Chapter 16.15 FLOOD HAZARD AREAS

The purpose of this chapter is to implement the provisions of chapter 86.16 RCW in coordinating the flood plain management regulation aspects of the National Flood Insurance Program. [Ord. 1583 § 91, 2013.]

16.15.040 Authority.

This chapter is adopted pursuant to chapter 18.86 RCW, chapter 173-158 WAC and WAC 173-220-030. [Ord. 1583 § 92, 2013.]

16.15.050 Basis for establishing the areas of special flood hazard.

The special flood hazard areas identified by the Federal Insurance Administrator in a scientific and engineering report entitled “The Flood Insurance Study (FIS) for King County, Washington and Incorporated Areas” dated August 19, 2020, and any revisions thereto, with accompanying flood insurance rate maps (FIRMs), and any revisions thereto, are hereby adopted by reference and declared to be a part of this Title. The FIS and the FIRM are on file at 21630 11th Ave. S., Suite D, Des Moines, WA 98198. The best available information for flood hazard area identification as outlined in DMMC 16.15.110 shall be the basis for regulation until a new FIRM is issued that incorporates data utilized under DMMC 16.15.110. [Ord. 1738 § 2, 2020; Ord. 1583 § 93, 2013.]

16.15.060 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. 1738 § 3, 2020; Ord. 1583 § 94, 2013.]

16.15.070 Interpretation.

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

(1) Considered as minimum requirements; and

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

(3) Deemed neither to limit nor repeal any other powers granted to the City under state statutes. [Ord. 1583 § 95, 2013.]

16.15.080 Warning and disclaimer of liability.

The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood hazard or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create any legal liability on the part of the City, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter or any lawfully made administrative decision. [Ord. 1583 § 96, 2013.]

16.15.090 Establishment of development permit.

A development permit shall be obtained before construction or development begins within any area of flood hazard established in DMMC 16.15.050. The permit shall be for all structures including manufactured homes and for all other development including fill and other activities. Application for a development permit shall be made on forms furnished by the Floodplain Administrator and shall 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, on-site storage of materials, drainage facilities; and the location of the foregoing. Specifically, the following information shall be furnished by the applicant:

(1) Elevation, in relation to mean sea level of the lowest floor (including basement) of all structures; and

(2) Elevation in relation to mean sea level to which any structure has been floodproofed; and

(3) Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria in DMMC 16.15.180(2); and

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

(5) Where a structure is proposed in a V, V1-30, or VE Zone, a V-Zone design certificate is required; and

(6) Where development is proposed in a floodway, an engineering analysis indicating no rise of the base flood elevation; and

(7) A report which identifies and assesses habitat impacts, if any, and proposes conservation methods consistent with federal permitting requirements. Preparation of the report shall be the responsibility of the applicant and shall utilize the expertise of a biologist specializing in wetland, riverine, or coastal zone ecology; and

(8) Any other such information that may be reasonably required by the Floodplain Administrator in order to review the application. [Ord. 1738 § 4, 2020; Ord. 1583 § 97, 2013.]

16.15.100 Designation and duties and responsibilities of the Floodplain Administrator.

The Floodplain Administrator is hereby appointed to administer and implement this Title by granting or denying development permit applications in accordance with its provisions.

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

(1) Reviewing all development permits to determine that the permit requirements of this chapter have been satisfied; and

(2) Reviewing 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; and

(3) The site is reasonably safe from flooding; and

(4) Notify FEMA when annexations occur in the special flood hazard area; and

(5) Reviewing 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 DMMC 16.15.200(1) are met. [Ord. 1738 § 5, 2020; Ord. 1583 § 98, 2013.]

16.15.110 Use of other base flood data (in A and V Zones).

When base flood elevation data has not been provided (in A or V Zones) in accordance with DMMC 16.15.050, the Floodplain Administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal, state, or other source, in order to administer DMMC 16.15.180 and 16.15.200. [Ord. 1738 § 6, 2020; Ord. 1583 § 99, 2013.]

16.15.120 Information to be obtained and maintained.

(1) Where base flood elevation data is provided through flood insurance studies, FIRMs, or as in DMMC 16.15.110, 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.

(2) Documentation of the elevation of the bottom of the lowest horizontal structural member in V or VE Zones.

(3) For all new or substantially improved floodproofed nonresidential structures where base flood elevation data is provided through the FIS, FIRM, or as required in DMMC 16.15.110:

(a) Obtain and record the actual elevation (in relation to mean sea level) to which the structure was floodproofed; and

(b) Maintain the floodproofing certifications required in DMMC 16.15.090(3).

(4) Certification required by DMMC 16.15.200(1) (floodway encroachments).

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

(6) Improvement and damage calculations.

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

(8) In coastal high hazard areas, certification shall be obtained from a registered professional engineer or architect that the structure is securely anchored to adequately anchored pilings or columns in order to withstand high velocity waters, storm surges, and tsunamis. [Ord. 1738 § 7, 2020; Ord. 1583 § 100, 2013.]

16.15.130 Alteration of watercourses.

(1) Notify adjacent communities and the state Department of Ecology (DOE) 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 the watercourse so that the flood-carrying capacity is not diminished. [Ord. 1583 § 101, 2013.]

16.15.140 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 DMMC 16.15.170. Such appeals shall be granted consistent with the standards of Section 60.6 of Appeals and Regulations of the National Flood Insurance Program (44 C.F.R. 59 through 76). [Ord. 1583 § 102, 2013.]

16.15.145 Changes to special flood hazard area.

(1) If a project will alter the base flood elevation (BFE) or boundaries of the special flood hazard area (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.

(2) 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. 1738 §§ 14, 18, 2020.]

16.15.150 Appeal and variances.

Appeals of administrative orders, decisions or determinations under this chapter shall be processed pursuant to chapter 18.20 DMMC. [Ord. 1738 § 8, 2020; Ord. 1583 § 103, 2013.]

16.15.160 Variance criteria and conditions.

(1) When considering an application for a variance to any provisions of this chapter, the Hearing Examiner shall consider all technical evaluations, all relevant factors and standards specified in other sections of this chapter, and:

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

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

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

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

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

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

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

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

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

(j) The expected height, velocity, duration, rate of rise, and sediment transport of the flood waters and the effects of wave action, if applicable, expected at the site; and

(k) The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, gas, electrical, and water systems, and streets and bridges.

(2) Conditions for Variances.

(a) Generally, the only condition under which a variance from the elevation standard may be granted shall be 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 base flood level; provided, that the variance criteria listed above have been fully considered.

(b) Variances may be granted for the reconstruction, rehabilitation, or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places, 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) Variances shall not be granted within a designated floodway if any increase in flood levels during the base flood discharge would result.

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

(e) Variances shall only be granted upon:

(i) A showing of good and sufficient cause; and

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

(iii) 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 such variances pertain to a physical piece of property; such variances are not personal in nature and do not pertain to a structure, inhabitants thereof, or economic or financial circumstances.

(g) Variances may be granted 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 has a low damage potential, complies with all other variance criteria except DMMC 16.15.180(2)(a)(iv), and otherwise complies with the general standards of this chapter.

(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. 1738 § 9, 2020; Ord. 1583 § 104, 2013.]

16.15.170 Provisions for flood hazard protection – 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 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, FEMA 85).

(2) Construction Materials and Methods.

(a) All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

(b) All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

(c) 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.

(3) Utilities.

(a) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.

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

(c) New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters.

(d) On-site waste disposal systems shall be located to avoid impairment to such systems or contamination from such systems during flooding. Locating such equipment below the base flood elevation may cause annual flood insurance premiums to be increased.

(4) Subdivision Proposals.

(a) All subdivision proposals shall be consistent with the need to minimize flood damage.

(b) All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize or eliminate flood damage.

(d) Base flood elevation data shall be provided for subdivision proposals and other proposed developments which contain at least 10 lots or one acre, whichever is less. 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 50 lots or five acres (whichever is less).

(5) Review of Building Permits. Where elevation data is not available either through the flood insurance study, FIRM, or from another authoritative source, applications for building permits shall be reviewed by the Building Official to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet above grade in these zones may result in higher insurance rates. [Ord. 1738 § 10, 2020; Ord. 1583 § 105, 2013.]

16.15.180 Specific standards.

In all areas of special flood hazards where base flood elevation data has been provided as set forth in DMMC 16.15.050 or 16.15.110, the following provisions are required:

(1) Residential Construction.

(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 residential structure shall have the lowest floor, including basement, elevated one foot or more above the BFE. Mechanical equipment and utilities shall be waterproof or elevated at least one foot above the BFE.

(b) New construction and substantial improvement of any residential structure in an unnumbered A Zone for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.

(c) New construction and substantial improvement of any residential structure in a V, V1-30, or VE Zone shall meet the requirements in DMMC 16.15.240.

(d) 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 flood waters. 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) A minimum of two openings having a total net area of not less than one square inch for every one 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, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of flood waters.

(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 flood waters.

(2) Nonresidential Construction. New construction and substantial improvement of any commercial, industrial, or other nonresidential structure shall meet the requirements of subsection (a) or (b) below:

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

(i) In AE and A1-30 Zones or other A-zoned areas where the BFE has been determined or can be reasonably obtained:

(A) 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.

(B) Mechanical equipment and utilities shall be waterproofed or elevated at least one foot above the BFE, or as required by ASCE 24, whichever is greater.

(ii) If located in an Unnumbered A Zone for which a BFE is not available and cannot be reasonably obtained, the structure shall be reasonably safe from flooding, but in all cases the lowest floor shall be at least two feet above the highest adjacent grade.

(iii) If located in a V, V1-30, or VE Zone, the structure shall meet the requirements in DMMC 16.15.240.

(iv) 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 flood waters. 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 flood water.

(D) A garage attached to a structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry and exit of flood waters.

(b) If the requirements of subsection (2)(a) 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:

(i) Be dry-floodproofed so that below one foot or more above the base flood level the structure is watertight with walls substantially impermeable to the passage of water or dry-floodproofed to the elevation required by ASCE 24, whichever is greater; and

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

(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 Floodplain Administrator; and

(iv) Nonresidential structures that are elevated but not floodproofed must meet the same standards for space below the lowest floor as described in subsection (2)(a)(iv) of this section; and

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

(3) 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. This subsection applies to new manufactured homes placed on any site, manufactured homes in a new or expanded manufactured home park or subdivision, and new manufactured homes in an existing manufactured home park and subdivision.

(4) Recreational Vehicles (44 CFR 60.3(c)(14)). Recreational vehicles placed on sites are required to either:

(a) Be on the site for fewer than 180 consecutive days; or

(b) 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

(c) Meet the requirements of DMMC 16.15.170 and this section and the elevation and anchoring requirements for manufactured homes.

(5) New 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.

(6) New Appurtenant Structures (Detached Garages and Small Storage Structures). For A Zones (A, AE, A1-30, AH, AO):

(a) 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:

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

(ii) The portions of the appurtenant structure located below the BFE must be built using flood resistant materials;

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

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

(v) The appurtenant structure must comply with floodway encroachment provisions in DMMC 16.15.200(1);

(vi) The appurtenant structure must be designed to allow for the automatic entry and exit of flood waters in accordance with subsection (1)(d) of this section;

(vii) The structure shall have low damage potential;

(viii) If the structure is converted to another use, it must be brought into full compliance with the standards governing such use; and

(ix) The structure shall not be used for human habitation.

(b) Detached garages, storage structures, and other appurtenant structures not meeting the above standards must be constructed in accordance with all applicable standards in subsection (1) of this section.

(c) Upon completion of the structure, certification that the requirements of this section have been satisfied shall be provided to the Floodplain Administrator for verification. [Ord. 1738 § 11, 2020; Ord. 1583 § 106, 2013.]

16.15.190 AE and A1-30 Zones with base flood elevations but no floodways.

In areas with base flood elevations (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 foot at any point within the community. [Ord. 1583 § 107, 2013.]

16.15.200 Floodways.

Located within areas of special flood hazard established in DMMC 16.15.050 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(1) Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic 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) Construction or reconstruction of residential structures is prohibited within designated floodways, except for:

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

(b) Repairs, reconstruction or improvements to a structure, the cost of which does not exceed 50 percent of the market value of the structure either:

(i) Before the repair or reconstruction is started; or

(ii) If the structure has been damaged, and is being restored, before the damage occurred. Any project for improvement of a structure to correct existing violations of 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 from the 50 percent.

(3) If subsection (1) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of DMMC 16.15.170 through 16.15.200. [Ord. 1738 § 12, 2020; Ord. 1583 § 108, 2013.]

16.15.210 Critical facility.

Construction of new critical facilities shall be, to the extent possible, located outside the limits of the 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 BFE shall be provided to all critical facilities to the extent possible. [Ord. 1738 §§ 15, 19, 2020.]

16.15.220 Wetlands management.

To the maximum extent possible, each development subject to this chapter shall avoid the short-term and long-term adverse impacts associated with the destruction or modification of wetlands, especially those activities which limit or disrupt the ability of the wetland to alleviate flooding impacts. The following process shall be implemented for such development:

(1) Review proposals for development within base floodplains for their possible impacts on wetlands located within the floodplain.

(2) Ensure that development activities in or around wetlands do not negatively affect public safety, health, and welfare by disrupting the ability of the wetland to reduce flood and storm drainage.

(3) Request technical assistance from the Department of Ecology in identifying wetland areas. Existing wetland map information from the National Wetlands Inventory (NWI) may be used in conjunction with the area’s FIRM to prepare an overlay zone indicating critical wetland areas deserving special attention. [Ord. 1583 § 109, 2013.]

16.15.230 Compliance with federal and state permits required.

No approval of an application for a development permit within an area of special flood hazard shall be issued without first demonstrating compliance with all necessary federal and state environmental permit requirements, including, but not limited to, Clean Water Act, 33 U.S.C. 1344, Section 404 permits and Endangered Species Act, 16 U.S.C. 1531, Section 10 permits. [Ord. 1583 § 110, 2013.]

16.15.240 Standards for coastal high hazard areas (V Zones).

Located within areas of special flood hazard established in DMMC 16.15.050 are coastal high hazard areas, which are designated as Zones V1-V30, VE, and V. These areas have special flood hazards associated with high velocity waters from surges and, therefore, in addition to meeting all provisions in this chapter, the following provisions shall also apply:

(1) All new allowable construction and substantial improvement in Zones V1-V30 and VE (V if base flood elevation data is available) on the community’s FIRM shall be elevated on pilings and columns so that:

(a) For residential buildings, the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated one foot or more above the base flood level; and

(b) For nonresidential buildings, the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated one foot or more above the base flood level or meets the elevation requirements of ASCE 24, whichever is higher; and

(c) The pile or column foundation and structure attached thereto is anchored to resist flotation, collapse, and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Wind and water loading values shall each have a one percent chance of being equaled or exceeded in any given year (100-year mean recurrence interval); and

(d) A registered professional engineer or architect shall develop or review the structural design, specifications, and plans for the construction and shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for meeting the provisions of subsections (1)(a) and (b) of this section.

(2) Obtain the elevation (in relation to mean sea level) of the bottom of the lowest structural member of the lowest floor (excluding pilings and columns) of all new and substantially improved structures in Zones V1-V30, VE, and V on the community’s FIRM, and whether or not such structures contain a basement. The Floodplain Administrator shall maintain a record of all such information.

(3) All new construction within Zones V1-30, VE, and V on the community’s FIRM shall be located landward of the reach of mean high tide.

(4) Provide that all new construction and substantial improvements within Zones V1-30, VE, and V on the community’s FIRM have the space below the lowest floor either free of obstruction or constructed with nonsupporting breakaway walls, open wood latticework, or insect screening intended to collapse under wind and water loads without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. For the purpose of this section, a breakaway wall shall have a design safe loading resistance of not less than 10 and no more than 20 pounds per square foot. Use of breakaway walls which exceed a design safe loading resistance of 20 pounds per square foot (either by design or when so required by local or state codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet the following conditions:

(a) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and

(b) The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement, or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and nonstructural). Maximum wind and water loading values to be used in this determination shall each have a one percent chance of being equaled or exceeded in any given year (100-year mean recurrence interval).

(5) If breakaway walls are utilized, such enclosed space shall be usable solely for parking of vehicles, building access, or storage. Such space shall not be used for human habitation.

(6) Prohibit the use of fill for structural support of buildings within Zones V1-30, VE, and V on the community’s FIRM.

(7) Prohibit manmade alteration of sand dunes within Zones V1-30, VE, and V on the community’s FIRM which would increase potential flood damage.

(8) Manufactured homes to be placed or substantially improved within Zones V1-30, V, and VE on the community’s FIRM on sites:

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

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

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

shall meet the standards of subsections (1) through (6) of this section and manufactured homes placed or substantially improved on other sites in an existing manufactured home park or subdivision within Zones V1-30, V, and VE on the FIRM shall meet the requirements of DMMC 16.15.180(3).

(9) Recreational vehicles placed on sites within V or VE Zones on the community’s FIRM shall either:

(a) Be on the site for fewer than 180 consecutive days; or

(b) Be fully licensed and ready for highway use, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or

(c) Meet the requirements of subsections (1) and (3) of this section and the anchoring requirements for manufactured homes (DMMC 16.15.170(1)(b)). [Ord. 1738 § 13, 2020; Ord. 1583 § 111, 2013.]

16.15.250 Encroachments.

The cumulative effect of any proposed development, when combined with all other existing and anticipated development, shall not increase the water surface elevation of the base flood more than one foot at any point. [Ord. 1583 § 112, 2013.]

16.15.260 Compliance.

All development within special flood hazard areas is subject to the terms of this Title and other applicable regulations. [Ord. 1738 § 16, 2020.]

16.15.270 Penalties for noncompliance.

No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this Title and other applicable regulations. Violations of the provisions of this Title by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction thereof be fined not more than $1,000 or imprisoned for not more than 90 days, or both, 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. [Ord. 1738 § 17, 2020.]