Sec. 74-907(1), Sec. 74-916
Dimensional standards
Servicing
- Geographic extent
- Areas within the floodway as shown on the FIRM, defined as capable of carrying the base flood without increasing water surface elevation more than 1 foot.
Uses
Permitted by right4
Prohibited1
Extracted standards
19 individual requirements pulled out of this section’s prose, each with the sentence it came from.
Other
- Anchoring required
New construction and substantial improvements shall be built according to this article and the Virginia USBC, and anchored to prevent flotation, collapse, or lateral movement of the structure.
- Flood damage-resistant materials
New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
- Flood opening requirements1 sqin per sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.
Provide a minimum of two (2) openings on different sides of each enclosed area subject to flooding. The total net area of all openings must be at least one (1) square inch for each square foot of enclosed area subject to flooding.
- Floodproofing option for nonresidential buildings2 ft
Nonresidential buildings located in all A1-30, AE, and AH zones may be floodproofed in lieu of being elevated provided that all areas of the building components below the elevation corresponding to the BFE plus two (2) feet are watertight with walls substantially impermeable to the passage of water...
- Floodway encroachment prohibition
Within any floodway area, no encroachments, including fill, new construction, substantial improvements, or other development shall be permitted unless it has been demonstrated through hydrologic and hydraulic analysis... that the proposed encroachment will not result in any increase in flood levels.
- Manufactured homeManufactured homeA dwelling built in a factory to a federal standard and transported to the site. prohibition in floodway
The placement of manufactured homes (mobile homes) is prohibited, except in an existing manufactured home (mobile home) park or subdivision.
- Manufactured homesManufactured homeA dwelling built in a factory to a federal standard and transported to the site. must meet new construction requirements
In zones A, AE, AH, and AO, all manufactured homes placed, or substantially improved, on individual lots or parcels, must meet all the requirements for new construction.
- Maximum accessoryAccessory useA secondary activity customarily incidental to the main use of the lot — a garage, a home office. structure floor area600 sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.
Accessory structures in the SFHA shall comply with the elevation requirements or, if not elevated or dry floodproofed, shall: ... Be limited to no more than six hundred (600) feet in total floor area; ...
- Lowest floor elevation for nonresidential structures18 in
New construction or substantial improvement of any commercial, industrial, or nonresidential building (or manufactured home) shall have the lowest floor, including basement, elevated to or above the base flood level plus eighteen (18) inches.
- Lowest floor elevation for residential structures18 in
New construction or substantial improvement of any residential structure (including manufactured homes) in zones A1-30, AE, AH, and A with detailed base flood elevations shall have the lowest floor, including basement, elevated to or above the base flood level plus eighteen (18) inches.
- Recreational vehicle requirements180 days
All recreational vehicles placed on sites must either: a. Be on the site for fewer than one hundred eighty (180) consecutive days, be fully licensed and ready for highway use... or b. Meet all the requirements for manufactured homes.
- Sanitary sewage flood protection
New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters.
- Use of space below lowest floor
In zones A, AE, AH, AO, and A1-A30, fully enclosed areas, of new construction or substantially improved structures, which are below the regulatory flood protection elevation shall not be designed or used for human habitation, but shall be used solely for parking of vehicles, building access, or limited storage of maintenance equipment.
- Subdivision proposals minimize flood damage
All subdivision proposals shall be consistent with the need to minimize flood damage.
- Utilities flood protection
Electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities, including duct work, shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.
Variances shall be issued only upon (i) a showing of good and sufficient cause, (ii) after the Board of Zoning Appeals has determined that failure to grant the variance would result in exceptional hardship to the applicant...
- On-site waste disposal flood protection
On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding.
- Water supply flood protection
New and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.
Overlay
- FloodplainFloodplainLand expected to flood at a stated frequency, where building carries extra conditions. districts are overlays to underlying districts
The floodplain districts described above shall be overlays to the existing underlying districts as shown on the official zoning ordinance map, and as such, the provisions for the floodplain districts shall serve as a supplement to the underlying district provisions. If there is any conflict between the provisions or requirements of the floodplain districts and those of any underlying district, the more restrictive provisions and/or those pertaining to the floodplain districts shall apply.
From the ordinance
Within any floodway area, no encroachments, including fill, new construction, substantial improvements, or other development shall be permitted unless it has been demonstrated through hydrologic and hydraulic analysis... that the proposed encroachment will not result in any increase in flood levels.