(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 perks, 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.
B. 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 so that below the Base Flood Elevation the structure is floodproofed in accordance with Section 1775.05
(e)(2).
C. For all new construction and substantial improvements, those fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which 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 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, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(2) Manufactured home placement.
A. Manufactured homes to be placed or substantially improved within any floodplain area on sites:
1. Outside of a manufactured home park or subdivision;
2. In a new manufactured home park or subdivision;
3. In an expansion to an existing manufactured home park or subdivision; or
4. In an existing manufactured home park or subdivision in which a manufactured home has incurred "substantial damage", as defined herein, as the result of a flood shall:
a. Be elevated on a permanent foundation so that the lowest floor of the manufactured home is elevated to or above the Base Flood Elevation and,
b. Be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
B. Manufactured homes to be placed or substantially improved within any floodplain area in an existing manufactured home park or subdivision and not subject to the provisions of the subsection above shall be elevated so that either:
1. The lowest floor of the manufactured home is at or above the Base Flood Elevation, or
2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
(3) Recreational vehicle placement. Recreational vehicles to be placed within any floodplain area shall either be on the site for fewer than 180 consecutive days and be fully licensed and ready for highway use or meet the provisions of subsection (a)(2)A. hereof. 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 utilities and security devices, and has no permanently attached additions.
(4) 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 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 feet beyond the building line, shall be provided to a minimum of twenty-five percent (25%) of the perimeter of a nonresidential structure.
B. Fill shall consist of soil or rock materials only. Sanitary landfills shall not be permitted.
C. Fill material shall be compacted to provide the necessary stability and resistance to erosion, or settling.
D. 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 Building Inspector.
(5) Placement of buildings. 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 the flood water.
(6) Anchoring.
A. 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.
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 fifty feet long.
2. Frame ties shall be provided at each corner of the home with five additional ties per side at intermediate points, with manufactured homes less than fifty 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.
(7) Storage.
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 discharge 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.
(8) Drainage. Adequate drainage shall be provided to reduce exposure to flood hazard. (Passed 5-7-90)