In all areas of special flood hazard, the following provisions are required:
(A) All new construction and substantial improvements including the placement of manufactured homes and prefabricated buildings in the floodplain district shall be designed and adequately anchored to prevent flotation, collapse or lateral movement of the structure, and shall be constructed of materials and utility equipment resistant to flood damage and using methods and practices that minimize flood damages.
(B) New and replacement water systems shall be designed to minimize infiltration of floodwaters. New and replacement sanitary systems shall be designed to minimize infiltration of floodwaters into the systems and discharge from the systems into floodwaters. On-site sanitary disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(C) New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above the base flood elevation.
(D) New construction and substantial improvement of any nonresidential structure shall have the lowest floor, including basement, elevated to or above the base flood elevation, or in lieu of being elevated, nonresidential structures may be dry flood-proofed to or above the base flood elevation provided that together with all attendant utilities and sanitary facilities the areas of the structure below the required elevation are watertight with walls substantially impermeable to the passage of water, and provided that such structures are composed of structural components have the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. A registered professional engineer or architect shall review and/or develop structural design specifications and plans for the construction, and shall certify that the design and methods of construction are in accordance with acceptable standards of practice for meeting the provisions this section. Electrical, plumbing, machinery or other utility equipment that service the structure must be elevated to or above the base flood elevation.
(E) For all new construction and substantial improvements, fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following criteria; 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 protected. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers or other coverings or devices provided that they permit automatic entry and exist of floodwaters. The enclosed area cannot be used as finished living space. Use of the enclosed area shall be the minimum necessary and shall only be used for the parking of vehicles, building access or limited storage.
(F) Manufactured homes.
(1) All manufactured homes (including mobile homes placed on a site for 180 consecutive days or longer) to be placed, or substantially improved shall be elevated so that the lowest floor is above the base flood elevation. This includes all manufactured homes located outside of a manufactured home park or subdivision, in a new manufactured home park or subdivision, in an existing 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 a result of a flood.
(2) It shall be placed on a permanent foundation which itself is securely anchored so that it will resist flotation, lateral movement, and hydrostatic and hydrodynamic pressures. Anchoring may include, but not be limited to, the use of over-the-top or frame ties to ground anchors.
(3) It shall be installed using methods and practices which minimize flood damage:
(a) Adequate access and drainage should be provided; and
(b) Elevation construction standards includes piling foundations placed no more than ten feet apart, and reinforcement is provided for piers more than six feet above ground level.
(4) Recreational vehicles placed on sites within an area of special flood hazard shall either be on the site for fewer than 180 consecutive days, and be fully licensed and ready for highway use or meet all the general standards of § 153.20 and the elevation and anchoring requirement of § 153.20(F)(1), (2) and (3). A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.
(G) No encroachment including fill, new construction, substantial improvements, and other development shall be permitted in a floodway unless certification, with supporting technical data, by a registered professional engineer demonstrates, through hydrologic and hydraulic analyses performed in accordance with standard engineering practice, that the encroachment will not result in any (0.00 feet) increase in flood levels during the base flood discharge. Fences in the floodway must be aligned with the flow and be of an open design. All other standards of this chapter must also be satisfied.
(H) For development proposals in unnumbered A Zones, where base flood elevation data has not been provided by the Federal Emergency Management Agency (FEMA), the Building Official shall obtain, review, and reasonably utilize any base flood elevation date available from a federal, state or other source, in order to administer the requirements of divisions (C) and (D) of this section. The Building Official may request floodway data of an applicant for watercourses without FEMA-published floodways. When such data is provided by an applicant or whenever such data is available from any other source (in response to the municipality’s request or not), the community shall adopt a regulatory floodway based on the principle that the floodway must be able to convey the waters of the base flood without increasing the water surface elevation more than one (1.0) foot at any point within the community. When BFEs have been determined within Zones A and AE on the community’s flood insurance rate map but a regulatory floodway has not been designated, the Building Official must require that no new construction, substantial improvements repair to structures which have sustained substantial damage or other development, including fill, shall be permitted which will increase the water surface elevation of the base flood more than one (1.0) foot at any point within the community when all existing and anticipated development is considered cumulatively with the proposed development.
(I) Electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of floodings.
(J) A structure already in compliance with the provisions of this chapter shall not be made noncompliant by any alteration, repair, reconstruction or improvement of the structure.
(K) Compensatory storage. The water holding capacity of the floodplain, except those areas which are tidally influenced, shall not be reduced. Any reduction caused by filling, new construction or substantial improvements involving an increase in footprint to the structure, shall be compensated for by deepening and/or widening of the floodplain. Storage shall be provided on-site, unless easements have been gained from adjacent property owners; it shall be provided within the same hydraulic reach and a volume not previously used for flood storage; it shall be hydraulically comparable and incrementally equal to the theoretical volume of flood water at each elevation, up to and including the 100-year flood elevation, which would be displaced by the proposed project. Such compensatory volume shall have an unrestricted hydraulic connection to the same waterway or water body. Compensatory storage can be provided off-site if approved by the municipality.
(L) Equal conveyance. Within the floodplain, except those areas which are tidally influenced, as designated on the Flood Insurance Rate Map (FIRM) for the community, encroachments resulting from filling, new construction or substantial improvements involving an increase in footprint of the structure, are prohibited unless the applicant provides certification by a registered professional engineer demonstrating, with supporting hydrologic and hydraulic analyses performed in accordance with standard engineering practice, that such encroachments shall not result in any (0.00 feet) increase in flood levels (base flood elevation). Work within the floodplain and the land adjacent to the floodplain, including work to provide compensatory storage shall not be constructed in such a way so as to cause an increase in flood state or flood velocity.
(M) Above-ground storage tanks. Above-ground storage tanks (oil, propane, and the like) which are located outside or inside of the structure must either be elevated above the base flood elevation (BFE) on a concrete pad; or be securely anchored with tie-down straps to prevent flotation or lateral movement, have the top of the fill pipe extended above the BFE, and have a screw fill cap that does not allow for the infiltration of flood water.
(N) Portion of structure in flood zone. If any portion of a structure lies within the Special Flood Hazard Area (SFHA), the entire structure is considered to be in the SFHA. The entire structure must meet the construction requirements of the flood zone. The structure includes any attached additions, garages, decks, sunrooms, or any other structure attached to the main structure. Decks or porches that extend into a more restrictive flood zone will require the entire structure to meet the standards of the more restrictive zone.
(O) Structures in two flood zones. If a structure lies within two or more flood zones, the construction standards of the most restrictive zone apply to the entire structure (i.e., V zone is more restrictive than A zone; structure must be built to the highest BFE). The structure includes any attached additions, garages, decks, sunrooms, or any other structure attached to the main structure. (Decks or porches that extend into a more restrictive zone will require the entire structure to meet the requirements of the more restrictive zone.)
(P) No structures entirely or partially over water. New construction, substantial improvements and repair to structures that have sustained substantial damage cannot be constructed or located entirely or partially over water unless it is a functionally dependent use or facility.
(Ord. passed 11-29-2010) Penalty, see § 153.99