Unified Development Ordinance, 25th Supplement, December 2022

Article 9.3. ​F​ loodprone Area Regulations | CHAPTER 9. ​NATURAL RESOURCE PROTECTION

Floodplain Administrator and/or his or her designee prior to issuance of flood permit. 2. If Sec. 9.3.7.A.1. is satisfied, all proposed development shall comply with all applicable flood hazard reduction standards in Sec. 9.3.5. 3. Provided they are not otherwise restricted activities per Sec. 9.3.7.A.1., the following structures and activities are allowed within drainage basin study and/or flood hazard soils-based floodway. a. General farming, pasture, outdoor plant or nurseries, horticulture, forestry, wildlife sanctuary, game preserves and other similar agricultural wildlife and related activities. b. Lawns, yards, gardens, parking areas, play areas and other similar uses. c. Golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, parks, greenways, bikeways, hiking or horseback-riding trails, botanical gardens, open space and other similar private and public recreational activities. d. Any other activity not employing a structure and not subject to floating away during a flood. e. Any activity employing a structure, provided all portions of any structure, including foundation and supports, shall be located outside the floodway area and that any structure which overhangs the floodway is elevated above the depth of the 500-year flood. 4. Legally permitted structures existing and lying within a drainage basin study and/or flood hazard soil-based floodway may be repaired, improved, strengthened and enlarged; provided that no construction is permitted which will: a. Enlarge the foundation area of the structure within the floodway; b. Increase the bulk of the building or structure within the floodway below the base flood; or c. Enlarge the surface area perpendicular to the direction of flow of the watercourse to which the floodway relates. B. Drainage Basin Study and Flood Hazard Soils Floodway Fringe Standards The following provisions shall apply to those areas designated as floodway fringe based on drainage basin studies or flood hazard soils:

designee demonstrating that such encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge. 2. The BFE used in determining the RFPE shall be determined based on the following criteria: a. When BFE data is available from other sources, all new construction and substantial improvements within areas without FEMA established BFEs shall comply with all applicable provisions of this Article and shall be elevated or floodproofed in accordance with the standards in Sec. 11.4.6. and Sec. 9.3.5. b. When data is available from a federal, state, or other City-accepted source for unestablished FEMA floodway and non-encroachment areas all new construction and substantial improvements within these floodway and non-encroachment areas established from available data shall comply with the requirements of Sec. 9.3.6.A. c. All subdivision, manufactured home park and other development proposals shall provide BFE data if development is greater than five (5) acres or has more than fifty (50) lots/manufactured home sites. Such BFE data shall be adopted by reference in accordance with Sec. 9.3.3.B.1. and utilized in implementing this Article. d. When BFE data is not available from a federal, state, or other City accepted source as outlined above, the reference level shall be elevated or floodproofed (nonresidential) to or above the RFPE. All other applicable provisions of Sec. 9.3.5. shall apply. Sec. 9.3.7. SFHA Based on Drainage Basin Study and Flood Hazard Soils Standards A. Drainage Basin Study and Flood Hazard Soils Floodway Standards The following provisions shall apply to those areas designated as floodways based on drainage basin studies or flood hazard soils: 1. No encroachments, including fill, new construction, substantial improvements, and other developments shall be permitted unless: a. It is demonstrated that the proposed encroachment would not result in any increase in the flood levels during the occurrence of the base flood

discharge, based on hydrologic and hydraulic analyses performed in accordance with standard engineering practice and presented to the

9 – 37 Pub l i s hed De c embe r 2022

Pa r t 10 : Un i f i ed Deve l opmen t Or d i nanc e C i t y o f Ra l e i gh , No r t h Ca r o l i na

Supp. No. 25