40.420.010    Introduction

A.    Purpose.

    The purpose of this chapter is to safeguard public health, safety and welfare by placing limitations on development in areas susceptible to flood waters consistent with the requirements of the Growth Management Act and WAC 365-190-080.

(Amended: Ord. 2005-04-15; Ord. 2012-07-15; Ord. 2018-01-03)

B.    Applicability.

1.    This chapter applies to all development in identified special flood hazard areas within the jurisdiction of Clark County. After the adoption of this chapter, no structure shall hereafter be constructed, substantially improved, located, extended, converted, or replaced, nor any land altered without full compliance with the terms of this chapter and other applicable regulations.

2.    This chapter is not intended to repeal or impair any existing easements, covenants or deed restrictions.

3.    Where this chapter and another code or ordinance conflict or overlap, that which imposes the more stringent restrictions shall prevail.

4.    In the interpretation and application of this chapter, all provisions shall be:

a.    Considered as minimum requirements;

b.    Liberally construed to achieve the purposes of this chapter; and

c.    Deemed neither to limit nor repeal any other powers granted under state statutes.

5.    Federal Flood Insurance Program. Council assures the Federal Insurance Administration that it will take legislative action needed to meet the requirements of the National Flood Insurance Regulations and will take such other appropriate official actions as may be reasonably necessary to carry out the requirements of the program.

(Amended: Ord. 2005-04-15; Ord. 2009-03-02; Ord. 2012-07-15; Ord. 2018-01-03; Ord. 2019-05-07)

C.    Definitions.

    For purposes of this chapter, the following definitions shall apply:

Base flood

“Base flood” means the flood having a one percent (1%) chance of being equaled or exceeded in any given year and is also referred to as the one-hundred-year (100-year) flood.

Base flood elevation

“Base flood elevation” means the height in relation to the North American Vertical Datum (NAVD) 1988 expected to be reached by the waters of the base flood at pertinent points in the floodplains of coastal and riverine areas.


“Basement” means any area of the building having its floor subgrade below ground level on all sides.

Critical facility

“Critical facility” means the following:

•    Structures or facilities that produce, use or store highly volatile, flammable, explosive, toxic and/or water-reactive materials;

•    Hospitals, nursing homes, and housing likely to contain occupants who may not be sufficiently mobile to avoid death or injury during a flood;

•    Police stations, fire stations, vehicle and equipment storage facilities, and emergency operations centers that are needed for flood response activities before, during and after a flood; and

•    Public and private utility facilities that are vital to maintaining or restoring normal services to flooded areas before, during, and after a flood.


“Development” means, in addition to the definition in Section 40.100.070:

•    Storage of equipment and materials.

Elevation certificate

“Elevation certificate” means the official form (FEMA 81-31) used to record the elevation of a structure on a given property relative to the NAVD 1988.


“Encroachment” means the intrusion of any building, structure, vegetation, fill, excavation, or other development or use into a special flood hazard area which may impede or alter the flow through or storage capacity of a special flood hazard area.


“FEMA” means the Federal Emergency Management Agency.

Flood or flooding

“Flood” or “flooding” means a general and temporary condition of partial or complete inundation of normally dry land areas from:

•    The overflow of inland waters, and/or

•    The unusual and rapid accumulation of runoff of surface waters from any source.

Flood Insurance Rate Maps

“Flood Insurance Rate Maps” (FIRMs) mean the official map on which the Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the county.

Flood Insurance Study

“Flood Insurance Study” means an official report published by FEMA in conjunction with the community’s Flood Insurance Rate Maps (FIRMs). The study contains such background data as the base flood discharges and water surface elevations that were used to prepare the FIRMs.


“Floodproofing” means any combination of structural and nonstructural additions, changes or adjustments to properties and structures which reduce or eliminate flood damages to lands, water and sanitary facilities, and structures and their contents.


“Floodway” means the channel of a river or other watercourse and adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one (1) foot.

Lowest floor

“Lowest floor” means the lowest floor of the lowest enclosed area (including the basement). An unfinished or flood-resistant enclosure usable solely for parking of vehicles or for 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 the applicable nonelevation design requirements of Section 40.420.020(E)(1)(b).

Special flood hazard area, or floodplain

“Special flood hazard area” or “floodplain” means any land area subject to a one percent (1%) or greater chance of flooding in any given year.

Start of construction

“Start of construction” means, in addition to the definition in Section 40.100.070, for a substantial improvement, the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.


“Structure” means, in addition to the definition in Section 40.100.070:

•    A gas or liquid storage tank that is principally above ground;

•    A manufactured home.

Substantial damage

“Substantial damage” means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed fifty percent (50%) of the market value of the structure before the damage occurred.

Substantial improvement

“Substantial improvement” means any repair, reconstruction, or improvement of a structure, the cost of which is equal to or greater than fifty percent (50%) of the market value of the structure either:

•    Before the improvement or repair is started; or

•    If the structure has been damaged and is being restored, before the damage occurred.

Substantial improvement can exclude:

•    Any project for improvement of a structure to correct pre-cited existing violations of state or local health, sanitary, or safety code specifications which have been identified by a code enforcement official and which are the minimum necessary to assure safe living conditions; or

•    Any alteration of a structure listed on the National Register of Historic Places or the Clark County Heritage Register.

(Amended: Ord. 2005-04-15; Ord. 2012-07-15; Ord. 2018-01-03)

D.    Flood Insurance Study and Maps.

1.    The areas of special flood hazard identified by the Federal Emergency Management Agency (FEMA) in a report entitled “Flood Insurance Study, Clark County, Washington and Incorporated Areas” (FIS), effective January 19, 2018, and accompanying Flood Insurance Rate Maps (FIRMs) and any revisions thereto are hereby adopted by reference. The FIS and the FIRMs are on file with the Public Works Department.

2.    For the FIS and the FIRMs, the vertical datum was converted from the National Geodetic Vertical Datum of 1929 (NGVD29) to the North American Vertical Datum of 1988 (NAVD88). In addition, the Transverse Mercator, State Plane coordinates, previously referenced to the North American Datum of 1927 (NAD27), are now referenced to the North American Datum of 1983 (NAD83).

3.    The best available information for flood hazard area identification as outlined in Section 40.420.030(D)(6)(c) shall be the basis for regulation until new information is incorporated into the FIRMs.

(Amended: Ord. 2012-07-15; Ord. 2018-01-03)

E.    Warning and Disclaimer of Liability.

    The degree of flood protection required by this chapter is considered reasonable for regulatory purposes, and is based upon scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside special flood hazard areas, or uses permitted within such areas, will be free from flooding or flood damages. This chapter shall not create liability on the part of Clark County, any officer or employee thereof, or the Federal Emergency Management Agency for any flood damages that result from reliance on this chapter or any administrative decision made thereunder.

(Amended: Ord. 2005-04-15; Ord. 2012-07-15; Ord. 2018-01-03)