§ 19.6-76

Floodplain

• AO zone lowest floor elevation

  All new construction and substantial improvements of residential structures shall have the lowest floor elevated to or above the flood depth specified on the FIRM, or at least two feet above highest adjacent grade if no depth number is specified.

• Anchoring to prevent flotation

  New construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.

• Adequate drainage paths on slopes

  Adequate drainage paths around structures on slopes shall be provided to guide floodwaters around and away from proposed structures.

• Maintain flood-carrying capacity

  The flood-carrying capacity within an altered or relocated portion of any watercourse shall be maintained.

• Floodproofing elevation for non-residential2 ft above BFE

  Non-residential buildings may be floodproofed in lieu of being elevated, provided that all areas below the elevation corresponding to the BFE plus two feet are watertight.

• No encroachment in floodway without analysis

  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.

• Lowest floor elevation for non-residential structures18 inches above BFE

  New construction or substantial improvement of any commercial, industrial, or non-residential building shall have the lowest floor, including basement, elevated to or above the base flood level plus 18 inches.

• Lowest floor elevation for residential structures18 inches above BFE

  New construction or substantial improvement of any residential structure 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 18 inches.

• Manufactured homesManufactured homeA dwelling built in a factory to a federal standard and transported to the site. prohibitedProhibitedNot allowed in the district at all, short of rezoning or a variance. in floodway

  The placement of manufactured homes (mobile homes) is prohibited, except in an existing manufactured home park or subdivision.

• Flood-resistant materials

  New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

• Sanitary sewage systems minimize infiltration

  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.

• Utilities designed to prevent water entry

  Electrical, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

• 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.

• Water supply systems minimize infiltration

  New and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.

• Permit required for watercourse alteration

  Prior to any proposed alteration or relocation of any channels or of any watercourse, a permit shall be obtained from the U.S. Corps of Engineers, the Virginia Department of Environmental Quality, and the Virginia Marine Resources Commission.