(a) Uses permitted. To allow for the appropriate development of land that is subject to flooding without unduly endangering life and property, the following uses are permitted in an FP area provided they are permitted in the underlying zoning district and comply with the requirements of Section 51A-5.105(g) and all applicable elevation requirements of the Federal Emergency Management Agency:
(1) Farm or ranch (excluding habitable structures).
(2) Utility services, electrical substation, detention basin, water reservoir or pumping station, and water treatment plant.
(3) Sanitary landfill and refuse transfer station.
(4) Public park or playground and golf course (excluding habitable structures).
(5) Commercial amusement (outside) approved by specific use permit.
(6) Helistop approved by specific use permit.
(7) Radio, television, or microwave tower, amateur communications tower, and tower/antenna for cellular communication.
(b) Improvements permitted.
(1) Structures. An uninhabitable structure customarily associated with a use listed in Subsection (a) may be constructed within an FP area only if the director of water utilities determines that the proposed structure meets the same engineering requirements applicable to filling in Section 51A-5.105(g) and issues a floodplain alteration permit.
(2) Improvements. The owner of a structure in an FP area shall not make any improvements to the structure without first obtaining approval from the director of water utilities. The director of water utilities may approve proposed improvements if the cumulative value of all improvements for the previous five years is less than 50 percent of the market or tax appraisal value of existing improvements on the property, whichever is greater. No substantial improvements are permitted. Improvement values are calculated per guidelines outlined in FEMA P-758 as revised. All improvements must comply with the requirements of Section 51A-5.105(g), including additions. Substantially damaged structures are considered substantial improvements.
(3) Completion of vested structures. The building official shall not withhold a final inspection or certificate of occupancy for a structure in an FP area if building permits for the structure were issued by the building official before FEMA's FIRM becomes effective designating such areas as A or AE, and the structure otherwise complies with all applicable requirements.
(4) Board of adjustment. The board of adjustment may only grant a special exception to allow the reconstruction of a structure in an FP area if the structure is a historical structure as defined by FEMA, or the property is zoned for a functionally dependent use. The board may grant a special exception upon a showing of good and sufficient cause and a determination that the reconstruction will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, or conflict with other local, state, or federal laws. The reconstructed structure must be protected by methods that minimize flood damage. The board may not grant a special exception to authorize reconstruction within any designated floodway if any increase in flood levels during the base flood discharge would result. Any special exception granted must be the minimum necessary, considering the flood hazard, to afford relief. The reconstruction of a structure in an FP area may not increase the lot coverage of the structure.
(A) The director of water utilities shall notify in writing the owner of a structure in an FP area that:
(i) the granting of a special exception to reconstruct the structure below the base flood level will result in increased premium rates for flood insurance that will be commensurate with the increased risk; and
(ii) the construction below the base flood level increases risks to life and property. The notification letter must be maintained with the record of the board's action.
(B) The FP administrator shall maintain a record of all actions involving applications for special exceptions and shall report special exceptions to FEMA upon request.
(5) Parking.
(A) Surface parking. All surface parking spaces must be constructed at a minimum elevation of two feet above the design flood elevation.
(B) Underground parking garages. The entrance elevation and any openings on underground parking garages constructed within or adjacent to a flood prone area may not be lower than two feet above the design flood elevation.
(C) Parking on piers. Parking lots elevated on piers such that the low chord is two feet above the design flood elevation are permitted if all engineering requirements for filling in Section 51A-5.105(g) are met, and do not violate any other part of the Dallas Development Code. A habitable structure may not be placed on piers.
(D) Parking in interior drainage (sump) areas. All surface parking spaces within an interior drainage area must be constructed at a minimum elevation of one foot above the design flood elevation.
(6) Storage in the floodplain is prohibited.
(A) A person shall not place, store, or maintain a shipping container, trailer, boat, inoperable vehicle, recreational vehicle, construction materials, waste materials, hazardous materials, or construction equipment in the floodplain. For purposes of this paragraph, the term "vehicle" includes but is not limited to automobiles, buses, and recreational vehicles. It is a defense to prosecution that the placement, storage, or maintenance of shipping containers, trailers, boats, inoperable vehicles, recreational vehicles, construction materials, waste materials, hazardous materials, or construction equipment is otherwise permitted by or in connection with a valid federal, state, county, or city permit, or is otherwise authorized by those entities.
(B) The director of water utilities shall give written notice and allow persons in violation of Subparagraph (A) a period of 90 days to come into compliance.
(7) Manufactured homes. Manufactured homes may not be placed within a floodplain area. Recreational vehicle camping and parking locations are not permitted within a floodplain area.
(8) Fences. Fences must comply with all applicable construction codes at the time of construction.
(A) Fences are not permitted within floodway easement areas without engineering analysis addressing Section 51A-5.105(g), regardless of fence type.
(B) Except as provided in this paragraph, fences in a floodplain area not designated as a floodway easement must be:
(i) constructed of wrought iron;
(ii) constructed with a one-foot gap along the bottom if located in areas where flooding is less than three feet of depth; or
(iii) constructed using flood vents, as outlined in the NFIP Technical Bulletin 1, as amended, if located in areas where flooding is greater than one foot and less than four feet of depth.
(C) Fences in a floodplain area not designated as a floodway easement that do not comply with Subparagraph (B) must be analyzed as an obstruction for compliance with Section 51A-5.105(g).
(c) Construction standards. All improvements and construction permitted in an FP area must comply with the following requirements:
(1) Structures must be:
(A) securely anchored to the foundation and otherwise designed to prevent flotation and collapse during inundation; and
(B) designed to prevent damage to nonstructural elements during inundation.
(2) Thermal insulation used below the first floor level must be of a type that does not absorb water.
(3) Adhesives must have a bonding strength that is unaffected by inundation.
(4) Doors and all wood trim must be sealed with a water-proof paint or similar product.
(5) Electrical, heating, ventilation, plumbing, air-conditioning equipment, and other mechanical service facilities must be designed and located at least three feet above the design flood elevation to prevent water from entering or accumulating in the components during flooding.
(6) Transportation systems such as elevators and escalators must be protected from flooding, and enclosures must be safe from flooding and protect life safety. See Code of Federal Regulations Title 44, Part 60.3 and the NFIP Technical Bulletin 4 as amended for more information.
(7) Basements.
(A) Basements are permitted only in nonresidential construction and only if they are designed to preclude inundation by the design flood level, either by:
(i) locating any exterior opening at least three feet above the level of the design flood elevation; or
(ii) using water-tight closures, such as bulkheads and flood shields.
(B) All basements must be constructed so that any enclosure area, including utilities and sanitary facilities below the flood-proofed design level, is watertight with impermeable walls.
(C) Basement walls must be built with the capacity to resist hydrostatic and hydrodynamic loads and the effects of buoyancy resulting from flooding to the flood-proofed design level so that minimal damage will occur from floods that exceed the flood-proofed design level.
(D) The area surrounding the structure must be filled to or above the elevation of the design flood. The fill must be compacted, and slopes must be protected by vegetative cover.
(E) Basements must be designed by a licensed professional engineer.
(F) Basement ceilings must consist of a sufficient wet strength and be installed to survive inundation.
(8) Plywood used at or below the first floor level must be of an "exterior" or "marine" grade and of a water-resistant or waterproof variety.
(9) Wood flooring used at or below the first floor level must be installed to accommodate a lateral expansion of the flooring, perpendicular to the flooring grain, without incurring structural damage to the building.
(10) Paints or other finishes used at or below the first floor level must be capable of surviving inundation.
(11) All air ducts, large pipes, and storage tanks located at or below the first floor level must be firmly anchored to prevent flotation.
(12) Tanks must be vented at a location above the 100-year flood level.
(d) 500-year frequency flood. All new construction located in a 500-year frequency flood zone must comply with the following:
(1) Building pad site must be filled to an elevation of at least two feet above the 100-year flood elevation.