(a) Design and Construction Standards. In order to prevent excessive damage to buildings, structures and related utilities and facilities, the following restrictions apply to all development, subdivision proposals, manufactured home parks, new construction and to construction of substantial improvements to existing structures occurring in the Flood Plain Area.
(1) Basements and lowest floors.
A. All new construction and substantial improvements of residential structures must have the lowest floor (including basement) elevated to or above the Base Flood Elevation. All new construction and substantial improvements of non-residential structures must have the lowest floor (including basement) elevated to or above the Base Flood Elevation; or, together with attendant utility and sanitary facilities, be designed sot that below the Base Flood Elevation the structure is floodproofed in accordance with Section 1751.08
(c)(2).
B. For all new construction and substantial improvements, those 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 must either by certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:
1. 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.
2. The bottom of all openings shall be no higher than one foot above grade.
3. Openings may be equipped with screens, louvers, valves, other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
C. Manufactured homes shall be elevated on a permanent foundation so that the lowest floor of the manufactured home will be at or above the Base Flood Elevation.
(2) Fill. If fill is used to raise the finished surface of the lowest floor to the Base Flood Elevation:
A. Fill shall extend beyond a structure for a sufficient distance to provide acceptable access. For residential structures, fill shall extend laterally fifteen (15) 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, with fill extending laterally fifteen (15) feet beyond the building line, shall be provided to a minimum of twenty-five (25) percent of the perimeter of a nonresidential structure.
B. Fill shall consist of soil or rock materials only. Sanitary land fills shall not be permitted.
C. Fill materials shall be compacted to provide the necessary stability and resistance to erosion, scouring, or settling.
D. Fill slopes shall be no steeper than one (1) vertical on two (2) horizontal, unless substantiating data justifying steeper slopes are submitted to and approved by the Building and Safety Inspector.
E. Fill shall be used only to the extent to which it does not adversely affect adjacent properties.
(3) Placement of Buildings.
A. All buildings and structures shall be constructed and placed on the lot 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 flood water.
(4) Anchoring.
A. All buildings and structures shall be firmly anchored in accordance with accepted engineering practices to prevent flotation, collapses, and lateral movement, thus reducing the threat to life and property and decreasing the possibility of the blockage of bridge opening and other restricted sections of the watercourse.
B. All air ducts, large pipes and storage tanks located at or below the Base Flood Elevation shall be firmly anchored to resist flotation.
C. All manufactured homes shall be anchored to resist flotation, collapse or lateral movement. Methods of anchoring may include but are not limited to the over-the-top and frame ties to ground anchors such as the following:
1. Over-the-top ties shall be provided at each of the four corners of the manufactured home, with two additional ties per side for manufactured homes less than 50 feet long.
2. Frame ties shall be provided at each corner of the home with the five additional ties per side at intermediate points, with manufactured homes less than 50 feet long requiring four additional ties per side.
3. All components of the anchoring system shall be capable of carrying a force of 4,800 pounds.
4. Any additions to a manufactured home shall be similarly anchored.
This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
(5) Storage. No materials that are buoyant, flammable, explosive, or in times of flooding could be injurious to human, animal or plant life, shall be stored below Base Flood Elevation.
(6) Utility and facility requirements.
A. All new or replacement water systems whether public or private, shall be designed to minimize or eliminate infiltration of flood waters into the systems.
B. All new or replacement sanitary disposal systems, whether public or private, shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters.
C. All other new or replacement public and/or private utilities and facilities shall be located and constructed to minimize or eliminate flood damage.
D. Onsite waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(7) Drainage. Adequate drainage shall be provided to reduce exposure to flood hazard.
(Ord. 1989-2. Passed 2-6-89.)