(B) (1) 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, and the like, or above-grade, enclosed areas such as crawl spaces or tuck-under garages. The base or floor of an enclosed area is considered above-grade and not a structure's basement or lowest floor if:
(a) The enclosed area is above-grade on at least one side of the structure;
(b) It is designed to internally flood and is constructed with flood resistant materials; and
(c) It is used solely for parking of vehicles, building access or storage.
(2) These alternative elevation methods are subject to the following additional standards:
(3) Design and certification. The structure's design and as-built condition must be certified by a registered professional engineer or architect as being in compliance with the general design standards of the State Building Code and, specifically, that all electrical, heating, ventilation, plumbing and air conditioning equipment, including ductwork, and other service facilities are placed at or above the regulatory flood protection elevation or are designed to prevent flood water from entering or accumulating within these components during times of flooding.
(4) Specific standards for above-grade, enclosed areas. Above-grade, fully enclosed areas such as crawl spaces or tuck under garages must be designed to internally flood. The design plans must stipulate:
(a) A minimum area of openings in the walls where internal flooding is to be used as a floodproofing technique. There must be a minimum of two openings on at least two sides of the structure and the bottom of all openings must be a maximum of one foot above grade. The automatic openings must have a net area of at least one square inch for every square foot of enclosed area subject to flooding, unless a registered professional engineer or architect certifies that a smaller net area would suffice. The automatic openings may be equipped with screens, louvers, valves, or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters without any form of human intervention; and
(b) That the enclosed area will be designed of flood resistant materials in accordance with the FP-3 or FP-4 classifications in the State Building Code and will be used solely for building access, parking of vehicles, or storage.
(C) Basements, as defined by § 152.018, are subject to the following:
(1) Residential basement construction is not allowed below the regulatory flood protection elevation.
(2) Non-residential basements may be allowed below the regulatory flood protection elevation provided the basement is structurally dry floodproofed in accordance with § 152.043(D).
(D) All areas of nonresidential structures, including basements, to be placed below the regulatory flood protection elevation must be floodproofed in accordance with the structurally dry floodproofing classifications in the State Building Code. Structurally dry floodproofing must meet the FP-1 or FP-2 floodproofing classification in the State Building Code, which requires making the structure watertight with the walls substantially impermeable to the passage of water and with structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. Structures wet floodproofed to the FP-3 or FP-4 classification are not permitted.
(E) The placement of more than 1,000 cubic yards of fill or other similar material on a parcel (other than for the purpose of elevating a structure to the regulatory flood protection elevation) must comply with an approved erosion/sedimentation control plan.
(1) The plan must clearly specify methods to be used to stabilize the fill on site for a flood event at a minimum of the regional (1% chance) flood event.
(2) The plan must be prepared and certified by a registered professional engineer or other qualified individual acceptable to the City Council.
(3) The plan may incorporate alternative procedures for removal of the material from the floodplain if adequate flood warning time exists.
(F) Storage of materials and equipment below the regulatory flood protection elevation must comply with an approved emergency plan providing for removal of such materials within the time available after a flood warning.
(G) Within an AO Zone, there must be adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures or structure additions.
(Ord. 1079, passed 4-14-14)