Studying Shifting Shorelines at Northeast Coastal Parks

NPS Photo

By Minh Phan

On a summer day at Cape Cod National Seashore’s Herring Cove Beach, you can find beachgoers cooling off with ice cold drinks at the concession stand or rinsing sand off in the showers. While visitors may not notice, there’s something quite unique about these facilities -- the concession stand and restrooms are modular. As sea levels rise and exacerbate the effects of storm surges and erosion over time, the National Park Service (NPS) can extend the life of these facilities by relocating the building further inland.

Coastal national parks have long been a living laboratory for shoreline scientists to study how storms and other processes like erosion and littoral drift affect the coast and the structures perched along the water.

With so many structures teetering on the edge of land and sea, the NPS is working to preserve access to the places people come to for summer fun. NPS facilities like boardwalks and buildings are being redesigned or relocated to ensure people can continue enjoying these attractions. Hurricane Sandy underscored the need to continue these studies and to rely on this science to plan for an uncertain future.

Hurricane Sandy recovery funding provided the unique opportunity to study shorelines that were impacted by the powerful cyclone and, in some cases, to compare shorelines before and after the storm. Methods for tracking shoreline position change have been refined over the years and help us understand how shifts in the land-water boundary take place over time. GPS data are used to capture snapshots of coastal boundaries, and technological improvements are providing park researchers with innovative methods for studying the shoreline and neighboring coastal landscapes in three dimensions. Precise coastal surveys can now indicate the position and the elevation of the shoreline, so researchers can estimate volumes of sand that protect the inland features of the coast.

Jet skis and land-to-sea amphibious vehicles help experts collect information on the underwater terrain that influences coastal change. Other sophisticated methods, including airplanes and state-of-the art laser scanning instruments help contribute a wealth of high-resolution data that reveal a detailed understanding of how sand dunes and other physical landscapes are washed away and replenished by the sea. All of the information collected gives context to park planners on how quickly the beach is shifting and identifies areas where facilities can be safely located.

At Gateway National Recreation Area, eight million people enjoy the park’s many activities, including camping on Floyd Bennett Field, sunbathing at Jacob Riis Park, and exploring the rich history of New York City. This urban national park uses shoreline science to prioritize the management of natural and cultural resource projects, the maintenance of park facilities, and the enhancement of overall visitor experience. In 2012, Hurricane Sandy destroyed a beach access road on the ocean side of Gateway near Fort Tilden.

Understanding that the road is important to local residents and serves as an emergency evacuation route during storms, the NPS decided to restore this important route with an eye towards sustainability. Shore Road will be rebuilt with clay and topped with shells so the natural materials will have less of an impact on the environment when washed away in future storms. Additionally, using this more cost-effective alternative will reduce expenses that may be required to repave the road.

Shoreline change research at Assateague Island National Seashore has also provided guidance to nearby Chincoteague National Wildlife Refuge in Virginia. There, resource managers made the decision to move a flood-prone recreational beach and parking area on an exposed narrow strip of land. The current beach and parking lot near Toms Cove sees sixty feet of change annually from storm surge and flooding. With repairs costing several million since 2003 and shoreline science research pointing to areas of the refuge less impacted by wind and waves, officials decided they will move the parking lot 1.5 miles north of the current location to a stable more protected location. This will ensure visitors to Chincoteague will have the proper accommodations to enjoy the beach.

While many parks use shoreline change research to adapt and make physical modifications to their resources, the management of the coastal features, themselves, proves to be a unique challenge. The NPS is charged with protecting coastal parks, which can mean protecting the processes that have shaped and will continue to shape the shoreline.

Along the barrier islands off of Long Island’s South Shore, the storm surge and powerful waves from Hurricane Sandy created three breaches -- or channels connecting the ocean and bay. One of these breaches is located within the Otis Pike Island High Dune Wilderness, a federally designated wilderness area at Fire Island National Seashore.

Before the wilderness breach, officials at Fire Island wanted to learn more on how these naturally occurring features might affect the surrounding land and water environments at the park. Since the breach opened in 2012 after Hurricane Sandy, the NPS and partners were granted an important opportunity to observe a newly created breach and monitor its movements over time. Due to the natural flow of sediment and sand around Fire Island, the breach began to migrate westward up until 2013, when it began to stabilize.

While erosion and sediment drift are often associated with the loss of sand in certain areas of the coast, these processes can also moderate change in other parts of barrier islands. The observed buildup of sand on the bay side of the Wilderness Breach will provide sediment to marshes that lie on the bayside of Fire Island. This will allow marshlands to grow vertically and keep pace with sea level rise, giving further protection to the island for future storms. While an abundance of information has been gathered from studying the breach, the NPS will continue monitoring this dynamic coastal feature, tracking changes to the its size, shape, and impacts on the park well into the future.

Whether it’s climbing to the top of a favorite lighthouse or taking a peaceful morning stroll on the beach, many of the beloved coastal resources visitors enjoy face challenges associated with strong storms and rising seas. The NPS recognizes the value of understanding these processes and investing in shoreline science research, which provides guidance on long-term planning. By protecting vulnerable natural and cultural features at coastal parks today, the NPS will ensure that future generations are able to enjoy these coastal gems for years to come.