2009.10.05 ORD 2009-434 - Laserfiche WebLink

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(2) Accessory structures in the floodway, if permitted, shall be constructed - and placed on the building site so as to offer the minimum obstruction to the flow of flood waters: (i) Whenever possible, structures shall be constructed with the longitudinal axis parallel to the direction of flood flow; and (ii) So far as practicable, structures shall be placed approximately on the same flood flow lines as those of adjoining structures. (3) Accessory structures not elevated on fill to the Regulatory Flood Protection Elevation may be flood proofed to the FP -3 or FP -4 flood proofing classification in the State Building Code provided the accessory structure constitutes a minimal investment, does not exceed 500 square feet in size at its largest projection, and for a detached garage, the detached garage must be used solely for parking of vehicles and limited storage. All flood proofed accessory structures must meet the following additional standards: (i) The structure must be adequately anchored to prevent flotation, collapse or lateral movement of the structure and shall be designed to equalize hydrostatic flood forces on exterior walls; (ii) Any mechanical and utility equipment in a structure must be elevated to or above the regulatory flood protection elevation or properly flood proofed; and (iii) To allow for the equalization of hydrostatic pressure, there must be a minimum of two "automatic" openings in the outside walls of the structure having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. There must be openings on at least two sides of the structure and the bottom of all openings must be no higher than one foot above the lowest adjacent grade to the structure. Using human intervention to open a garage door prior to flooding will not satisfy this requirement for automatic openings. c. Alternative elevation methods other than the use of fill may be utilized to elevate a structure's lowest floor above the regulatory flood protection elevation. These alternative methods may include the use of stilts, pilings, parallel walls, etc., or above -grade, enclosed areas such as crawl spaces or tuck under garages. The base or floor of an enclosed area shall be considered above -grade and not a structure's basement or lowest floor if. 1) the enclosed area is above -grade on at least one side of the structure; 2) it is designed to internally flood and is constructed with flood resistant materials; and 3) it is used solely for parking of vehicles, building access or storage. The above -noted alternative elevation methods are subject to the following additional standards: 22