22.14.140 Additional standards where flood elevation data has been provided.
In addition to meeting the general development standards set forth in Garfield Municipal Code 22.14.100 through 22.14.130, above, the following standards shall apply where the anticipated elevation of flood having a 100-year or more frequent expectation of occurrence has been developed and shown on a map or in a report adopted by the Town:
(1) 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 1 foot or more about the level of the base flood elevation; or, together with the structure’s utility and sanitary facilities, shall:
(a) be flood proofed so that below the base flood level the structure is watertight with walls impermeable or 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 Garfield Municipal Code 22.14.075(3)(b);
(d) Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in Garfield Municipal Code 22.14.140(2), below. Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building constructed to the base flood level will be rated as one foot below that level).
(2) Residential construction:
(a) New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one foot or more above base flood elevation.
(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:
(i) 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.
(ii) The bottom of all openings shall be no higher than one foot above grade.
(iii) Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(3) Critical facility:
Construction of new critical facilities shall be, to the extent possible, located outside the limits of the Special Flood Hazard Area (SHFA) (100-year floodplain). Construction of new critical facilities shall be permissible within the SHFA if no feasible alternative site is available. Critical facilities constructed within the SHFA shall have the lowest floor elevated to three feet or move above the sea level of the base flood elevation at the site or to the height of the 500-year flood, whichever is higher. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be displaced by or released into flood waters. Access routes elevated to or above the level of the base flood plain shall be provided to all critical facilities to the extent possible.
(4) Manufactured Homes:
All manufactured homes to be placed or substantially improved on sites within the floodplain designated on the community’s FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is one foot or more above the base flood elevation; and be securely anchored to an adequately anchored foundation system in accordance with the provisions of Garfield Municipal Code 22.14.100. (Ord. 405-N, §7, 2011; Ord. 289-N, §4, 2002; Ord. 171-N, §2, 1988; Ord. 159-N, §11, 1987)