(A) General standards. In all areas of special flood hazards, the following standards are required.
(1) Anchoring.
(a) All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy.
(b) All manufactured homes shall be anchored to resist flotation, collapse or lateral movement resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors.
(2) Construction materials and methods. All new construction and substantial improvements shall be constructed using methods, materials and utility equipment that resist or minimize flood damage.
(3) Utilities.
(a) All electrical, heating, ventilating, plumbing, air conditioning and other service facilities shall be designed and located to prevent water from entering or accumulating within the components during flooding conditions.
(b) All new and replacement water supply systems and sanitary sewer systems shall be designed to minimize or eliminate infiltration of floodwaters into the system. Sanitary sewer systems shall be designed to minimize or eliminate discharge into floodwaters.
(c) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(4) Subdivision proposals.
(a) All proposed subdivisions, manufactured home parks and subdivisions and other developments shall be consistent with the need to minimize flood damage.
(b) All proposed subdivisions, manufactured home parks and subdivisions and other developments shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.
(c) All proposed subdivisions, manufactured home parks and subdivisions and other developments shall have adequate drainage provided to reduce exposure to flood damage.
(d) Base flood elevation data shall be provided for proposed subdivisions, manufactured home parks and subdivisions and other developments which contain at least 50 lots or five acres (whichever is less).
(B) Specific standards.
(1) Where base flood elevation and floodway data have been provided, the standards below are required.
(2) If data have not been provided, the Floodplain Administrator must use judgment and be guided by the mapped 100-year flood boundaries, past flood accounts described in newspapers, photos, eyewitness accounts or by high water marks on buildings, telephone poles, bridges or other structures.
(3) The Floodplain Administrator, wherever possible, should designate the base flood elevations.
(4) If the base flood elevations can be established, the following standards would then be required.
(a) Residential construction.
1. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above the base flood elevation.
2. Manufactured homes shall be placed so that the lowest floor is at least to or above the base flood elevation.
(b) Nonresidential construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to or above the base flood elevation or, together with attendant utility and sanitary facilities, shall:
1. Be flood-proofed so that to or above the base flood elevation level the structure is watertight with walls substantially impermeable to the passage of water;
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
3. Be certified by a registered professional engineer or architect that the standards of this division (B)(4)(b) are satisfied. Such certification shall be provided to the responsible person as set forth in Chapter 6 of this title.
(5) Fully enclosed areas below the lowest floor subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet the following minimum criteria:
(a) A minimum of two openings having a total net area of not less than one square foot of enclosed area subject to flooding shall be provided;
(b) The bottom of all openings shall be no higher than one foot above grade; and
(c) Openings may be equipped with screens, louvers or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(6) A registered professional engineer or architect shall develop and/or review structural design, specifications and plans for the construction and certify that the design and methods of construction are in accordance with accepted standards of practice. The engineer or architect shall also certify that the standards of this division (B)(6) are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in Chapter 6 of this title.
(1985 Code, § 11.06.050)