The legislature of the State of Washington has delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry in accordance with RCW 86.16, Floodplain Management.

(Ord. No. 1275, § 3(Exh. A), 1-19-2021)

A.

It is the purpose of this chapter to promote the public health, safety, and general welfare; reduce the annual cost of flood insurance; and minimize public and private losses due to flood conditions in specific areas by provisions designed:

1.

To protect human life and health;

2.

To minimize expenditure of public money and costly flood control projects;

3.

To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

4.

To minimize prolonged business interruptions;

5.

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;

6.

To help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future flood blight areas;

7.

To ensure that potential buyers are notified that property is in an area of special flood hazard;

8.

To ensure that those who occupy the areas of special flood hazard assume responsibility for their actions.

B.

In order to accomplish its purposes, this chapter includes methods and provisions for:

1.

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;

2.

Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

3.

Controlling the alteration of natural floodplains, stream channels, and natural protective barriers, which help accommodate or channel floodwaters;

4.

Controlling filling, grading, dredging, and other development which may increase flood damage; and

5.

Preventing or regulating the construction of flood barriers that unnaturally divert floodwaters or may increase flood hazards in other areas.

(Ord. No. 1275, § 3(Exh. A), 1-19-2021)

The following definitions shall apply to all areas of special flood hazards within the City of Duvall.

"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 waterbody.

"Appeal" means a request for a review of the interpretation of any provision of this chapter or a request for a variance.

"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. The special flood hazard area (SFHA) is shown on the Flood Insurance Rate Map (FIRM) as zones A, AO, AH, A1—30, AE, A99, AR (V, VO, V1—30 and VE. Area of special flood hazards and SFHA are often referred to as the "100-year" floodplain.

"Base flood" means the flood having a one-percent chance of being equaled or exceeded in any given year (also referred to as the "100-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 floor subgrade (below ground level) on all sides.

"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 (25) percent of the market value of the structure before the damage occurred. These damages are also referred to as repetitive loss.

"Development" means any manmade change to improved or unimproved real estate in the SFHA including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations, storage of equipment or materials, subdivision of land, removal of more than five percent of the native vegetation on the property, or alteration of natural site characteristics.

"Elevated building" means for insurance purposes, a non-basement building that has its lowest elevated floor raised above ground level by foundation walls, shear walls, post, piers, pilings, or columns.

"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 (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 to 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

1.

a general and temporary condition of partial or complete inundation of normally dry land areas from the following:

i.

The overflow of inland or tidal waters;

ii.

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

iii.

Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in paragraph (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 paragraph (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 (FIS)," 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.

"Flood proofing" 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. Flood proofed 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" Any structure that is:

1.

Listed individually in the National Register of Historic Places (a listing maintained by the Department of 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 Interior; or

4.

Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either

i.

By an approved state program as determined by the Secretary of the Interior, or

ii.

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 so as to render the structure in violation of the applicable non-elevation design requirements of this chapter found at Section 5.2-1(2), (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 attached to the required utilities. The term "manufactured home" does not include a "recreational vehicle."

"Mean Sea Level" means, for the 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.

"Reasonably Safe from Flooding" describes 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.

"Recreational Vehicle" means a vehicle that is:

1.

Built on a single chassis;

2.

400 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

"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 (180) 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 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, 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 ground.

"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 (50) 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 (50) percent of the market value of the structure before the "start of construction." The term includes structures which have incurred substantial damage, cumulative substantial damage or repetitive loss. The term does not include:

1.

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

2.

Any alteration of a structure listed on the National Register of Historic Places or a State Inventory of Historic Places.

"Variance" means a grant of relief from the requirements of this chapter that 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. No. 1275, § 3(Exh. A), 1-19-2021)

This chapter shall apply to all areas of special flood hazards within the City of Duvall.

A.

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 for King County and Incorporated Areas," dated August 19, 2020, and any revisions thereto, with an accompanying Flood Insurance Rate Map (FIRM), dated August 19, 2020, and any revisions thereto, are hereby adopted by reference and declared to be a part of this chapter. The FIS and FIRM are on file at the City of Duvall. The best available information for flood hazard area identification as outlined in DMC [Section] 14.84.050.E. shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under DMC 14.84.050.E.

B.

Compliance. All development within special flood hazard areas is subject to the terms of this ordinance and other applicable regulations.

C.

Penalties for Noncompliance. No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this ordinance and other applicable regulations. Violations of the provisions of this ordinance 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 ordinance or fails to comply with any of its requirements shall upon conviction thereof be fined not more than two hundred fifty dollars ($250.00) per day for each violation, and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent the City from taking such other lawful action as is necessary to prevent or remedy any violation.

D.

Abrogation and Greater Restrictions. This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this ordinance and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.

E.

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

1.

Considered as minimum requirements;

2.

Liberally construed in favor of the governing body; and

3.

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

F.

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 ordinance 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 of Duvall, any officer or employee thereof, or the Federal Insurance Administrator, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder.

(Ord. No. 1275, § 3(Exh. A), 1-19-2021)

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 14.84.040.A. The permit shall be for all structures including manufactured homes, as set forth in the "Definitions," and for all development including fill and other activities, also as set forth in the "Definitions."

B.

Application for Development Permit. Application for a development permit shall be made on forms furnished by the City of Duvall 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 recorded on a current elevation certificate with Section B completed by the Floodplain Administrator;

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 floodproofing criteria in Section 14.84.060;

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 the 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.

C.

Designation of the Floodplain Administrator. The Planning Director is hereby appointed to administer, enforce, and implement this chapter by granting or denying development permit applications in accordance with its provisions. The Floodplain Administrator may delegate authority to implement these provisions.

D.

Duties and Responsibilities of the Floodplain Administrator. Duties of the Floodplain Administrator shall include, but not be limited to:

1.

Review all development permits to determine the following:

a.

The permit requirements of this ordinance have been satisfied;

b.

All other required state and federal permits have been obtained;

c.

The site is reasonably safe from flooding;

d.

The proposed development is not located in the floodway. If located in the floodway, ensure the encroachment provisions of DMC 14.84.060.M. are met.

e.

Notify FEMA when annexations occur in the SFHA.

2.

Information to be Obtained and Maintained:

a.

Where base flood elevation data is provided through the FIS or FIRM, 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.

Documentation of the elevation of the bottom of the lowest horizontal structural member V or VE zones.

c.

For all new or substantially improved floodproofed nonresidential structures where base flood elevation data is provided through the FIS or FIRM:

i.

Obtain and maintain a record of the elevation (in relation to mean sea level) to which the structure was floodproofed.

ii.

Maintain the floodproofing certifications required in DMC 14.84.050.B.3.

d.

Certification required by DMC 14.84.060.K. for floodway encroachments.

e.

Records of all variance actions including justification for their issuance.

f.

Improvement and damage calculations.

g.

Maintain for public inspection all records pertaining to the provisions of this chapter.

3.

Alteration of Watercourses.

a.

Notify the Department of Ecology, adjacent communities and appropriate agencies prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administrator through appropriate means; and

b.

Require that maintenance is provided within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.

4.

Interpretation of FIRM Boundaries. Make interpretations where needed as to exact location of the boundaries of the areas of special flood hazards (e.g. 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. Such appeals shall be granted consistent with the standards of Section 60.6 of the Rules and Regulations of the National Flood Insurance Program.

5.

Review of Building Permits (44 CFR 60.3(a)(3)). Where elevation data is not available either through the FIS, FIRM, or from another authoritative source, applications for floodplain development 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 habitable buildings at least two feet above the highest adjacent grade in these zones may result in higher insurance rates.)

6.

Changes to Special Flood Hazard Area.

a.

If a project will alter the BFE or boundaries of the SFHA, then the project proponent shall provide the community with engineering documentation and analysis regarding the proposed change. If the change to the BFE or boundaries of the SFHA would normally require a Letter of Map Change, then the project proponent shall initiate, and receive approval of, a Conditional Letter of Map Revision (CLOMR) prior to approval of the development permit. The project shall be constructed in a manner consistent with the approved CLOMR.

b.

If a CLOMR application is made, then the project proponent shall also supply the full CLOMR documentation package to the Floodplain Administrator to be attached to the floodplain development permit, including all required property owner notifications.

E.

Variances. The variance criteria set forth in this section (E) are based on the general principle of zoning law that variances pertain to a piece of property and are not personal in nature. A variance may be granted for a parcel of property with physical characteristics so unusual that complying with the requirements of this ordinance would create an exceptional hardship to the applicant or the surrounding property owners. The unique characteristic must pertain to the land itself, not to the structure, its inhabitants, or the property owners. It is the duty of the City of Duvall to help protect its citizens from flooding. This need is so compelling and the implications of the cost of ensuring a structure built below the Base Flood Elevation are so serious that variances from the flood elevation or from other requirements in the flood ordinance are quite rare. The long-term goal of preventing and reducing flood loss and damage can only be met if variances are strictly limited. Therefore, the variance guidelines provided in this ordinance are more detailed and contain multiple provisions that must be met before a variance can be properly granted. The criteria are designed to screen out those situations in which alternatives other than a variance are more appropriate.

1.

Variances shall only be issued:

a.

Upon 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, or conflict with existing local laws or ordinances;

b.

For the repair, 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;

c.

Upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.

d.

Upon showing of good and sufficient cause;

e.

Upon a determination that failure to grant the variance would result in exceptional hardship to the applicant;

f.

Upon a showing that the use cannot perform its intended purpose unless it is located or carried out in close proximity to water. This includes only facilities defined in this ordinance as a "Functionally Dependent Use."

2.

Variances shall not be issued within any floodway if any increase in flood levels during the base flood discharge would result.

3.

Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the BFE, provided the procedures of DMC 14.84 of this ordinance have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases.

4.

Variance Criteria.

a.

In considering variance applications, the Planning Director shall consider all technical evaluations, all relevant factors, all standards specified in other sections of this ordinance, and;

i.

The danger that materials may be swept onto other lands to the injury of others;

ii.

The danger to life and property due to flooding and erosion damage;

iii.

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

iv.

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

v.

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

vi.

The availability of alternative locations for the proposed use, which are not subject to flooding or erosion damage;

vii.

The compatibility of the proposed use with existing and anticipated development;

viii.

The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;

ix.

The safety of access to the property in time of flood for ordinary and emergency vehicles;

x.

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

xi.

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, water system, and streets and bridges.

5.

Additional Requirements for the Issuance of a Variance.

a.

Any applicant to whom a variance is granted shall be given written notice over the signature of the Planning Director that:

i.

The issuance of a variance to construct a structure below the BFE will result in increased premium rates for flood insurance up to amounts as high as twenty-five dollars ($25.00) for one hundred dollars ($100.00) of insurance coverage, and

ii.

Such construction below the BFE increases risks to life and property.

b.

The Floodplain Administrator shall maintain a record of all variance actions, including justification for their issuance.

c.

The Floodplain administrator shall condition the variance as needed to ensure that the requirements and criterial of this chapter are met.

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 flood elevations should be quite rare.

(Ord. No. 1275, § 3(Exh. A), 1-19-2021)

A.

General Standards. In all areas of special flood hazards, the following standards are required:

1.

Anchoring.

a.

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.

b.

All manufactured homes shall 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.

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 so as to prevent water from entering or accumulating within the components during conditions of flooding. Locating such equipment below the base flood elevation may cause annual flood insurance premiums to be increased.

C.

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.

D.

Utilities.

1.

All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems;

2.

Water wells shall be located on high ground that is not in the floodway.

3.

New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters;

4.

Onsite waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

E.

Subdivision Proposals and Other Development. All subdivisions and new development shall:

1.

Be consistent with the need to minimize flood damage.

2.

Locate and construct public utilities and facilities, such as sewer, gas, electrical, and water systems, to minimize or eliminate flood damage.

3.

Have adequate drainage provided to reduce exposure to flood damage.

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 (50) lots or five acres whichever is less.

F.

Specific Standards. In all areas of special flood hazards where base flood elevation data has been provided as set forth in DMC Section 14.84.040.A>, Basis for establishing the areas of special flood hazard, the following provisions are required:

1.

Residential Construction.

a.

New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one foot or more above the base flood elevation (BFE). Mechanical equipment and utilities shall be waterproof or elevated least one foot above the 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 floodwaters. Designs for meeting this requirement meet or exceed the following minimum criteria:

i.

A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.

ii.

The bottom of all openings shall be no higher than one foot above grade.

iii.

Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters. Alternatively, a registered engineer or architect may design and certify engineered openings.

iv.

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.

Alternatively, a registered engineer or architect may design and certify engineered openings.

2.

Nonresidential Construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet the following requirements:

a.

New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:

i.

In AE zones 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 have the lowest floor, including basement, elevated one foot or more above the BFE, or elevated as required by ASCE 24, whichever is greater. Mechanical equipment and utilities shall be waterproofed or elevated least one foot above the BFE, or as required by ASCE 24, whichever is greater.

ii.

Fully enclosed areas below the lowest floor that are subject to flooding are prohibited or shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:

A.

Have a minimum of two openings with a total net area of not less than one square inch for every square foot of enclosed area subject to flooding.

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 floodwater.

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.

Alternatively, a registered engineer or architect may design and certify engineered openings.

b.

If the requirements of subsection (a) are not met, then new construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet all of the following requirements:

i.

Be dry flood proofed 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 flood proofed to the elevation required by ASCE 24, whichever is greater;

ii.

Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

iii.

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 DMC 14.84.050.D.2.;

iv.

Nonresidential structures that are elevated, not flood proofed, must meet the same standards for space below the lowest floor as described in 5.2-1(2);

Note: Applicants who are flood proofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the flood proofed level (e.g. a building flood proofed to the base flood level will be rated as one foot below). Flood proofing the building an additional foot will reduce insurance premiums.

G.

Manufactured Homes. All manufactured homes in the floodplain 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 anchored foundation system to resist flotation, collapse and lateral movement.

H.

Recreational Vehicles. Recreational vehicles placed on sites are required to either:

1.

Be on the site for fewer than one hundred eighty (180) consecutive days; or

2.

Be fully licensed and ready for highway use, on wheels or jacking system, 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 DMC Section 14.84.060(J), and the elevation and anchoring requirements for manufactured homes.

I.

Enclosed Area Below the Lowest Floor. If buildings or manufactured homes are constructed or substantially improved with fully enclosed area below the lowest floor, the areas shall be used solely for parking of vehicles, building access, or storage.

J.

Appurtenant Structures (Detached Garages and Small Storage Structures) For A Zones (A, AE, A1—30, AH, AO):

1.

Appurtenant 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.

Use of the appurtenant structure must be limited to parking of vehicles or limited storage;

b.

The portions of the appurtenant structure located below the BFE must be build using flood resistant materials;

c.

The appurtenant structure must be adequately anchored to prevent flotation, collapse, and lateral movement;

d.

Any machinery or equipment servicing the appurtenant structure must be elevated or floodproofed to or above the BFE;

e.

The appurtenant structure must comply with floodway encroachment provisions in DMC 14.84.060.K.;

f.

The appurtenant structure must be designed to allow for the automatic entry and exit of flood waters in accordance with DMC 14.84.060.F.2.a.ii.;

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.

i.

Detached garages, storage structures, and other appurtenant structures not meeting the above standards must be constructed in accordance with all applicable standards in DMC 14.84.060.F.

ii.

Upon completion of the structure, certification that the requirements of this section have been satisfied shall be provided to the Floodplain Administrator for verification.

K.

Floodways. Located within areas of special flood hazard established in DMC 14.84.040.A., are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that can carry debris, and increase erosion potential, the following provisions apply:

1.

No Rise Standard. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels during the occurrence of the base flood discharge.

2.

Residential Construction in Floodways. Construction or reconstruction of residential structures is prohibited within designated floodways, except for (i) repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and (ii) repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty (50) percent of the market value of the structure either, (A) before the repair, or reconstruction is started, or (B) if the structure has been damaged, and is being restored, before the damage occurred. Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions, or to structures identified as historic places, may be excluded in the fifty (50) percent.

3.

If DMC 14.84.060.N.1. is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of DMC 14.84.060, Provisions for flood hazard reduction.

L.

General Requirements for Other Development. All development, including manmade changes to improved or unimproved real estate for which specific provisions are not specified in this ordinance or the state building code with adopted amendments and any Duvall amendments, shall:

1.

Be located and constructed to minimize flood damage;

2.

Meet the encroachment limitations of this ordinance if located in a regulatory floodway;

3.

Be anchored to prevent flotation, collapse, or lateral movement resulting from hydrostatic loads, including the effects of buoyancy, during conditions of the design flood;

4.

Be constructed of flood damage-resistant materials;

5.

Meet the flood opening requirements of DMC 14.84.060.F.2.; and

6.

Have mechanical, plumbing, and electrical systems above the design flood elevation or meet the requirements of ASCE 24, except that minimum electric service required to address life safety and electric code requirements is permitted below the design flood elevation provided it conforms to the provisions of the electrical part of building code for wet locations.

M.

Critical Facility. Construction of new critical facilities shall be, to the extent possible, located outside the limits of the Special Flood Hazard Area (SFHA) (100-year floodplain). Construction of new critical facilities shall be permissible within the SFHA if no feasible alternative site is available. Critical facilities constructed within the SFHA shall have the lowest floor elevated three feet above BFE or to the height of the 500-year flood, whichever is higher. Access to and from the critical facility should also be protected to the height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be displaced by or released into floodwaters. Access routes elevated to or above the level of the base flood elevation shall be provided to all critical facilities to the extent possible.

(Ord. No. 1275, § 3(Exh. A), 1-19-2021)