Areas of special flood hazard established as regulatory floodways in the Charleston County Flood Insurance Rate Map (FIRM) and/or the Charleston County Flood Insurance Study, are the Charleston County designated floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles and has erosion potential, the following provisions shall apply:
(A) Prohibition of encroachments, including fill, new construction, substantial improvements and other development within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice in accordance with the Charleston County Flood Insurance Study or as otherwise deemed appropriate by FEMA or the Building Official, certified by a state licensed engineer, that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharges.
(B) (1) Encroachments may be permitted within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the town first applies for a conditional FIRM and floodway revision, fulfills the requirements for such revisions as established under the provisions of § 65.12 of 44 CFR and receives the approval of the federal insurance administrator.’
(2) (a) Standards for streams with established base flood elevations but without floodways along rivers and streams where base flood elevation data is provided but no floodway is identified for a Special Flood Area on the FIRM or in the FIS. The following provisions apply within such areas:
(b) No encroachments, including fill material, new construction, or substantial improvement 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 at any point.
(C) The area chosen for the regulatory floodway must be designed to carry the waters of the base flood, without increasing the water surface elevation of that flood more than one-half foot at any point.
(Ord. 2016-14, passed 1-19-2017; Ord. 2020-11, passed 12-17-2020)