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A. General Standards: (44 CFR 60.3(a)(b))
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. (44 CFR 60.3(a)(3)(i))
b. All manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement, and shall be installed using methods and practices that minimize flood damage.
2. AH Zone Drainage: Adequate drainage paths are required around structures on slopes to guide floodwaters around and away from proposed structures.
3. Construction Materials And Methods: (44 CFR 60.3(a)(3)(ii-iv))
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 standard methods and practices within the construction industry 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. Locating such equipment below the base flood elevation may cause annual flood insurance premiums to be increased.
4. Utilities: (44 CFR 60.3(a)(5)(6))
a. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems;
b. Water wells shall be located on high ground that is not in the floodway;
c. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters;
d. Onsite waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
5. Subdivision Proposals: (44 CFR 60.3(a)(4)(b)(3))
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 or eliminate flood damage;
c. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage;
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.
6. Review Of Building Permits: Where elevation data is not available either through the Flood Insurance Study, FIRM, or from another authoritative source (subsection 14-1-4C2 of this chapter), applications for building permits shall be reviewed to assure that 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, etc., where available.
B. Specific Standards: (44 CFR 60.3(c)(1))
Specific standards applies to all areas of special flood hazards. The following provisions are required:
1. Residential Construction: (44 CFR 60.3(c)(2)(5))
a. Lowest Floor Elevation: New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to the flood protection elevation (FPE). Minimum FEMA standards require the lowest floor to be elevated "to or above" the BFE; however, adding an additional foot of freeboard increases safety and can reduce insurance premiums by as much as thirty percent (30%). Additional freeboard is strongly encouraged by FEMA and the City.
b. Crawlspaces/Enclosed Spaces Below The BFE: All new construction or substantial improvements of an existing structure, including a structure that has been substantially damaged, that includes a fully enclosed area located below the lowest floor formed by the foundation and other exterior walls shall be designed to be an unfinished or flood resistant enclosure. The enclosure shall be designed to equalize hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwater.
(1) Designs for complying with this requirement must be certified by a licensed professional engineer or architect or meet the following minimum criteria:
(A) Provide a minimum of two (2) openings with a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;
(B) The bottom of all openings shall be no higher than one foot (1') above the higher of the exterior or interior grade or floor immediately below the opening;
(C) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwater in both directions without manual intervention.
(2) To comply with the "lowest floor" criteria of this chapter, the unfinished or flood resistant enclosure shall only be used for parking of vehicles, limited storage of maintenance equipment used in connection with the premises, or entry to the elevated area.
(3) The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(4) For crawlspace foundation types, construction must follow the guidelines in FEMA TB 11-01, Crawlspace Construction for Structures Located in Special Flood Hazard Areas: National Flood Insurance Program Guidance, specifically:
(A) Below grade crawlspaces are prohibited at sites where the velocity of floodwaters exceed five feet (5') per second;
(B) Interior grade of the crawlspace below the BFE must not be more than two feet (2') below the lowest adjacent exterior grade (LAG);
(C) Height of the below grade crawlspace, measured from the lowest interior grade of the crawlspace to the bottom of the floor joist must not exceed four feet (4') at any point;
(D) Contain an adequate drainage system that removes floodwaters from the interior area of the crawlspace.
2. Nonresidential Construction: (44 CFR 60.3(c)(3)(4))
New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the flood protection elevation; or, together with attendant utility and sanitary facilities, shall:
a. Be floodproofed one foot (1') or more above the base flood level so that 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 14-1-4C3b of this chapter;
d. Applicants who are floodproofing nonresidential buildings should be notified that flood insurance premiums will be based on rates that are one foot (1') below the floodproofed level (e.g., a building floodproofed to the base flood level will be rated as 1 foot below). Floodproofing the building an additional foot will reduce insurance premiums significantly.
3. Manufactured Homes: (44 CFR 60.3(c)(6)(12))
a. All manufactured homes in the floodplain to be placed or substantially improved on sites shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to the flood protection elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement. All manufactured homes in the floodplain need to minimize flood damage within the flood prone area.
b. In all areas of special flood hazard where the base flood elevation has not been established, manufactured homes placed, substantially improved, or have incurred substantial damage must be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated two feet (2') above the highest adjacent grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
c. Manufactured homes placed on solid perimeter walls shall meet the flood vent requirements in subsection B1b of this section, except when the first floor, including enclosed areas and crawlspace is located above the base flood elevation.
4. Recreational Vehicles: (44 CFR 60.3(c)(14))
Recreational vehicles placed on sites are required to either:
a. Be on the site for fewer than one hundred eighty (180) consecutive days; and
b. Be fully licensed and ready for highway use, on wheels or jacking system, 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.
5. Critical Facility: Construction of new critical facilities shall be, to the extent possible, located outside the limits of the special flood hazard area (SFHA) (100-year floodplain). Construction of new critical facilities shall be permissible within the SFHA if no feasible alternative site is available. Critical facilities constructed within the SFHA shall have the lowest floor elevated three feet (3') above BFE or to the height of the 500-year flood, whichever is higher. Access to and from the critical facility should also be protected to the height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be displaced by or released into floodwaters. Access routes elevated to or above the level of the base flood elevation shall be provided to all critical facilities to the extent possible.
C. AE Zones With Base Flood Elevations But No Floodways: (44 CFR 60.3(c)(10))
In areas with base flood elevations (but a regulatory floodway has not been designated), no new construction, substantial improvements, or other development (including fill) shall be permitted within Zone AE on the City's FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the City.
D. Floodways: Located within areas of special flood hazard established in subsection 14-1-3B of this chapter are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that can carry debris and increase erosion potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels during the occurrence of the base flood discharge. (44 CFR 60.3(d)(3))
2. If subsection D1 of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section.
E. Standards For Zones Without Base Flood Elevations And/Or Floodway (A Zones): New construction, manufactured homes and substantial improvements of existing structures shall have the lowest floor of the lowest enclosed area (including basement or crawlspace) elevated no less than two feet (2') above the highest adjacent grade at the building site. Openings sufficient to facilitate the unimpeded movement of flood waters shall be provided in accordance with the construction standards in subsection B1b of this section. (Ord. 2015-02, 6-10-2015)