In order to prevent excessive damage to buildings and structures, the following restrictions shall apply to all new construction and any substantial improvement to an existing structure within the Flood Plain Overlay District.
(a) Basements and Lowest Floors. All new construction and substantial improvements of residential structures shall have the lowest floor including basement elevated to the one hundred year flood elevation (base flood elevation). All new construction and substantial improvements of nonresidential structures shall have the lowest floor, including basement, elevated to the base flood elevation; or together with attendant utility and sanitary facilities, be designed so that below the base flood elevation, the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
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 the entry and exit of floodwaters. Designs for meeting this requirement shall either be certified by a registered professional engineer or architect or meet or exceed the following minimum 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 provided.
The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.
(b) Fill. If fill is used to raise the finished surface of the lowest floor to the base flood elevation:
(1) Fill shall extend beyond a structure for a sufficient distance to provide acceptable access. For residential structures, fill shall extend laterally fifteen feet beyond the building line from all points. For nonresidential structures, fill shall be placed to provide access acceptable for intended use. At grade access, fill shall extend laterally fifteen feet beyond the building line to a minimum of twenty-five percent (25%) of the perimeter of a nonresidential structure.
(2) Fill shall consist of soil or rock materials only. Sanitary land fills shall not be permitted.
(3) Fill material shall be compacted to provide the necessary stability and resistance to erosion, scouring or settling.
(4) Fill slopes shall be no steeper than one vertical on two horizontal, unless substantiating data justifying steeper slopes are submitted to and approved by the Division of Code Administration.
(5) Fill shall be used only to the extent to which it does not adversely effect adjacent properties or cause drainage problems.
(c) Placement of Buildings, Structures and Manufactured Housing.
(1) All buildings and structures shall be constructed and placed on the lots so as to offer the minimum obstruction to the flow of water and shall be designed to have a minimum obstruction effect upon the flow and height of floodwater. (Ord. 0-531. Passed 2-23-88.)
(2) Manufactured homes, including those which have incurred “substantial damage” as the result of a flood, and any improvements thereto shall be elevated on a permanent foundation so that the lowest floor of each manufactured home will be at the base flood elevation.
(Ord. 0-835. Passed 12-10-96.)
(3) All manufactured homes shall be provided with adequate surface drainage and access for a mobile home hauler.
(d) Anchoring.
(1) All buildings and structures shall be firmly anchored in accordance with accepted engineering practices to prevent flotation, collapse and lateral movement, thus reducing the threat to life and property and decreasing the possibility of the blockage of bridge openings, and other restricted sections of the watercourse.
(2) All air ducts, large pipes and storage tanks located at or below the first floor level shall be firmly anchored to resist flotation.
(Ord. 0-531. Passed 2-23-88.)
(3) All manufactured homes shall be anchored to resist flotation, collapse or lateral movement by providing over-the-top and frame ties to ground anchors. Specifically:
A. Over-the-top ties shall be provided at each of the four corners of the manufactured home, with two additional ties per side at intermediate locations and manufactured homes less than fifty feet long requiring one additional tie per side.
B. Frame ties shall be provided at each corner of the manufactured home with five additional ties per side at intermediate points, with manufactured homes less than fifty feet long requiring four additional ties per side.
(Ord. 0-575. Passed 8-29-89.)
C. All components of the anchoring system shall be capable of carrying a force of 4,800 pounds.
(Ord. 0-531. Passed 2-23-88.)
D. Any additions to a manufactured home shall be anchored in the same manner. (Ord. 0-575. Passed 8-29-89.)
(e) Storage. No materials that are buoyant, explosive or in time of flooding could be injurious to human, animal or plant life shall be stored below the base flood elevation.
(f) Utility and Facility Requirements. For all new construction, proposed subdivisions, mobile manufactured home parks or subdivisions or other development, the following utility and facility requirements shall be required.
(1) All new or replacement water systems located within the Flood Plain Overlay District, whether public or private, shall be floodproofed to the base flood elevation.
(2) All new or replacement sanitary disposal systems located within the Flood Plain Overlay District, whether public or private, shall be floodproofed to the base flood elevation.
(3) All other new or replacement public and/or private utilities and facilities shall be floodproofed to the base flood elevation.
(4) All 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 flooding.
(g) Drainage. Adequate drainage shall be provided to reduce exposure to flood hazards.
(Ord. 0-531. Passed 2-23-88.)