State of the Beach/State Reports/NY/Beach Erosion
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Hazards on the New York's marine coast include storm surge, tidal inundation, shoreline erosion, bluff failure, and flooding from high rainfall events.
Approximately 47% of New York's shoreline is critically eroding, according to the report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores" (T. Bernd-Cohen and M. Gordon), Coastal Management 27:187-217. 1999.
The average coastal erosion rate along the south shore of Long Island, NY has been calculated at 1-2 ft/year. This erosion rate is relatively small compared to most of the rest of the East Coast. The beaches along the south shore of Long Island are relatively stable but tend to experience significant erosion during major coastal storms. Although not well understood by the general public, breaches, washovers and inlet migration are natural processes that help accumulate sand for natural protective features such as dunes, beaches and marshes. Prevention of these processes could lead to long term instability of the coastal barriers.
According to the Office of Communities and Waterfronts (C&W) website, ongoing coastal erosion and flooding present complex problems that must be addressed by coastal residents, coastal users, and all levels of government in the state. C&W is undertaking actions which are intended to correct past mistakes and improve decision-making. These include implementation of sand bypassing at inlets to restore the natural system of shore protection, erosion monitoring to enrich the coastal processes database for making informed coastal management decisions, and technical assistance to all levels of government to ensure best management practices in addressing site-specific problems.
A cooperative program has been established by NYSDOS with the US Army Corps of Engineers, New York Sea Grant, and local governments to monitor coastal erosion on barrier islands and beaches along the south shore of New York City and Long Island. The New York Sea Grant Website provides a nice summary of erosion issues and New York's collaborative monitoring effort in the Winter 2000 issue of its Coastlines publication.
Erosion data for the south shore of Long Island are kept by NYSDOS, the U.S. Army Corps of Engineers, and New York Sea Grant. Erosion data were last updated in Spring 2003. Erosion information on the entire New York coast is kept by the Department of Environmental Conservation (DEC). Coastal Erosion Hazard Area maps are available for the coast of New York from the DEC.
C&W continues to participate in the New York Atlantic Coast Monitoring Program (NYACMP). Since its inception in 1995, the NYACMP has been gathering data on shoreline conditions along the south shore of Long Island and distributes data to local governments for hazard management. NYACMP partners have developed a data viewer Website for coastal managers, planners, and government officials. Officials have been able to use the Website data to identify areas in need of erosion mitigation before roads are damaged and to evaluate erosion management strategies for heavily used parks. During NOAA's most recent evaluation period the Division of Coastal Resources continued to participate in the ongoing development of the Fire Island Inlet to Montauk Point Reformulation Study, which is an Army Corps of Engineers’ funded storm damage reduction strategy involving the preparation of an implementable, comprehensive, long-term regional strategy for the 83-mile portion of the south shore of Suffolk County, Long Island. C&W remains committed to emphasizing non-structural options wherever possible.
New York has identified areas of high erosion rates ("Structural Hazard Areas"), which they define as having long-term erosion rates greater than one foot per year. These areas are mapped (see above paragraph), but the maps are not available online.
Long Island's coast is a dynamic environment, constantly changing in response to natural processes and human activities. The 125 miles of ocean coast stretching across its densely populated south shore from Coney Island to Montauk is of particular interest due to the high level of development in this area. For example, Long Beach is a barrier island with a year round population of 50,000. "Coastal erosion along the south shore is a significant problem for all levels of government," says NYSG coastal processes and facilities specialist Jay Tanski. "Historical maps and aerial photos show that the patterns of shoreline change are highly variable in this area. Some areas appear to be stable or even gaining sand over the last century while others are eroding at tens of feet per year." The key to sound coastal management is having a good understanding of how the shoreline is behaving and what is causing these changes. "In addition to natural processes such as storms and sea level rise," Tanski says, "human activities - primarily those associated with stabilizing and dredging the inlets for navigation purposes - have impacted the patterns and rates of erosion in the area."
An article Coastal Bluff Recession and Impacts on Littoral Transport: Special Reference to Montauk, NY by Frank S. Buonaiuto Jr. and Henry Bokuniewicz was published in the Fall 2005 issue of Shore & Beach, a publication of the American Shore & Beach Preservation Association. Data analysis indicates that bluff recession for the Montauk reach delivered approximately 34,480 cubic meters of sediment to the shoreline per year during the six-year study period, containing an estimated 21,720 cubic meters of beach-suitable sand. Volumetric bluff recession rates varied from 1.0 m3/m/yr to 19.6 m3/m/yr. The study noted that "Bluffs can be stabilized through various combinations of slope reduction, controlled drainage, vegetation, and engineered structures, however this will reduce the volume of material supplied to the littoral system."
In recent years, Long Island's south shore has been impacted by a number of major storms that have resulted in serious flooding and erosion in many communities. Estimates of the value of public and private structures and property in these south shore areas prone to erosion and flood are upwards of $10 billion.
Working with Dr. Henry Bokuniewicz, a researcher at the State University of New York (SUNY) at Stony Brook's Marine Sciences Research Center (MSRC) and DeWitt Davies of Suffolk County Planning, Tanski developed a model monitoring program based on the experiences of similar programs across the country and input from local officials. This resulting monitoring program, specifically designed to provide managers, planners and their coastal users with information they could use to make better decisions regarding erosion management along the south shore, incorporates six different elements. They include periodic aerial photography of the shoreline, measurements of the condition of the beach twice a year and measurements of the waves causing shoreline changes.
Using the information and materials from Sea Grant's efforts, the NYSDOS Division of Coastal Resources worked with the U.S. Army Corps of Engineers New York District to begin implementing the program. With the support of both federal and state legislators, a $1.4 million annual appropriation to fund the Atlantic Coast of New York Monitoring Program (ACNYMP) was included in the Federal Water Resources Development Act.
The monitoring program, which was administered by the Planning Division of the Corps New York District, is a cooperative effort with overall program guidance and direction provided by a "study team." This group comprises representatives from the Corps, the NYSDOS Office of Coastal, Local Government and Community Sustainability, the NY Department of Environmental Conservation and New York Sea Grant.
Although lapses in the funding stream have prevented full implementation of the program, a considerable amount of data has been collected from some 348 locations along the shore. In addition to taking measurements of beach volume and elevation, aerial photographs of the entire shoreline have been taken twice a year since 1995. State supplemental funds are used by the NYSDOS to address additional data gathering needs. "We want to be sure that we are getting all the data needed by local governments and regulators to facilitate wise management of our coastal resources," says Fred Anders of the State's Office of Coastal, Local Government and Community Sustainability.
Each of the cooperating agencies in the program serves as a repository for data products, enhancing dissemination of the information generated by ACNYMP to the widest range of audiences: local governments, regulatory agencies, scientists, engineers, and other interested parties. New York has more recently developed a coastal analysis package in partnership with the State University of New York at Stony Brook. Principal authors of that package are Dr. Henry Bokuniewicz and Dr. Brian Batten. The package can be viewed within the Atlantic Coast of New York Monitoring Program Website by clicking on the "View Data" link.
The Long Island Regional Planning Board prepared a report, Proposed Long Island South Shore Hazard Management Program that contains shoreline change information for Fire Island to Montauk. The Atlantic Coast of New York Erosion Monitoring Program plans to update the data in this report, which is now 20 years old but still useful for long-term trends. In addition, topographic maps and orthophotos of the entire state, including all the coastal areas, can be viewed and downloaded at http://www.nysgis.state.ny.us/
Erosion rates on the open ocean beaches of New York can range from 0 to 7 feet per year. Beaches along the south shore are susceptible to long-term erosion, but the eastern end of Fire Island and other sites down-drift of inlet jetties, have experienced significant erosion. Other than this, little detailed information appears to be readily available.
In April 2012 it was reported that long stretches of East Hampton‘s Georgica Beach were gone, washed away in some of the worst erosion in half a century. The erosion was so bad that officials said they might have to be close the beach for the season, saying sand replenishment is not an option due to the high cost.
In the winter of 2005-2006, beaches and dunes on the South Shore of Long Island and bluffs on the island's north shore sustained significant erosion for early "nor'easter" storms in October 2005.
A Guide to Coastal Erosion Processes (1985) is an informative New York Sea Grant publication.
A USGS report National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts was released in February 2011. The New England and Mid-Atlantic shores were subdivided into a total of 10 analysis regions for the purpose of reporting regional trends in shoreline change rates. The average rate of long-term shoreline change for the New England and Mid-Atlantic coasts was -0.5 meters per year. The average rate of short-term shoreline change for the New England and Mid-Atlantic coasts was also erosional but the rate of erosion decreased in comparison to long-term rates. The net short-term rate as averaged along 17,045 transects was -0.3 meters per year.
Another USGS report Coastal Change from Hurricane Sandy and the 2012–13 Winter Storm Season: Fire Island, New York was published in 2013. From the report's abstract:
The beaches and dunes on Fire Island were severely eroded during Hurricane Sandy, and the island breached in three locations on the eastern segment of the island. Landward shift of the upper portion of the beach averaged 19.7 meters (m) but varied substantially along the coast. Shoreline change was also highly variable, but the shoreline prograded during the storm by an average of 11.4 m, due to the deposition of material eroded from the upper beach and dunes onto the lower portion of the beach. The beaches and dunes lost 54.4 percent of their pre-storm volume, and the dunes experienced overwash along 46.6 percent of the island. The inland overwash deposits account for 14 percent of the volume lost from the beaches and dunes, indicating that the majority of material was moved offshore.
In the winter months following Hurricane Sandy, seven storm events with significant wave heights greater than four m were recorded at a wave buoy 30 nautical miles south of Fire Island. Monthly shoreline and profile surveys indicate that the beach continued to erode dramatically. The shoreline, which exhibited a progradational trend immediately after Sandy, eroded an average of 21.4 m between November 2012 and mid-March 2013, with a maximum landward shift of nearly 60 m. By March 2013 the elevation of the beach in the majority of the surveyed profiles was lowered below the mean high water level (0.46 m), and the beach lost an additional 18.9 percent of its remaining volume. In the final time period of the field surveys (March to April 2013), the beach began to show signs of rapid recovery, and in 90 percent of the profiles, the volume of the beach in April 2013 was similar to the volume measured immediately after Hurricane Sandy.
Overall, Hurricane Sandy profoundly impacted the morphology of Fire Island and resulted in an extremely low elevation, low relief configuration that has left the barrier island vulnerable to future storms. The coastal system subsequently began to show signs of recovery, and although the beach is likely to experience continued recovery in the form of volume gains, the dunes will take years to rebuild. Events such as Sandy result in a coastal environment that is a more vulnerable to future storm impacts, but they are an important natural process of barrier islands that allow these systems to evolve in response to sea-level rise.
The Heinz Center's Evaluation of Erosion Hazards, conducted for the Federal Emergency Management Agency (FEMA), studied the causes of coastal erosion hazards and proposed a variety of national and regional responses. The study, published in April 2000, concentrates on the economic impacts of erosion response policies as well as the cost of erosion itself to homeowners, businesses, and governmental entities.
A NOAA website that has graphs of sea level data for many coastal locations around the country over the last 40 to 50 years and projections into the future is Sea Levels Online.
NOAA Shoreline Website is a comprehensive guide to national shoreline data and terms and is the first site to allow vector shoreline data from NOAA and other federal agencies to be conveniently accessed and compared in one place. Supporting context is also included via frequently asked questions, common uses of shoreline data, shoreline terms, and references. Many NOAA branches and offices have a stake in developing shoreline data, but this is the first-ever NOAA Website to provide access to all NOAA shorelines, plus data from other federal agencies. The site is a culmination of efforts of NOAA and several offices within NOS (including NOAA’s Coastal Services Center, National Geodetic Survey, Office of Coast Survey, Special Projects Office, and Office of Ocean and Coastal Resource Management) and other federal agencies to provide coastal resource managers with accurate and useful shoreline data.
A related site launched in 2008 is NOAA Coastal Services Center's Digital Coast, which can be used to address timely coastal issues, including land use, coastal conservation, hazards, marine spatial planning, and climate change. One of the goals behind the creation of the Digital Coast was to unify groups that might not otherwise work together. This partnership network is building not only a website, but also a strong collaboration of coastal professionals intent on addressing coastal resource management needs. Website content is provided by numerous organizations, but all must meet the site’s quality and applicability standards. More recently, NOAA Coastal Services Center has developed a Sea Level Rise and Coastal Flooding Impacts Viewer as part of its Digital Coast website. Being able to visualize potential impacts from sea level rise is a powerful teaching and planning tool, and the Sea Level Rise Viewer brings this capability to coastal communities. A slider bar is used to show how various levels of sea level rise will impact coastal communities. Completed areas include Mississippi, Alabama, Texas, Florida, and Georgia, with additional coastal counties to be added in the near future. Visuals and the accompanying data and information cover sea level rise inundation, uncertainty, flood frequency, marsh impacts, and socioeconomics.
The Heinz Center study notes that average shoreline positions in parts of Long Island have fluctuated over the past 160 years but overall have receded approximately 350 feet. The report states that average erosion rates are 1-2 ft/year in Suffolk, NY.
Erosion Contact Info
New York State Department of State
Office of Coastal, Local Government and Community Sustainability
99 Washington Avenue
Albany, NY 12231
Phone: (518) 486-3277
Hazard Avoidance Policies/Erosion Response
See the Erosion Response section.
- Fred Anders, NYSDOS. Surfrider State of the Beach survey response. January 9, 2003.
- NY Sea Grant, with update from Fred Anders, NYSDOS, written correspondence. February 6, 2002.
- Fred Anders, NYSDOS. Personal communication. June 28, 2000.
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