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For Coastal Zone Managers
Beach Erosion
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.
Program Examples
MAINE
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 Web site 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 Web site 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 Web site
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. More information on this project
can be found at: http://www.geology.um.maine.edu/beach/
While this Web site appears to be stalled in construction, it's still great. Besides
the table below, you'll find links to detailed information such as monthly profile
data for each of the beaches.
Development Status of Beaches Involved
| Beach Name |
Development Status |
Replenishment History |
Erosional Status |
| Higgins |
High |
none |
Moderate |
| Scarborough |
Low |
none |
Low |
| Western |
Low |
none |
Low |
| East Grand |
High |
none |
Low |
| Kinney Shores |
Medium |
none |
Low |
| Biddeford Pool/Fortune's Rocks |
medium/high |
none |
low/high |
| Goochs |
High |
none |
High |
| Laudholm Farm |
Low |
none |
moderate |
| Ogunquit |
Low |
several times |
moderate |
| Long Sands |
High |
none |
High |
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.
MARYLAND
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. The Shore Erosion Task Force Final Report can be downloaded at: http://www.mgs.md.gov/esic/publications/download/drnerostf.pdf
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
can be found at: http://www.mgs.md.gov/coastal/shoreline.html
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 can
be found at: http://www.mgs.md.gov/coastal/index.html
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
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.
http://www.mass.gov/czm/hazards/shoreline_change/shorelinechangeproject.htm
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. http://www.mass.gov/czm/hazards/beach/barrierbeachinventory.htm
MICHIGAN
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. http://www.michigan.gov/deq/0,1607,7-135-3313_3677_3700-10854--,00.html
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.
NORTH CAROLINA
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. http://www.nccoastalmanagement.net/Maps/erosion.htm
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. http://www.nccoastalmanagement.net/Hazards/hazards.htm
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.
http://www.csc.noaa.gov/products/nchaz/startup.htm
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 in Adobe Acrobat format. http://www.nccoastalmanagement.net/Rules/Text/t15a-07h.0300.pdf
For a more user-friendly overview of these policies check out the NCDCM
Coastal Hazards and Storm Information website noted above. http://www.nccoastalmanagement.net/Hazards/hazards.htm
RHODE ISLAND 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. http://www.stormwatercenter.net/Model%20Ordinances/rhode_island_buffer_ordinance.htm
SOUTH CAROLINA
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 Report summarizes 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 2008 State of the Beaches Report can be viewed at:
http://www.scdhec.gov/environment/ocrm/pubs/docs/SOB/SOB_08_PDF.pdf
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
TEXAS
The Gulf and Bay Shoreline Change Rate Maps, which are available online,
depict the average annual erosion rate along segments of the Texas
shoreline.
http://www.glo.state.tx.us/coastal/erosion/erosionrates.html.
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.
http://www.glo.state.tx.us/coastal/beachdune.html
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