Coastal erosion is an integral part of natural beach processes. Beaches are not stagnant, but instead are dynamic systems that shift, migrate, fill and erode; sometimes taking and sometimes giving. While many coastal communities throughout the United States and around the world point to coastal erosion as the cause of their shrinking beaches, erosion really only becomes a problem when we build houses, roads and other structures too close to the water. Unfortunately that is how development has been occurring along our coasts, and we haven't given our beaches the room they need to naturally maintain themselves.
Compounding the erosion issues that many beaches face are sea level rise, storm damage, subsidence of land, and interruption of natural sources of sand caused by revetments and jetties. Faced with a steady inland migration of the ocean that may range from a few inches to several feet per year, coastal communities have limited options to deal with the situation. Many houses along the coasts of the United States have already been lost on eroding beaches.
The potential responses to coastal erosion include seawalls, beach fill, and managed retreat. Seawalls, rock revetments and other hard structures built to hold back the advance of the sea often fail and need to be rebuilt over and over again. This approach is not desirable for several reasons, not the least of which is that these structures inevitably lead to the loss of sand from beaches – sand trapped underneath and behind the seawall, and sand eroded directly in front and down drift of the seawall. Waterfront properties receive only a temporary respite, while public beaches are often lost for good.
Another approach is beach fill, also known as beach nourishment, whereby sand is typically dredged from a harbor or offshore source and pumped/placed/spread on a beach to widen it. Issues associated with beach fill include sand compatibility/quality, ecological effects, changes to the beach and offshore bottom contours, effects on wave quality, and damage to offshore reefs. In addition, these projects may be very costly and typically must be repeated every few years. Who pays for the project (Federal/state/local government? Beach town property owners? Only beach front property owners? Users of the beach?) is often a difficult issue to resolve. Coastal cities in Florida have already tapped out their sources of compatible off-shore sand from constant dredge and fill projects and are now looking to ship in sand from the Bahamas at an exorbitant cost.
That leaves the option of managed retreat.
Managed or planned retreat (also known as managed realignment) allows the shoreline to advance inward unimpeded. As the shore erodes, buildings and other infrastructure are either demolished or relocated inland. It can also involve setting back a line of actively maintained defenses to a new line inland of the original – or preferably to rising ground – and promoting the creation of intertidal habitat between the old and new defenses. This can either be a complete removal or a breach of the defense (dike, seawall, revetment, etc.).
Coastal managers realize that in many situations attempting to stop erosion through structural or non-structural solutions is a losing battle. Shoreline protection efforts and/or their repeated maintenance would be too costly and ultimately ineffective at preventing further erosion. A managed retreat approach typically involves establishing thresholds to trigger demolition or relocation of structures threatened by erosion. Therefore, this approach is frequently coupled with several other planning and regulatory techniques including: shoreline planning, to identify high-risk areas where this type of policy would be the only cost-effective, long-term solution; regulating the type of structure allowed near the shore to ensure that buildings are small enough and constructed in a way to facilitate relocation when needed; and instituting relocation assistance and/or buy-back programs to help with relocation costs or compensate property owners when their property becomes unusable. While the overall policy emphasizes retreat, a managed retreat approach may allow some erosion control measures using soft-stabilization techniques to prolong the life of shorefront buildings and other infrastructure for a limited, defined period of time. However, hard stabilization structures or repeated beach renourishment are generally not permitted.
This approach is usually less expensive then costly structural stabilization projects that may only be a temporary solution, especially in highly erosive areas. Managed retreat maintains natural shoreline dynamics and enables shoreline habitats to migrate inland as the shoreline erodes to prevent loss of wetlands and other intertidal areas. Surfrider Foundation's Beach Preservation Policy emphasizes managed retreat as an appropriate long-term strategy for dealing with coastal erosion, stating:
"In areas where erosion threatens existing coastal development, the Surfrider Foundation advocates appropriate long-term solutions that maximize public benefit. These include:
- Landward retreat of structures from dynamic shorelines"
In 2012 NOAA's Office of Ocean and Coastal Resource Management (OCRM) published a report How Coastal States and Territories Use No‐Build Areas along Ocean and Great Lake Shorefronts. The report looks specifically at where states and territories employ no-build areas (e.g., through setbacks, rolling easements, or zoning) along ocean and Great Lake shorefronts, typically on dry, privately owned land, to protect the public interest.
In 2013 Columbia Law School, Center for Climate Change Law published Managed Coastal Retreat, A Legal Handbook on Shifting Coastal Development Away From Vulnerable Areas. This Handbook collects examples, case studies, and lessons learned from successful and unsuccessful attempts at managed retreat in the hope that their lessons can inform future efforts to limit the exposure of communities to coastal threats.
In the wake of the destruction caused by Hurricane Sandy in October 2012, coastal managers in New York, New Jersey and other states are re-thinking their options for dealing with future major storms and future sea level rise. New York offered coastal homeowners in certain areas a buyout program to incentivize moving away from the coast and turning that land into greenspace intended to provide protection from future storms. Former New York City mayor Michael Bloomberg has spoken in favor of limited retreat as well as the development of natural buffer zones. An Op-Ed In a Global Warming World: Protect and Rebuild or Retreat? by Bill Chameides, Dean, Nicholas School of the Environment, Duke University further explores these options.
Needless to say, managed retreat is not often a popular option and can be politically difficult to implement, especially where significant development has already occurred. It may cause depreciation of shorefront property values or, in some cases, complete loss of property values.
However, managed retreat has been implemented successfully at several locations.
Perhaps the most famous example of managed retreat in recent years was the relocation of the Cape Hatteras Lighthouse 2900 feet inland in 1999. When constructed in 1870, the lighthouse was 1,500 feet from the shore. Protective measures to reduce the rate of beach erosion in front of the lighthouse provided a temporary solution, but by late 1987 the lighthouse stood only 160 feet from the sea and was in danger of collapsing. A 1988 National Academy of Sciences Study and a 1996 study conducted by several researchers at the North Carolina State University found that relocating the lighthouse was the only feasible option. Adding additional groins, sea walls and sand to the beach would be more costly and were only estimated to last 20 or 30 years. In 1999, after several years of debate and lawsuits aimed at blocking relocation, the National Park Service successfully moved the lighthouse back 2,900 feet over the course of 23 days at a cost of $9.8 million. See also here and here.
Earlier lighthouse relocations were the move of Highland Lighthouse (pdf) (commonly known as Cape Cod Light) approximately 450 feet back from an eroding cliff in July-August 1996 and moving Nauset Lighthouse in Eastham, Cape Cod, Massachusetts, 300 feet back from the edge of a sixty-foot high eroding cliff in November 1996. More recently, Gay Head Lighthouse in Aquinnah, Massachusetts was moved back 135 feet in May 2015.
A similar issue currently exists with the Montauk Point Lighthouse in New York. The Army Corps of Engineers is proposing to expand the rock wall that surrounds Montauk Point. Concerned with increased erosion of adjacent beaches and lack of sand at down drift beaches, Surfrider Foundation's Eastern Long Island Chapter is trying to convince authorities to investigate the feasibility of moving the lighthouse back away from the eroding cliffs to protect it for centuries to come. In Massachusetts, the Gay Head Lighthouse is one of the most important navigational tools on the East Coast. In July 2014 The Board of Selectmen in Aquinnah, on Martha’s Vineyard, approved a new location for the lighthouse, moving it back 140 feet, which is predicted to keep it safe from coastal erosion for 140 years. More on this.
A very early example of managed retreat occurred at Coney Island, New York. In 1888 the beach became so badly eroded in front of the Brighton Beach Hotel that waves threatened the structure. To save the 500 foot long, three story hotel that weighed 6,000 tons, workers jacked up the entire hotel, placed it on 120 rail cars, and eased it inland six hundred feet. Six locomotives in two teams of three each moved the building so gently that not a pane of glass was broken nor a mirror in a room was cracked.
A small number of managed retreat projects have been undertaken in the UK, mainly along the Essex coastline. The first deliberate attempt at managed retreat in the UK was on a small island located in the Blackwater Estuary in Essex. The Northey Island project, organized by the National Trust (the landowners of the site), the Environment Agency and English Nature involved breaching and lowering a seawall to encourage salt marsh development on its landward side. Aided by high sedimentation rates the scheme has been successful, with a viable salt marsh community now established at the site. A similar but larger project that has been equally successful is the Medmerry Managed Realignment Project, completed in November 2013. The £28 million project is the largest of its kind anywhere in Britain. A new, 7km sea wall was constructed 2km inland of where a stretch of the old shingle wall was removed and the area in-between is now intertidal marsh. Acquiring the land cost over £8 million. Three hundred and fifty homes, two resorts and a water treatment plant are now protected from a one thousand year flood. In addition, the community now has a massive new wildlife refuge for wading birds, and endangered species like the water vole.
In the Pacific Ocean, the President of the island nation of Kiribati has stated that it may be more practical to flee to higher ground than to stay and defend the country's low-lying atolls.
An example of a coastal development that is ripe for relocating inland (and almost was) is The Riggings condominium development in North Carolina. The development in Kure Beach obtained permission to install a wall of sandbags in 1985. In 2008 (23 years after installation) the sandbags were still in place and a majority of the complex's 48 homeowners had rejected a $3.6 million federal grant that would have helped them relocate their oceanfront condominiums across U.S. 421. The grant would have dedicated oceanfront land the complex is currently on as parkland. In January 2008 the CRC denied the homeowners' request for another extension of their sandbag permit.
A similar situation exists at the Wild Dunes Resort in Kiawah Island, South Carolina where the property owners are trying to hold out with sandbags until an estimated $9.9 million beach fill project can be funded and implemented – now scheduled for completion by the end of July 2008. Property owners will pay a negotiated civil penalty of $18,000 for littering the coast and marshes with tens of thousands of small sandbags that washed away in storms in spring 2007.
Hurricane Sandy in October 2012 has caused inadvertent but inevitable retreat in several locations in New York, New Jersey and adjacent states. In some areas, subsequent damage assessments, along with rising flood insurance premiums, has prompted other relocations and government buy-out programs. In February 2013 Gov. Andrew Cuomo proposed to spend as much as $400 million to purchase homes wrecked by Hurricane Sandy, have them demolished and then preserve the flood-prone land permanently, as undeveloped coastline. In December 2013 New Jersey offered to buy out owners of 33 homes and additional vacant lots in the remote Cumberland County community of Bay Point, a rational move to protect local people from inevitable sea-level rise and a commendable measure to protect more habitat for Delaware Bay wildlife. Property owners are being offered the buyouts after being devastated by Sandy, and after chronic flooding of the only access road through surrounding wetlands. Those who accept the state’s terms would see their homes – only two of which are occupied year-round -- demolished. Eight homes were destroyed by Sandy while some others remain uninhabitable. The owners are motivated in part by the $30,000-$80,000 cost of elevating their houses by about 5 feet to the new level of 13 feet that’s required to qualify for federal flood insurance. In addition, many owners are faced with a bill of around $8,000 for repairs to septic systems damaged by Sandy, as well as other storm-related repairs. The buyout will use $4.4 million in funds from Green Acres, a state DEP bond-funded program, and $3 million from the U.S. Department of Agriculture. In addition, state and federal governments will each provide about $1 million for the ecological restoration of the properties. The peninsula will become a Wildlife Management Area operated by the New Jersey Division of Fish and Wildlife. State and federal governments are providing $9.4 million to buy the properties. The plan is to convert 41 of the 46 acres on Bay Point peninsula to open space that will act as a buffer against coastal flooding while creating more habitat for wildlife, especially migratory birds.
In June 2014 a managed retreat project was being implemented at Hammonasset Beach State Park’s West Beach in Connecticut. A 3,430-square-foot bathhouse is being built 280 feet inland from the one it replaces, with the public spaces 14.5 feet above ground, surrounded by a deck, to allow storm surges to flow underneath. The bathhouse project, along with repositioning of walkways to foster dune restoration and a new $2.4 million nature center on higher ground than the obsolete structure it’s replacing, are part of an overall “move up the beach” strategy the state Department of Energy and Environmental Protection is employing at the park.
Following are two managed retreat case studies in California, one implemented and one in the process of being implemented. In addition, Surfrider Foundation's San Francisco Chapter has been working with many other stakeholders for several years to develop and implement a response to erosion problems at Ocean Beach that involves managed retreat. Read more on that project here and here. For some interesting history that directly contributed to the erosion problems at Ocean Beach, read The Untold Story Behind the Erosion Mess South of Sloat. Surfrider Foundation's Santa Barbara and Isla Vista Chapters have been participants in a managed retreat project at Goleta Beach County Park, called Goleta Beach County Park Managed Beach Retreat Project 2.0.
In San Mateo County, California, the City of Pacifica had long battled chronic coastal flooding and beach erosion. For decades, the city had employed structural stabilization techniques to armor Pacifica State Beach and channelize San Pedro Creek. Despite these earlier stabilization activities, the City continued to face three main shoreline management issues: flooding of homes and businesses; erosion of Pacifica/Linda Mar State Beach; and maintaining habitat for the steelhead trout in San Pedro Creek.
In 1982, a major flood damaged more than 300 homes. One home was eventually lost, and two homes and a restaurant remained threatened by storm surges and erosion. Therefore, the U.S. Army Corps of Engineers and the City's Flood Control Committee supported proposals to further harden and channelize the creek to reduce the risk of flooding.
At the same time, community members were also concerned about on-going erosion at Pacifica/Linda Mar State Beach - a popular surfing location. The surfing community, led by Pacifica's mayor, favored shoreline restoration and argued that shoreline armoring was accelerating long-term erosion at the community's beach.
Further complicating the issue, San Pedro Creek supports a native population of steelhead trout. The California Coastal Conservancy and other partners therefore argued for restoration of the lower channel and creek mouth to improve habitat for steelhead and other species.
In the early 1990s the City of Pacifica, the California Coastal Conservancy, and the Pacifica Land Trust decided to collaborate to work toward a managed retreat strategy that combined "soft" stabilization techniques to enhance steelhead habitat, reduce flooding threats and preserve the sandy beach, with the removal of vulnerable structures along the beach. During the 1990s, the City of Pacifica partnered with the California Coastal Conservancy, the California Department of Fish and Game, the Army Corps of Engineers, and the State Water Resources Control Board to expand and enhance the tidally influenced wetlands at the creek mouth and restore more than 1900 feet of eroding creek banks. This restoration both enhanced steelhead habitat and achieved 100-year flood protection for the nearby community. The wetland project also cost the community significantly less than other proposed flood control measures because it required less physical construction.
To address the remaining flood threat to homes and businesses, the City also removed the most vulnerable structures. In 2002, the City partnered with the Pacifica Land Trust and the California Coastal Conservancy to purchase two homes and their surrounding acreage for $2.2 million. They demolished and removed the homes and excavated concrete, rubble, asphalt, reinforcing steel, and tires. They also delivered 4,000 cubic yards of sand to rebuild dunes and restore four acres of beach and the nearby estuary. The city plans to relocate the one remaining shoreline structure—a Taco Bell restaurant -- to the other side of Highway 1 as part of a planned retreat strategy.
The end result of all this work is that flood hazards have been reduced, the wetland habitat is functioning, and the use of the recreational beach has increased.
Creative partnerships at the local and state level helped leverage the public support needed to implement a project that cost millions of dollars and took a decade to complete. Support of local government leaders, particularly the mayor, helped finance the up-front expenses for the ongoing project. Finally, a planned retreat strategy was made more politically viable because project partners had the capital necessary to purchase threatened structures outright.
The City of Ventura is facing on-going erosion at Surfers' Point, a popular surfing spot, adjacent to the mouth of the Ventura River. A California State Park bike path along the shoreline and an adjacent County Fairground parking lot, have also experienced frequent damage from erosion. Since the mid-1980s the Surfrider Foundation has been advocating for relocating the bike path inland, to prevent the future need of a seawall and destruction of a famous surf break. However, to protect the Point, the City decided to place boulders above the mean high tide line along its upper end. The project ended up exacerbating erosion further down the coast and the Fairground parking lot and bike path have continued to erode into the ocean; in some places more than 60 feet of land have been lost. When the City applied for a permanent permit for the rock revetment, the California Coastal Commission denied their request but recommended that the parties involved should work together to resolve the issue.
Therefore, in 1995, a working group was formed which included representatives from the City, County Fairgrounds, California Department of Parks and Recreation, the Commission, the Ventura Chapter of Surfrider Foundation, and other interested parties. The California State Coastal Conservancy facilitated the group. While "managed retreat" was a favored strategy, the group disbanded a year later because they could not reach a consensus. The County Fairgrounds did not agree to a managed retreat approach as it would have reduced the number of parking spaces for the Fairground.
Nonetheless, Surfrider continued to advocate for a planned retreat strategy. A few years later, the former chairman of the Ventura Chapter of Surfrider was elected to the Ventura City Council, providing further support for a "managed retreat" option, and discussions over what should be done with Surfers' Point resumed. Another working group was created. In 2001 the group reached a consensus for a "managed retreat" project that included:
As of summer 2005, the initial planning and design process and environmental documentation for the project had been completed. The City of Ventura allocated one million dollars of U.S. Department of Transportation's TEA-21 funding for the design and relocation of the bike path. The total construction cost was estimated to be $3.8 million and the City was pursuing funding for the remaining costs. In addition, the California Coastal Commission approved a permit for a renourishment project that includes a five-year plan for opportunistic beach replenishment at Surfers' Point.
Project design was completed in 2008. An updated estimate placed total construction costs at $8.1M. Increases were the result of general inflation in construction costs. A significant portion of the cost is cobble to rebuild and protect the shoreline. A cobble source was found from a County Flood Control project. Approximately $1M in possible cost-cutting measures were identified by leaving abandoned pipes in place, reducing landscaping costs, and limiting grass-pave to high use areas.
The City of Ventura has a federal transportation grant of $1.5M for the bike path. California's Ocean Protection Council members toured Surfers' Point as well as Matilija Dam in late February 2008.
Construction on this project finally began in Fall 2010 and Phase 1 construction was completed in July 2011.
See also Surfers' Point Task Force, Ventura River Ecosystem and Climate Change Success Stories from California Sea Grant Extension Program. Surfers' Point has been used as a case study for the use of natural infrastructure.
Often, the initial response to shoreline erosion is to build a seawall. Because managed retreat has not been a widely employed approach to shoreline management, it has been difficult to convince others that planned retreat might be the best economic and environmental solution for their erosion problems. Adopting a managed retreat policy at Surfers' Point has been successful because it began at a grassroots level. The Ventura County Chapter of the Surfrider Foundation has continuously championed this approach for two decades and highlighted the benefits of the option to the City Council and general public. The project was also successful, because it involved all major players in the planning process. Although the process took time, and was aided by a change in leadership in one agency, a consensus was reached that managed retreat was the best alternative.
The video report Swept Away from KCET in Los Angeles compares three different responses to sea level rise and coastal erosion - shoreline armoring at Broad Beach in Malibu, the Surfers Point managed retreat project in Ventura and a head-in-the-sand total denial from a local politician.
Managed Coastal Retreat, A Legal Handbook on Shifting Coastal Development Away From Vulnerable Areas, Columbia Law School, 2013.
Online Managed Realignment Guide (U.K. and Europe)
Pacifica State Beach Managed Retreat, Beach and Estuary Restoration, Philip Williams and Associates
“Relocation of the Highland Lighthouse, North Truro, MA” by Joseph J. Jakubik (pdf)
Surfer's Point Project Description, Philip Williams and Associates
“The Search for Sand Is No Day at the Beach”, Charles Passy, New York Times, September 16, 2007 (as printed in boston.com)