(A) For the purposes of this section, the following definitions shall apply:
BERM. A compacted mound of earth, soil, or sand, which may be used independently or to cover riprap, constructed to protect against flooding.
BULKHEAD. A vertical erosion control device installed on high ground which is adjacent to the marsh front critical line as defined by OCRM.
RETAINING WALL. A vertical erosion control or stabilization device installed on high ground within 15 feet of the OCRM critical line.
REVETMENT. Sloping material installed seaward of a seawall facing the oceanfront baseline as defined by OCRM.
RIPRAP. Sloping material installed in front of a bulkhead on the side of the bulkhead facing the marsh front critical line as defined by OCRM or as the foundation of a berm.
SEAWALL. A vertical erosion control device installed on high ground which is adjacent to the oceanfront baseline as defined by OCRM.
(B) The following minimum construction standards are enacted.
(1) All erosion control structures placed wholly or partly within the Dune Management Area or the setback from the critical line must be maintained in an intact usable condition or removal may be sought at the owners expense.
(2) New or substantially improved seawalls and associated revetments on the beach constructed after March 1, 2019 and placed wholly or partly within the Dune Management Area must be constructed so that the top of the vertical seawall is at an elevation of eight feet NAVD 88. Any portion of the Dune Management Area disturbed for the repair of an existing seawall or the construction of a new or substantially improved seawall after March 1, 2019 shall be filled such that the finished grade of the area of disturbance is at an elevation of ten feet NAVD 88 and planted with appropriate vegetation as designated by the Building Official.
(3) New or substantially improved bulkheads, retaining walls, or associated riprap constructed within 15 feet of the critical line after March 1, 2019 and placed wholly or partly within the required setback from the critical line must be constructed so that the top of the vertical structure is no higher than the adjacent grade on the landward face. Any portion of the critical line setback disturbed for the repair of an existing bulkhead or the construction of a new or substantially improved bulkhead after March 1, 2019 shall be filled such that the finished grade of the area of disturbance is at an elevation similar to the grade on the landward side and planted with appropriate vegetation as designated by the Building Official.
(4) New or substantially improved berms constructed within 15 feet of the critical line after March 9, 2021 and placed wholly or partly within the required setback from the critical line must be constructed so that the highest point of the berm is no more than three feet above the highest adjacent grade.
(5) New or substantially improved erosion control methods cannot be combined in a manner that would compound flooding, significantly impair drainage, cause adjacent shoreline impacts, or cause any negative impacts to marsh growth. However, mix use of erosion control methods dictated by site conditions on homeowner property can be permissible in the same contiguous linear plane.
(6) Construction of bulkheads, seawalls, retaining walls and berms within 15 feet of the critical line, and revetments as well as the placement of riprap shall require a permit from the city and proof of location behind the SCDHEC OCRM critical line or baseline in the form of a pre-construction survey with an OCRM certified critical line or baseline location and an as-built survey showing as-built improvement and the certified baseline or critical line as applicable.
(7) No portion of a bulkhead, riprap, seawall, retaining wall, revetment, or berm shall be placed seaward of the baseline or beyond the critical line without approval of SCDHEC OCRM.
(8) Bulkhead, riprap, seawalls, retaining walls, berms and revetments shall be designed by a certified design professional, registered in the state and shall meet the following minimum standards:
(a) Bulkhead, retaining walls and seawall requirements.
1. Materials.
i. Reinforced concrete six inches thick designed with adequate reinforcement to achieve a 3,000 psi 28-day strength.
ii. Pressure treated wood three inches by ten inches or three inches by 12 inches tongue and groove, or a double thickness of two inches sheeting with staggered joints is acceptable for walls with a standing height of under four feet.
2. Depth of embedment. The depth of embedment of a bulkhead shall be at least equal the height of the wall above the ground. An allowance should be made to account for erosion scour after construction.
3. Tiebacks. Tiebacks shall be located at a spacing of eight feet or less and attached to secure anchors capable of withstanding a 2,000- pound pull. Tiebacks may be deleted if a revetment is placed seaward of the bulkhead.
4. Backfill. The bulkhead will be backfilled with a compacted clean granular material to provide adequate support. “Clean” shall mean no metal, wood or glass.
5. Protection from flanking. Bulkheads will either tie into adjacent bulkheads or will have an adequate return wall meeting the same requirements as the seaward wall.
6. Seawalls. No new vertical unfaced seawall shall be allowed on the ocean front. Any new vertical seawall surface must be faced with a sloping revetment.
(b) Revetments.
1. Materials. Broken pavement, blocks or bricks are not acceptable materials for the outer layer of a revetment. However, they may be used for under layers. The outside of a revetment shall consist of at least two layers of armor stones whose pieces shall range in weight from a minimum of ten pounds to a maximum of 250 pounds; at least 60% shall weigh more than 150 pounds.
2. Construction. Revetments shall be underlain with a commercial grade porous filter cloth designed for ocean erosion control and approved by the Building Official (i.e. Phillips 66 stock or equal), and placed on a slope no steeper than one vertical to two horizontal. The toe at the revetment shall extend at least two feet below the existing beach elevation and the ends shall be protected from flanking.
(c) Riprap.
1. Materials. Broken pavement, blocks or bricks are not acceptable.
2. Design. Riprap placement, including when used as the foundation of a berm, must be designed by a licensed marine contractor or a certified designed professional registered in the State of South Carolina so as to prevent movement into the critical area.
(d) Berms within 15 feet of the critical line shall be designed by a certified design professional registered in the State of South Carolina and shall meet the following minimum standards:
1. Berms shall be designed to prevent shedding of storm, flood and tide waters onto adjacent properties and a no adverse impact statement in congruence with other city ordinances including floodplain shall be included on designs provided during permitting.
2. Berms shall be tied into existing grades along the entire length of their perimeter to ensure that berms are naturally appearing, and floodwaters are not impacting surrounding properties.
3. Berms shall be compacted prior to planting, landscaping, or revegetation.
4. Berms shall be landscaped along the landward side with appropriate native vegetation such that at least 50% of the surface of the berm is covered by plant material when calculated using the average mature size of the proposed plantings. In the case of damage or erosion resulting in the loss of required vegetation, berms must be repaired and replanted to meet the requirements of this section.
5. Naturally occurring, protected trees shall not be "buried" or incorporated within the berm so as to cause the trees to die unnaturally from piling up and stacking of soils above and around the natural ground level surrounding the tree trunks. Boxing of protected trees is acceptable.
6. Any riprap used as the foundation of a berm must be completely covered by compacted earth so that no riprap is visible. In the case of damage or erosion resulting in the exposure or disturbance of riprap, berms must be repaired to meet the requirements of this section.
(C) Adherence to these minimum standards will not guarantee that the bulkhead, riprap, seawall or revetment will withstand wave or tide forces or that it will protect against erosion. These standards are to prevent unsightly and inferior structures that would have little or no chance of success, and could possibly become a hazard or nuisance.
(D) Seawall construction activity from May 1 through October 31 is subject to the following requirements.
(1) The permit holder must contact the Folly Beach Turtle Watch Permit Holder each day prior to the commencement of work. The Folly Beach Turtle Watch Permit Holder will provide verification that there are no active turtle nests in the work area. Verification will be provided prior to 8:00 a.m.
(2) If an active nest is located in the work area, work must stop until the nest is relocated. If a turtle nest located in the work area is established before permitted work begins and can’t be relocated, construction cannot begin until the nest hatches.
(3) The WORK AREA shall be defined as the area within 25 feet of the location of the seawall or the path used to access the site.
(`95 Code, § 5-3-22) (Ord. 83-10, passed 8-2-83; Am. Ord. 83-18, passed 1-3-84; Am. Ord. 84-29, passed 12-18-84; Am. Ord. 02-05, passed 1-25-05; Am. Ord. 10-15, passed 8-11-15; Am. Ord. 09-19, passed 2-11-19; Am. Ord. 26-19, passed 8-13-19; Am. Ord. 04-20, passed 6-9-20; Am. Ord. 03-21, passed 3-10-2021)