ARTICLE V.   PROVISIONS FOR FLOOD HAZARD REDUCTION


15.24.150   General standards.

In all areas of special flood hazards, the following standards are required:

A.

Anchoring.

1.

All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.

2.

All manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement, and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to, use of over-the-top or frame ties to ground anchors.

B.

Construction Materials and Methods.

1.

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

2.

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

3.

Electrical, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

C.

Utilities.

1.

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

2.

Water wells shall be located on high ground that is not in the floodway.

3.

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.

4.

Onsite waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

D.

Subdivision Proposals.

1.

All subdivision proposals 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 or eliminate flood damage.

3.

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

4.

Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain at least fifty lots or five acres (whichever is less).

E.

Review of Building Permits. Where elevation data is not available either through the flood insurance study, FIRM, or from another authoritative source (Section 15.24.130(B)), applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet above the highest adjacent grade in these zones may result in higher insurance rates.

(Ord. No. 997, § 2(5.1), 2-7-2013)

15.24.160   Specific standards.

A.

Residential Construction.

1.

New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated three feet or more above the base flood elevation (BFE).

2.

Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or 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 must meet or exceed the following minimum criteria:

a.

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.

b.

The bottom of all openings shall be no higher than one foot above grade.

c.

Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

B.

Nonresidential Construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated three feet or more above the base flood elevation; or, together with attendant utility and sanitary facilities, shall:

1.

Be flood-proofed so that below one foot or more above the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

2.

Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

3.

Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the official as set forth in Section 15.24.130(C)(2); and

4.

Nonresidential structures that are elevated, not flood-proofed, must meet the same standards for space below the lowest floor as described in Section 15.24.160(A)(2).

C.

Manufactured Homes.

1.

All manufactured homes in the floodplain to be placed or substantially improved on sites shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated three foot or more above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.

D.

Recreational Vehicles. Recreational vehicles placed on sites are required to either:

1.

Be on the site only during the months between June 1st and September 31st; or

2.

Be fully licensed and ready for highway use, on wheels or jacking systems, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or

3.

Meet the requirements of Section 15.24.160(C) above and the elevation and anchoring requirements for manufactured homes.

(Ord. No. 997, § 2(5.2), 2-7-2013)

15.25.170   AE and A1-30 zones with base flood elevations but no floodways.

In areas with base flood elevations (but a regulatory floodway has not been designated), no new construction, substantial improvements, or other development (including fill) shall be permitted within zones A1-30 and AE on the community's FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community.

(Ord. No. 997, § 2(5.3), 2-7-2013)

15.24.180   Floodways.

Located within areas of special flood hazard established in Section 15.24.070 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that can carry debris, and increase erosion potential, the following provisions apply:

A.

Encroachments, including fill, new construction, substantial improvements, and other development are prohibited unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels during the occurrence of the base flood discharge;

B.

Construction or reconstruction of residential structures is prohibited within designated floodways, except for (i) repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and (ii) repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty percent of the market value of the structure either, (A) before the repair, or reconstruction is started, or (B) if the structure has been damaged, and is being restored, before the damage occurred. Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions, or to structures identified as historic places, may be excluded in the fifty percent; and

C.

If Section 15.24.180(A) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Article V, provisions for flood hazard reduction.

(Ord. No. 997, § 2(5.4), 2-7-2013)

15.24.190   Critical facility.

Construction of new critical facilities shall be located outside the limits of the special flood hazard area (SFHA) (one hundred-year floodplain).

(Ord. No. 997, § 2(5.5), 2-7-2013)