State of the Beach/Model Programs/Beach Erosion
|Bad and Rad
Below examples pertaining to beach erosion follow an outline of the Surfrider Foundation's goals in this area.
Beach Erosion Goals
- Naturally functioning beaches, with an uninterrupted supply of sand.
- An accurate and up-to-date inventory of erosion hotspots, eroding and accreting shorelines.
- Comprehensive long-term monitoring of shoreline change.
- Public education about beach erosion that is easily understood by a range of audiences.
Erosion Response Goals
- Statewide oceanfront construction setbacks for new development based on current and accurate erosion rates that ensure adequate long-term health of beaches.
- Shoreline management plans that explicitly recognize erosion and/or sea level rise.
- Statewide policies to implement "managed retreat/relocation" or policies which consider retreat/relocation a viable option.
- Statewide policies to implement incentives for relocation which can include relocation assistance funds and buy-back programs.
- At a minimum strict limitations on, and ideally prohibition of post-damage reconstruction.
- Dedicated funds for land acquisition which is targeted towards high hazard shoreline property.
- Application of regional policies that take into account cumulative effects of non-natural shoreline alterations.
- Full disclosure of coastal hazards/high-risk erosion areas as part of real estate transactions.
- Public education and/or outreach about the risks of living 'close to the edge'.
- The removal of state subsidies which support high-risk shoreline development which can include builder’s risk insurance, beach nourishment, and permissive sea walls.
Since 1996 the Maine Geological Survey (MGS) has been conducting field studies that identify and rate coastal hazards along bluff shorelines. Eroding bluffs have been found all along Maine's coast, with most concentrated along the developed waterfront of inner coastal bays and estuaries. Casco Bay shorelines and islands with bluffs include the towns of Falmouth, Yarmouth, Freeport, Brunswick, and Harpswell. Peninsular mid-coast towns with numerous bluffs include Phippsburg, Georgetown, Westport, Friendship, and Thomaston. Beach dynamics and sand movement along the shoreline at Popham Beach State Park and Seawall Beach in Phippsburg is a continuing saga of extreme shoreline change and dune erosion. This website looks at Seawall Beach, the Morse River, and the large sand spit (bar) connected to Seawall Beach that extends seaward of Popham Beach.
The Penobscot Bay and River region also has extensive bluffs in Castine and Bucksport. Bluff erosion affects about 10 times more shoreline than beach erosion.
Statistics compiled for the mapped region show that 53% of the Maine coast is characterized as bluff shoreline. Of this, 1.9% (40 miles) is highly unstable, 13.7% (280 miles) is unstable, and 37.5% (760 miles) is stable.
Sandy beaches along the Maine coastline are typically confined into "littoral cells", bound by rocky headlands, and comprise approximately 70 miles, or 2% of the total Maine coastline. The majority of these beaches are located in the southern portion of the state, from Portland south to Kittery. Through geophysical surveys, MGS has also determined that sandy areas along the inner shelf of the Gulf of Maine are relatively rare, occupying only 8% of the seafloor. The relative rarity of sandy beaches and sand sources in Maine make sandy areas an important natural resource. Most sandy beaches in Maine are relatively stable or are slightly eroding (<1 foot/year), while several erosional "hotspots" where erosion is greater than 2 feet/year do exist.
Camp Ellis Beach, located in Saco, Maine, is a community that faces some of the highest erosion rates along the Maine coastline. Over the last century, the erosion has pushed the shoreline back by 400 feet. Since 1968, 33 homes have been lost. The erosion along Camp Ellis is attributed to a mile-long federal jetty built in 1869 that stabilizes the northern edge of the Saco River; this jetty effectively precludes new sediment from reaching the adjacent beaches. In strong northeast storms, high water levels and large waves batter the Camp Ellis shoreline, flooding streets. The erosion is contributed to by the high reflectivity of the 1000-landwardmost feet of the jetty, which reflects waves onto the Camp Ellis shoreline. The MGS recently completed an open file report, titled Variation of Beach Morphology Along the Saco Bay Littoral Cell: An Analysis of Recent Trends and Management Alternatives which discusses beach erosion and management issues facing Camp Ellis and the rest of Saco Bay. A technical report by Peter Slovinsky of MGS Shoreline Change and Management in Saco Bay, With a Focus on Camp Ellis, Saco, Maine was presented at the 13th Biennial Coastal Zone Conference in Baltimore, Maryland in July 2003.
Shoreline change studies suggest that portions of Maine's coast face the prospect of significant coastal erosion, even without accelerated sea level rise. When sea level rise is accounted for, projected shoreline change ranges from 15 to 45 meters along bluff shorelines to 50 to 600 meters along beach and dune shorelines.
MGS has developed a scoring system to identify sections of the Maine shoreline that require beach management. The "Scoring System for Management of Maine's Sand Beaches" MGS initiated is a program that developed a model which aids the coastal planner in determining the most appropriate beach management action for different beach shorelines, based on a variety of physical, land-use, and economic criteria. The system ranks beach stretches to determine what management action (e.g., dune restoration, beach fill, or no action) would be the best alternative. The scoring system has been completed for the Saco Bay area, and is currently being developed to identify management measures along the Wells Embayment.
The source of much of the information presented above is from a series of collaborative efforts involving the Coastal Marine Geology Section of the Maine Geological Survey. Their website has a discussion of coastal processes and hazards and summarizes past and ongoing efforts, including:
Monitoring Maine's Beaches
The University of Maine and the MGS launched a volunteer beach profiling program in 2000, monitoring changes in beach profiles monthly by ten teams of volunteers. The elevation of beaches is measured using the Emery method of beach profiling, and results are posted on the Web. The Website provides such information as the table below, and links to detailed information such as monthly profile data for each of the beaches. Seasonal changes to the beaches are being documented to understand natural cycles and volumes of erosion and accretion. Results of the profiling will be compared to coastal wave and wind data to understand how storms (northeasters, southeasters, tropical storms) affect various beaches in southern Maine. Data collected by the volunteer profiling program are typically presented and discussed at the annual State-of-Maine's Beaches conference. Besides gathering needed information, the project is building an important new constituency of beachgoers. Storm-generated bottom currents offshore of beaches are being measured with current meters placed on moorings in about 20 meters of water offshore of Old Orchard Beach and Wells Beach. Wave-orbital currents will be studied to determine the direction and relative rate of beach sand transport during storms of various types and strengths.
The table below classifies several beaches in terms of development status, replenishment history and erosional status.
Development Status of Beaches Involved
|Biddeford Pool/Fortune's Rocks
MGS was being funded by the Maine Marine Research Fund to construct and use a nearshore survey system (NSS) for conducting nearshore bathymetric profiling within the surf zone. The system includes a personal watercraft outfitted with a real-time kinematic global positioning system (RTK GPS) and high-precision depth sounder in order to record bathymetric changes within the nearshore coastal marine environment. This system will permit long-shore and cross-shore imaging of the nearshore, and will be used to greatly enhance the currently limited volunteer beach profiling that only extends to the low-water mark.
MGS is also working with the Maine Coastal Program on a project entitled "Current Studies for Swim Beach Response Planning". This project, funded by MCP, entails the use of a current profiling instrument mounted on the personal watercraft NSS to monitor current patterns in the vicinity of stormwater and sewage outfalls. Detailed current measurements will be compared with meteorological conditions and water quality test results in order to develop a predictive tool for planning when swim beach water quality may be compromised due to rainfall or changes in wind directions.
Mapping Maine's Beaches
Detailed air photographs are being used to map the location of geologic environments of the Coastal Sand Dune System for use in permits for building in dune environments. The new combination of air photo-geologic maps supplements existing MGS Coastal Sand Dune Maps and will be used in the Department of Environmental Protection's permit process within the Maine Natural Resources Protection Act.
Coastal Bluff Mapping
A large portion of Maine's coast has shorelines with sedimentary bluffs, particularly in bays and estuaries. Field work of the last few years resulted in the recent release of Coastal Bluff Maps of about half of the Maine coast. These maps indicate the relative stability of bluffs for coastal planning and development near the shoreline. Field work and GIS mapping continue to increase the geographic coverage of maps in this series. A full suite of 50 color maps of Coastal Bluffs, depicting bluff stability and shoreline type, is available from the MGS. The maps use a red, yellow, green "stoplight" theme to show the condition of the bluff shoreline, in 150 feet segments of shoreline. The maps include text and photographs to describe the origin of bluffs, the chronic nature of erosion, and the variety in shoreline types in a way that can be understood by the general public.
Landslide Susceptibility Mapping
Some of Maine's coastal bluffs are susceptible to rapid slope failure in the form of slumps and slides. Landslides result in permanent loss of upland and can threaten coastal development. Work is under way to identify shoreline areas where landslides have occurred in the past and where site-specific geologic investigations are needed to evaluate future risks. This study will result in maps that complement the Coastal Bluff Maps, which can be used in coastal zone management and land-use planning. A companion series to these maps identifies landslide hazards. This map series identifies four main types of shoreline: areas where there have been landslide; areas where there are potential landslide areas (bluffs with features that might be conducive to a landslide); areas where there are bluff that are not landslide-prone; and other shorelines that are not at risk of a landslide. Characteristics and recommendations accompany each map unit.
Erosion Hazard Mapping
MGS was funded through a grant provided by SPO to map erosion hazard areas along most of the sandy beaches of Maine. The project uses both historical and short-term shoreline change data in conjunction with beach profile data to develop an average shoreline change rate. The project will result in basemaps that designate a projected 100-yr shoreline position, thus defining the expected 100-yr erosion hazard area. Additional publications and information are also available at http://www.maine.gov/doc/nrimc/mgs/pubs/index.htm
The Wells Bay Regional Beach Management Plan (February 2002) includes the following findings:
- The primary source of sand to the Wells Bay Region is from offshore glacial deposits. Roughly 10% of the sand within the coastal sand dune system is located on land, with 4.2 million cubic yards in the frontal dunes and 9 million cubic yards in the back dunes. The remaining sand (135 million cubic yards) is within the submerged shore face.
- Thinly dispersed offshore is another 42 million cubic yards. A deposit of roughly 15 million cubic yards of sand is located offshore of Bald Head and the Ogunquit River.
The Wells jetties have had a considerable impact on the sand budget within Wells Bay. Over 1 million cubic yards of sand has been displaced from the beach system. Between 200,000- 300,000 cubic yards of sand has accreted adjacent to the south jetty, and between 100,000- 200,000 cubic yards adjacent to the north jetty. The accretion equals about 5 acres of “new” land. The fillets of sand adjacent to each jetty appears to have stabilized and reached equilibrium with surrounding beaches. About 400,000 cubic yards of sand and gravel from harbor dredging rests on salt marsh adjacent to the harbor. Open water disposal of dredged harbor sand removed about 400,000 cubic yards from the system in the early 1960s.
A Governor-appointed Shore Erosion Task Force was formed in 1999 to collect, review, and discuss current knowledge and concerns and to make recommendations concerning shoreline erosion. The Task Force was charge with identifying shore erosion control needs by County in Maryland, clarifying local, State, and federal roles regarding shore erosion, establishing 5- and 10-year plans, and reviewing contributing factors to shore erosion.
The Task Force published a set of nine recommendations to be implemented under the umbrella of a Comprehensive Shore Erosion Control Plan. As the name suggests, the Comprehensive Plan is designed to move Maryland from the current uncoordinated approach towards shore erosion control to an approach that quantifies regional shore erosion impacts and uses sound planning, based on best available data, to achieve the objectives outlined by the Governor's Task Force. Shore Erosion Task Force Final Report.
The Maryland Geological Survey (MGS) Coastal and Estuarine Geology Program currently has two projects that assess erosion along the Maryland coast. The Shoreline Changes Project that uses data from the past 150 years to map shoreline change along the state's coast. Information on the Shoreline Changes Mapping Project along with interactive maps.
Also, the Maryland Geological Survey (MGS) Coastal and Estuarine Geology Program periodically surveys the beach face at 19 locations in Ocean City and 7 locations within Assateague Island State Park. These profile locations were established in the early 1970's to monitor changes in beach width and dune heights. These locations are usually profiled every spring and fall and after major storm events to document seasonal and storm related changes. Information on the beach profile data and additional erosion data and maps.
Also, according to the 2001 Assessment shoreline position maps for the entire state are being updated and digitized. From these maps, updated shore erosion rates will then be calculated. LIDAR topographic data will be collected for small stretches of shoreline in three counties. The new shoreline positions will then be utilized to determine potential costs of impacted public and private infrastructure and other valuable resources. This information will be used as a public education and outreach tool and to develop mitigation strategies.
Massachusetts did a study of shoreline change that occurred from 1800 to 1978, with updates in 1997 and 2002. 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.
Massachusetts has been working to update their Historic Shoreline Change Maps, providing more recent information and making the information more accessible and user-friendly. They have added a 1994 shoreline; there are now 3 to 5 shorelines dating from the 1800s through 1994 for the entire Massachusetts coast. They have also updated the statistical analysis for transects spaced approximately 50 meters apart along the shoreline, and created a new fact sheet to facilitate correct use and interpretation of the 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 South Shore Coastal Hazards Characterization Atlas is the first in a series of atlases 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, 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.
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.
Michigan law requires that the MDEQ conduct erosion studies to document the long-term rate of shoreline movement. Initial, detailed erosion studies were completed in 1986, and coastal erosion research is conducted on a county-by-county basis approximately every ten years. This data is used to identify hazard areas, and establish setbacks for new construction under state regulations.
The MLWMD Shorelands Management Program (MSMP) website provides a useful summary on hazard avoidance policies in Michigan.
Part 323, Shorelands Protection and Management, of the Natural Resources and Environmental Protection Act, 1994 Public Act 451 (formerly known as 1970 PA 245) is the key state statute pertaining to coastal erosion and flooding, as well as environmental protection of our fragile coastal areas. Part 323 is closely integrated with Part 325, the Great Lakes Submerged Lands program and the Coastal Management Program, which includes Part 353, Sand Dunes Management, as well as grants to state and local units of government.
The high-risk erosion area regulations establish a required setback distance to protect new structures from erosion for a period of 30 to 60 years, depending on the size, number of living units and type of construction. Other setback requirements apply to additions to existing structures. Structures threatened by erosion must either be moved landward (where possible), protected by costly shore protection, or lost. Local units of government may adopt a zoning ordinance for high-risk erosion areas, which, if approved by the Department, replaces the need for a state high-risk erosion area permit. (Other state permits such as for critical dune areas, wetlands or shore protection may still be necessary from the Department.) The Department then monitors the performance of the community and provides technical assistance.
The shorelands of the Great Lakes, connecting waterways and river mouths areas are regulated to protect sensitive habitat. Michigan's Shorelands Protection and Management Act provides for the designation of environmental areas up to 1000 feet landward of the ordinary high water mark of a Great Lake or 1000 landward of the ordinary high water mark of lands adjacent to waters affected by levels of the Great Lakes. If the environmental area boundary encompasses an entire parcel, a 12,000 square foot structure zone is identified where construction can be permitted. Approximately 275 linear miles of essential habitat exists along Michigan's Great Lakes shorelands representing about 8.5% of the Great Lakes shoreline. About 607 parcels of land were designated as environmental areas from 1976 to 1985. Of the approximately 118 environmental areas, each containing one to several parcels of land, less than 6% utilize the full 1,000-foot setback. Most of the parcels containing environmental areas extending inland 1,000 feet are State and/or federally owned. Designation of these sensitive coastal shorelands assures an increased level of protection over these valuable resources.
Using current and historical aerial photography and sophisticated computer software, the Division of Coastal Management evaluates erosion rates about every five years. Their Erosion Rate Maps indicate that average annual shoreline change rates (1942-1992) range from 0 to more than 40 feet/year on the southern end of Ocracoke Island. There are a few places that accreted over the 50-year period, such as Sunset Beach. However, most of the beaches showed some erosion. Chronically eroding areas include Masonboro Island, Ocracoke Island, and much of the Outer Banks. The 50-year average does not reflect short-term erosion, but does indicate where erosion has occurred over the last 50 years. The Erosion Rate Maps for all 17 coastal segments through 1992 are available from the NCDCM website in Adobe Acrobat format.
The NCDCM also has great Coastal Hazards and Storm Information website. From here you can link to 'What you should know about erosion and oceanfront development', where you'll find a nice explanation of how erosion rates are determined and how they are used to by the Coastal Resources Commission (CRC) to establish oceanfront setbacks. You'll also find links to: 'Rebuilding After a Storm', common questions and answers about the repair or replacement of oceanfront houses following a major storm; and 'Protecting Oceanfront Property from Erosion', what oceanfront property owners can do to protect their homes. There you'll also find the NC Storm Path page, as well as a wealth of other hurricane tracking and pre/post disaster preparedness information.
The Community Vulnerability Assessment Tool: New Hanover County North Carolina Case Study is a product created by the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center for the coastal resource manager. This project is an informational aid designed to assist communities in their efforts to reduce hazard vulnerability. It includes a newly developed methodology for conducting a community-wide vulnerability assessment applied to New Hanover County, North Carolina. In addition to demonstrating the vulnerability assessment methodology, the case study illustrates the use of geographic information system (GIS) technology as a valuable resource for conducting hazards-related analysis. Further, as part of this project, major weather and erosion events affecting Hanover County between 1962 and 1998 were summarized.
North Carolina uses oceanfront setbacks to keep development out of ocean hazard areas. Within 'Ocean Hazard Areas of Environmental Concern' - sand dunes, ocean beaches, and other areas exhibiting substantial possibility of excessive erosion - setbacks are based on average annual recession rates, natural site features, and the nature of the proposed development. The setback is measured from the first line of stable natural vegetation or from aerial photos and ground survey where there is no stable vegetation. New structures smaller than 5,000 square feet and fewer than five residential units must be setback the farthest landward of the following: a distance equal to 30 times the average annual erosion rate; the crest of the primary dune; the landward toe of the frontal dune; or 60 feet landward of the vegetation line. The law requires that larger structures be setback 60 times the average annual recession rate, or 120 feet landward of the vegetation line. Where erosion exceeds 3.5 feet per year, the setback line for larger structures is 30 times the average annual recession rate plus 105 feet. This law was passed in 1974, made part of the coastal program in 1978, and amended in 1981 to make additional allowances for single-family dwellings.
If the cost of repairing damages to a house will be greater than half the physical value of the house itself (just the house -- not the lot, deck or furnishings), then you are considered as having to rebuild. That means you must have a permit before you begin construction. It also means you must meet all current regulations, including setback requirements. The complete text of North Carolina's Administrative Code Title 15 A, Chapter 7, Subchapter 7H, Section 0.0300 Ocean Hazard Areas is available online.
For a more user-friendly overview of these policies check out the NCDCM Coastal Hazards and Storm Information website noted above.
According to Bernd-Cohen and Gordon (1999), the Rhode Island coastal program regulates defined coastal features. The Coastal Resources Management Council (CRMC) regulates activities within and 200 feet landward of coastal beaches and dunes, barrier beaches, bluffs, cliffs, banks, rocky shores, and manmade shorelines. Complex coastal zoning designates what types of activities are permissible on shoreline features, tied to six state water classifications. About 75% of the shoreline is adjacent to Type I Waters (conservation) or Type II Waters (low intensity use areas), where alteration or construction of shoreline features and undeveloped beaches is prohibited. In addition, activities are regulated by different setbacks from beaches and dunes, critical erosion areas, and coastal buffer zones. There are also regulations for specific types of activities, such as dredging, filling, and new residential structures, as well as 17 designated coastal hazard areas and 18 identified erosion-prone areas. On the dunes of barrier beaches, residential or non-water dependent structures destroyed by more than 50% may not be rebuilt regardless of insurance carrier coverage. Additions are allowed to structures designated for priority permissible uses. CRMC policies prohibit new development on undeveloped and moderately developed barrier beaches. Data show that at least 65% of all barrier beaches have had no new permitted development or shoreline stabilizations since 1971.
The complete text of Rhode Island's Coastal Zone Buffer Program can be found on the Stormwater Manager's Resource Center website.
The SCOCRMP Beach Monitoring Program website notes that following passage of the 1988 Beachfront Management Act, the Coastal Council established a beach-monitoring program at approximately 400 survey benchmarks along the coast. Each benchmark, a metal disk set in concrete has a known vertical elevation, which is used as the starting point for the beach survey. In addition, the horizontal coordinates of each benchmark have been established, so the benchmark can be replaced in the same location if it is ever destroyed. The information from this beach-monitoring program was used to delineate the position of the baseline, set at either the actual dune crest for natural beaches or the theoretical dune crest for armored beaches. With grant support from the US Geological Survey, this monitoring program collects beach profiles at all stations twice a year to a depth of -5 feet, as a surveyor wades into chest-deep water at low tide. In addition, offshore profiles to a depth of -20 feet are collected annually at selected stations, using a submersible survey rig towed by a boat.
As called for under the Beachfront Management Act, all beaches in the state have been classified as standard zones or inlet zones. Inlet zones are regions in close proximity to a tidal inlet, where the presence of the inlet plays a dominant role in erosion or accretion patterns on the beach. Most inlet zones are unstabilized, meaning the inlet channel is not anchored by jetties or groins, and the surrounding shoreline is often quite dynamic.
The State of the Beach Reports summarize changes to South Carolina's beaches within the past two years. The report contains individual summaries for each island or beach in the state. Summaries are presented in a south-to-north progression, from Daufuskie Island to Waites Island. The geographic setting of each beach is discussed, along with any significant long-term trends. A typical beach profile plot is provided, with a location map showing survey monument locations.
The statewide summary reports that the years 1999 and 2000 were fairly mild for the beaches of South Carolina. Although hurricane Floyd appeared to be headed for the state in September 1999, it ultimately made landfall in North Carolina and caused only minor to moderate beach erosion along South Carolina's coast. A moderate northeast storm caused some beach erosion during March 2000. In September 2000, Hurricane Gordon moved from the Gulf of Mexico up the southeastern US coast, also causing some minor beach erosion in South Carolina.
In general the inlet zones, those beaches closest to unstabilized tidal inlets, are the most dynamic beaches and may experience the greatest shoreline erosion or accretion. Areas with chronic sand deficits and a minimal beach width, which provides a buffer between the ocean and high-ground development, include the following:
- Beaufort County - the northeastern end of Fripp Island, all of Hunting Island, and the northeastern end of Harbor Island.
- Colleton County - the northeastern end of Edisto Beach, including the state park.
- Charleston County - the central portion of Seabrook Island, the county park at the southwestern end of Folly Beach, and the northeastern end of Sullivans Island on Breach Inlet.
- Georgetown County - the southern end of Debidue Beach, including the southern end of the bulkhead, the southern end of Pawleys Island, and the southern end of Garden City.
The 2001 Assessment reports that from the fall of 1997 to fall of 1999, a NOAA Fellow developed a computer based post-storm damage assessment procedure, which included the following:
- Complete digital imagery of the beachfront;
- Digital photographic inventory of individual structures;
- An erosion control structure inventory;
- Parcel level data regarding oceanfront property ownership; and
- A GPS based data dictionary and protocol for conducting post-storm field assessments.
The 2001 Assessment also reports that in 1998, SCDHE-OCRM contracted for new aerial orthophotography of the beachfront areas. This updated photography was utilized in determining shoreline positions and, consequently, long-term erosion rates for establishing the setback line positions.
The SCOCRMP Beach Monitoring Program website notes that as shoreline armoring proliferated during the late 1970's and the 1980's the state recognized that the original Coastal Zone Management Act did not provide adequate jurisdiction to enable the Coastal Council to effectively protect the integrity of the beach/dune system. In response to growing concern that the public recreational beach was being lost, the South Carolina General Assembly passed the Beachfront Management Act in 1988. The Beachfront Management Act changed the way that the Coastal Council regulated oceanfront property. The Coastal Council was mandated to establish a new line of jurisdiction, called the baseline, for all oceanfront property. For most areas, the baseline was drawn along the dune crest. For armored shorelines, the baseline was drawn at the theoretical dune crest location--the position where the dune crest was calculated to exist if the shoreline had not been armored. For most erosional beaches with a sand deficit, this theoretical dune crest location was significantly landward of the seawall or bulkhead. Finally, for inlet zones, which are sections of beach in close proximity to tidal inlets, the baseline was drawn at the most landward shoreline position at any time during the past 40 years. For areas with dynamic shorelines, this baseline position could also be significantly landward of the present day shoreline.
Once the baseline was established a second line of jurisdiction, called the setback line, was drawn. The setback line was intended to be a projection of where the baseline would be located in 40 years. It was located landward from the baseline, at a distance equal to the average annual erosion rate multiplied by 40. For stable or accretional beaches with a zero rate, the setback line was located a minimum of 20 feet landward of the baseline. This setback line, which for some highly erosional beaches fell hundreds of feet landward of the baseline, marked the landward limit of the Coastal Council's jurisdiction. All new structures seaward of this line were limited to 5,000 square feet of space, and were required to be located as far landward as practical. These changes in state law were designed to give property owners reasonable use of their land, while at the same time keeping large commercial structures off the beach. In addition, new erosion control devices such as seawall, bulkheads, and revetments were prohibited seaward of the setback line, and existing erosion control structures could not be rebuilt if they were more than two-thirds damaged.
The South Carolina Coastal Zone 309 Assessment and Strategy notes that the South Carolina Beachfront Management Act calls for all jurisdictional lines in the beach/dune critical area to be revised every 8-10 years. It reports that the latest revision occurred between winter 1999 and Spring 2000. The revisions took into account physical changes to the beach since 1990 as well as a more detailed analysis of historical aerial photographs. In several areas, the agency's jurisdictional lines moved landward and the agency has assumed greater regulatory review.
It also reports that the establishment of a State Building Code in 1997 addresses concerns with new development and repairs to existing development in high hazard areas. Given the adoption of this legislation, the establishment of programs to train and certify building codes enforcement officers, and the creation of the Loss Mitigation Grant Program to encourage local communities to develop risk reduction plans, have addressed these concerns
The Gulf and Bay Shoreline Change Rate Maps depict the average annual erosion rate along segments of the Texas shoreline.
Information on habitat protection via the Dune Protection Act is also available on the TCMP website. Texas's Dune Protection Act requires counties to establish a dune protection line on the Gulf shoreline. Only limited uses and activities are allowed seaward of this line.