Chapter 18.70 — FLOOD HAZARD (FH) ZONE

The FH zone is an overlay zone and is applied in combination with principal zones to minimize or avoid hazards to life and property from flooding in the special flood hazard areas established by the Federal Emergency Management Agency (FEMA), and in other areas of significant flood hazard designated by the county. The FH zone is consistent with all general plan land use designations.

(Ord. 236-73 Exh. A(part), 1991)

The regulations set out in this chapter shall apply in all FH zones, and shall supersede conflicting or less restrictive regulations of the zones which they overlay. The FH zone includes all areas designated "Zone A, AE, AH, AO, Al-30, or A99" on the adopted flood insurance rate maps and any amendments thereto, and may be additionally applied to other areas of significant flood hazard designated on the zoning maps by the county.

(Ord. 236-73 Exh. A(part), 1991)

The adoption of this ordinance does not imply that land outside the FH zone will be free from flooding or flood damages. Larger floods can occur and flood heights can be increased by man-made or natural causes. This chapter shall not create liability on the part of the county or any person for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.

(Ord. 236-73 Exh. A(part), 1991)

The words and phrases set out in this section shall have the designated meanings in this chapter.

A.

"Area of shallow flooding" means the designation AO or AH on the flood insurance rate map. The base flood depths range from one to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and undetermined; and velocity flow may be evident.

B.

"Base flood" means the flood having a one percent chance of being equalled or exceeded in any given year (also called the "100-year flood").

C.

"Basement" means any area of the building having its floor subgrade (below ground level) on all sides.

D.

"Development" means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation, or drilling operations located within the area of special flood hazard.

E.

"Flood or flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of floodwaters, and/or the unusual and rapid accumulation or runoff of surface waters from any source.

F.

"Flood Boundary Map" means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated the areas of flood hazard.

G.

"Flood insurance rate map (FIRM)" means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the special flood hazard areas and the risk premium zones applicable to the community.

H.

"Flood Insurance Study" means the official report provided by the Federal Insurance Administration that includes flood profiles, the FIRM, the Flood Boundary Map, and the water surface elevation of the base flood. Each flood insurance study which accompanies an adopted FIRM shall be hereby adopted by reference.

I.

"Flood plain or flood-prone area" means any land area susceptible to being inundated by water from any source (see "flooding").

J.

"Flood plain administrator" means the county official responsible for carrying out the duties associated with the permit for which an application has been made.

K.

"Floodproofing" means any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents. A floodproofed structure means that below the base flood

level the structure is watertight with walls substantially impermeable to the passage of water, and structural components are capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

L.

"Lowest floor" means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access, or storage in an area other than a basement area is not considered a building's lowest floor; provided, that such enclosure is not built so as to render the structure in violation of applicable non-elevation design requirements of this title.

M.

"Manufactured dwelling" also includes camp trailers, travel trailers and other similar vehicles when placed on a site for more than one hundred eighty consecutive days.

N.

"Manufactured dwelling park or subdivision" means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for sale or rent.

O.

"Mean sea level" means, for purposes of the National Flood Insurance Program, the National Geodetic Vertical Datum (NGVD) of 1929 or other datum to which base flood elevations shown or a community's flood insurance rate map are referenced.

P.

"New construction" means structures for which the "start of construction" commenced on or after the effective date of a flood plain regulation adopted by the county.

Q.

"One hundred year flood" or "100-year flood". See Base flood.

R.

"Start of construction" includes substantial improvement, and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement, or other improvement was within one hundred eighty days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured dwelling on a foundation. Permanent construction does not include (1) land preparation, such as clearing, grading and filling, (2) installation of streets or walkways, (3) excavation for a basement, footings, piers, or foundations or the erection of temporary forms, or (4) installation of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure.

S.

"Special flood hazard area" means an area having special flood hazards, shown on the FIRM as Zone A, AE, AO, Al-30, or A99, and is equivalent to the FH zone.

T.

"Structure" means a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured dwelling.

U.

"Substantial improvement" means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds fifty percent of the market value of the structure (1) before the improvement or repair is started, or (2) if the structure has been damaged, and is being restored, before the damage occurred. "Substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. "Substantial improvement" does not include (1) any project for improvement of a structure to comply with existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions, or (2) any alteration of a structure listed on the National Register of Historic Places or a state inventory of historic places.

(Ord. 236-73 Exh. A(part), 1991)

Applications for building permits and all land use entitlements in the FH zone shall include plans and specifications for all proposed construction and the following:

A.

Proposed elevation in relation to mean sea level of the lowest floor (including basement) of all structures.

B.

Proposed elevation in relation to mean sea level to which any structure will be floodproofed.

C.

Location and type of drainage facilities, amount of fill or storage, and the extent to which any watercourse will be altered or relocated.

D.

All appropriate certifications required by this chapter.

E.

Subdivision and use permit applications shall identify the flood hazard area and elevation of the base flood.

F.

Any other information deemed necessary by the building or planning department in order to carry out the purposes of this chapter, and as necessary to make the determinations required by this chapter.

(Ord. 236-73 Exh. A(part), 1991)

A.

Findings: No building permit or other land use entitlement shall be granted unless the approving body makes the following findings:

That the requirements in Section 18.70.070 have been met.

That the development is reasonably safe from flooding.

Drainage has been designed to reduce exposure of proposed and anticipated development to flood hazards.

That all subdivision and use permit proposals are consistent with the need to minimize flood damage.

B.

Use of other base flood data: When base flood elevation data has not been provided by FEMA, the flood plain administrator shall obtain, review, and reasonably utilize the best data available from any source, including high water marks, floods of record and private engineering reports.

C.

Elevation certificates: The flood plain administrator shall obtain and maintain the elevation certifications necessary to confirm that the elevation requirements in Section 18.70.070 have been met.

D.

Watercourse modification: The flood plain administrator shall notify adjacent communities and the Department of Water Resources prior to any permitted alteration or relocation of a watercourse.

(Ord. 236-73 Exh. A(part), 1991)

All uses in the FH zone shall comply with the following standards and restrictions:

A.

Other permits. All permits from governmental agencies whose approval of development in the FH zone is required by federal or state law shall be obtained prior to commencement of any construction or installation of any structure, water supply or sewage disposal system.

B.

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

C.

Construction materials and methods. All construction materials shall be resistant to flood damage, construction methods and practices which will minimize flood damage shall be used, and all public utilities shall be located and constructed to minimize flood damage.

D.

Sewage disposal and water supply. All new and replacement water supply and sewage disposal systems shall be designed and installed to prevent infiltration from and discharge into floodwaters.

E.

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

F.

Elevation of residential structures. For all residential structures or substantial improvements to existing residential structures:

In FIRM Zone AH or AO: The lowest floor, including the basement, shall be elevated above the highest adjacent grade or at least as high as the depth number specified in feet on the FIRM, or at least two feet if no depth number is specified, and certified as such by a registered professional engineer or surveyor, or verified by the flood plain administrator as being properly elevated.

In FIRM Zone A, AE, A1-30, or A99: The lowest floor, including the basement, shall be at or above the base flood elevation, and certified as such by a registered professional engineer or surveyor, or verified by the flood plain administrator as being properly elevated.

G.

Elevation of nonresidential structures. Nonresidential construction shall either be elevated in conformance with subsection F, or shall be floodproofed below the base flood level and certified as such by a registered professional engineer or architect.

H.

Enclosed areas below lowest floor. For all new construction and substantial improvements, 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.

I.

Manufactured dwellings in manufactured dwelling parks or subdivisions.

When a manufactured dwelling located in an existing manufactured dwelling park or manufactured dwelling subdivision is damaged as the result of a flood, requiring substantial improvement or replacement, all future placements or substantial improvements on that site shall be elevated to or above the base flood elevation. The elevation shall be certified by a registered professional engineer or surveyor.

All other manufactured dwellings placed or substantially improved in existing manufactured dwelling parks or subdivisions must be elevated on reinforced piers or other foundation elements that are at least three feet in height above grade or have their lowest floor at or above the base flood elevation if this allows for a lower foundation. The flood elevation shall be certified by a registered professional engineer or surveyor.

J.

Subdivisions and use permits. When the base flood elevation is not provided by FEMA, subdivision and use permit applications shall provide the location of the flood hazard area and the elevation of the base flood. Final subdivision and use permit plans shall provide the elevation of the proposed structure(s) and pads, and if the site is filled above the base flood elevation, the final pad elevation shall be certified by a registered professional engineer or surveyor.

K.

Watercourse alteration or relocation. No work that alters or relocates any portion of a watercourse shall diminish the flood carrying capacity of the altered or relocated portion of the watercourse.

(Ord. 236-73 Exh. A(part), 1991)

Any person may appeal the decision of the flood plain administrator as provided in Chapter 18.144. Notice of hearing shall be given as provided in Section 18.140.060, or if the appeal is heard in conjunction with a decision on a proposed land use entitlement, the appeal may follow the same procedures as an appeal to the land use entitlement being considered. In granting an appeal the factors in subsection C of Section 18.70.100 shall be considered.

(Ord. 236-73 Exh. A(part), 1991)

In interpreting the provisions of this chapter, the flood plain administrator may on his or her own motion allow modifications or exceptions, provided that the flood plain administrator assumes the responsibilities of the planning commission under subsections C through F of Section 18.70.100.

(Ord. 236-73 Exh. A(part), 1991)

A.

Application. Applications for variances from the provisions of this chapter shall be made pursuant to Chapter 18.132 and this section.

B.

Variances permitted.

Variances may be issued for new construction and substantial improvements and for other development necessary for the conduct of uses requiring proximity to water, provided that the provisions of this section are met and the structure or other development is protected by methods that minimize flood damages during the base flood and create no additional threats of public safety.

Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, provided the factors in subsection C of this section have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases.

C.

Factors to be considered. In making a determination, the commission (or appellate body) shall consider all technical evaluations, all relevant factors and standards specified in this chapter, and the following:

The danger that materials may be swept into other lands and injure others.

The danger to life and property due to flooding.

The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner.

The importance of the services provided by the proposed facility to the community.

The necessity to the facility of a waterfront location, where applicable.

Availability of alternative locations for the proposed use which are not subject to flood damage.

Compatibility of the proposed use with existing and anticipated development.

The relationship of the proposed use to the general plan and flood plain management program for that area.

Safety of access to the property in time of flood for ordinary and emergency vehicles.

The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters expected at the site.

The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, electrical, and water systems, and streets and bridges.

D.

Findings. In addition to the findings in Chapter 18.132, no variance shall be granted unless the planning commission finds that: (1) the variance allowed is the minimum necessary, considering the flood hazard, to afford relief, and (2) the granting of a variance will not result in increased flood heights, additional threats to

public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances.

E.

Conditions. In granting a variance the planning commission may attach conditions deemed necessary to further the purposes of this chapter and this title.

F.

Effect of Action. An applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with the lowest floor elevation below the base flood elevation and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation. A copy of the notice shall be directed to be recorded by the flood plain administrator in the office of the county recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

(Ord. 236-73 Exh. A(part), 1991)