Erosion and other Hazards
- What hazards can affect real estate along South Carolina's shorelines?
- What causes shoreline erosion?
- Do South Carolina's ocean beaches experience "long-term" erosion?
- As a buyer of coastal property, will I automatically be informed about erosion and erosion rates?
State Beachfront Jurisdiction
- What is the Beachfront Management Act?
- What is the State's Beachfront Jurisdiction?
- How often do the state jurisdictional lines change?
- How and where are jurisdictional lines drawn?
- How are erosion rates calculated?
- Will state beachfront jurisdictional lines affect my homeowners insurance?
Beachfront Development
- If I purchase undeveloped oceanfront property, where should I build on the lot?
- What types of activities are reviewed within DHEC OCRM's beachfront jurisdiction, the beach/dune system and beaches critical areas?
- Can I rebuild or repair my beachfront structure if it is damaged by a hurricane or other coastal storm?
- What does "Destroyed Beyond Repair" or "DBR" mean?
Protection from Erosion and Other Hazards
- What building construction features help reduce or prevent damage from natural events?
- If my oceanfront property becomes threatened by erosion, can I construct a seawall?
- If my oceanfront property becomes threatened by erosion, can I move my house away from the eroding shoreline?
- If my oceanfront property becomes threatened by erosion, can I construct sand dunes?
- If my oceanfront property becomes threatened by erosion, can I place sandbags in front of my home?
What hazards can affect real estate along South Carolina's shorelines?
South Carolina's coastline is constantly changing due to coastal hazards, including beach erosion and flooding. Coastal erosion can be long-term, chronic erosion from a variety of causes, or it may be short-term as the result of a single or series of storm events. In addition to these hazards, beachfront homes may also be threatened by high winds generated by coastal storms. Finally, in South Carolina, there is the possible threat of earthquakes. The last big one rocked the Charleston area in 1886 and registered 7.6 on the Richter Scale. Smaller earthquakes occur regularly in coastal South Carolina. More information on earthquakes is available through the South Carolina Geological Survey. ( Top )
What causes shoreline erosion?
Hurricanes, nor'easters, and other storms cause seasonal fluctuations of the shoreline. Generally, beaches erode more in the stormy fall and winter months than in the calm summer months. Of course, when a beach is hit directly by a hurricane, beachfront erosion can be even more dramatic. Inlets are also affected by seasonal storms and can change configuration rapidly and severely as tremendous amounts of water and sand flow through them. In severe storms, it is even possible for new inlets to form and existing inlets to close. On sandy beaches, erosion associated with storms is often severe because large quantities of sand can be moved quickly offshore from the beach and dunes. This type of erosion is usually called "short-term" erosion because the shoreline may return to its original profile as conditions improve over time. Beaches need time to recover after a storm, so a series of storm events can lead to prolonged erosional conditions. Long-term, chronic erosion can also occur from a variety of causes including shoal bypassing events near inlets or a reduction of sand in the sand-sharing system. ( Top )
Do South Carolina's ocean beaches experience "long-term" erosion?
Yes. Long-term erosion, often called "beach migration," is generally associated with rising sea levels, but can also be caused by a variety of other factors. Sea level in the Charleston area has risen nearly a foot during the last century, causing beaches to migrate landward.
Although this process can cause erosion along the entire oceanfront, areas adjacent to inlets are often the most profoundly affected.
In addition to natural causes, erosion can be set in motion by human activities. For example, a jetty constructed to stabilize an inlet or a structure built to stabilize a beach can trap sand on one side but increase erosion on the other. Such erosion will continue until the structure is removed or adjusted or the beach is renourished. ( Top )
As a buyer of coastal property, will I automatically be informed about erosion and erosion rates?
Not necessarily. Purchasers should always research coastal hazards, seeking information on pertinent laws and regulations from local government, DHEC OCRM and your realtor.
Erosion rates vary not only from municipality to municipality, but sometimes even from one stretch of beach to another part of that same beach. If you are working with a licensed real estate agent, the agent has a duty to disclose material facts that she or he knows or reasonably should know. Although real estate agents might not always know the erosion rates for particular oceanfront properties, they should advise you of the possibility of erosion and direct you to available sources of information. If a beachfront property is located, in whole or in part, seaward of the beachfront jurisdictional baseline or setback line, a contract of sale or transfer of real property must contain a disclosure statement. The statement must indicate that the property is or could be affected by these lines and the statement must include the long term erosion rate most recently made available by DHEC OCRM for that zone. The jurisdictional lines and the adopted erosion rates statewide may be accessed through the SC Beachfront Jurisdictional Lines Viewer. ( Top )
What is the Beachfront Management Act?
The Coastal Tidelands and Wetlands Act of 1977 was enacted to protect our coastal resources and promote responsible development. This legislation served the beaches well during its first decade, but as South Carolina became a more popular tourist destination, it became apparent that the portion of the Act that dealt with beaches was inadequate. As development crept seaward, seawalls and rock revetments proliferated, damaging public beaches.
In many areas with seawalls and revetments, there was little or no beach left at high tide. In some areas, there was no beach at low tide, either. In 1988, South Carolina's legislators took action to amend and strengthen the Coastal Tidelands and Wetlands Act, resulting in the Beachfront Management Act. The Beachfront Management Act protects South Carolina's sandy shores by establishing jurisdictional areas and encouraging soft solutions to erosion like beach renourishment. ( Top )
What is the State's Beachfront Jurisdiction?
Beachfront critical areas include the beach/dune system and beaches critical area. The beach/dune system critical area begins at the high water mark, and extends landward to the jurisdictional setback line.
DHEC has direct permitting authority over beaches critical area and the active beach as those terms are defined in the Coastal Tidelands and Wetlands Act. If any portion of your property falls seaward of the setback line, within beaches critical area, or on the active beach, speak with a member of DHEC OCRM’s Beachfront Management Section before beginning construction. Failure to do so may result in a fine and/or the removal of the structure at the property owner's expense.
The Folly Beach Exception
Folly Beach in Charleston County is the only beach without a setback line. The Charleston Harbor jetties, a federal project built in the late 1800s, are a major contributing factor of erosion on Folly Beach. To compensate property owners for their loss, the General Assembly set Folly Beach's baseline along the beach's erosion control structures. There is no setback area on Folly Beach, thus the state's jurisdiction is seaward of the baseline, except in cases where the beaches critical area extends landward of the baseline. ( Top)
How often do the state jurisdictional lines change?
DHEC is mandated by the Beachfront Management Act (48-39-280-C) to review the position of the beachfront baseline and 40-year setback line, the state's beachfront jurisdictional lines, every 7 to 10 years. The next line review cycle will begin no earlier than 2024. (Top)
How and where are jurisdictional lines drawn?
State beachfront jurisdictional lines are determined depending on the classification of the beach zone:
Standard Zones
Within a standard erosion zone (a segment of shoreline which is subject to essentially the same set of coastal processes, has a fairly constant range of profiles and sediment characteristics and is not directly influenced by tidal inlets or associated inlet shoals) the baseline is typically established at the location of the crest of the primary oceanfront sand dune in that zone. The primary oceanfront sand dune is defined as a dune that has a minimum height of 3 feet from the toe to the crest, and forms a nearly continuous ridge for 500 shore parallel feet.
If the primary oceanfront sand dune is more than 200 feet landward of the current line of stable vegetation, then the baseline is established seaward of the primary oceanfront sand dune at a distance equal to 30% of the measured distance from the vegetation line to the primary dune.
If there is no primary oceanfront sand dune, then the baseline is established at the landward edge of active beach or at the baseline’s proposed 2017 location or at the baseline’s 2008 – 2012 established location, whichever is further landward.
Unstabilized Inlet Zones
Within an unstabilized inlet zone (inlets that have not been stabilized by jetties, terminal groins, or other structures) the baseline must be determined by DHEC as the most landward point of erosion at anytime during the past forty years, unless the best available scientific and historical data of the inlet and adjacent beaches indicate that the shoreline is unlikely to return to its former position. In collecting and utilizing the best scientific and historical data available for the implementation of the preservation policy, DHEC, among other factors, must consider: historical inlet migration, inlet stability, channel and ebb tidal delta changes, the effects of sediment bypassing on shorelines adjacent to the inlets, and the effects of nearby beach restoration project on inlet sediment budgets.
Stabilized Inlet Zones
Within a stabilized inlet zone (inlets which are stabilized by jetties, terminal groins, or other structures) the baseline location must be determined in the same manner as provided for in a standard erosion zone. However the actual location of the crest of the primary oceanfront sand dune of that erosion zone is the baseline of that zone, not the location if the inlet had remained unstabilized.
Setback Lines
A setback line must be established landward of the baseline a distance which is forty times the average annual erosion rate or not less than twenty feet from the baseline for each erosion zone based upon the best historical and scientific data (48-39-280). ( Top )
How are long-term erosion rates calculated?
Long-term erosion rates are determined by analyzing historical shoreline positions from aerial photographs and survey sheets, and calculating annual erosion rates based on movement of the shoreline positions. ( Top )
Will state jurisdictional lines directly affect my homeowners insurance?
No. State beachfront jurisdictional lines only affect what can be built or rebuilt seaward of the baseline and within the setback area. ( Top )
If I purchase undeveloped oceanfront property, where should I build on the lot?
DHEC OCRM regulations guide development away from the highest hazard areas along the beachfront. The location of the beach/dune system critical area, the beaches critical area, and active beach influence building location authorization. The beach/dune system starts at the high water mark and continues landward to the setback line. Beaches critical area begins at the low tide mark, includes the intertidal zone and dry sand beach, and continues landward until reaching vegetation that is not characteristic of the beach environment (i.e. shrubby or woody species). Seaward of the setback line, new habitable structures must be built as far landward as possible and are limited to a maximum of 5,000 square feet of heated space. Special permits must be obtained to build seaward of the baseline. If a structure is constructed under a special permit, and the beach erodes and the permitted structure becomes situated on the active beach, the property owner, at his or her own expense, must remove the structure if so ordered by DHEC OCRM. Additionally, structures cannot be constructed on the primary oceanfront sand dune or on active beach.
The Federal Emergency Management Agency (FEMA) provides additional information on where to site residential structures on coastal property in their Coastal Construction Manual (FEMA 55 - 6/2000). A copy of the publication can be requested by contacting FEMA at 1-800-480-2520. ( Top )
What types of activities are reviewed within DHEC OCRM's beachfront jurisdiction, the beach/dune system and beaches critical areas?
DHEC OCRM reviews a variety of activities within the beachfront critical areas. Examples of activities include but are not limited to: construction of habitable structures and pools, maintenance & repair of pre-existing erosion control structures, landscaping, decks, gazebos, drives & parking lots, service lines, sand fencing, beach renourishment, dune management, golf courses, and fishing piers. Anyone interested in activities within DHEC OCRM’s beachfront jurisdiction will need to obtain a permit or letter of authorization from DHEC. Please reach out to the Beachfront Management Section, 843-953-0200, with any questions. (Top)
Can I rebuild or repair my beachfront house if it is damaged by a hurricane or other coastal storm?
A habitable structure that has been destroyed beyond repair due to a natural cause and that is wholly or partially in the setback area may be replaced or rebuilt provided all of the following requirements are met:
- The replacement structure is not constructed on active beach or the primary oceanfront sand dune or within the beaches critical area. After a storm, you may need to seek and obtain a permit from DHEC OCRM for dune restoration prior to rebuilding on your lot.
- The total square footage of the replaced structure seaward of the setback line does not exceed the total square footage of the original structure seaward of the baseline;
- The linear footage of the replaced structure parallel to the coast does not exceed the original linear footage parallel to the coast;
- The replacement structure is no farther seaward than the original structure;
- Where possible, the replaced structure is moved landward of the setback line or if not possible, then as far landward as practicable, considering local zoning and parking regulations;
- Meets the requirements for new construction as defined in the local community's flood damage prevention ordinance. ( Top )
What does "Destroyed Beyond Repair" or "DBR" mean?
For habitable structures, destroyed beyond repair means more than sixty-six and two-thirds percent of the replacement value of the habitable structure has been destroyed. See R.30-14(D)(3)(a) for more information.
For pools, destroyed beyond repair means more than sixty-six and two-thirds percent of the replacement value of the pool has been destroyed. See R.30-14(D)(3)(b) for more information.
For seawalls, bulkheads and revetments damage must be judged on the percentage of the structure remaining intact at the time of the damage assessment. Destroyed beyond repair means more than fifty percent above grade has been destroyed. See R.30-14(D)(3)(c) for more information. ( Top )
What building construction features help reduce or prevent damage from natural events?
Several features can prevent or substantially reduce the likelihood of damage from severe storms, erosion, or earthquakes. Pilings raise the first floor above expected flood elevations and waves. In many areas, embedding the tip of pilings deeper than ten feet below sea level can help a building stand during severe erosion. Any first floor walls constructed between pilings should be designed to break away when hit by waves to prevent damage to the elevated portion of the building.
Elevating a building to protect it from storm surge and flood increases its exposure to storm winds. The key to reducing storm wind damage lies in the quality of the building's design and construction. If you are building a new home on the beach, consider employing the services of a professional engineer to help ensure an adequate structural design. If you are buying an existing home, a professional engineer can help you assess the structure's strengths and weaknesses, as well as suggest structural and non-structural modifications which may help make the house more damage resistant.
Modifications may include:
- adding "hurricane clips" to improve the roof's ability to withstand uplift forces of high winds
- installing storm window protection to protect window and door openings from wind-driven rain and debris
- replacing asphalt roof shingles
- reinforcing gable end roofs
- reinforcing the attachment of plywood roof decking to roof rafters with additional nails, screws or adhesives
- reinforcing the attachments of porches and decks to a house's main structure
Remember, however, no home is disaster-proof. There are inherent and unavoidable dangers associated with building homes along the beach. Because of the substantial cost of coastal property, a professional engineering analysis could be a wise investment.
Note: Sand dunes are natural features that also provide significant protection during the most severe storms. You can protect and enhance frontal dunes by keeping vehicles and people off them, planting additional dune grasses, and installing sand fences. Keep in mind, however, that dunes protect against short-term erosion caused by very severe, infrequent storms but offer little protection from long-term erosion.
FEMA's Coastal Construction Manual (FEMA 55 - 6/2000) provides guidance for the design and construction of coastal residential buildings that will be more resistant to the damaging effects of natural hazards. A copy of the publication can be requested by contacting FEMA at 1-800-480-2520. (Top )
If my oceanfront property becomes threatened by erosion can I construct a seawall?
No. Erosion control structures are not compatible with South Carolina’s policy of beach preservation. On an erosional beach, seawalls and rock revetments may actually accelerate erosion, effectively destroying the beach. In South Carolina, no new erosion control structures are allowed within the beach/dune system or beaches critical areas or on the active beach. Grandfathered erosion control structures may not be enlarged, strengthened or rebuilt, but may be maintained in their present condition. If destroyed, the structure must be removed at the owner's expense. ( Top )
If my oceanfront property becomes threatened by erosion, can I move my house away from the eroding shoreline?
Yes. House-moving is an allowable means of getting a structure out of harm's way. If space allows, a structure may be moved landward on the same lot; otherwise, it can be relocated to new property. Regardless of where the building is moved, it must meet requirements within OCRM's jurisdiction. ( Top )
If my oceanfront property becomes threatened by erosion, can I construct sand dunes?
Yes. Sand dunes provide some of the best protection against high tides and minor storms. DHEC OCRM's " How to Build A Dune " is a helpful guide for creating and preserving sand dunes. Contact DHEC OCRM to inquire about permitting requirements for constructing sand dunes on your property. ( Top )
If my oceanfront property becomes threatened by erosion, can I place sandbags in front of my home?
Emergency situations before or after a storm event may prompt the DHEC, or an appointed official of a county or municipality or of the state to issue emergency orders under R.30–5, allowing property owners to construct temporary barriers against wave uprush. A structure is determined to be in imminent danger when the erosion comes within twenty (20) feet of that structure. DHEC OCRM or the local government may issue an emergency order allowing sand scraping, minor beach renourishment, or the temporary use of sandbags to provide protection (Top)