In all areas of special flood hazards, the following standards are required:
(1) 
Anchoring.
(a) 
All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.
(b) 
All manufactured homes must likewise 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 (Reference FEMA's “Manufactured Home Installation in Flood Hazard Areas” guidebook for additional techniques).
(2) 
AH Zone Drainage. Adequate drainage paths are required around structures on slopes to guide floodwaters around and away from proposed structures.
(3) 
Construction Materials and Methods.
(a) 
All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
(b) 
All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.
(c) 
Electrical, heating, ventilation, plumbing, and 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.
(4) 
Utilities.
(a) 
All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems;
(b) 
The proposed water well shall be located on high ground that is not in the floodway (WAC 173-160-171);
(c) 
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; and
(d) 
On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(5) 
Subdivision Proposals.
(a) 
All subdivision proposals shall be consistent with the need to minimize flood damage;
(b) 
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;
(c) 
All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and
(d) 
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 50 lots or five acres (whichever is less).
(6) 
Review of Building Permits. Where elevation data is not available either through the Flood Insurance Study, FIRM, or from another authoritative source (CMC § 15.08.120(2)), 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. 524 § 5.1, 2004)
In all areas of special flood hazards where base flood elevation data has been provided as set forth in CMC § 15.08.050, Basis for establishing the areas of special flood hazard, or CMC § 15.08.120(2), Use of Other Base Flood Data, the following provisions are required:
(1) 
Residential Construction.
(a) 
New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one foot or more above the base flood elevation.
(b) 
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:
(i) 
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.
(ii) 
The bottom of all openings shall be no higher than one foot above grade.
(iii) 
Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(2) 
Nonresidential Construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated one foot or more above the base flood elevation; or, together with attendant utility and sanitary facilities, shall:
(a) 
Be floodproofed 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;
(b) 
Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
(c) 
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 CMC § 15.08.120(2);
(d) 
Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in CMC § 15.08.030;
(e) 
Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building floodproofed to the base flood level will be rated as one foot below).
(3) 
Manufactured Homes.
(a) 
All manufactured homes to be placed or substantially improved on sites:
(i) 
Outside of a manufactured home park or subdivision,
(ii) 
In a new manufactured home park or subdivision,
(iii) 
In an expansion to an existing manufactured home park or subdivision, or
(iv) 
In an existing manufactured home park or subdivision on which a manufactured home has incurred “substantial damage” as the result of a flood; shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated one foot or more above the base flood elevation and be securely anchored to an adequately designed foundation system to resist flotation, collapse and lateral movement.
(b) 
Manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision that are not subject to the above manufactured home provisions be elevated so that either:
(i) 
The lowest floor of the manufactured home is elevated one foot or more above the base flood elevation, or
(ii) 
The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately designed foundation system to resist flotation, collapse, and lateral movement.
(4) 
Recreational Vehicles. Recreational vehicles placed on sites are required to either:
(a) 
Be on the site for fewer than 180 consecutive days;
(b) 
Be fully licensed and ready for highway use, on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions; or
(c) 
Meet the requirements of subsection (3) if this section and the elevation and anchoring requirements for manufactured homes.
(Ord. 524 § 5.2, 2004)
In areas where 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. 524 § 5.3, 2004)
Located within areas of special flood hazard established in CMC § 15.08.050 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:
(1) 
Prohibit encroachments, including fill, new construction, substantial improvements, and other development 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.
(2) 
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 50 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 shall not be included in the 50 percent.
(3) 
If subsection (1) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this article.
(Ord. 524 § 5.4, 2004)
Shallow flooding areas appear on FIRMs as AO zones with depth designations. The base flood depths in these zones range from one to three feet above ground where a clearly defined channel does not exist, or where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as sheet flow. In these areas, the following provisions apply:
(1) 
New construction and substantial improvements of residential structures and manufactured homes within AO zones shall have the lowest floor (including basement) elevated above the highest adjacent grade to the structure, one foot or more above the depth number specified in feet on the community’s FIRM (at least two feet above the highest adjacent grade to the structure if no depth number is specified).
(2) 
New construction and substantial improvements of nonresidential structures within AO zones shall either:
(a) 
Have the lowest floor (including basement) elevated above the highest adjacent grade of the building site, one foot or more above the depth number specified on the FIRM (at least two feet if no depth number is specified); or
(b) 
Together with attendant utility and sanitary facilities, be completely floodproofed to or above that 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. If this method is used, compliance shall be certified by a registered professional engineer or architect as in CMC § 15.08.150(2)(c).
(3) 
Require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.
(4) 
Recreational vehicles placed on sites within AO zones on the community’s FIRM either:
(a) 
Be on the site for fewer than 180 consecutive days;
(b) 
Be fully licensed and ready for highway use, on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions; or
(c) 
Meet the requirements of subsections (1) and (3) of this section and the anchoring requirements for manufactured homes (CMC § 15.08.140(1)(b)).
(Ord. 524 § 5.5, 2004)
Construction of new critical facilities shall be, to the extent possible, located outside the limits of the Special Flood Hazard Area (SFHA) (100-year floodplain). Construction of new critical facilities shall be permissible within the SFHA if no feasible alternative site is available. Critical facilities constructed within the SFHA shall have the lowest floor elevated three feet or to the height of the 500-year flood, whichever is higher. Access to and from the critical facility should also be protected to the height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be displaced by or released into floodwaters. Access routes elevated to or above the level of the base flood elevation shall be provided to all critical facilities to the extent possible.
(Ord. 524 § 5.6, 2004)