Chapter 15.08
FLOODPLAIN MANAGEMENT1

Sections:

15.08.010    Statutory authorization.

15.08.020    Findings of fact.

15.08.030    Statement of purpose.

15.08.040    Methods of reducing flood losses.

15.08.050    Definitions.

15.08.060    Lands and activities to which this chapter applies.

15.08.070    Basis for establishing the areas of special flood hazard.

15.08.080    Penalties for noncompliance.

15.08.090    Abrogation and greater restrictions.

15.08.100    Interpretation.

15.08.110    Warning and disclaimer of liability.

15.08.120    Changes to special flood hazard area.

15.08.130    Establishment of development permit.

15.08.140    Designation of the town of Index.

15.08.150    Duties and responsibilities of the town of Index.

15.08.160    Variance procedure – Appeal board.

15.08.170    Conditions for variances.

15.08.180    Provisions for flood hazard reduction – General standards.

15.08.190    Provisions for flood hazard reduction – Specific standards.

15.08.200    Floodways.

15.08.210    AE and A1-30 zones with base flood elevations but no floodways.

15.08.220    Standards for shallow flooding areas (AO zones).

15.08.230    Critical facility.

15.08.010 Statutory authorization.

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. Therefore, the council of the town of Index, Washington, does ordain as follows in this chapter. (Ord. 480 § 1 (part), 2020).

15.08.020 Findings of fact.

(A) The flood hazard areas of the town of Index 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. 480 § 1 (part), 2020).

15.08.030 Statement of purpose.

This chapter is intended to put the town of Index in compliance with the floodplain management standards and regulations of the National Flood Insurance Program (NFIP). The enactment of this chapter is recommended, as it includes standards and provisions that encourage sound floodplain management and may allow property owners to obtain flood insurance at a more affordable rate. 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 so as to minimize future flood blight areas;

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

(H) To ensure that those who occupy the areas of special flood hazard assume responsibility for their actions. (Ord. 480 § 1 (part), 2020).

15.08.040 Methods of reducing 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 protective barriers, which help accommodate or channel floodwaters;

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

(E) Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or may increase flood hazards in other areas. (Ord. 480 § 1 (part), 2020).

15.08.050 Definitions.

Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application.

(A) “Appeal” means a request for a review of the Snohomish County department of planning and community development’s interpretation of any provision of this chapter or a request for a variance.

(B) “Area of shallow flooding” means a designated AO or AH zone on the flood insurance rate map (FIRM). The base flood depths range from one (1) to three (3) 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.

(C) “Area of special flood hazard” means the land in the floodplain within a community subject to a one percent (1%) 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, or AR (V, VO, V1-30, VE). “Special flood hazard area” is synonymous in meaning with the phrase “area of special flood hazard.”

(D) “Base flood” means the flood having a one percent (1%) chance of being equaled or exceeded in any given year. Also referred to as the “one hundred (100) year flood.” Designation on maps always includes the letters A or V.

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

(F) “Breakaway wall” means a wall that is not part of the structural support of the building and is intended through its design and construction to collapse under specific lateral loading forces, without causing damage to the elevated portion of the building or supporting foundation system.

(G) “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, installations which produce, use or store hazardous materials or hazardous waste.

(H) “Development” means any manmade change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials located within the area of special flood hazard.

(I) “Elevated building” means, for insurance purposes, a nonbasement building which has its lowest elevated floor raised above ground level by foundation walls, shear walls, posts, piers, pilings, or columns.

(J) “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.

(b) The unusual and rapid accumulation or 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.

(K) “Flood insurance rate map (FIRM)” means the official map of a community, on which the Federal Insurance Administrator has delineated both the special hazard areas 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).

(L) “Flood insurance study” means the official report provided by the Federal Insurance Administration that includes flood profiles, the flood boundary-floodway map, and the water surface elevation of the base flood.

(M) “Floodplain administrator” means the community official designated by title to administer and enforce the floodplain management regulations.

(N) “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.”

(O) “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.

(P) “Highest adjacent grade” means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

(Q) “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.

(R) Letter of Map Amendment (LOMA). A letter of map amendment (LOMA) is an official amendment, by letter, to an effective National Flood Insurance Program (NFIP) map. A LOMA establishes a property’s location in relation to the special flood hazard area (SFHA). LOMAs are usually issued because a property has been inadvertently mapped as being in the floodplain but is actually on natural high ground above the base flood elevation. Because a LOMA officially amends the effective NFIP map, it is a public record that the community must maintain. Any LOMA should be noted on the community’s master flood map and filed by panel number in an accessible location.

(S) “Letter of map change” (LOMC) is a general term used to refer to the several types of revisions and amendments to FEMA maps that can be accomplished by letter. They include letter of map amendment (LOMA), letter of map revision (LOMR), and letter of map revision based on fill (LOMR-F).

(T) Letter of Map Revision (LOMR). A letter of map revision (LOMR) is FEMA’s modification to an effective flood insurance rate map (FIRM), or flood boundary and floodway map (FBFM), or both. LOMRs are generally based on the implementation of physical measures that affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway, the effective base flood elevations (BFEs), or the special flood hazard area (SFHA). The LOMR officially revises the flood insurance rate map (FIRM) or flood boundary and floodway map (FBFM), and sometimes the flood insurance study (FIS) report, and, when appropriate, includes a description of the modifications. The LOMR is generally accompanied by an annotated copy of the affected portions of the FIRM, FBFM, or FIS report.

(U) “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 nonelevation design requirements of Section 15.08.190.

(V) “Manufactured home” means a structure, transportable in one (1) 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.”

(W) “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.

(X) “New construction” means structures for which the “start of construction” commenced on or after the effective date of the ordinance codified in this chapter.

(Y) “Recreational vehicle” means a vehicle which is:

(1) Built on a single chassis;

(2) Four hundred (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 dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

(Z) “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.

(AA) “Structure” means, for floodplain management purposes, a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home.

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

(CC) “Substantial improvement” means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure either:

(1) Before the improvement or repair is started; or

(2) If the structure has been damaged and is being restored, before the damage occurred.

For the purposes of this definition “substantial improvement” is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either:

(1) 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

(2) Any alteration of a “historic structure”; provided, that the alteration will not preclude the structure’s continued designation as a “historic structure.”

(DD) “Variance” means a grant of relief by a community from the terms of a floodplain management regulation.

(EE) “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. (Ord. 480 § 1 (part), 2020).

15.08.060 Lands and activities to which this chapter applies.

This chapter shall apply to all areas of special flood hazards within the jurisdiction of the town of Index. All development within special flood hazard areas is subject to the terms of this chapter and other applicable regulations. (Ord. 480 § 1 (part), 2020).

15.08.070 Basis for establishing the areas of special flood hazard.

The areas of special flood hazard identified by the Federal Insurance Administration in a scientific and engineering report entitled the Flood Insurance Study (FIS) for Snohomish County, Washington, and Incorporated Areas, dated June 19, 2020, as amended, with an accompanying flood insurance rate map (FIRM), as amended, are hereby adopted by reference and declared to be a part of this chapter. The flood insurance study is on file at the Index Town Hall, PO Box 88, Index, WA 98256. The best available information for flood hazard area identification as outlined in Section 15.08.150(B) shall be the basis for regulation until a new FIRM is issued which incorporates the data utilized under Section 15.08.150(B). (Ord. 480 § 1 (part), 2020).

15.08.080 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 be subject to the processes, procedures and penalties set forth in Chapter 17.52, Land Use Enforcement. Nothing herein contained shall prevent the town of Index from taking such other lawful action as is necessary to prevent or remedy any violation. (Ord. 480 § 1 (part), 2020).

15.08.090 Abrogation and greater restrictions.

This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail. (Ord. 480 § 1 (part), 2020).

15.08.100 Interpretation.

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

(A) Considered as minimum requirements;

(B) Liberally construed in favor of the governing body; and

(C) Deemed neither to limit nor repeal any other powers granted under state statutes. (Ord. 480 § 1 (part), 2020).

15.08.110 Warning and disclaimer of liability.

The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood 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 town of Index, 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. 480 § 1 (part), 2020).

15.08.120 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. (Ord. 480 § 1 (part), 2020).

15.08.130 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 15.08.070. The permit shall be for all structures including manufactured homes, as set forth in the Section 15.08.050, Definitions, and for all development including fill and other activities, also as set forth in the Section 15.08.050, Definitions.

(B) Application for Development Permit. Application for a development permit shall be made on forms furnished by the town of Index 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 15.08.190(B);

(4) Description of the extent to which a watercourse will be altered or relocated as a result of proposed development; and

(5) A fee in the amount of seventy-five dollars ($75.00), or such amount as subsequently set by resolution by the Index town council, for each flood hazard permit request shall be paid to the town of Index at the time an application is presented; and

(6) Where development is proposed in a floodway, an engineering analysis indicating no rise of the base flood elevation. (Ord. 480 § 1 (part), 2020).

15.08.140 Designation of the town of Index.

The mayor, or his or her designee, and the town council are hereby appointed to administer and implement this chapter by granting or denying development permit applications in accordance with the provisions of Chapter 14.04, Land Use Projects. (Ord. 480 § 1 (part), 2020).

15.08.150 Duties and responsibilities of the town of Index.

Duties of the town of Index 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 15.08.200(A) are met.

(4) The site is reasonably safe from flooding;

(5) Notify FEMA when annexations occur in the special flood hazard area.

(B) Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 15.08.070, Basis for establishing the areas of special flood hazard, the town of Index 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 15.08.190, specific standards, and 15.08.200, Floodways.

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

(b) Maintain the floodproofing certifications required in Section 15.08.130(B).

(3) Certification required by Section 15.08.200(A) (floodway encroachments).

(4) Records of all variance actions, including justification for their issuance.

(5) Improvement and damage calculations.

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

(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 Administration.

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

(E) Interpretation of FIRM Boundaries. Make interpretations where needed, as to exact location of the boundaries of the areas of special flood hazards (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 15.08.160. (Ord. 480 § 1 (part), 2020).

15.08.160 Variance procedure – Appeal board.

(A) The Index town council, as established by the town of Index, shall hear and decide appeals and requests for variances from the requirements of this chapter.

(B) The Index town council shall hear and decide appeals when it is alleged there is an error in any requirement, decision, or determination made by the town of Index in the enforcement or administration of this chapter.

(C) Those aggrieved by the decision of the Index town council, or any taxpayer, may appeal such decision to the Evergreen district court.

(D) In passing upon such applications, the Index town council shall consider all technical valuations, all relevant factors, standards specified in other sections of this chapter, and:

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

(2) The danger to life and property due to flooding or erosion damage;

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

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

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

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

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

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

(9) The safety of access to the property in times of flood for ordinary and emergency vehicles;

(10) The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site; and

(11) The 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.

(E) Upon consideration of the factors of subsection (D) of this section and the purposes of this chapter, the Index town council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

(F) The town of Index shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration upon request. (Ord. 480 § 1 (part), 2020).

15.08.170 Conditions for variances.

(A) 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 Section 15.08.160(D)(1) through (11) have been fully considered. As the lot size increases the technical justification required for issuing the variance increases.

(B) Variances may be issued for the reconstruction, rehabilitation, or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places, without regard to the procedures set forth in this section; provided, that there has been 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) Variances shall not be issued within a designated floodway if any increase in flood levels during the base flood discharge would result.

(D) Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.

(E) Variances shall only be issued upon:

(1) A showing of good and sufficient cause;

(2) A determination that failure to grant the variance would result in exceptional hardship to the applicant;

(3) A determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances.

(F) Variances as interpreted in the National Flood Insurance Program are based on the general zoning law principle that they pertain to a physical piece of property; they are not personal in nature and do not pertain to the structure, its inhabitants, economic or financial circumstances. They primarily address small lots in densely populated residential neighborhoods. As such, variances from the flood elevations should be quite rare.

(G) Variances may be issued for nonresidential buildings in very limited circumstances to allow a lesser degree of floodproofing than watertight or dry floodproofing, where it can be determined that such action will have low damage potential, complies with all other variance criteria except subsection (A) of this section and otherwise complies with Sections 15.08.180(A) and (B) of the general standards.

(H) 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. 480 § 1 (part), 2020).

15.08.180 Provisions for flood hazard reduction – General standards.

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

(A) Anchoring.

(1) All new construction and substantial improvements 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 so 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 designed to minimize or eliminate infiltration of floodwaters into the system.

(2) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

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

(4) 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.

(D) Subdivision Proposals. All subdivision and other new development proposals:

(1) Shall be consistent with the need to minimize flood damage;

(2) Shall have public utilities and facilities such as gas, electrical, and water systems located and constructed to minimize flood damage;

(3) 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 source, base flood elevation data shall be provided for subdivision proposals and other proposed developments which contain at least fifty (50) lots or five (5) 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 15.08.150(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 (2) feet above grade in these zones may result in higher insurance rates.

(F) The importation or placement of fill material which materially raises the grade of a property located in zone AE or A1-30 shall not be allowed unless the project proponent successfully demonstrates that the activity will not result in a loss of flood storage. (Ord. 480 § 1 (part), 2020).

15.08.190 Provisions for flood hazard reduction – Specific standards.

In all areas of special flood hazards where base flood elevation data has been provided as set forth in Section 15.08.070, Basis for establishing the areas of special flood hazard, or Section 15.08.150(B), Use of Other Base Flood Data, 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 floor, including basement, elevated one (1) foot or more above the BFE. Mechanical equipment and utilities shall be waterproof or elevated at least one (1) foot above the BFE.

(2) 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 (2) feet above the highest adjacent grade.

(3) 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 must meet or exceed the following minimum criteria:

(a) Have a minimum of two (2) openings with a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding.

(b) The bottom of all openings shall be no higher than one (1) 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) Nonresidential Construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall meet the requirements of subsection (B)(1) or (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 have the lowest floor, including basement, elevated one (1) 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 (1) 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 (2) feet above the highest adjacent grade.

(c) 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:

(i) Have a minimum of two (2) openings with a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding.

(ii) The bottom of all openings shall be no higher than one (1) foot above grade.

(iii) Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwater.

(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) If the requirements of subsection (B)(1) of this section are not met, then 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 (1) 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 15.08.150(C)(2);

(d) Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection (A) of this section.

Applicants who are floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one (1) foot below the floodproofed level (e.g., a building floodproofed to the base flood level will be rated as one (1) foot below). Floodproofing the building an additional foot will reduce insurance premiums.

(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 (1) 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. This applies to manufactured homes:

(a) Outside of a manufactured home park or subdivision;

(b) In a new manufactured home park or subdivision;

(c) In an expansion to an existing manufactured home park or subdivision; or

(d) In an existing manufactured home park or subdivision on a site which a manufactured home has incurred “substantial damage” as the result of a flood; and

(2) Manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision that are not subject to the above manufactured home provisions shall be elevated so that either:

(a) The lowest floor of the manufactured home is elevated one (1) foot or more;

(b) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six (36) inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

(D) Recreational Vehicles. Recreational vehicles placed on sites within zones A1-30, AH, and AE on the community’s FIRM shall either:

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

(2) Be fully licensed and ready for highway use, on their 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 subsection (C) of this section and the elevation and anchoring requirements for manufactured homes.

(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. (Ord. 480 § 1 (part), 2020).

15.08.200 Floodways.

Located within areas of special flood hazard established in Section 15.08.070 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(A) Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer or architect is provided demonstrating through hydrologic analysis performed in accordance with standard engineering practice that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.

(B) Construction or reconstruction of residential structures is prohibited within designated floodways, except for:

(1) Repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and

(2) Repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty percent (50%) 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 shall not be included in the fifty percent (50%).

(C) If subsection (A) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Sections 15.08.180 through 15.08.230. (Ord. 480 § 1 (part), 2020).

15.08.210 AE and A1-30 zones with base flood elevations but no floodways.

In areas with BFEs (but 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 (1) foot at any point within the community. (Ord. 480 § 1 (part), 2020).

15.08.220 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 (1) to three (3) feet above ground where a clearly defined channel does not exist, or where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as sheet flow. In these areas, the following provisions apply:

(A) New construction and substantial improvements of residential structures and manufactured homes within AO zones shall have the lowest floor (including basement) elevated above the highest grade adjacent to the building, one (1) foot or more above the depth number specified in feet on the FIRM (at least two (2) 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 (1) foot or more above the depth number specified on the FIRM (at least two (2) 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 as in Section 15.08.190(B)(2)(c).

(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 (180) consecutive days;

(2) Be fully licensed and ready for highway use, on their 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 this section and the elevation and anchoring requirements for manufactured homes. (Ord. 480 § 1 (part), 2020).

15.08.230 Critical facility.

Construction of new critical facilities shall be, to the extent possible, located outside the limits of the special flood hazard area (SFHA) (one hundred (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 (3) feet or more above the level of the base flood elevation (one hundred (100) year) at the site. 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. 480 § 1 (part), 2020).


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Code reviser’s note: Ord. 480 is an interim ordinance effective until November 12, 2020, unless extended as provided by statute.