(a) General.
(1) Purpose. Certain areas within Richland County are subject to periodic inundation by floodwater, which results or may be reasonably foreseen to result in loss of life or property, health and safety hazards, disruption of commerce and governmental services, and extraordinary public expenditures for flood protection and relief, all of which adversely affect the public health, safety, and general welfare of the citizens of Richland County. These hazards are caused or extended in part by the occupancy of flood hazard areas by uses that increase flood damage upon other lands, or uses that are vulnerable to floods because they are inadequately elevated or not otherwise protected from flood damages. In order for owners of property located within the county that is subject to periodic inundation to obtain flood damage insurance through the National Flood Insurance Program, the United States government, by statute and through regulations promulgated by the Federal Emergency Management Agency (FEMA) requires that the county enact floodplain regulations designed to reduce the amount of potential flood losses. It is, therefore, the intent of this section to lessen such hazards and losses and ensure insurance coverage by those affected property owners by restricting or prohibiting uses that are dangerous to health, safety, or property in times of flood or that cause excessive increases in flood heights or velocities. This shall be accomplished by requiring that uses vulnerable to floods be protected against flood hazards at the time of initial construction, and by controlling filling, grading, mineral extraction, placing of obstructions within the flood channels, and other activities, uses, or characteristics of use which may increase flood damage.
(2) Warning and disclaimer of liability. The degree of flood protection required by this Section is considered reasonable for regulatory purposes and is based on scientific and engineering standards. Larger floods can and will occur on rare occasions. Flood heights may be increased by man-made or natural causes. This Section does not imply that land outside the areas of special flood hazard, or uses permitted within such areas, will be free from flooding or flood damages. This Section shall not create liability on the part of Richland County or by any officer or employee thereof for any flood damage that results from reliance on the provisions contained herein or on any administrative decision lawfully made hereunder.
(b) Applicability/establishment. The FP Overlay District shall function as an overlay district providing additional requirements to the regulations of the underlying general use zoning classification(s). It shall be applied to those areas designated on the Federal Emergency Management Agency's Flood Insurance Study, dated December 21, 2017, with accompanying Flood Insurance Rate Maps (FIRM), dated December 21, 2017, as areas of special flood hazard. In addition to other required development approvals, development applicants subject to the FP Overlay District must also receive a floodplain development permit from the county's flood coordinator. Review of developments subject to these requirements shall be conducted as part of the review for a grading or land development permit, whichever is applicable.
(c) Permitted uses, permitted uses with special requirements, and special exceptions.
(1) General: Any use permitted outright, with special requirements, or permitted as an accessory use in the general use district(s) to which the FP Overlay District is affixed to, is permitted; provided that such use complies with all applicable regulations set forth below and in the other sections of this chapter. (See however, restrictions for development in the designated floodway as set forth in subsection (d)(2)h. below). All applications for land development permits for uses permitted in the FP Overlay District shall be reviewed by the flood coordinator in accordance with the requirements of subsection (d) below. Before the planning department may issue a land development permit, a floodplain development permit must be issued. The findings and recommendations of the flood coordinator shall be binding upon the planning department unless otherwise appealed.
(2) Permitted special exceptions. Any use listed as a special exception in the general use district(s) to which the FP Overlay District is affixed to may be permitted by the Richland County Board of Zoning Appeals as set forth in Section 26-56 of this chapter; provided that such uses comply with all applicable regulations set forth below and in the other sections of this chapter. (See, however, restrictions for development in the designated floodway as set forth in subsection (d)(2)h. below). All applications for special exceptions in the FP Overlay District shall be reviewed by the flood coordinator prior to review by the board of zoning appeals in accordance with the requirements of subsection (d) below. Before the board of zoning appeals may approve a special exception, a floodplain development permit must be issued. The findings and recommendations of the flood coordinator shall be binding upon the board of zoning appeals.
(d) Standards in the floodplain.
(1) General standards.
a. Before a permit is issued, the applicant shall demonstrate that encroachments onto the floodplain are minimized. New development, if permitted in the area of special flood hazard, shall minimize disruption to shorelines, stream channels, stream banks, and the regulatory floodway. As used in this paragraph, the term "minimize" shall mean the lowest degree of interruption (i.e. the uniformity or continuity) to the natural course of action or activity. All permit applications will be reviewed to determine whether proposed building sites will be reasonably safe from flooding.
b. Anchoring. All new construction and substantial improvements shall be designed and anchored to prevent flotation, collapse, or lateral movement of the structures.
c. Materials/methods to be used. All new construction and substantial improvements shall be constructed with flood resistant materials and utility equipment resistant to flood damage. All new construction and substantial improvements shall be constructed by methods and practices that minimize flood damages.
d. Electric, ventilation, plumbing, heating, and air conditioning equipment. Electric, ventilation, plumbing, heating, and air conditioning equipment (including ductwork), and other service facilities, shall be designed and elevated two (2) feet above the base flood elevation so as to prevent water from entering or accumulating within the components during conditions of flooding as specifically provided for below:
1. When not substantial improvement. The replacement of existing electrical, ventilation, plumbing, heating, and air conditioning equipment (including ductwork) and other service facilities, that do not constitute a substantial improvement, are encouraged to be elevated at least two (2) feet above the base flood elevation, but they may be located at the original location and elevation.
2. New construction and substantial improvement. All electrical, ventilation, plumbing, heating, and air conditioning equipment (including ductwork), and other service facilities, for new construction and substantial improvement must be elevated at least two (2) feet above the base flood elevation.
3. Outdoor faucets. The requirements listed above do not preclude the installation of outdoor faucets for shower heads, sinks, hoses, etc. as long as cut off devices and back flow devices are installed to prevent contamination to the service components and thereby minimize any flood damages to the building.
e. Water and sanitary sewage systems. All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the sanitary sewage systems into flood waters.
f. On-site waste disposal systems. On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding.
g. Foundation systems. Hydrodynamic pressure must be considered in the design of any foundation system when velocity waters or the potential for debris flow exists. If flood velocities are excessive (greater than five (5) feet per second), foundation systems other than solid foundation walls should be considered so that obstructions to damaging flood flows are minimized.
h. Non-conforming buildings or uses (see also Article X of this chapter on nonconforming uses generally). Non-conforming buildings or uses may not be enlarged, replaced, or rebuilt unless such enlargement or reconstruction is accomplished in conformance with the provisions of this section. Provided, however, nothing in this section shall prevent the repair, reconstruction, or replacement of an existing building or structure located totally or partially within the floodway, if the bulk of the building or structure below base flood elevation in the floodway is not increased, and provided that such repair, reconstruction, or replacement meets all of the other requirements of this section. Reconstructions or replacements of existing buildings or structures sh.all be placed with their longitudinal axis parallel to the predicted direction of the flow of flood waters or be placed so that their longitudinal axis are on lines parallel to those of adjoining structures so as to offer the minimum resistance to the flow of floodwaters.
i. American with Disabilities Act (ADA). A building must meet the specific standards for floodplain construction as outlined in subsection (d)(2) below, as well as any applicable ADA requirements. The cost of improvements required to meet the ADA provisions shall be included in the costs of the improvements for calculating substantial improvement.
j. Watercourse alterations and maintenance. In addition to the notifications required for watercourse alterations per Section 26-36(a)(2)c., a maintenance requirement will be included in Floodplain Development Permits whenever a watercourse is altered or relocated within a Special Flood Hazard Area. Such maintenance activities shall ensure that the flood-carrying capacity of the watercourse is not diminished, and shall consist of periodic inspections, and routine channel clearing and dredging, or other related functions. In addition, the permittee shall keep a written record describing all maintenance activities performed, the frequency of performance, and the name of the person(s) responsible for such maintenance and provide copies to the Flood Coordinator. The Flood Coordinator shall keep permitting records on file for FEMA inspection.
(2) Specific standards.
a. Residential construction. New construction and substantial improvement of any residential structure (including manufactured homes) shall have the lowest floor elevated no lower than two (2) feet above the base flood elevation. No basements are permitted. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with subsection f. below.
b. Nonresidential construction. New construction and substantial improvement of any commercial industrial, or nonresidential structure shall have the lowest floor (including basement), or mechanical and utility equipment, elevated no lower than two (2) feet above the level of the base flood elevation or be flood-proofed to a level no lower than two (2) feet above the level of the base flood elevation, provided that all areas of the building (including mechanical and utility equipment) below the required elevation are watertight with walls substantially impermeable to the passage of water, and use structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with subsection f. below. A South Carolina licensed registered land surveyor, engineer, or architect authorized by law to certify such information shall certify that the standards of this subsection are satisfied. Flood-proofed structures shall have an approved maintenance plan with an annual exercise as required by FEMA. The maintenance plan must be approved by the flood coordinator and notification of the annual exercise shall be provided to same.
c. Foundation protection. A land surveyor, engineer, or architect authorized by law to certify such information shall develop or review the structural design, specifications, and plans for the foundation of all new buildings and shall certify that the design and methods of construction are in accordance with accepted practices to withstand flotation, collapse, lateral movement, erosion, scour, undermining, and the effects of water and wind acting simultaneously on all building components during the occurrence of the base flood.
d. Manufactured homes.
1. Substantially damaged homes. Manufactured homes that are on sites outside a manufactured home park or subdivision, in a new manufactured home park or subdivision, in an expansion to an existing manufactured home park or subdivision, or in an existing manufactured home park or subdivision, which have incurred “substantial damage,” must be subsequently elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated no lower than two (2) feet above the base flood elevation and must be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
2. Existing manufactured homes. Manufactured homes proposed to be placed or substantially improved on sites in an existing manufactured home park or subdivision that are not subject to the provisions of subsection d.1. above, must be elevated so that the lowest floor of the manufactured home is elevated no lower than two (2) feet above the base flood elevation, and must be securely anchored to an adequately anchored foundation to resist flotation, collapse, and lateral movement.
3. Anchoring. Manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement. For the purpose of this requirement, manufactured homes must be anchored to resist flotation, collapse, or lateral movement in accordance with Section 19-425.42 of the South Carolina Manufactured Housing Board Regulations, effective date May 25, 1990, as amended. Additionally, when the elevation requirement would be met by an elevation of the chassis at thirty-six (36) inches or less above the grade at the site, the chassis shall be supported by reinforced piers or other foundation elements of at least equivalent strength. When the elevation of the chassis is above thirty-six (36) inches in height, an engineering certification is required.
4. Evacuation plan for parks and subdivisions. An evacuation plan indicating vehicular access and escape routes for residents of manufactured home parks and subdivisions located in or surrounded by an area of special flood hazard must be developed. The owner of the manufactured home park or subdivision shall be responsible for filing this plan with the flood coordinator and shall see that each tenant thereof has received an evacuation plan prior to the tenant’s moving into the manufactured home park or subdivision. This plan shall be approved by the flood coordinator and the local emergency preparedness coordinator.
e. Recreational vehicles. Recreational vehicles placed on sites within a floodplain shall either be on site for fewer than one hundred and eighty (180) consecutive days and be fully licensed and ready for highway use, or meet the general standards listed in subsection (d)(1) above, as well as the standards for manufactured housing in subsection (d)(2)d. above. A recreational vehicle is ready for highway use if it is on wheels or a jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.
f. Elevated buildings. New construction and substantial improvements of elevated buildings that include fully enclosed areas formed by foundation and other exterior walls and are used solely for the parking of vehicles, building access, or limited storage in an area other than a basement, and are subject to flooding, shall be designed to preclude finished space and shall be designed to automatically equalize flood forces on exterior walls by allowing for the entry and exit of floodwaters.
1. Designs for elevated buildings. Designs for complying with this requirement must either be certified by a South Carolina licensed registered land surveyor, engineer, or architect authorized by law to certify such information, or meet the following minimum criteria:
[a] Provide a minimum of two (2) openings on different walls having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding;
[b] The bottom of all openings shall be no higher than one (1) foot above grade;
[c] Only the portions of openings that are below the base flood elevation can be counted towards the required net opening amount;
[d] Openings may be equipped with screens, louvers, valves, or other coverings or devices, provided they permit the automatic flow of floodwaters in both directions, including engineered vents; and
[e] Fill placed around foundation walls shall be graded so that the grade inside the enclosed area is equal to or higher than the adjacent grade outside the building on at least one side of the building.
2. Access to enclosed area. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standards exterior door) or entry to the living area (stairway or elevator).
3. Interior portion of enclosed area. The interior portion of such enclosed area shall not be partitioned or finished into separate rooms, except to enclose a limited storage area. In addition, the interior portion must be void of utilities, except for essential lighting as required, and cannot be temperature controlled. One wet location switch and/or outlet connected to a ground fault interrupt breaker may be installed below the required lowest floor elevation as specified in subsections (d)(2)a., b., and d., above.
4. Construction materials. All construction materials below the required lowest floor elevation, as specified in subsections (d)(2)a., b., and d. above, shall be of flood resistant materials.
g. Accessory structures. An accessory structure or garage, the cost of which is greater than $1,000.00 must comply with the elevated structure requirements of subsection (d)(2) a. and b. above. When accessory structures of $1,000.00 or less are to be placed in the floodplain, the following criteria shall be met:
1. One-story. Accessory structures shall be no higher than a single-story building.
2. Not for habitation. Accessory structures shall not be used for human habitation (including work, sleeping, living, cooking, or restroom areas);
3. Flood damage potential. Accessory structures shall be designed to have low flood damage potential;
4. Placement. Accessory structures shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters;
5. Anchoring. Accessory structures shall be firmly anchored to prevent flotation, collapse, or lateral movement of the structure;
6. Service facilities. Service facilities, such as electrical and heating equipment, shall be installed in accordance with subsection (d)(1) f. above; and
7. Openings. Openings to relieve hydrostatic pressure during a flood shall be provided below base flood elevation in conformance with subsection (d)(2) f. above.
h. Floodways. The following provisions shall apply within the floodway areas:
1. Permitted uses, excluding buildings. The following uses shall be permitted in areas designated floodway areas, but only if such uses are permitted within the basic district to which the FP overlay is appended, and excluding buildings in connection with such uses:
[a] Agricultural and horticultural uses, and plant nurseries.
[b] Parking and loading areas.
[c] Open-air uses generally accessory to residential uses, such as lawns, gardens, play areas, and parking areas.
[d] Recreational uses which are primarily open-air uses and which do not offer a substantial impediment to water flow, such as swimming areas, fishing areas, beaches, boat launching ramps, floating docks, life guard stations, parks, playgrounds, play fields, picnic grounds, wildlife or nature preserves, hiking trails, horseback riding trails, golf courses, driving ranges, archery ranges, and tennis courts.
[e] Airport runways and landing strips.
[f] Streets, bridges, overhead utility lines, storm drainage facilities, sewerage lines, waste treatment plant outlets, water supply intake structures, and electronic transmission structures; provided that the structure is demonstrated, by hydraulic and hydrologic analysis performed with standard engineering practice and reviewed and approved by the County Floodplain Coordinator, to cause no rise in the base flood elevation as established by the Flood Insurance Study and further provided that:
[1] All structures are designed and constructed to minimize infiltration by floodwaters; and
[2] The lowest horizontal member of bridges, excluding pilings or columns, is elevated at least one foot above the base flood elevation and the superstructure attached thereto is designed to resist flotation, collapse, and lateral movement due to the effects of wind and water loads acting simultaneously on all structural components.
2. Permitted uses, other. The following uses shall be permitted in areas designated floodway areas, but only if such uses are permitted within the basic district to which the FP overlay is appended:
[a] Any existing or future facility that is or will be a part of or used by any public or private school that was constructed and operated before January 1, 2001 on property subsequently classified as a regulatory floodway;
[b] Any existing or future facility that is or will be a part of or used by any publicly owned wastewater treatment facility that was constructed and operated before January 1, 2001 on property subsequently classified as a regulatory floodway.
i. Fill. Fill is the placement of natural sands, dirt, soil, or rock above the natural grade in order to raise the elevation of the ground. Dredged material may only be used as fill upon certification of suitability by a South Carolina licensed registered professional geotechnical engineer. The use of fill shall be limited to the elevation of individual structures (including garages and garage aprons), utilities, infrastructure, and public road crossings. Other methods of elevating structures should be considered first.
1. To allow the elevation of individual structures, the amount of fill used shall be the minimum necessary. Floodplain authorization for fill shall be based on findings by the county engineer that the minimum fill being used for raising the structure is the most feasible alternative.
2. Fill, if approved, shall meet the following conditions:
[a] The flood storage capacity of the floodplain shall not be affected and flood heights shall not be increased. The space occupied by the authorized fill below Base Flood Elevation for all encroachment within the special flood hazard areas within unincorporated Richland County, with the exception of the special flood hazard area adjacent to Lake Murray, shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the Base Flood Elevation. All such excavations shall be constructed to drain freely to the watercourse.
[b] Flooding from any source shall not be increased for neighboring properties. Neighboring and adjacent properties shall not be adversely affected in any way nor shall drainage problems be caused or aggravated as a result of fill.
[c] Fill shall not be placed in the floodway except for essential utilities and necessary infrastructure, and must meet the approval of the county engineer.
[d] Fill shall not be placed in nontidal wetlands without the required state and federal permits.
3. In the event buildings on adjacent properties are known or determined to be subject to flooding under current conditions, the county engineer may require submission of hydrologic and hydraulic analyses to adequately demonstrate that the effects of the proposed fill wiil not increase flooding on neighboring properties. Additional fill for landscaping purposes is not permitted. Landscaping mulch (tree bark or pine needles) is not considered fill and is allowed.
4. Where allowed, fill material shall meet the following additional requirements:
[a] Fill material shall be compacted to 95% of the maximum density, obtainable with the standard proctor test method issued by The American Society For Testing And Materials (ASTM standard D-698) to provide the necessary stability and resistance to erosion, scouring or settling.
[b] Fill shall be performed in such manner as to maintain or increase flood storage and conveyance capacity, and to not increase FEMA base flood elevations, nor to have an adverse impact on neighboring properties.
[c] All fill placed at or below the flood elevation in the floodplain shall be balanced with at least an equal amount of soil material removal from the same parcel(s) or from subwatershed for all special flood hazard areas within unincorporated Richland County, with the exception of the special flood hazard area adjacent to Lake Murray. Compensatory storage required to offset floodplain fill must be created before the project begins and should be available throughout the construction period. The required volume of compensatory storage must be provided within the project boundary.
[d] Excavation shall not be counted as compensating for fill if such areas will be filled with water in non-storm conditions.
[e] Fill shall be performed in a manner to maintain or increase slope stability and maintain or decrease erosive velocities. Fill slopes shall be no greater than two (2) horizontal to one (1) vertical. Flatter slopes may be required where velocities may result in erosion.
[f] Applicants must submit an as-built survey certification by a South Carolina registered professional engineer that demonstrates that the required volume of storage has been created on site in order to ensure no net loss as outlined and demonstrated per the approved plans.
5. Any change in the flood flow within a regulatory floodplain through fill must be submitted and approved through the FEMA "Letter of Map Revision" process in addition to review by the flood coordinator and county engineer.
6. A South Carolina registered professional engineer shall certify that all of the above standards and requirements within this subsection 26-106(i) have been met.
j. Critical facilities. Construction of critical facilities is prohibited in the five hundred (500) year floodplain (A, 1AE and X500 Zones on the FIRM).
(e) Standards for streams not having established base flood elevations and floodways. Located within the areas of special flood hazard are small streams where no base flood elevation data have been provided and where no floodways have been identified. The following provisions shall apply to these areas:
No encroachments, including fill, new construction, substantial improvement, or other development shall be permitted within one hundred (100) feet of the stream bank unless certification (with supporting technical data by a South Carolina licensed registered land surveyor, engineer, or architect authorized by law to certify such information) is provided demonstrating that such encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge. Such data shall be submitted to the flood coordinator.
(1) Standards for determining a Base Flood Elevation. When base flood elevation (BFE) data is not available from a federal, state or other source one of the following methods may be used to determine a BFE. For further information regarding the methods for determining the BFEs listed below, refer to FEMA's manual Managing Floodplain Development in Approximate Zone A Areas:
a. Contour Interpolation.
1. Superimpose approximate zone A boundaries onto a topographic map and estimate a BFE.
2. Add one-half of the contour interval of the topographic map that is used to the BFE.
b. Data Extrapolation - A BFE can be determined if a site within 500 feet upstream of a stream reach for which a 100-year profile has been computed by detailed methods, and the floodplain and channel bottom slope characteristics are relatively similar to downstream reaches. No hydraulic structures shall be present.
c. Hydrologic and Hydraulic Calculations - Perform hydrologic and hydraulic calculations to determine the BFEs using FEMA approved methods and software.
(f) Standards for streams with established base flood elevations without floodways. Along rivers and streams where Base Flood Elevation (BFE) data is provided but no floodway is identified for a Special Flood Hazard Area on the Flood Insurance Rate Map (FIRM) or in the Flood Insurance Study (FIS).
No encroachments including fill, new construction, substantial improvements, or other development shall be permitted unless certification with supporting technical data by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community. Any increase shall not adversely impact any portion of the community.
(1) General. All subdivisions, planned development communities, and large-scale development proposals shall be consistent with the need to minimize or eliminate flood damage. In all areas where base flood elevation data is not available, applications for subdivision proposals and other proposed developments containing at least 50 lots or 5 acres, whichever is less, shall include a hydrologic and hydraulic analysis that generates base flood elevations. In lieu of the aforementioned, the entire Zone A special flood hazard area shall be placed in a perpetual deeded open space with no future construction authorized.
(2) Public utilities. All subdivisions, planned development communities, and large scale development proposals shall have public utilities and facilities, such as sewer, gas, electric and water systems, located and constructed to minimize or eliminate flood damage.
(3) Access. An access road above the base flood elevation shall be provided for all subdivision, planned development community, or other large-scale development proposals to allow emergency access to flooded areas during flood conditions.
(4) Drainage. All subdivision, planned development community, or other large-scale development proposals shall have adequate drainage, in compliance with all other applicable code regulations provided to reduce or eliminate exposure to flood hazards.
(g) Standards for areas of shallow flooding (AO and AH Zones). Located within the areas of special flood hazard are areas designated as shallow flooding.
The following provisions shall apply within such areas:
(1) Residential structures. All new construction and substantial improvements of residential structures shall have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM. If no depth number is specified, the lowest floor (including basement) shall be elevated at least three (3) feet above the highest adjacent grade.
(2) Nonresidential structures. The lowest floor (including the basement) for all new construction and substantial improvements of nonresidential structures shall meet one of the following standards:
a. Elevation. The nonresidential structures(s) shall be elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM. If no depth number is specified, the lowest floor (including basement) shall be elevated at least three (3) feet above the highest adjacent grade; or
b. Construction. The nonresidential structure(s), together with attendant utility and sanitary facilities, must be designed so that below the base flood elevation the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A South Carolina licensed registered land surveyor, engineer or architect authorized by law to certify such information shall submit a certification to the flood coordinator that the standards of this section are satisfied. There shall be adequate drainage paths around structures on slopes to guide floodwaters around and away from the proposed structures.
(3) Slopes. All structures on slopes must have drainage paths around them in order to guide water away from such structure; provided, however, such drainage paths must not adversely affect adjacent properties. (Design information is defined in the Richland County Stormwater Design Manual).
(h) Standards for levees.
(1) General standards. All levees protecting residential structures or nonresidential structures that are not flood-proofed shall be designed, constructed, and maintained to provide protection against the 500-year flood, plus three (3) feet of freeboard. Flood elevations shall be as shown on the latest Flood Insurance Rate Maps as determined by appropriate hydrologic methods. Any levee constructed or improved under this subsection shall also comply with the other applicable provisions of Section 26-202 of this chapter.
(2) Specific standards.
a. Design and construction. Design and construction shall be in accordance with the latest edition of the U.S. Army Corps of Engineers' (USACE's) Manual EM 1110-2-1913 Design and Construction of Levees. The design and construction of drainage systems within levees shall be in accordance with the latest edition of the USACE's Manual EM 1110-2-1413 Hydrologic Analysis of Interior Areas. A South Carolina Registered Professional Engineer shall certify that he has been involved in the design, construction, and inspection phases and shall certify that the construction meets requirements of the U.S. Army Corps of Engineers.
b. Records. Owners of levees will perform the necessary and required maintenance and provide appropriate records to the county engineer. These records shall include:
1. Signed agreements of perpetual operation and maintenance between the constructor and/or owner and Richland County;
2. As-built construction plans sealed by a South Carolina Registered Professional Engineer;
3. A description of the levee maintenance program in accordance with Levee Maintenance Standards and Procedures of Richland County (see subsection (h)(3) below); and
4. Periodic maintenance reports as required by the county engineer.
(3) Maintenance standards and procedures. Levees shall be maintained as necessary to ensure serviceability against flood at all times, as follows:
a. Sod growth. Maintenance of a sturdy sod growth on levee embankments is highly important, as sod is one of the most effective means of protecting the levee against erosion from rain, water current, and wavewash. Periodic mowing with tractor-operated equipment is essential to maintaining a good sod growth, and shall be done at such intervals as necessary to keep down weeds and other noxious growth and to prevent the grass height from exceeding twelve (12) inches. However, the grass shall not be mowed to a height of less than two (2) inches. The number of mowings required each season will depend on local conditions. The last mowing of the season will be accomplished under conditions that allow the grass to obtain a height of approximately eight (8) inches to ten (10) inches entering the winter season. Mowing will be performed to a distance of at least five (5) feet beyond the toe of the levee or berm. Burning grass and weeds is not permitted in the levee maintenance program, except during appropriate seasons when it is not detrimental to sod growth. During the growing season, spraying with herbicides on an as-needed basis is permissible and desirable for weed and brush control on levees and berms. Reseeding and fertilizing shall be completed frequently enough to sustain sod growth on levee embankments for erosion control.
b. Earth embankments. Levee embankments shall be maintained to not less than the grade and section, as designed, by replacing any material lost from the crown or slopes. Ruts, washes, slides, and subsidence should be promptly repaired and the entire embankment maintained sufficiently smooth for power mowing. Levee crowns shall be graded as necessary to drain freely and prevent impoundment of rainwater. All brush, trees, and other undesirable growth shall be removed from the levee embankment.
c. Animal burrows. Levees and adjacent landward areas shall be maintained free of all types of animal burrows. Animal burrows, when found, shall be backfilled with compacted material and sodded. To prevent recurrence, effort shall be made to exterminate the burrowing animals.
d. Prevention of encroachment. Care shall be taken to assure that levees are not encroached upon. Buildings, structures, and storage of materials or equipment are not permitted on the levee. Refuse dumps are not permitted. Following each high water, any debris deposited on the riverside slope of the levee shall be removed promptly.
e. Roads and ramps. Access roads to and on the levees, including ramps, shall be bladed as necessary to keep the roadway shaped properly and free of ruts, pockets, and washes. Ramp embankments shall be maintain the section and grade as designed.
Maintenance shall be performed as necessary to correct any encroachment into the levee crown where roads cross levees. Road surfacing material shall be replaced as necessary to maintain the road surface in good condition.
f. Miscellaneous levee facilities and appurtenances. Levee facilities and appurtenances that are constructed on, over, or through the levee shall be maintained in a good state of repair and/or inspected at least annually. Facilities and appurtenances that operate only during high water must be checked carefully and repaired as necessary, immediately prior to high water season. Relief wells shall be checked during periods of high water. Wells that do not flow for an extended period of time may have to be tested by pumping to determine the extent of deterioration. Critically deteriorated wells shall be rehabilitated by cleaning, surging, and pumping. Check valves shall be inspected to ensure that they open freely and that the gaskets are in good condition. The most common of the facilities and appurtenances referred to herein are:
1. Drainage structures through the levee,
2. Toe drainage systems,
3. Relief wells,
4. Levee slope protection and protection on dike ends,
5. Gates, cattle guards, and fences, and
6. Siphons and pipe crossings.
(4) Inspection. Frequent inspections are essential to a good levee maintenance program. In addition to the formal inspections required by the county engineer, inspections will be made prior to the beginning of the flood season, during and immediately following each high water period, and at such intermediate times as necessary to ensure satisfactory care of the levee.
(Ord. No. 074-04HR, § V, 11-9-04; Ord. No. 032-06HR, § III, 5-2-06; Ord. No. 114-06HR, § I, 12-5-06; Ord. No. 043-07HR, § XXIII, 5-1-07; Ord. No. 061-08HR, § 2, 6-5-08; Ord. No. 054-09HR, § XXIII, 11-3-09; Ord. No. 056-09HR, § II, 11-3-09; Ord. No. 060-10HR, § VI - VIII, 9-28-10; Ord. No. 053-17HR, §§ IX - XX, 11-14-17)