§ 15.36.160. Floodway fringe (FF) overlay district

A. Permitted Uses. Uses permitted in the underlying zoning district shall also be permitted in the floodway fringe district in accordance with these regulations.

B. Special Uses. Uses permitted as special uses in the underlying zoning district shall also be permitted special uses in the floodway fringe district.

C. Use Limitations.

1. New construction and substantial improvements shall be constructed on fill so that the first floor and basement floor are above the regulatory flood protection elevation. The fill shall be at a point no lower than one foot above the regulatory flood elevation for the particular area and shall extend at such elevation at least fifteen (15) feet beyond the limits of any structure or building erected thereon. Fill must be protected against erosion and fill material must be approved by the city engineer. However, floodproofing may substitute for this fill requirement for any part of a nonresidential structure below a level one foot above the regulatory flood elevation. Applications for a building permit shall provide certification by a registered professional engineer or architect that the floodproofing plans are adequate to be watertight with walls impermeable to the passage of water and capable to withstand the hydrostatic and hydrodynamic forces associated with the one hundred (100) year flood and the effect of buoyancy. Where the regulatory flood elevation is not specified in the flood insurance study, the best available data from federal, state or other sources shall be used until the flood insurance administration or its equivalent provide such information.

2. All new construction and substantial improvements that have fully enclosed areas below the lowest floor 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 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.

3. No use or fill shall be constructed which will adversely affect the capacity of channels or floodways of any tributary to the main stream, drainage ditch or any other drainage facility.

4. All manufactured homes shall be anchored to resist flotation, collapse, or lateral movement. Manufactured homes must be anchored in accordance with local building codes or FEMA guidelines. In the event that over-the-top frame ties to ground anchors are used, the following specific requirements (or their equivalent) shall be met:

a. Over-the-top ties 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 (50) feet long requiring one additional tie per side;

b. Frame ties be provided at each corner of the home with five additional ties per side at intermediate points and manufactured homes less than fifty (50) feet long requiring four additional ties per side;

c. All components of the anchoring system be capable of carrying a force of four thousand eight hundred (4,800) pounds; and

d. Any additions to the manufactured home be similarly anchored.

All manufactured homes to be placed within Zones A1-30, AH and AE on the commun-ity's FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood elevation, and be securely anchored to an adequately anchored foundation system in accordance with the provisions of Section 15.36.090.

5. New streets shall be constructed not more than one foot below the regulatory flood elevation.

(Ord. 8707 § 1 (part), 1987: prior code § 16-306)