when it began to stabilise.

Erosion and drift remove sand in some places but can moderate change in others. Sand building up on the bay side of the Wilderness Breach will feed the marshes behind Fire Island, letting them build upward to keep pace with sea level rise and further protecting the island from future storms. The Park Service will keep monitoring the breach's size, shape and effects on the park.

Why it matters

From climbing a favourite lighthouse to a morning walk on the beach, many of the coastal places visitors love face stronger storms and rising seas. Investing in shoreline science guides long-term planning, so that vulnerable natural and cultural features are protected for future generations.

Sources

• Minh Phan, "Studying Shifting Shorelines at Northeast Coastal Parks", National Park Service. https://www.nps.gov/articles/studying-shifting-shorelines-at-northeast-coastal-parks.htm
• Correction: the source calls the wilderness the "Otis Pike Island High Dune Wilderness"; its name is the Otis Pike Fire Island High Dune Wilderness.
• Rewritten in hubnx's own words.