Chapter 15.48
FLOOD DAMAGE PREVENTION
Sections:
15.48.020 Statement of purpose.
15.48.030 Methods of reduced flood losses.
15.48.050 Lands to which this chapter applies.
15.48.060 Basis for establishing the areas of special flood hazard.
15.48.070 Penalties for noncompliance.
15.48.080 Abrogation and greater restrictions.
15.48.100 Warning and disclaimer of liability.
15.48.110 Establishment of development permit.
15.48.120 Designation of the floodplain administrator.
15.48.130 Duties and responsibilities of the floodplain administrator.
15.48.170 Additional floodway requirements.
15.48.190 Standards for shallow flooding areas (AO zones).
15.48.010 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 hazards 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. 1543, 2024)
15.48.020 Statement of 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 and health;
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 interruptions;
E. To minimize damage to public facilities and utilities, such as water and gas mains, electric, telephone and sewer lines, 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 as to minimize future flood blight areas;
G. To ensure that potential buyers are notified that property is in area of special flood hazard;
H. To ensure that those who occupy the areas of special flood hazard assume responsibility for their actions; and
I. Participate in and maintain eligibility for flood insurance and disaster relief. (Ord. 1543, 2024)
15.48.030 Methods of reduced flood losses.
In order to accomplish its purposes, 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 protection barriers, which help accommodate 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 may increase flood hazards in other areas. (Ord. 1543, 2024)
15.48.040 Definitions.
Unless specifically defined in this section, words or phrases used in this chapter shall be interpreted as to give them the meaning they have in common usage and to give this chapter its most reasonable application.
“Accessory structure” means a structure on the same parcel of property as a principal structure and the use of which is incidental to the use of the principal structure. For floodplain management purposes, the term includes only accessory structures used for parking and storage.
“Alteration of watercourse” means any action that will change the location of the channel occupied by water within the banks of any portion of a riverine water body.
“Appeal” means a request for a review of the interpretation of any provision of this chapter or a request for a variance.
“Area of shallow flooding” means a designated AO, AH, AR/AO or AR/AH (or VO) on the flood insurance rate map (FIRM) with a one percent or greater annual chance of flooding. The base flood depths range from one to three feet; 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 and AH indicates ponding.
“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. It is shown on the flood insurance rate map (FIRM) as zone A, AO, AH, A1-30, AE, A99, AR (V, VO, V1-30, VE). “Special flood hazard area” is synonymous in meaning with the phrase “area of special flood hazard.”
“ASCE 24” means the most recently published version of ASCE 24, Flood Resistant Design and Construction, published by the American Society of Civil Engineers.
“Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year. Also referred as the one-hundred-year flood.
“Base flood elevation (BFE)” means the elevation to which floodwater is anticipated to rise during the base flood.
“Basement” means any area of the building having its flood subgrade (below ground level) on all sides.
Building. See “Structure.”
“Building Code” means the currently effective versions of the International Building Code and the International Residential Code adopted by the State of Washington Building Code Council.
“Critical facility” means a facility that 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.
“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 located within the area of special flood hazard.
“Elevation certificate” means an administrative tool of the National Flood Insurance Program (NFIP) that can be used to provide elevation information, to determine the proper insurance premium rate, and to support a request for a letter of map amendment (LOMA) or letter of map revision based on fill (LOMR-F).
“Elevated building” means, for insurance purposes, a nonbasement building which has its lowest level elevated floor raised above the ground level by foundation walls, shear walls, posts, piers, pilings or columns.
Essential Facility. This term has the same meaning as “essential facility” defined in ASCE 24. Table 1-1 in ASCE 24-14 further identifies building occupancies that are essential facilities.
“Existing manufactured home park or subdivision” means a manufactured home park subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the adopted floodplain management regulations.
“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).
“Farmhouse” means a single-family dwelling located on a farm site where resulting agricultural products are not produced for the primary consumption or use by the occupants and the farm owner.
“Flood” or “flooding” means:
1. A general and temporary condition of partial or complete inundation of normally dry land areas from:
a. The overflow of inland or tidal waters; and/or
b. The unusual and rapid accumulation of runoff of surface waters from any source.
c. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in subsection (1)(b) of this definition and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current.
2. The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in subsection (1)(a) of this definition.
“Flood elevation study” means an examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation and determination of mudslide (i.e., mudflow) and/or flood-related erosion hazards. Also known as a flood insurance study (FIS).
“Flood insurance rate map (FIRM)” means the official map on which the Federal Insurance Administrator has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. A FIRM that has been made available digitally is called a digital flood insurance rate map (DFIRM).
Flood Insurance Study. See “Flood elevation study.”
“Floodplain or flood-prone area” means any land area susceptible to being inundated by water from any source. See “Flood” or “flooding.”
“Floodplain administrator” means the community official designated by title to administer and enforce the floodplain management regulations.
“Floodplain management regulations” means zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as floodplain ordinance, grading ordinance and erosion control ordinance) and other application of police power. The term describes such state or local regulations, in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.
“Floodproofing” means any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate risk of flood damage to real estate or improved real property, water and sanitary facilities, structures, and their contents. Floodproofed structures are those that have the structural integrity and design to be impervious to floodwater below the base flood elevation.
“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 a designated height. Also referred to as “regulatory floodway.”
“Functionally dependent use” means a use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, and does not include long term storage or related manufacturing facilities.
“Highest adjacent grade” means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
“Historic structure” means any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the Department of the Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;
2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of the Interior; or
4. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:
a. By an approved state program as determined by the Secretary of the Interior, or
b. Directly by the Secretary of the Interior in states without approved programs.
“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 as to render the structure in violation of the applicable nonelevation design requirements of this chapter found at Section 15.48.160(A)(2).
“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 attached to the required utilities. The term “manufactured home” does not include a recreational vehicle.
“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, for purposes of the National Flood Insurance Program, the vertical datum to which base flood elevations shown on a community’s flood insurance rate map are referenced.
“New construction” means, for the purposes of determining insurance rates, structures for which the “start of construction” commenced on or after the effective date of an initial flood insurance rate map or after December 31, 1974, whichever is later, and includes any subsequent improvements to such structures. For floodplain management purposes, “new construction” means structures for which the “start of construction” commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures.
“New 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 (including at a minimum the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of adopted floodplain management regulations.
One-Hundred-Year Flood or 100-Year Flood. See “Base flood.”
“Reasonably safe from flooding” means development that is designed and built to be safe from flooding based on consideration of current flood elevation studies, historical data, high water marks and other reliable data known to the community. In unnumbered A zones where flood elevation information is not available and cannot be obtained by practicable means, “reasonably safe from flooding” means that the lowest floor is at least two feet above the highest adjacent grade.
“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 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 home on a foundation. Permanent construction does not include land preparation, 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 of the property or accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the “actual start of construction” means 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 a walled and roofed building, including a gas or liquid storage tank that is principally above the ground, as well as a manufactured home.
“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 of the market value of the structure before the damage occurred.
“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 before the “start of construction” of the improvement. This term includes structures which have incurred “substantial damage,” regardless of the actual repair work performed.
The term does not, however, include either:
1. Any project for improvement of a structure to correct previously identified with existing violations of state or local health, sanitary, or safety code specifications that have been identified by the local code enforcement officer and that are the minimum necessary to assure safe living conditions; or
2. Any alteration of a “historic structure”; provided, that the alteration will not preclude the structure’s continued designation as a “historic structure.”
“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 which cannot exist in any other location and is dependent on the water by reason of the intrinsic nature of its operations.
“Water surface elevation” means the height, in relation to the vertical datum utilized in the applicable flood insurance study of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas. (Ord. 1543, 2024)
15.48.050 Lands to which this chapter applies.
This chapter shall apply to all areas of special flood hazards within the jurisdiction of the city. (Ord. 1543, 2024)
15.48.060 Basis for establishing the areas of special flood hazard.
The areas of special flood hazard identified by the Federal Insurance Administrator in a scientific and engineering report entitled “The Flood Insurance Study (FIS) for Klickitat County, Washington and Incorporated Areas” dated November 18, 2024, and revisions thereto, with accompanying flood insurance rate maps (FIRMs) dated November 18, 2024, and any revisions thereto, are hereby adopted by reference and declared to be a part of this chapter. The FIS and the FIRM are on file at city of Goldendale, City Hall, 1103 S. Columbus, Goldendale, Washington. The best available information for flood hazard area identification as outlined in Section 15.48.130(B) shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under Section 15.48.130(B). (Ord. 1543, 2024)
15.48.065 Compliance.
All development within special flood hazard areas is subject to the terms of this chapter and other applicable regulations. (Ord. 1543, 2024)
15.48.070 Penalties for noncompliance.
No structure or land shall hereafter be constructed, located, extended, converted or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of the provisions of this chapter by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction thereof be fined not more than two thousand dollars or imprisoned for not more than ninety days, or both, for each violation, and in addition shall pay all costs and expenses involved in the case. Nothing contained in this section shall prevent the city from taking such other lawful action as is necessary to prevent or remedy any violation. (Ord. 1543, 2024)
15.48.080 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. 1543, 2024)
15.48.090 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. Deemed neither to limit nor repeal any other powers granted under state statutes. (Ord. 1543, 2024)
15.48.100 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 hazards or uses permitted within such areas 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 hereunder. (Ord. 1543, 2024)
15.48.105 Severability.
This chapter and the various parts thereof are hereby declared to be severable. Should any section of this chapter be declared by the courts to be unconstitutional or invalid, such decision shall not affect the validity of the chapter as a whole, or any portion thereof other than the section so declared to be unconstitutional or invalid. (Ord. 1543, 2024)
15.48.110 Establishment of development permit.
A. Development Permit Required. A development permit shall be obtained before construction or development begins within any area of special flood hazard established in Section 15.48.060. The permit shall be for all structures, including manufactured homes, as set forth in Section 15.48.040, Definitions, and for all development, including fill and other activities, also as set forth in Section 15.48.040, Definitions.
B. Application for Development Permit. Application for a development permit shall be made on forms furnished by the floodplain administrator 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. Specifically, the following information is required:
1. Elevation in relation to mean sea level of the lowest floor (including basement) 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 15.48.160(B); and
4. Description of the extent to which a watercourse will be altered or relocated as a result of proposed development;
5. Where development is proposed in a floodway, an engineering analysis indicating no rise of the base flood elevation; and
6. Any other such information that may be reasonably required by the floodplain administrator in order to review the application. (Ord. 1543, 2024)
15.48.120 Designation of the floodplain administrator.
The city planner or the mayor’s designee is appointed to administer and implement this chapter by granting or denying development permit applications in accordance with its provisions. (Ord. 1543, 2024)
15.48.130 Duties and responsibilities of the floodplain administrator.
Duties of the city planner or the mayor’s designee shall include, but not be limited to:
A. Permit Review.
1. Review all development permits to determine that the permit requirements of this chapter have been satisfied;
2. Review all development permits to determine that all necessary permits have been obtained from those federal, state, or local governmental agencies from which prior approval is required;
3. Review all development permits to determine if the proposed development is located in the floodway. If located in the floodway, assure that the encroachment provisions of Section 15.48.170(A) are met; and
4. Review all development permits to determine if the proposed building sites will be reasonably safe from flooding;
5. Notify FEMA when annexations occur in the special flood hazard area;
6. Notify FEMA of changes to the base flood elevation within six months of when technical information of such changes becomes available. Such notification shall include technical or scientific information;
B. Use of Other Base Flood Data (In A Zones). When base flood elevation data has not been provided in accordance with Section 15.48.060, Basis for establishing the areas of special flood hazard, the floodplain administrator shall obtain, review and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, in order to administer Sections 15.48.160, Specific standards, and 15.48.170, Additional floodway requirements.
C. Information to Be Obtained and Maintained.
1. Where base flood elevation data is provided through the FIS, FIRM, or required as in subsection B of this section, obtain and maintain 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.
2. For all new or substantially improved floodproofed nonresidential structures where base flood elevation data is provided through the FIS, FIRM, or as required in subsection B of this section:
a. Obtain and maintain a record of the actual elevation (in relation to mean sea level) to which the structure was floodproofed; and
b. Maintain the floodproofing certifications required in Section 15.48.110(B)(3).
3. Maintain for public inspection all records pertaining to the provisions of this chapter.
4. Certification required by Section 15.48.170(A)(2) (floodway encroachments).
5. Records of all variance actions, including justification for their issuance.
6. Improvement and damage calculations.
D. Alteration of Watercourses.
1. 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 Administrator through appropriate notification means.
2. Assure that the flood carrying capacity of said watercourse is maintained.
E. Interpretation of FIRM Boundaries. 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 Section 15.48.140. (Ord. 1543, 2024)
15.48.140 Variance procedure.
A. Appeal Board.
1. The board of adjustment as established by the city shall hear and decide appeals and requests for variances from the requirements of this chapter.
2. The board of adjustment shall hear and decide appeals when it is alleged there is an error in any requirement, decision or determination made by the floodplain administrator or their designee in the enforcement or administration of this chapter.
3. Those aggrieved by the decision of the board of adjustment, or any taxpayer, may appeal such decision to the city council, as provided in Chapter 17.60.
4. In passing upon such applications, the board of adjustment shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:
a. The danger that materials may be swept onto other lands to the injury of others;
b. The danger to life and property due to flooding or erosion damage;
c. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;
d. The importance of the services provided by the proposed facility to the community;
e. The necessity to the facility of a waterfront location, where applicable;
f. The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;
g. The compatibility of the proposed use with existing and anticipated development;
h. The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;
i. The safety of access to the property in times of flood for ordinary and emergency vehicles;
j. 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
k. The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities, such as sewer, gas, electrical, and water systems, and streets and bridges.
5. Upon consideration of the factors of subsection (A)(4) of this section and the purposes of this chapter, the board of adjustment may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.
6. The city shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administrator upon request.
B. Conditions for Variances.
1. Generally, the only condition under which a variance from the elevation standard may be issued is 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, providing items in subsections (A)(4)(a) through (A)(4)(k) of this section have been fully considered. As the lot size increases, the technical justification required for issuing the variance increases.
2. Variances may be issued for the reconstruction, rehabilitation or restoration of historic structures upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as a historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.
3. Variances shall not be issued within a designated floodway if any increase in flood levels during the base flood discharge would result.
4. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
5. Variances shall only be issued upon:
a. A showing of good and sufficient cause;
b. A determination that failure to grant the variance would result in exceptional hardship to the applicant;
c. 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 subsections (A)(4)(a) through (A)(4)(k) of this section, or conflict with existing local laws or ordinances.
6. 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.
7. 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, complies with all other variance criteria except subsection (B)(1) of this section, and otherwise complies with Sections 15.48.150(A) and (B).
8. 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. (Ord. 1543, 2024)
15.48.150 General standards.
In all areas of special flood hazards, the following standards are required:
A. Anchoring.
1. All new construction and substantial improvements, including those related to manufactured homes, shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
2. 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).
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, and air-conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located 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 designated to minimize or eliminate infiltration of floodwaters into the system;
2. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters;
3. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding;
4. Water wells shall be located on high ground that is not in the floodway.
D. Subdivision Proposals and Other Proposed New Development.
1. All subdivision proposals and other new development, including manufactured home parks, shall be consistent with the need to minimize flood damage;
2. All subdivision proposals and other new development, including manufactured home parks, shall have public utilities and facilities, such as sewer, gas, electrical and water systems, located and constructed to minimize flood damage;
3. All subdivision proposals and other new development, including manufactured home parks, shall have adequate drainage provided to reduce exposure to flood damage; and
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 or from another authoritative source (Section 15.48.130(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 grade in these zones may result in higher insurance rates.
F. Storage of Materials and Equipment.
1. The storage or processing of materials that could be injurious to human, animal, or plant life if released due to damage from flooding is prohibited in special flood hazard areas.
2. Storage of other material or equipment may be allowed if not subject to damage by floods and if firmly anchored to prevent flotation, or if readily removable from the area within the time available after flood warning. (Ord. 1543, 2024)
15.48.160 Specific standards.
In all areas of special flood hazards where base flood elevation data has been provided as set forth in Section 15.48.060 or 15.48.130(B), the following provisions are required:
A. Residential Construction.
1. In AE and A1-30 zones or other A zoned areas where the BFE has been determined or can be reasonably obtained, new construction and substantial improvement of any residential structure shall have the lowest level, including basement, elevated one foot or more above the base flood elevation. Mechanical equipment and utilities shall be waterproofed or elevated at least one foot above the 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 be either 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, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
d. A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry and exit of floodwaters.
3. New construction and substantial improvement of any residential structure in an unnumbered A zone for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.
4. New construction and substantial improvement of any residential structure in an AO zone shall meet the requirements in Section 15.48.190.
B. Nonresidential Construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet the requirements of subsection (B)(1) or (B)(2) of this section:
1. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:
a. In AE and A1-30 zones or other A zoned areas where the BFE has been determined or can be reasonably obtained, 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 elevated as required by ASCE 24, whichever is greater. Mechanical equipment and utilities shall be waterproofed or elevated at least one foot above the BFE, or as required by ASCE 24, whichever is greater;
b. If located in an unnumbered A zone for which a BFE is not available and cannot be reasonably obtained, the structure shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.
c. Meet the requirements in subsection (A)(2) of this section.
d. If located in an AO zone, the structure shall meet the requirements in Section 15.48.190;
2. If the requirements of subsection (B)(1) of this section are not met, then the new construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:
a. Be dry 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 or dry floodproofed to the elevation required by ASCE 24, whichever is greater;
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 Section 15.48.130(C)(2);
d. Applicants of 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).
C. Manufactured Homes.
1. 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 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.
D. Recreational Vehicles. Recreational vehicles placed on sites shall either:
1. Be on the site for fewer than one hundred eighty consecutive days;
2. Be fully licensed and ready for highway use, on its wheels or jacking system, be attached to the site only by quick disconnect type utilities and security devices, and have no permanent attached additions; or
3. Meet the requirements of this chapter and the elevation and anchoring requirements for manufactured homes in subsection C of this section.
E. Enclosed Area Below the Lowest Floor. If buildings or manufactured homes are constructed or substantially improved with fully enclosed areas below the lowest floor, the areas shall be used solely for parking of vehicles, building access, or storage.
F. Detached Accessory Structures (Detached Garages and Small Storage Structures).
1. Detached accessory structures used solely for parking of vehicles or limited storage may be constructed such that the floor is below the BFE, provided the structure is designed and constructed in accordance with the following requirements:
a. In special flood hazard areas other than coastal high hazard areas (Zones A, AE, AH, AO, and A1-30), the structure is not larger than a one-story two-car garage;
b. The portions of the structure located below the BFE must be built using flood-resistant materials;
c. The structure must be adequately anchored to prevent flotation, collapse, and lateral movement;
d. Any machinery or equipment servicing the structure must be elevated or floodproofed to or above the BFE;
e. The structure must comply with floodway encroachment provisions in Section 15.48.170(A)(1);
f. The structure must be designed to allow for the automatic entry and exit of floodwaters in accordance with subsection (A)(2) of this section;
g. The structure shall have low damage potential;
h. If the structure is converted to another use, it must be brought into full compliance with the standards governing such use; and
i. The structure shall not be used for human habitation.
2. Detached garages, storage structures, and other appurtenant structures not meeting the above standards must be constructed in accordance with all applicable standards in subsection A of this section.
3. Upon completion of the structure, certification that the requirements of this section have been satisfied shall be provided to the floodplain administrator for verification.
G. AE and A1-30 Zones With Base Flood Elevations But No Floodways. In areas with BFEs (when 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.
H. Critical Facility. Construction of new critical facilities shall be, to the extent possible, located outside the limits of the 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 BFE or to the height of the five-hundred-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 BFE shall be provided to all critical facilities to the extent possible.
I. Livestock Sanctuary Areas. Elevated areas for the purpose of creating a flood sanctuary for livestock are allowed on farm units where livestock is allowed. Livestock flood sanctuaries shall be sized appropriately for the expected number of livestock and be elevated sufficiently to protect livestock. Proposals for livestock flood sanctuaries shall meet all procedural substantive requirements of this chapter. (Ord. 1543, 2024)
15.48.170 Additional floodway requirements.
A. Located within areas of special flood hazard established in Section 15.48.060 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 analysis 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: (a) repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and (b) repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty percent of the market value of the structure either (i) before the repair or reconstruction is started, or (ii) 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 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.
3. If this subsection A is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Sections 15.48.150 through 15.48.190.
B. A residential dwelling located partially within a designated floodway will be considered as totally within a designated floodway and must comply with the provisions of this chapter; provided, however, that the floodway prohibition in this subsection does not apply to existing farmhouses in designated floodways that meet the provisions of WAC 173-158-075, or to substantially damaged residential dwellings other than farmhouses that meet the depth and velocity and erosion analysis provisions of WAC 173-158-076.
C. Replacement of Farmhouses in Floodway.
1. Repairs, reconstruction, replacement, or improvements to existing farmhouse structures located in designated floodways and that are located on lands designated as agricultural lands of long-term commercial significance under RCW 36.70A.170 may be permitted subject to the following:
a. The new farmhouse is a replacement for an existing farmhouse on the same farm site;
b. There is no potential building site for a replacement farmhouse on the same farm outside the designated floodway;
c. Repairs, reconstruction, or improvements to a farmhouse shall not increase the total square footage of encroachment of the existing farmhouse;
d. A replacement farmhouse shall not exceed the total square footage of encroachment of the farmhouse it is replacing;
e. A farmhouse being replaced shall be removed, in its entirety, including foundation, from the floodway within ninety days after occupancy of a new farmhouse;
f. For substantial improvements and replacement farmhouses, the elevation of the lowest floor of the improvement and farmhouse respectively, including basement, is a minimum of one foot higher than the BFE;
g. New and replacement water supply systems are designed to eliminate or minimize infiltration of floodwaters into the system;
h. New and replacement sanitary sewerage systems are designed and located to eliminate or minimize infiltration of floodwater into the system and discharge from the system into the floodwaters; and
i. All other utilities and connections to public utilities are designed, constructed, and located to eliminate or minimize flood damage.
2. Substantially Damaged Residences in Floodway.
a. For all substantially damaged residential structures, other than farmhouses, located in a designated floodway, the floodplain administrator may make a written request that the Department of Ecology assess the risk of harm to life and property posed by the specific conditions of the floodway. Based on analysis of depth, velocity, flood-related erosion, channel migration, debris load potential, and flood warning capability, the Department of Ecology may exercise best professional judgment in recommending to the local permitting authority repair, replacement, or relocation of a substantially damaged structure consistent with WAC 173-158-076. The property owner shall be responsible for submitting to the local government and the Department of Ecology any information necessary to complete the assessment. Without a favorable recommendation from the department for the repair or replacement of a substantially damaged residential structure located in the regulatory floodway, no repair or replacement is allowed per WAC 173-158-070(1).
b. Before the repair, replacement, or reconstruction is started, all requirements of the NFIP, the state requirements adopted pursuant to Chapter 86.16 RCW, and all applicable local regulations must be satisfied. In addition, the following conditions must be met:
i. There is no potential safe building location for the replacement residential structure on the same property outside the regulatory floodway.
ii. A replacement residential structure is a residential structure built as a substitute for a legally existing residential structure of equivalent use and size.
iii. Repairs, reconstruction, or replacement of a residential structure shall not increase the total square footage of floodway encroachment.
iv. The elevation of the lowest floor of the substantially damaged or replacement residential structure is a minimum of one foot higher than the BFE.
v. New and replacement water supply systems are designed to eliminate or minimize infiltration of floodwater into the system.
vi. New and replacement sanitary sewerage systems are designed and located to eliminate or minimize infiltration of floodwater into the system and discharge from the system into the floodwaters.
vii. All other utilities and connections to public utilities are designed, constructed, and located to eliminate or minimize flood damage.
D. Special Flood Hazard Areas Without Designated Floodways. When a regulatory floodway for a stream has not been designated, the city may require applicants for new construction and substantial improvements to reasonably utilize the best available information from a federal, state, or other source to consider the cumulative effect of existing, proposed, and anticipated future development and determine that the increase in the water surface elevation of the base flood will not be more than one foot at any point in the city. Building and development near streams without a designated floodway shall comply with the requirements of 44 CFR 60.3(b)(3) and (4) and (c)(10) of the NFIP regulations. (Ord. 1543, 2024)
15.48.190 Standards for shallow flooding areas (AO zones).
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 addition to other provisions in this code, the following provisions also apply in AO zones:
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 grade adjacent to the building, one foot or more above the depth number specified on the FIRM (at least two feet 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, one foot or more above the depth number specified on the FIRM (at least two feet, 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.
C. Require adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.
D. Recreational vehicles placed on sites within AO zones on the community’s FIRM shall either:
1. Be on the site for fewer than one hundred eighty consecutive days;
2. Be fully licensed and ready for highway use, on its wheels or jacking system, be 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 subsections A and C of this section and the elevation and anchoring requirements for manufactured homes (Section 15.48.160(C)). (Ord. 1543, 2024)