Chapter 18.12
FLOODPLAIN MANAGEMENT
Sections:
Article I. General Provisions
18.12.010 Statutory authority.
18.12.020 Findings of fact.
18.12.030 Purpose.
18.12.040 Methods of reducing flood losses.
18.12.050 Definitions—Alphabetical listing.
18.12.060 Applicability.
18.12.070 Basis for establishing the areas of special flood hazard.
18.12.080 Compliance required.
18.12.090 Abrogation and greater restrictions.
18.12.100 Interpretation.
18.12.110 Warning and disclaimer of liability.
Article II. Administration
18.12.120 Development permit required.
18.12.130 City planner—Designated.
18.12.140 City planner—Duties.
18.12.150 Use of other base flood data.
18.12.160 Information to be obtained and maintained.
18.12.170 Alteration of watercourses.
18.12.180 Interpretation of FIRM boundaries.
Article III. Variances
18.12.190 Criteria.
18.12.200 Conditions for issuance.
Article IV. Flood Hazard Reduction
18.12.210 General standards.
18.12.220 Anchoring.
18.12.230 Construction materials and methods.
18.12.240 Utilities.
18.12.250 Subdivision and mobile home park proposals.
18.12.260 Review of building permits.
18.12.270 Specific standards.
18.12.280 Residential construction.
18.12.285 AE and A1-30 zones with base flood elevations but no floodways.
18.12.290 Nonresidential construction.
18.12.295 Standards for shallow flooding areas (AO zones).
18.12.300 Manufactured homes.
18.12.305 Recreational vehicles.
18.12.310 Accessory structures.
18.12.315 Critical facility.
18.12.320 Floodways.
Article I. General Provisions
18.12.010 Statutory authority.
The Legislature of the state has in RCW 35.63.080 delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety and general welfare of its citizenry. Therefore, the city, county and state ordain as set forth in this chapter. (Ord. 3627 § 1, 2006; prior code § 15.12.010)
18.12.020 Findings of fact.
A. The flood hazard areas of the city are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.
B. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazard which increase flood heights and velocities, and when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed, elevated or otherwise protected from flood damage also contribute to the flood loss. (Ord. 3627 § 1, 2006; prior code § 15.12.020)
18.12.030 Purpose.
It is the purpose of this chapter to promote the public health, safety and general welfare, and to minimize public and private losses due to flood conditions in specific areas by provisions designed:
A. To protect human life;
B. To minimize expenditure of public money and costly flood-control projects;
C. To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;
D. To minimize prolonged business interruption;
E. To minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, and streets and bridges located in areas of special flood hazard;
F. To help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard;
G. To ensure that potential buyers are notified that property is in an area of special flood hazard;
H. To ensure that those who occupy the areas of special flood hazard assume responsibility for their actions;
I. To implement the Washington State Flood Control Zone Permit Program pursuant to the requirements of RCW 86.16.060 and Chapter 508-60 WAC;
J. To fully implement the Flood Damage Prevention Program requirements of the Department of Housing and Urban Development’s (HUD) Federal Flood Insurance Program. (Ord. 3627 § 1, 2006; prior code § 15.12.030)
18.12.040 Methods of reducing flood losses.
In order to accomplish its purpose, this chapter includes methods and provisions for:
A. Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;
B. Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;
C. Controlling the alteration of natural floodplains, stream channels and natural protective barriers, which help accommodate or channel floodwaters;
D. Controlling filling, grading, dredging and other development which may increase flood damage; and
E. Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. (Ord. 3627 § 1, 2006; prior code § 15.12.040)
18.12.050 Definitions—Alphabetical listing.
Unless specifically defined in this section, words or phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application:
“Accessory building” means a detached subordinate building, the use of which is incidental to that of the main building on the same lot and which does not change or alter the character of the premises.
“Appeal” means a request for a review of the board of appeals interpretation of any provision of this chapter or a request for a variance.
“Area of shallow flooding” means an area designated AO or AH zone on the Flood Insurance Rate Map (FIRM). AO zones have base flood depths that range from one to three feet above the natural ground; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and velocity flow may be evident. AO is characterized as sheet flow; AH indicates ponding, and is shown with standard base flood elevations.
“Area of special flood hazard” means the land in the floodplain within a community subject to a one percent or greater chance of flooding in any given year. These areas are always designated on Flood Insurance Rate Maps by the letters A or V.
“Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year (also referred to as the “one-hundred-year flood”). These areas are designated on Flood Insurance Rate Maps by the letters A or V.
“Basement” means any area of the building having its floor sub-grade (below ground level) on all sides.
“Breakaway wall” means a wall that is not part of the structural support of the building and is intended through its design and construction to collapse under specific lateral loading forces, without causing damage to the elevated portion of the building or supporting foundation system.
“Critical facility” means a facility for which even a slight chance of flooding might be too great. Critical facilities include, but are not limited to, schools, nursing homes, hospitals, police, fire and emergency response installations, and installations which produce, use or store hazardous materials or hazardous waste.
“Cumulative substantial damage” means flood-related damages sustained by a structure on two separate occasions during a ten-year period for which the cost of repairs at the time of each such flood event, on the average, equals or exceeds twenty-five percent of the market value of the structure before the damage occurred.
“Development” means any manmade 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, or storage of equipment or materials located within the area of special flood hazard.
“Elevation Certificate” means the official form (FEMA Form 81-31) used to track development, provide elevation information necessary to ensure compliance with community floodplain management ordinances, and determine the proper insurance premium rate with Section B completed by community officials.
“Existing manufactured home park or subdivision” means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed is completed before the effective date of the adopted floodplain management regulations, including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads.
“Expansion of an existing manufactured home park or subdivision” means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed, including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads.
“Flood” or “flooding” means a general and temporary condition of partial or complete inundation of normally dry land from:
1. The overflow of inland or tidal waters; and/or
2. The unusual and rapid accumulation of runoff of surface water from any source.
“Flood fringe” means the area adjoining the floodway which would be covered by floodwater during a base flood.
“Flood Insurance Rate Map (FIRM)” means the official map on which the Federal Insurance Administration has delineated both the areas of special flood hazard and the risk premium zones applicable to the community.
“Flood insurance study” means the official report provided by the Federal Insurance Administration that includes flood profiles, the Flood Insurance Rate Maps (FIRM), and the water surface elevation of the base flood.
“Floodplain” means those areas of the city which are subject to inundation by the base flood of the Columbia River or its tributaries.
“Floodway” means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.
“Habitable floor” means any floor usable for living purposes, which includes working, sleeping, eating, cooking or recreation, or a combination thereof.
“Lowest floor” means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood-resistant enclosure, usable solely for vehicle parking, building access or storage, in an area other than a basement area, is not considered a building’s lowest floor; provided, that such an enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements found at Section 18.12.290 of this chapter (i.e., provided there are adequate flood ventilation openings).
“Manufactured home” means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term “manufactured home” also includes park trailers, travel trailers and similar vehicles placed on a site for greater than one hundred eighty consecutive days. For flood insurance purposes, the term “manufactured home” does not include park trailers, travel trailers and other similar vehicles.
“Manufactured home park or subdivision” means a parcel, or contiguous parcels of land divided into two or more manufactured home lots for rent or sale.
“Mean sea level” means the average height of the sea for all stages of the tide. All elevations are referenced to the National Geodetic Vertical Datum of 1929 (NGVD).
“New construction” means structures for which “start of construction” commenced on or after the effective date of the ordinance codified in this chapter.
“Recreational vehicle” means a vehicle which is:
1. Built on a single chassis;
2. Four hundred square feet or less when measured at the largest horizontal projection;
3. Designed to be self-propelled or permanently towable by a light-duty truck; and
4. Designed primarily not for use as a permanent dwelling, but as temporary living quarters for recreational, camping, travel or seasonal use.
“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 such as the pouring of slabs or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land reparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a “substantial improvement” as defined below, the actual “start of construction” means the first alteration of any wall, ceiling, floor, or other structural part of the building, whether or not that alteration affects the external dimensions of the building.
“Structure” means, for the purposes of this chapter, a walled and roofed building, including a gas or liquid storage tank that is principally above ground.
“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 either:
1. Before the improvement or repair is started; or
2. If the structure has been damaged and is being restored, before the damage occurred. For the purposes of this definition, “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, however, include either:
a. Any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which have been previously identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or
b. Any alteration of a structure listed on the National Register of Historic Places or a State Inventory of Historic Places.
“Variance” means a grant of relief from the requirements of this chapter which permits construction in a manner that would otherwise be prohibited by this chapter.
“Water dependent” means a structure for commerce or industry that cannot exist in any other location and is dependent on the water by reason of the intrinsic nature of its operations. (Ord. 3627 § 1, 2006; Ord. 3486 § 1, 2001; Ord. 3077 § 1, 1987; prior code § 15.12.050)
18.12.060 Applicability.
This chapter shall apply to all areas of special flood hazard within the city. (Ord. 3627 § 1, 2006; prior code § 15.12.060)
18.12.070 Basis for establishing the areas of special flood hazard.
The areas of special flood hazard identified by the Federal Insurance Administration and recognized by the State Department of Ecology (DOE) in a scientific and engineering report entitled “Flood Insurance Study for the City of Kelso, Washington,” dated December 20, 2001, and any revisions thereto, with accompanying Flood Insurance Rate Maps (FIRM), and any revisions thereto, are hereby adopted by reference and declared to be a part of this chapter. The flood insurance study and the FIRM are on file at Kelso City Hall, 203 S. Pacific Avenue, Kelso, Washington, 98626. The best available information for flood hazard area identification as outlined in Section 18.12.150 of this chapter shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under Section 18.12.150 of this chapter. (Ord. 3627 § 1, 2006; Ord. 3486 § 3, 2001; Ord. 3219 § 1, 1993; prior code § 15.12.070)
18.12.080 Compliance required.
No structure or land within the areas of special flood hazard shall hereafter be constructed, located, extended, converted, altered or divided without full compliance with the terms of this chapter and other applicable regulations. Any violation or failure to comply with the terms of this chapter shall constitute a misdemeanor making the violator subject to the penalties prescribed for other misdemeanors in the city. A conviction under this code does not relieve the violator from compliance with provisions of this chapter. (Ord. 3627 § 1, 2006; prior code § 15.12.080)
18.12.090 Abrogation and greater restrictions.
This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants or deed restrictions. However, where this chapter and another ordinance, easement, covenant or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail. (Ord. 3627 § 1, 2006; prior code § 15.12.090)
18.12.100 Interpretation.
In the interpretation and application of this chapter, all provisions shall be:
A. Considered as minimum requirements;
B. Liberally construed in favor of the governing body; and
C. Neither to limit nor repeal any other powers granted under state statutes. (Ord. 3627 § 1, 2006; prior code § 15.12.100)
18.12.110 Warning and disclaimer of liability.
The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on 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 the areas of special flood hazard or uses permitted within such will be free from flooding or flood damages. This chapter shall not create liability on the part of the city, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder. (Ord. 3627 § 1, 2006; prior code § 15.12.110)
Article II. Administration
18.12.120 Development permit required.
A. A development permit shall be obtained before construction or development begins within any area of special flood hazard established in Section 18.12.070 of this chapter. This permit shall be for all structures, including mobile homes, as set forth in the definitions in Section 18.12.050 of this chapter, and for all other development including fill and dike buildings, and other activities, also as set forth in the definitions in Section 18.12.050 of this chapter. Application for a development permit shall be made on forms furnished by the building inspector and may include, but not be limited to, plans in duplicate drawn to scale showing the nature, location, dimensions and elevations of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities; and the location of the foregoing.
B. Specifically, the following information is required:
1. Elevation in relation to mean sea level of the lowest habitable floor (including basements) of all structures;
2. Elevation in relation to mean sea level to which any structure has been floodproofed;
3. Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria in Section 18.12.290 of this chapter; and
4. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development. (Ord. 3627 § 1, 2006; Ord. 3077 § 2, 1987; prior code § 15.12.130)
18.12.130 City planner—Designated.
The city planner is appointed to administer and implement this chapter by granting or denying development flood permit applications in accordance with its ordinance procedures. (Ord. 3627 § 1, 2006; Ord. 3077 § 3, 1987; prior code § 15.12.140)
18.12.140 City planner—Duties.
Duties of the city planner shall include, but not be limited to:
A. Review all flood zone “A” development permit applications to determine that the permit requirements of this chapter have been satisfied;
B. To determine that all necessary permits have been obtained from those federal, state or local governmental agencies from which prior approval is required. A permit may be issued on the condition that the specified state or federal permits are subsequently obtained;
C. To determine if the proposed development is located in the floodway. If located in the floodway, assure that the encroachment provisions of Section 18.12.320A of this chapter are met;
D. Process all development permit applications within thirty days of receipt of such application;
E. Fees. As a condition precedent to the processing of a floodplain development permit application, the applicant shall pay a permit processing fee to the city clerk in an amount established by council resolution. (Ord. 3627 § 1, 2006; Ord. 3171 § 11, 1991; Ord. 3077 § 4, 1987; prior code § 15.12.150)
18.12.150 Use of other base flood data.
When base flood elevation data has not been provided in accordance with Section 18.12.070 of this chapter, the city planner shall obtain, review and reasonably utilize any base flood elevation data available from a federal, state or other source, in order to administer Sections 18.12.280 and 18.12.290 of this chapter. (Ord. 3627 § 1, 2006; Ord. § 5, 1987; prior code § 15.12.160)
18.12.160 Information to be obtained and maintained.
The building inspector shall:
A. Where base flood elevation data is provided through the Flood Insurance Study (FIS), FIRM, or required as in Section 18.12.150 of this chapter, obtain and record the actual as-built elevation (in relation to mean sea level) of the lowest floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.
B. For all new or substantially improved floodproofed nonresidential structures where base flood elevation data is provided through the FIS, FIRM, or as required in Section 18.12.150 of this chapter:
1. Obtain and record the actual elevation (in relation to mean sea level) to which the structure was floodproofed;
2. Maintain the floodproofing certifications required in Section 18.12.120 of this chapter;
C. Maintain for public inspection all records pertaining to the provisions of the ordinance codified in this chapter. (Ord. 3627 § 1, 2006; Ord. 3077 § 6, 1987; prior code § 15.12.170)
18.12.170 Alteration of watercourses.
The building inspector shall:
A. Notify adjacent communities and the Department of Ecology prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration;
B. Require that maintenance is provided within the altered or relocated portion of such watercourse so that the flood carrying capacity is not diminished. (Ord. 3627 § 1, 2006; prior code § 15.12.180)
18.12.180 Interpretation of FIRM boundaries.
The building inspector shall make interpretations where needed as to exact location of the boundaries of the areas of special flood hazard (for example, where there appears to be a conflict between a mapped boundary and actual field conditions). The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in Sections 18.12.190 and 18.12.200 of this chapter. (Ord. 3627 § 1, 2006; Ord. 3607 § 1, 2006; prior code § 15.12.190)
Article III. Variances
18.12.190 Criteria.
A. The board of appeals as established by the city shall hear and decide appeals and requests for variances from the requirements of this chapter.
B. The board of appeals shall hear and decide appeals when it is alleged there is an error in any requirement, decision or determination made by the city planner in the enforcement or administration of this chapter.
C. Those aggrieved by the decision of the board of appeals may appeal such decision to the superior court.
D. In passing upon such applications, the board of appeals shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:
1. The danger that materials may be swept into other lands to the injury of others;
2. The danger to life and property due to flooding or erosion damage;
3. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;
4. The importance of the services provided by the proposed facility to the community;
5. The necessity to the facility of a waterfront location, where applicable;
6. The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;
7. The compatibility of the proposed use with existing and anticipated development;
8. The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;
9. The safety of access to the property in times of flood for ordinary and emergency vehicles;
10. The expected heights, velocity, duration, rate of rise and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site; and
11. The cost of providing governmental services during the afterflood including maintenance and repair of public utilities and facilities such as sewer, gas, electrical and water systems, and streets and bridges.
E. Upon consideration of the factors of subsection D of this section and the purposes of this chapter, the board of appeals may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.
F. The city planner shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration or Department of Ecology upon request.
G. Fees. As a condition precedent to the processing of an application for a floodplain development permit variance or an appeal from the denial of a floodplain development permit request, the applicant shall pay a fee as established by council resolution. (Ord. 3627 § 1, 2006; Ord. 3619 § 1, 2006; Ord. 3607 § 1, 2006; Ord. 3171 § 12, 1991; Ord. 3077 § 7, 1987; prior code § 15.12.200)
18.12.200 Conditions for issuance.
A. Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places, without regard to the procedures set forth in the remainder of this section.
B. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.
C. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
D. Variances shall only be issued upon:
1. A showing of good and sufficient cause;
2. A determination that failure to grant the variance would result in exceptional hardship to the applicant; and
3. A determination that 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 as identified in Section 18.12.190D of this article, or conflict with existing local laws or ordinances.
E. Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with a 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.
F. Variances as interpreted in the National Flood Insurance Program are based on the general zoning law principle that they pertain to a physical piece of property; they are not personal in nature and do not pertain to the structure, its inhabitants, economic or financial circumstances. They primarily address small lots in densely populated residential neighborhoods. As such, variances from the flood elevations should be quite rare.
G. Variances may be issued for nonresidential buildings in very limited circumstances to allow a lesser degree of floodproofing than watertight or dry-floodproofing, where it can be determined that such action will have low damage potential, and complies with Sections 18.12.220 and 18.12.230 of this chapter. (Ord. 3627 § 1, 2006; Ord. 3077 § 8, 1987; prior code § 15.12.210)
Article IV. Flood Hazard Reduction
18.12.210 General standards.
In all areas of special flood hazard the standards set forth in Sections 18.12.220 through 18.12.260 of this article are required. (Ord. 3627 § 1, 2006; prior code § 15.12.220)
18.12.220 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 not be limited to, use of over-the-top or frame ties to ground anchors or other techniques as described in the Federal Emergency Management’s guidebook entitled, “Manufactured Home Installation in Flood Hazard Areas.”
C. An alternative method of anchoring may involve a system designed to withstand a wind force of ninety miles per hour or greater. Certification must be provided by a registered professional engineer or architect to the city planner that this standard has been met. (Ord. 3627 § 1, 2006; Ord. 3077 § 9, 1987; prior code § 15.12.230)
18.12.230 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. (Ord. 3627 § 1, 2006; prior code § 15.12.240)
18.12.240 Utilities.
A. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems;
B. Water wells shall be located on high ground that is not in the floodway (WAC 173-160-171);
C. New and replacement sanitary sewerage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters;
D. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding; and
E. 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 the conditions of flooding. (Ord. 3627 § 1, 2006; Ord. 3077 § 10, 1987; prior code § 15.12.250)
18.12.250 Subdivision and mobile home park proposals.
A. All subdivision and mobile home park proposals shall be consistent with the need to minimize flood damage.
B. All subdivision and mobile home park proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.
C. All subdivision and mobile home park proposals shall have adequate drainage provided to reduce exposure to flood damage.
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 development which contain at least fifty lots or five acres (whichever is less). (Ord. 3627 § 1, 2006; Ord. 3077 § 11, 1987; prior code § 15.12.260)
18.12.260 Review of building permits.
Where elevation data is not available either from the Flood Insurance Study or from another authoritative source (Section 18.12.150), 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 grade in these zones may result in higher insurance rates. (Ord. 3627 § 1, 2006; Ord. 3077 § 12, 1987; prior code § 15.12.270)
18.12.270 Specific standards.
In all areas of special flood hazard where base flood elevation data has been provided as set forth in Section 18.12.070 or 18.12.150 of this chapter, the provisions set forth in Sections 18.12.280 through 18.12.310 of this article are required. (Ord. 3627 § 1, 2006; prior code § 15.12.280)
18.12.280 Residential construction.
A. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated two feet or more above the base flood elevation (BFE).
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 floodwater. 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:
1. A minimum of two openings which have a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;
2. The bottom of all openings shall be no higher than one foot above grade;
3. Openings may be equipped with screens, louvers or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters. (Ord. 3627 § 1, 2006; Ord. 3077 § 13, 1987; prior code § 15.12.290)
18.12.285 AE and A1-30 zones with base flood elevations but no floodways.
In areas with base flood elevations, but where a regulatory floodway has not been designated, no new construction, substantial improvements, or other development, including infill, shall be permitted within zones AE and A1-30 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. 3627 § 1, 2006)
18.12.290 Nonresidential construction.
New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest habitable floor, elevated to the level of the base flood elevation; or, together with attendant utility and sanitary facilities, shall:
A. Be floodproofed so that below 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 certification shall be provided to the official as set forth in Section 18.12.160B;
D. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in Section 18.12.280;
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 constructed to the base flood level will be rated as one foot below that level). (Ord. 3627 § 1, 2006; Ord. 3077 § 14, 1987; prior code § 15.12.310)
18.12.295 Standards for shallow flooding areas (AO zones).
Shallow flooding areas appear on FIRMs as AO zones. 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:
A. 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, two feet or more above the depth number specified in feet on the community’s FIRM, or at least three and a half feet above the highest adjacent grade to the structure if no depth number is specified;
B. New construction and substantial improvements of nonresidential structures within AO zones shall either:
1. Have the lowest floor (including basement) elevated above the highest adjacent grade of the building site, two feet or more above the depth number specified on the FIRM, or at least three and a half feet above the highest adjacent grade to the structure if no depth number is specified; or
2. 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 specified in Section 18.12.290 of this chapter;
C. Require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures. (Ord. 3627 § 1, 2006)
18.12.300 Manufactured homes.
All manufactured homes 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 two feet or more above the base flood elevation and is securely anchored to an adequately anchored foundation system in accordance with the provisions of Section 18.12.220. This section applies to all manufactured homes:
A. In existing manufactured home parks or subdivisions;
B. In expansions to existing manufactured home parks or subdivisions;
C. In new manufactured home parks or subdivisions; and
D. Outside of a manufactured home park or subdivision. (Ord. 3627 § 1, 2006; Ord. 3077 § 15, 1987; prior code § 15.12.310)
18.12.305 Recreational vehicles.
Recreational vehicles placed on sites are required to either:
A. Be on the site for fewer than one hundred eighty consecutive days;
B. Be fully licensed and ready for highway use, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or
C. Meet the requirements of Sections 18.12.295 and 18.12.300 of this chapter. (Ord. 3627 § 1, 2006; Ord. 3486 § 2, 2001)
18.12.310 Accessory structures.
A. Accessory structures shall not be used for human habitation.
B. Accessory structures shall be designed to have low flood damage potential.
C. Accessory structures shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters.
D. Accessory structures shall be firmly anchored to prevent flotation which may result in damage to other structures.
E. Service facilities such as electrical and heating equipment shall be elevated above the base flood level or floodproofed. (Ord. 3627 § 1, 2006; prior code § 15.12.320)
18.12.315 Critical facility.
Construction of new critical facilities shall be, to the extent possible, located outside of the limits of the special flood hazard area (SFHA) (one-hundred-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 above the base flood elevation (BFE) or to the height of the five-hundred-year flood, whichever is higher. Access to and from the critical facility shall 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 BSE shall be provided to all critical facilities to the extent possible. (Ord. 3627 § 1, 2006)
18.12.320 Floodways.
Located within areas of special flood hazard established in Section 18.12.070 of this chapter 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:
A. 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.
B. Construction or reconstruction of residential structures is prohibited within designated floodways (WAC 173-158-070), except for:
1. Repairs, reconstruction or improvements to structures which do not increase the ground floor area; and
2. Repairs, reconstruction or improvements to the structure, provided the cost of such repairs, reconstruction or improvements do not exceed fifty percent of the market value of the structure, either (a) before the repair, reconstruction or improvement 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 fifty percent market value determination procedure.
C. If subsection A of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Sections 18.12.210 through 18.12.310 of this chapter. (Ord. 3627 § 1, 2006; Ord. 3486 § 4, 2001; Ord. 3113 § 1, 1989; prior code § 15.12.330)