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A. General Standards: In all areas of special flood hazards, the following standards are required:
a. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.
b. All manufactured homes must likewise be anchored to prevent flotation, collapse or lateral movement, and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to use of over-the-top or frame ties to ground anchors (reference FEMAs "Manufactured Home Installation in Flood Hazard Areas" guidebook for additional techniques).
2. Construction Materials and Methods:
a. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
b. All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.
c. Electrical, heating, ventilation, plumbing and air- conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding.
a. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system;
b. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters; and
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 subdivision proposals shall be consistent with the need to minimize flood damage;
b. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage;
c. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and
d. Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain at least fifty (50) lots or five (5) acres, whichever is less. (Ord. 463, 5-4-87)
5. Review of Building Permits: Where elevation data is not available, either through the flood insurance study or from another authoritative source, applications for building permits shall be reviewed to assure that the proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, the City's contour flood plain map, etc., where available. Failure to elevate at least two feet (2') above grade in flood hazard areas may result in higher insurance rates. (Ord. 488-91, 7-8-91)
B. Specific Standards: In all areas of special flood hazards where base flood elevation data has been provided as set forth in subsection 13-1-6B of this Chapter, "Basis for Establishing the Areas of Special Flood Hazard", or subsection 13-1-7C2 of this Chapter, "Use of Other Base Flood Data", the following provisions are required: (Ord. 463, 5-4-87)
1. Residential Construction:
a. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to at least one foot (1') above the base flood elevation. (Ord. 499-93, 12-13-93)
b. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited or 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 must meet or exceed the following minimum criteria:
(1) 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.
(2) The bottom of all openings shall be no higher than one foot (1') above grade.
(3) Openings may be equipped with screens, louvers or other coverings or devices; provided, that they permit the automatic entry and exit of flood waters.
2. 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 the level of the base flood elevation or, together with attendant utility and sanitary facilities, shall:
a. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
c. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the official as set forth in subsection 13-1-7C3b of this Chapter.
d. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection B1b of this section.
e. Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot (1') below the floodproofed level (e.g., a building constructed to the base flood level will be rated as 1 foot below that level). (Ord. 463, 5-4-1987)
3. Manufactured Homes:
a. All manufactured homes to be placed or substantially improved on sites:
(1) Outside of a manufactured home park or subdivision; or
(2) 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 the result of a flood;
shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated one foot (1') above the base flood elevation and be securely anchored to an adequately designed foundation system to resist flotation, collapse and lateral movement.
b. Manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A1-30, AH, and AE on the community's FIRM that are not subject to the above manufactured home provisions shall be elevated so that either: 1) the lowest floor of the manufactured home is elevated one foot (1') above the base flood elevation, or 2) the manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty six inches (36") in height above grade and be securely anchored to an adequately designed foundation system to resist flotation, collapse, and lateral movement. (Ord. 547-04, 9-13-2004)
4. All Accessory Structures: Accessory structures, such as sheds and small unattached garages, located outside of the floodway may be exempt from elevation and floodproofing standards, provided the following conditions are met:
a. The accessory structures are not designed for human habitation;
b. The accessory structure shall be designed to have low flood damage potentials;
c. Accessory structure shall be constructed and placed on the building site so as to offer minimum resistance to the flow of water; and
d. Accessory structures shall be firmly anchored to prevent flotation which may result in damage to other structures. (Ord. 488-91, 7-8-1991)
5. Recreational Vehicles: Recreational vehicles placed on sites are required to either:
a. Be on the site for fewer than one hundred eighty (180) consecutive days;
b. Be fully licensed and ready for highway use, on its wheels or jacking system, shall be attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or
c. Meet the requirements of subsection B3 of this section and the elevation and anchoring requirements for manufactured homes. (Ord. 547-04, 9-13-2004)
C. Floodways: Floodways located within areas of special flood hazard established in subsection 13-1-6B of this chapter are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions apply: (Ord. 463, 5-4-1987)
1. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional civil engineer is provided demonstrating thorough hydrologic and hydraulic analyses performed in accordance with standard engineering practice that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge. (Ord. 547-04, 9-13-2004)
2. If subsection C1 of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section. (Ord. 463, 5-4-1987)
3. The city recognizes that utilities, flood prevention structures and improvement projects that are in the public's best interest must sometimes encroach on designated floodways. In compliance with FEMA regulations, the city will permit floodway encroachments under the following conditions:
a. The city has determined the proposed project to be of public necessity; and
b. FEMA has approved the proposed project. (Ord. 488-91, 7-8-1991)
D. Encroachments: The cumulative effect of any proposed development, when combined with all other existing and anticipated development, shall not increase the water surface elevation of the base flood area more than one foot (1') at any point. (Ord. 463, 5-4-1987)