A. General Standards: In all areas of special flood hazard the following provisions are required for all new construction and substantial improvements:
1. All new construction and substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
2. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
3. All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
4. All new construction or substantial improvements shall 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;
5. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system;
6. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from the systems into flood waters; and
7. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
B. Specific Standards: In all areas of special flood hazard where base flood elevation data has been provided as set forth in Section 12-1-3, subsection 12-1-9C4 or 12-1-16B8, the following provisions are required:
1. Residential Construction: New construction and substantial improvement of any residential structure shall have the lowest floor (including basement) elevated to or above the base flood elevation. A registered professional engineer, architect or land surveyor shall submit a certification to the Flood Plain Administrator that the standard of this subsection as proposed in subsection 12-1-11A1 is satisfied.
2. 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 elevation or, together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially 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 subsection. A record of such certification, which includes the specific elevation (in relation to mean sea level) to which such structures are floodproofed, shall be maintained by the Flood Plain Administrator.
3. Enclosures: New construction and substantial improvements, with fully enclosed areas below the lowest floor that 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:
a. A minimum of two (2) 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 (1') above grade.
c. 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.
4. Manufactured Homes:
a. Require that all manufactured homes to be placed within Zone A shall be installed using methods and practices which minimize flood damage. For the purpose 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.
b. All manufactured homes shall be in compliance with subsection B1 of this Section.
c. Require that all manufactured homes to be placed or substantially improved within Zones A1-30, AH and AE on the community's FIRM be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood elevation and be securely anchored to an adequately anchored foundation system in accordance with the provisions of subsection B4 of this Section.
C. Standards for Subdivision Proposals:
3. Base flood elevation data shall be generated for subdivision proposals and other proposed development including manufactured home parks and subdivisions which is greater than fifty (50) lots or five (5) acres, whichever is lesser, if not otherwise provided pursuant to Section 12-1-8 or subsection 12-1-16B8 of this Chapter.
4. All subdivision proposals including manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.
5. All subdivision proposals including manufactured home parks and subdivisions shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
D. Standards for Areas of Shallow Flooding (AO/AH Zones): Located within the areas of special flood hazard established in Section 12-1-8 of this Chapter are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one foot (1') to three feet (3') where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply:
1. All new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet in the community's FIRM (at least 2 feet if no depth number is specified).
2. All new construction and substantial improvements of nonresidential structures:
a. Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet in the community's FIRM (at least 2 feet if no depth number is specified); or
b. Together with attendant utility and sanitary facilities be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads of effects of buoyancy.
3. A registered professional engineer or architect shall submit a certification to the Flood Plain Administrator that the standards of this Section, as proposed in subsection 12-1-11A1 are satisfied.
4. Require within Zones AH or AO adequate drainage paths around structures on slopes, to guide flood waters around and away from proposed structures. (Ord. 89-01, 1-3-89)
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