(A) Residential construction. New construction and substantial improvement of any residential structure shall have the lowest floor (including basement), elevated at least one foot above the base flood elevation. A registered professional engineer, architect or land surveyor shall submit a certification to the Floodplain Administrator that the standard of this division as proposed in § 151.04(C) is satisfied.
(B) Below-grade residential crawlspace construction. New construction and substantial improvement of any below-grade crawlspace shall:
(1) Have the interior grade elevation that is below base flood elevation no lower than two feet below the lowest adjacent grade;
(2) Have the height of the below-grade crawlspace measured from the interior grade of the crawlspace to the top of the foundation wall, not exceed four feet at any point;
(3) Have an adequate drainage system that allows flood waters to drain from the interior area of the crawlspace following a flood;
(4) Be anchored to prevent flotation, collapse or lateral movement of the structure and be capable of resisting the hydrostatic and hydrodynamic loads:
(5) Be constructed with materials and utility equipment resistant to flood damage;
(6) Be constructed using methods and practices that minimize flood damage;
(7) Be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding; and
(8) Be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:
(a) 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;
(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 flood waters.
(C) Nonresidential construction. New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated to or above the base flood level or together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is water-tight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall develop and/or review structural design, specifications and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this division. A record of the certification which includes the specific elevation (in relation to mean sea level) to which the structures are floodproofed shall be maintained by the Floodplain Administrator.
(D) Enclosures. New construction and substantial improvements, with fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria.
(1) 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.
(2) The bottom of all openings shall be no higher than one foot above grade.
(3) Openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of flood waters.
(E) Manufactured homes.
(1) Require that all manufactured homes to be placed within Zone A on a community’s FHBM or FIRM shall be installed using methods and practices which minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
(2) Require that manufactured homes that are placed or substantially improved within Zones A1-30, AH and AE on the community’s FIRM on sites: outside of a manufactured home park or subdivision; in a new manufactured home park or subdivision; in an expansion to an existing manufactured home park or subdivision; or in an existing manufactured home park or subdivision on which a manufactured home has incurred “substantial damage” as a result of a flood, be elevated on a permanent foundation so that the lowest floor of the manufactured home is elevated at least one foot above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(3) Require that manufactured homes be placed or substantially improved on sites in an existing manufactured home park or subdivision with Zones A1-30, AH and AE on the community’s FIRM that are not subject to the provisions of division (D) above be elevated so that either:
(a) The lowest floor of the manufactured home is at least one foot above the base flood elevation; or
(b) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(F) Recreational vehicles.
(1) Require that recreational vehicles placed on sites within Zones A1-30, AH and AE on the community’s FIRM either:
(a) Be on the site for fewer than 180 consecutive days;
(b) Be fully licensed and ready for highway use; or
(c) Meet the permit requirements of § 151.04(C), and the elevation and anchoring requirements for “manufactured homes” of this section.
(2) A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.
(Ord. 10.03R, passed 11-15-2011)