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Sea-level rise and coastal storms are the primary causes of coastal erosion in Massachusetts. Woods Hole Oceanographic Institution estimates that relative sea level in Massachusetts is rising approximately one vertical foot every 100 years.
Approximately 11% of Massachusetts' 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. Coastal Zone Management (CZM) staff estimates that approximately 65% to 70% of the coastline is eroding.
According to a mapping and hazard evaluation project, Massachusetts has an average erosion rate of approximately 0.6 ft/year. The town of Harwich on Cape Cod Bay experienced the highest accretion rates of +1.3 ft/year. The south side of Nantucket, West Tisbury, and Chilmark experienced the highest erosion with rates of 2.2 ft/year, 2.3 ft/year and 2.2 ft/year, respectively. Sections of the south side of Nantucket experience erosion rates up to 12 ft/year. Massachusetts loses approximately 65 acres of coastal upland per year due to passive shoreline retreat as a result of relative sea level rise (0.01 ft/year).
Massachusetts did a study of shoreline change that occurred from 1800 to 1978. The state coastal management program published a map summarizing the information from the studies. The map displays absolute shoreline change in feet at 231 points along the coastline. The period of observation is different for many of the points, so not all the data is comparable for these points. However, the map displays very well the overall erosion trends on the Massachusetts coast. The map shows that the overall trend on the Massachusetts coast is shoreline retreat; however, at specific sites the rate of erosion is highly variable. For more information on specific areas, consult either the Shoreline Change Summary Map or the Massachusetts Coastal Zone Management Program. [Note: the summary map referred to here only shows the data from 1800 through 1978, and does not include the newer shorelines] In addition to the information above, the Coastal Zone Management Program has 92 detailed shoreline change maps with a wealth of information.
The Massachusetts Historic Shoreline Change Maps provide short and long term shoreline change rate information which is provided in an accessible and user-friendly format. There are now 3 to 5 shorelines dating from the 1800s through 1994 for the entire Massachusetts coast. The project also includes statistical analysis for shore-perpendicular transects spaced approximately 50 meters apart along the shoreline, and a fact sheet to facilitate correct use and interpretation of the shoreline change data and maps. Hard copies of the maps were distributed to officials in each coastal community and to the Massachusetts Department of Environmental Protection. The maps are available through the state's CZM Website or on CD.
The Massachusetts Shoreline Change Mapping and Analysis Project, 2013 Update provides information on rates and trends of shoreline change from 1844 through 2009. New coast-wide shoreline data were developed for approximately 1,121 miles of shoreline using color aerial orthoimagery from 2008 and 2009 and topographic Light Detection and Ranging (LIDAR) data from 2007. This new shoreline data were integrated with existing historical shoreline data to compute long- and short-term rates of shoreline change and to analyze trends. The information on rates and trends can be used to improve the understanding of the underlying causes and potential effects of coastal erosion on coastal populations and infrastructure and can support informed coastal management decisions. The report was done in conjunction with CZM’s Massachusetts Shoreline Change Project.
The South Shore Coastal Hazards Characterization Atlas was developed to provide local coastal managers with information that can help with the review of projects that are in areas that are vulnerable to coastal hazards. Further, it is hoped that the information provided in the Atlas will assist local reviewers with the implementation of sound coastal hazard mitigation strategies that promote the natural storm damage protection and flood control functions of coastal landforms. For South Shore communities (from Hull to the Cape Cod Canal), the Atlas provides maps that illustrate shoreline variables at a scale of 1:40,000 and depict such features as littoral cell boundaries, short term shoreline change (1952-2001), shoreline type, distribution of properties with multiple federal flood insurance claims between 1978 and 2002, and beach width fronting coastal banks. Tide range, wave climate, and storm susceptibility are also characterized for the entire coast of Massachusetts, while the rate of relative sea level rise is provided for stations along the northeastern coast of the United States. Check out the Atlas here.
James O'Connell of Woods Hole Oceanographic Institution Sea Grant Program has cautioned that in order to continue to compare older shorelines (as represented by topographic maps) with recent shorelines to estimate shoreline change, regional quantification of the variability of shoreline reference features is necessary. Accurately surveyed beach profiles are one way to provide this quantification. He also cautions:
"In no circumstances should a long-term average annual shoreline change rate be used exclusively for land-use decisions without analyzing the intermediate short-term shoreline movements that were used to generate the long-term rate. An understanding of coastal geomorphological principles and knowledge of recent human alterations in sediment supply and transport are crucial to the art and science of interpreting and applying shoreline change data for coastal hazards planning and management purposes."
A March 2003 report on Massachusetts’ coastal erosion change can be found here.
Two articles by Doug Fraser appeared in capecodonline in May 2007 that discussed erosion problems on Cape Cod and attempts to utilize sand from dredging projects to replenish beaches. Article 1 and Article 2. Another article by Mr. Fraser appeared in capecodonline in April 2014 which discussed erosion problems at Town Neck Beach in Sandwich. Erosion there may be caused or exacerbated by a large breakwater built to stop migrating sand from creating shoals at the eastern end of the Cape Cod Canal which blocks the source of the sand to replace and rebuild protective sandbars, beaches and dunes on Town Neck. Here's an update from February 2015, detailing more erosion woes in Sandwich.
An article At 50, The Cape Cod National Seashore Is Literally Washing Away by Adam Ragusea was published in August 2011. From the article: "It [the shoreline] has retreated an average of three feet per year for as long as anyone’s been keeping records, which is why the namesake lighthouse at Nauset Beach had to be moved back." However, an article published in wickedlocal.com in November 2015 cites a study by the Woods Hole Group that indicates from 1994 on the number has jumped to 13 feet a year.
An article Island's northern end slowly melts away appeared in newburyportnews.com on November 12, 2014. The article discussed severe erosion occurring in the northern end of Plum Island. From the article:
"The rebuilt Plum Island jetty is causing a funneling effect that is stripping away huge quantities of sand, gradually bringing the ocean closer to dozens of homes in the Reservation Terrace neighborhood. The sand being lost there is migrating to a massive sandbar at the entrance of the river and along a seaside stretch of Plum Island’s northern end in the Newburyport section of the island."
At the end of 2010, CZM secured $148,800 through a competitive grant program offered by the National Oceanic and Atmospheric Administration’s (NOAA) Office of Ocean and Coastal Resources Management, to expand, modernize, and improve the Massachusetts Ocean Resources Information System (MORIS). A major component of this project is the delineation of a new, contemporary oceanfront shoreline for Massachusetts. CZM recently began work with the U.S. Geological Survey’s (USGS) Woods Hole Coastal and Marine Science Center on this effort, which will include: the interpretation, digitization, and ground-truthing of the mean high-water shoreline based on aerial orthophotographs; analysis of shoreline change rates; and hosting of the resulting information on MORIS. This work will update the Shoreline Change Project, which was launched by CZM in 1989 to identify erosion-prone areas of the coast by producing maps depicting the statistical analysis of historic locations of ocean-facing shorelines from the mid-1800s to 1978 using multiple data sources. In 2001, a 1994 shoreline was added to calculate both long- and short-term shoreline change rates at 40-meter intervals along ocean-facing sections of the Massachusetts coast. Updated and improved shoreline change information will support informed and responsible decisions by coastal managers, shorefront landowners, and potential property buyers.
In January 2012, CZM released the new Massachusetts Ocean Resource Information System (MORIS)—an online mapping tool for searching data related to the coastal zone and creating maps displaying the data. Produced by CZM and the MassGIS office within the Information Technology Division in Administration and Finance, MORIS enables users to interactively combine sets of coastal data into new maps to analyze patterns, seek relationships, and monitor trends. The upgrades make using MORIS faster, easier, and more effective. Enhanced MORIS features include:
- Increased speed on both the front-end (the web interface) and the back-end (the software that builds and renders the image displayed in the browser).
- More basemaps, including Google, Bing, and OpenStreetMaps.
- Ability to easily search available data layers.
- Access to select federal and other external data directly from the agency of origin.
- Symbology that can modified by the user.
- Code that can be readily shared and modified because it is 100% open source.
- Easy printing and sharing of maps with new print/save tool.
- Modernized look and feel.
Development of the new MORIS was the product of a partnership between CZM, MassGIS, SeaPlan (formerly called the Massachusetts Ocean Partnership), and Applied Science Associates.
The 2014 Budget Bill included a section that established a Coastal Erosion Commission. This commission is charged with investigating and documenting the levels and impacts of coastal erosion in the Commonwealth and developing strategies and recommendations to reduce, minimize, or eliminate the magnitude and frequency of coastal erosion and its adverse impacts on property, infrastructure, public safety, and beaches and dunes. Here are the working group tasks. On January 7, 2015 the Massachusetts Coastal Erosion Commission released its draft report for public comment. Since it convened in March 2014, the commission held five meetings, reviewed the work and findings of similar state- and national-level commissions on coastal shoreline and floodplain management, convened five regional public workshops, and created three working groups. The draft report presents the work, findings, and recommendations of the commission. Volume 1 contains the body of the report and Volume 2 contains the working group technical reports (Science and Technology, Legal and Regulatory, and Erosion Impacts). On December 3, 2015 the Massachusetts Coastal Erosion Commission released its final report.
Geoscientists at the University of Massachusetts Amherst and the Massachusetts Geological Survey, in partnership with CZM, received a $200,000 award in 2014 from the federal Bureau of Ocean Energy Management to characterize sediment types and document current beach and dune profiles at 22 public beaches along the Massachusetts coast over the next two years. This project will establish baseline characteristics (i.e., grain size statistics and elevation profiles) and provide data needed for evaluating shoreline management options including beach and dune nourishment. The beaches being assessed in year one of the project are located in Cuttyhunk, Falmouth, Nantucket, Oak Bluffs, and Westport. In 2015-2016, the field team will assess beaches in Hull, Marshfield, Nahant, Newbury, Newburyport, Plymouth, Revere, Rockport, Salisbury, Sandwich, Scituate, and Winthrop.
To implement Executive Order No. 181, CZM undertook the Massachusetts Barrier Beach Inventory Project. In 1982, CZM completed this comprehensive effort to identify and delineate the 681 barrier beaches in Massachusetts and to place them on topographic maps. CZM distributes copies of the maps generated through this project.
People, private property, public infrastructure, and natural resources continue to be at risk as a result of inappropriate development in hazard-prone areas along the Massachusetts coast. There is a significant amount of development located too close to the shoreline in areas with relatively high erosion rates, structures (public and private) in "Velocity Zones" and on low-lying barrier beaches that are not constructed to withstand 100-year storm events, and public infrastructure (e.g. sewer lines, water lines, roads, etc.) located in areas prone to erosion and storm damage. Natural resources are also at risk from development and redevelopment where the beneficial functions of the resources are not protected by the regulations.
CZM has identified information needed to help assess the level of risk associated with episodic erosion, hurricanes, "Nor'easters", storm surge, and flooding, including identifying the littoral cells along the Massachusetts coast, mapping areas repetitively damaged by storms, and analyzing the potential effects of various sea level rise rates predicted in studies of the Massachusetts coast. All these pieces of information are needed to determine the level of risk associated with various hazards.
CZM has identified several specific gaps that affect their ability to discourage or prevent development or redevelopment in high hazard areas. These include: littoral cell mapping; mapping of repetitively damaged areas; flood maps that do not reflect the 1989 FEMA NFIP regulatory changes in Velocity Zone mapping methodology; regulatory performance standards for the Land Subject to Coastal Storm Flowage resource area under the state Wetlands Protection Act regulations; consideration of setback requirements based on erosion rates and flood zones; clear regulatory requirements to protect sensitive coastal resources and their ability to provide storm damage and flood control protection to landward areas; and a policy regarding sea level rise. CZM needs to address these data gaps before they can make reasonable progress in addressing the programmatic objectives for coastal hazards.
Other impediments in this area include political climate, lack of funding, difficulty in obtaining data, and the difficulty in providing enough education and outreach as part of each effort. There is also a lack of geology skills in many other state agencies, which results in many others relying on the CZM geologist for assistance.
Erosion of glacial landforms (including moraines, drumlins, outwash plains, and kames) provides the primary source of sand and cobble for Massachusetts' 1,500 miles of beaches, dunes, and barrier beaches. Without erosion, many of the Commonwealth's biologically productive bays, estuaries, salt marshes, and tidal flats would not exist. Yet coastal erosion is considered a major economic problem in Massachusetts and nationally.
The importance of the coast, economically, is easier to measure, in some cases, than its aesthetic value. Waterfront property, for example, generates much of the residential tax base for coastal communities. According to Soundings magazine, proximity to waterfront adds approximately 28% to the value of real estate. Mirroring worldwide trends, 75% of Massachusetts' development, historically, has occurred in the coastal zone. And in many cases, development proceeds without considering long- and short-term shoreline change, particularly erosion. Currently, hundreds of millions of dollars of Massachusetts shorefront real estate is at risk due to both chronic, long-term erosion of coastal bluffs and episodic, storm-induced erosion of dunes and barrier beaches.
A 1994 Army Corps of Engineers report stated that, at that time, 74 structures could potentially be lost in the next 50 years along Hummarock Beach in Scituate as a result of erosion. Many homes along the 100-foot-plus coastal banks of southern Plymouth and the east shore of Nantucket are at high risk of loss due to long- and short-term erosion and slumping.
The causes of shoreline change are both natural and human-induced. The primary natural causes of erosion in Massachusetts are relative sea level rise and storms. The results of a study completed several years ago by scientists at the Woods Hole Oceanographic Institution (WHOI) document that relative sea level in Massachusetts is rising approximately one vertical foot every 100 years. Each year, on average, approximately 65 acres of coastal upland are passively submerged as a result of relative sea level rise. In fact, authors found that the contribution to shoreline retreat in Massachusetts from relative sea level rise is far greater in some areas than erosion caused by wave action. For example, the total upland loss on Cape Cod from passive submergence due to relative sea level rise is approximately 24 acres per year, while wave-induced erosion causes a loss of approximately nine acres.
According to the Army Corps of Engineers, the most important cause of human-induced erosion is interruption of sediment sources and longshore sediment transport. Examples include the armoring of sediment sources with seawalls, revetments, and bulkheads, and the interruption of longshore sediment transport by the construction of groins and jetties.
Identifying areas subject to both long- and short-term erosion, and understanding the causes of erosion are important to avoid building homes, structures, and infrastructure in high hazard coastal areas. Shoreline change maps and data for Massachusetts, as well as maps showing areas subject to storm waves and flooding, are available for viewing on the web or electronically on CD (see above).
The correct interpretation of shoreline change data can help coastal planners, resource managers, and property owners identify appropriate and inappropriate areas to place structures. The combination of long-term shoreline change data analysis, measurements of short-term shoreline movements, an understanding of coastal processes, and knowledge of the effects of seawalls, revetments, bulkheads, groins, and jetties, is essential to proper citing of coastal structures.
Learning from past mistakes, though unfortunate, can also aid coastal planners. Consider the following lessons learned about shoreline change in Massachusetts:
- Jetty construction at the mouth of Sandwich Harbor on Cape Cod Bay resulted in down-drift erosion for approximately 5,600 linear feet, with a maximum erosion of the down-drift shoreline of approximately 361 feet. However, following readjustment of the shoreline to the new, artificially induced equilibrium profile, the shoreline has eroded only 38 feet.
- The erosion rate along the Humarock Beach shoreline of Scituate has accelerated since the 1950s. The principal sediment sources for this barrier beach, up-drift glacial drumlins, have been armored with revetments. This has significantly reduced the major source material for the beach. The apparent cause and effect nature of the revetments seem to indicate that the rate of shoreline change since the construction of these revetments should take precedence over the long-term rate of change in future planning and management for this area.
- On Nantucket and in other areas, trend reversals -- erosion followed by accretion, and vice versa -- complicate matters. In many cases, short-term shoreline fluctuations can be orders of magnitude greater than the long-term rate of shoreline change. Nantucket's southeast shore has a long-term average shoreline change rate of +0.10 feet per year (net accretion of 2.1 feet between 1846 and 1978), suggesting a relatively stable area. However, between 1846 and 1978 the shoreline accreted 238 feet, then eroded 236 feet. This same phenomenon occurred at Codfish Park on Nantucket. Unfortunately, many homes were constructed during the accretion phase. Since the trend reversed to erosion beginning in mid-1950s, many houses have been lost to erosion and storms.
These examples make it clear that to properly manage the shoreline, analysis of both long- and short-term shoreline changes are required to determine which is more reflective of the potential future shoreline configuration. Note: these examples are from an older Sea Grant publication that doesn't use all of the current data.
Many additional reports, references and links can be found on the Website of Woods Hole Oceanographic Institution's Coastal Ocean Institute and Rinehart Coastal Research Center. Their report The Moving Shoreline and website Changing Shorelines and Erosion have many excellent references.
The EPA estimates that the rate of increase in sea level at Boston may double by the year 2100 (from 11 inches per century to 22 inches per century) due to global warming.
The beaches of the Massachusetts shore are pummeled by both hurricanes (infrequent) and Nor'easters (more frequent). The beaches of Cape Cod retreat further each year. The islands of Nantucket and Martha's Vineyard face a more uncertain future that anyone would have imagined fifty years ago; if the coast of Nantucket retreats thirty feet per year, the island will be gone in 600 years.
Cape Cod's oldest lighthouse, the Highland Light (also known as Cape Cod Light) was moved 450 feet back from an eroding cliff in 1996. The $1.5 million Army Corps of Engineers project was funded by the National Park Service, Cape Cod National Seashore, and the U.S. Coast Guard, and with contributions from a local preservation group. Nauset Lighthouse in Eastham, Cape Cod, Massachusetts, was rescued from the edge of a sixty-foot high eroding cliff in November 1996 by moving it 300 feet west.
14,000 years ago, Cape Cod and Martha's Vineyard were formed by melting glaciers. The two areas have no bedrock to anchor them and prevent the ocean from pushing around their beaches. In Chatham, nine homes have fallen victim to the sea in recent years. Here's a history of erosion events in this area from just April 2007 through January 2008:
- April 16, 2007: A northeaster stalls east of the Cape and helps carve out a channel through North Beach between the Atlantic Beach and Pleasant Bay. The break threatens 26 privately owned cabins and camps.
- July 31: Chatham voters at a special town meeting shoot down a proposal to spend $4.1 million to fill a wide breach in the North Beach barrier system.
- September: A house owned by the Cape Cod National Seashore is razed by a private contractor hired by the Seashore. The structure is taken down when it becomes apparent it will soon be claimed by the ocean,
- Nov. 3: Tropical Storm Noel slams into the Cape and deposits the roof of Russell Broad's summer camp in Chatham nearly a mile away from its original North Beach location, along with the fishing boat Three Graces. The house had been in Broad's family for 61 years. A house next door, owned by Donald Harriss and his nephew Peter Harriss, is shaken free of its foundation. On Dec. 28, the 110-year-old cottage succumbs to an overnight tide.
- Jan. 17, 2008: Fred Truelove, knowing his cottage is doomed, chooses to take his cottage down before the sea gets it. Workers from Daniels Recycling in Orleans pull down the small house that had been rebuilt in 1992, after the legendary 1991 Halloween storm destroyed it.
- Jan. 27: Steve Batty's camp, located close to the northern edge of the new, rapidly expanding inlet, is lifted off its foundation and comes to rest on a beach on the new island to the south. The house is co-owned by Batty, his brother and a third individual. This makes five camps lost to erosion since the fall.
In mid-2009 noted coastal geologist Dr. Graham Giese of the Provincetown Center for Coastal Studies predicted that the new inlet in North Beach would become the primary ocean access to Pleasant Bay and Chatham Harbor in less than 20 years. He also predicted the next break may occur in about 2057 as the barrier beach again stretches south to Chatham Light.
Since colonial times, the South Shore of Nantucket has retreated a half mile. The eastern shore has lost some hundred feet of beach in the last decade. Muskeget Island off Nantucket has moved more than 1,000 feet eastward since the 1800s. Nantucket has nothing to slow down breaking waves except the Nantucket Shoals to the east, which are the sandy remains of what was dry land several thousand years ago. These shoals have most likely caused a dramatic increase in erosion that occurs episodically at Codfish Park on Nantucket. Storms can shift the shoals so that waves are funneled through the breaks in the sand and concentrated on Codfish Park.
Erosion on Nantucket's South Shore is at a rate of about fifteen feet a year. At least 25 buildings have either been condemned or destroyed since the 1980s. If nothing is done to curb erosion, 50 to 60 more homes could be destroyed in the next ten years.
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.
General Reference Documents
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 in Massachusetts, long-term erosion rates average approximately 3 feet per year along the outer shore of Cape Cod, and often exceed 6 feet per year along the south shore of Martha's Vineyard and 8 feet per year along the south shore of Nantucket Island.
Erosion Contact Info
CZM Coastal Geologist
Phone: (617) 626-1200
Hazard Avoidance Policies/Erosion Response
See the Erosion Response section.
- Rebecca Haney, MA Office of Coastal Zone Mgmt. personal communication. July 28, 2000.
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