An area within the flood fringe, shown on the flood insurance rate map (FIRM) as an AO or an AH zone, susceptible to shallow flooding with depths range from one (1') to three feet (3'). See - AREA OF SHALLOW FLOODING or AO ZONE.
A. General Standards - AO Zone:
1. Drainage: Adequate drainage paths around structures on slopes shall be provided in an AO zone to guide floodwaters around and away from proposed structures.
2. Grading: Any site work in excess of ten (10) cubic yards of cut or fill will require a detailed grading permit. All grading shall be done so as to minimize impacts and maintain compensatory storage within all special flood hazard areas. Depending on the extent and nature of the grading, an FES may be required along with an LOMC.
3. Hazardous Velocities: Where hazardous velocities are noted on the FIRM, proper construction techniques and methods shall be used to mitigate the effects of the velocities.
B. Residential Structure: All new construction and/or substantial improvement of a residential structure proposed within an AO zone requires elevation certificates as set forth in subsection 8-3F-6D2 of this article that certify compliance with the following standards:
1. New construction and substantial improvements of residential structures within AO zones shall have the lowest floor (including basement and/or crawl space) elevated above the highest adjacent grade of the building site by a height equal to the depth number specified on the FIRM plus one foot (1'), or at least two feet (2'), if no depth number is specified. Where appropriate, such structures shall be elevated above the crown of the nearest roadway by a height equal to the depth number specified on the FIRM plus one foot (1').
C. Nonresidential Structure: All new construction and/or substantial improvement of any commercial, industrial, or other nonresidential (accessory or agricultural) structure within an AO zone shall either be elevated or floodproofed in compliance with the following standards:
1. Elevation: If the structure is not going to be elevated, elevation certificates are required as set forth in subsection 8-3F-6D2 of this article that certify compliance with the following standards:
a. The lowest floor (including basement and/or crawl space) shall be elevated above the highest adjacent grade of the building site by a height equal to the depth number specified on the FIRM plus one foot (1'), or at least two feet (2'), if no depth number is specified.
2. Floodproofing: If the structure is not going to be floodproofed, a floodproof certificate is required as set forth in subsection 8-3F-6D3 of this article that certify compliance with the following standards:
a. For Dry-Floodproofing: The lowest floor (including basement and/or crawl space), together with attendant electrical, mechanical and plumbing facilities, shall be completely floodproofed to or above a height equal to the depth number specified on the FIRM plus one foot (1') so that any space below that level is watertight, with walls substantially impermeable to the passage of water.
b. For Wet-Floodproofing: The electrical, mechanical and plumbing facilities shall be completely floodproofed to or above a height equal to the depth number specified on the FIRM plus one foot (1').
D. Subdivision And/Or Manufactured Home Park: An FES, as set forth in subsection 8-3F-6D4 and 8-3F-7A8 of this article, shall be submitted concurrently with an application for a subdivision or manufactured home park within an AO zone. The applicant and/or owner shall submit a signed copy of an LOMC prior to approval of the final plat or prior to issuance of any building permit within a subdivision or manufactured home park.
E. Manufactured Home: A manufactured home placed or substantially improved within an AO zone requires elevation certificates as set forth in subsection 8-3F-6D2 of this article that demonstrate compliance with the following standards:
1. A manufactured home shall be installed using methods and practices which minimize flood damage. Said methods and practices shall include the anchoring of the home to resist flotation, collapse, or lateral movements. Methods of anchoring may include, but are not to be limited to, use of over the top or frame ties to ground anchors in addition to any applicable anchoring requirements for resisting wind forces. Other anchoring techniques are described in the FEMA publication "Manufactured Home Installation In Flood Hazard Areas"; and
2. A manufactured home shall be elevated so the lowest floor (including basement and/or crawl space) is elevated above the highest adjacent grade of the building site by a height equal to the depth number specified on the FIRM plus one foot (1'), or at least two feet (2'), if no depth number is specified, as confirmed by an elevation certificate as set forth in subsection 8-3F-6D2 of this article.
F. Pit, Mine Or Quarry: Approval of an FES as set forth in subsection 8-3F-6D4a of this article, shall be required as a condition of approval for a pit, mine or quarry. The FES shall demonstrate that the extraction site will be designed to avoid river avulsion. The FES must be approved prior to commencement of the use or breaking ground. Gravel mining operations or excavations are not permitted within one hundred feet (100') of the top of river bank regardless of floodway or floodplain designation. Material stockpiles and permanently installed structures shall not be located within the regulatory floodway. (Ord. 835, 12-3-2014; Ord. 914, 6-10-2020)