Sec. 50-51(b)

Floodplain

• Base flood elevation required within distance of drainage channel50 ft

  The city reserves the right to require that base flood elevation be provided for development in flood-prone areas within 50 feet of any main drainage channel or stream that is not included in the flood insurance study.

• 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 openings shall be no higher than one foot above grade.

• Minimum flood opening area ratio1 sqin/sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.

  A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.

• Floodway encroachment rule0 ft

  In the floodway district no encroachments, including fill, new construction, substantial improvements, or other development shall be permitted unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in the BFE.

• Lowest floor elevation for residential structures1 ft

  In the flood-fringe district, the elevation of the lowest floor of approved residential structures shall be one foot above the base flood elevation.

• Lowest floor elevation for non-residential structures1 ft

  Non-residential structures must have the lowest floor elevated or flood-proofed to one foot above the base flood elevation or more.

• Manufactured homeManufactured homeA dwelling built in a factory to a federal standard and transported to the site. lowest floor elevation above BFE1 ft

  All manufactured homes to be placed or substantially improved within the SFHA shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is one foot above the base flood elevation;

• 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.

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

• Maximum base flood elevation increase1 ft

  using the criterion that certain area within the floodplain must be capable of carrying the waters of the base flood without increasing the water surface elevation of that flood more than one foot at any point.

• Maximum base flood elevation increase for flood-fringe without floodway1 ft

  For any flood-fringe district without a designated floodway, new development shall not be permitted unless it is demonstrated that the cumulative effect of all past and projected development will not increase the BFE by more than one foot.

• Recreational vehicle maximum consecutive days180 days

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

• Substantial improvement threshold50 pct

  The modification, alteration, repair, reconstruction, or improvement of any kind to a structure and/or use, regardless of its locations in a floodplain area, to an extent or amount of 50 percent or more of its market value shall be undertaken only in full compliance with the provisions of this division and the Virginia Uniform Statewide Building Code.