Sec. 3-1516

Floodplain

• Minimum elevation for A zone without BFE18 inches above BFE

  When such base flood elevation data is utilized, the lowest floor shall be elevated to or above the base flood level plus 18 inches.

• Maximum accessoryAccessory useA secondary activity customarily incidental to the main use of the lot — a garage, a home office. structure floor area in SFHA600 sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.

  Be limited to no more than 600 square feet in total floor area;

• AE/AH zone encroachment rule1 ft increase in BFE

  Until a regulatory floodway is designated, no new construction, substantial improvements, or other development (including fill) shall be permitted within the areas of special flood hazard, designated as Zones A1—30 and AE or AH on the FIRM, unless it is demonstrated that the cumulative effect of the proposed development... will not increase the water surface elevation of the base flood more than one foot at any point...

• Minimum elevation for AO zone without depth number2 ft above highest adjacent grade

  If no flood depth number is specified, the lowest floor, including basement, shall be elevated no less than two feet above the highest adjacent grade.

• Freeboard requirement in Coastal A Zone1 ft

  Buildings and structures within this zone shall have the lowest floor elevated to or above the base flood elevation plus one foot of freeboard...

• Maximum heightMaximum heightThe tallest a building may be, given in feet, in storeys, or both — whichever binds first. of flood opening bottom above grade1 ft

  The bottom of all required openings shall be no higher than one foot above the adjacent grade.

• Minimum number of flood openings2 openings

  Provide a minimum of two openings on different sides of each enclosed area subject to flooding.

• Minimum flood opening area per square foot of enclosed area1 sq inch per sq ftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.

  The total net area of all openings must be at least one square inch for each square foot of enclosed area subject to flooding.

• Floodproofing elevation for non-residential buildings2 feet above BFE

  Buildings located in all A1—30, AE, and AH zones may be flood-proofed in lieu of being elevated provided that all areas of the building components below the elevation corresponding to the BFE plus two feet are water tight...

• Floodway encroachment rule0 increase in flood level

  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 (or manufactured home) 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 (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.

• 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.

• Special exception required for emergency/medical/government storage in mapped floodplainFloodplainLand expected to flood at a stated frequency, where building carries extra conditions.

  In this area no emergency service, medical service, or government storage shall be allowed except by special exception using the variance process.

• Maximum days recreational vehicle may be on site180 days

  Be on the site for fewer than 180 consecutive days, be fully licensed and ready for highway use...

• Subdivision size threshold for BFE data requirement50 lots or 5 acresacre43,560 square feet — about the size of an American football field without the end zones.

  Base flood elevation data shall be obtained from other sources or developed using detailed methodologies comparable to those contained in a FIS for subdivision proposals and other proposed development proposals (including manufactured home parks and subdivisions) that exceed 50 lots or five acres, whichever is the lesser.

• Substantial improvement threshold50 pct of structure value

  The change, when added to all the changes made during a rolling five-year period does not constitute 50 percent of the structure's value.

• Maximum accessoryAccessory useA secondary activity customarily incidental to the main use of the lot — a garage, a home office. structure size for varianceVariancePermission to depart from a specific dimensional rule, granted on a showing of hardship.600 sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.

  No variance shall be granted for an accessory structure exceeding 600 square feet.

• Maximum lot size for varianceVariancePermission to depart from a specific dimensional rule, granted on a showing of hardship. consideration0.5 acresacre43,560 square feet — about the size of an American football field without the end zones.

  While the granting of variances generally is limited to a lot size less than one-half acre...

• Breakaway wall design safe loading resistance in VE/V zones20 psf

  For the purpose of this section, a breakaway wall shall have a design safe loading resistance of not less than ten and no more than 20 pounds per square foot.

• Elevation of lowest horizontal structural member in VE/V zones (parallel to wave approach)18 inches above BFE

  The bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood level plus 18 inches if the lowest horizontal structural member is parallel to the direction of wave approach...

• Elevation of lowest horizontal structural member in VE/V zones (perpendicular to wave approach)1 ft above BFE

  ...or elevated at least one foot above the base flood level if the lowest horizontal structural member is perpendicular to the direction of wave approach;

• Maximum enclosed space below lowest floor in VE/V zones300 sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.

  The enclosed space shall be less than 300 square feet.