A. General Standards. In all areas of special flood hazards (Zones A, A1-30, AE, AO, AH) the following provisions are required:

1. All new construction, including manufactured homes and substantial improvements, shall be designed (or modified), and substantial improvements shall be designed (or modified), and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

2. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

3. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage.

4. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.

5. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters.

6. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

7. The storage or processing of materials that are in time of flooding buoyant, flammable, explosive or could be injurious to human, animal or plant life is prohibited.

8. Storage of other material or equipment may be allowed if not subject to major damage by floods and firmly anchored to prevent flotation or if readily removable from the area within the time available after flood warning.

9. That until a floodway has been designated, no development, including landfill, may be permitted within Zones A1-30 and AE on the city's FIRM unless the applicant for the land use has demonstrated that the proposed use, when combined with all other existing and reasonably anticipated uses, will not increase the water surface elevation of the one-hundred-year flood more than one foot on the average cross section of the reach in which the development or landfill is located as shown on the flood insurance rate study incorporated by reference.

10. All new construction or substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designated and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

11. That all recreational vehicles placed on sites within Zones A1-30, AH, and AE on the community's FIRM shall either:

a. Be on the site for fewer than one hundred eighty (180) days;

b. Be fully licensed and ready for highway use; or

c. Meet the permit requirements of Section 15.48.070(A) and the elevation and anchoring requirements for "manufactured homes" in subsection (C)(4) of this section.

B. Standards for Subdivision Proposals.

1. All subdivision proposals and other proposed new developments, including manufactured home parks or subdivisions, shall be consistent with the need to minimize flood damage.

2. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.

3. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage.

4. Base flood elevation data shall be provided for subdivision proposal and proposed development including proposals for manufactured home parks and subdivisions, which is greater than either fifty (50) lots or five acres.

C. Specific Standards. In all areas of special flood hazards where base flood elevation data has been provided as set forth in Section 15.48.060(B) or 15.48.070(C)(3) of this chapter, (Zones A1-30 and AH) the following provisions are required:

1. Residential Construction. New construction or substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above 1.0 feet above the base flood elevation. The elevation of the lowest floor shall be certified by a licensed land surveyor.

2. Nonresidential Construction. New construction or substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to one foot above the level of the base flood elevation or, together with attendant utility and sanitary facilities, be flood-proofed so that below such a level 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. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. Such certification shall be provided to the official as set forth in Section 15.48.070 (A)(6) of this chapter. The elevation of the lowest floor shall be certified by a licensed land surveyor.

3. Requirements for all New Construction and Substantial Improvements. That 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 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.

4. Manufactured Homes.

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

i. Over-the-top ties be provided at each of the four corners of the manufactured home with two additional ties per side at the intermediate locations and manufactured homes less than fifty (50) feet long requiring one additional tie per side;

ii. 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;

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

iv. Any additions to manufactured homes be similarly anchored.

b. All manufactured homes to be placed within Zones A1-30, AH and AE on the community's FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home one foot above the base flood elevation; and shall be securely anchored to an adequately anchored foundation system in accordance with the provisions of subdivision (4)(a) of this subsection. The elevation of the lowest floor shall be certified by a licensed land surveyor.

D. Floodways. Located within areas of special flood hazard established in Section 15.48.060(B) of this chapter are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles and erosion potential, the following provisions shall apply:

1. Prohibits encroachments, including fill, new construction, substantial improvements and other developments unless certification by a professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during occurrence of the base flood discharge.

2. If 18-608, Section D(1) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of 18-608.

3. Prohibit the placement of any manufactured home, except in an existing manufactured home park or existing manufactured home subdivision.

E. Areas of Shallow Flooding (AO and AH Zones). Located within the areas of special flood hazard established in Section 15.48.060(B) of this chapter are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one to three feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate; therefore, the following provisions apply:

1. Within AO Zones.

a. All new construction and substantial improvement of residential structures have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as one foot above the depth number specified in feet on the community's FIRM.

b. All new construction and substantial improvements of nonresidential structures shall:

i. Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as one foot above the depth number specified in feet on the community's FIRM. The elevation of the lowest floor shall be certified by a licensed land surveyor;

ii. Together with attendant utility and sanitary facilities be completely flood-proofed to or above the level so that any space below that level 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.

c. Adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from proposed structures.

d. The anchoring requirements for manufactured homes as established in subsection (C)(4)(a) of this section shall be required.

2. Within AH Zones.

a. The specific standards for all areas of special flood hazards where base flood elevation data has been provided shall be required as set forth in subsection (C) of this section.

b. Adequate drainage paths around structures in slopes shall be required in order to guide floodwaters around and away from proposed structures. (Ord. G-898 §§ 6--12, 2001; prior code § 18-608)