Chapter 15.16
FLOOD DAMAGE PREVENTION

Sections:

15.16.010    Applicability.

15.16.020    Statutory authorization.

15.16.030    Findings of fact.

15.16.040    Purpose.

15.16.050    Methods of reducing flood losses.

15.16.060    Definitions.

15.16.070    Basis for establishing areas of special flood hazard and floodways.

15.16.080    Compliance with chapter required.

15.16.090    Abrogation and greater restrictions.

15.16.100    Interpretation.

15.16.110    Warning and disclaimer of liability.

15.16.120    Establishment of development permit.

15.16.130    Designation of planning and community development director.

15.16.140    Planning and community development director – Duties generally.

15.16.150    Permit review.

15.16.160    Use of other base flood data.

15.16.170    Information to be obtained and maintained.

15.16.180    Alteration of watercourses.

15.16.190    Interpretation of FIRM boundaries.

15.16.200    Appeal board.

15.16.210    Conditions for variances.

15.16.220    Provisions for flood hazard reduction – Generally.

15.16.230    Anchoring.

15.16.240    Construction materials and methods.

15.16.250    Utilities.

15.16.260    Subdivision proposals.

15.16.270    Review of building permits.

15.16.280    Specific standards – Generally.

15.16.290    Residential construction.

15.16.300    Nonresidential construction.

15.16.310    Manufactured homes.

15.16.320    Encroachments.

15.16.325    Floodways.

15.16.330    Standards for shallow flooding areas (AO zones).

15.16.340    Coastal high hazard areas.

15.16.350    Flood Insurance Rate Maps and Flood Boundary and Floodway Map.

15.16.010 Applicability.

This chapter shall apply to all areas of special flood hazards and all areas of shallow flooding within the jurisdiction of the city. (Ord. 87-5 § 3.1)

15.16.020 Statutory authorization.

The Legislature of the state has, in ORS 221.410, delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety and general welfare of its citizenry. (Ord. 87-5 § 1.1-1)

15.16.030 Findings of fact.

A. The flood hazard areas of the city are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.

B. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities and, when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed, elevated or otherwise protected from flood damage also contribute to the flood loss. (Ord. 87-5 § 1.1-2)

15.16.040 Purpose.

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

A. Protect human life and health;

B. Minimize expenditure of public money and costly flood control projects;

C. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

D. Minimize prolonged business interruptions;

E. Minimize damage to public facilities and utilities, such as water and gas mains; electric, telephone and sewer lines; and streets and bridges located in areas of special flood hazard;

F. 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. Ensure that potential buyers are notified that property is in an area of special flood hazard; and

H. Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions. (Ord. 87-5 § 1.1-3)

15.16.050 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 flood heights or velocities;

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

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

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

E. Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. (Ord. 87-5 § 1.1-4)

15.16.060 Definitions.

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

“Appeal” means a request for a review of the planning and community development director’s or designee’s interpretation of any provision of this chapter or a request for a variance.

“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 to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and velocity flow may be evident. AO is characterized as sheet flow and AH indicates ponding.

“Area of special flood hazard” means the land in the floodplain within a community subject to a one percent or greater chance of flooding in any given year. Designation on maps always includes the letters A or V.

“Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year; also referred to as the “100-year flood.” Designation on maps always includes the letters A or V.

“Breakaway walls” means any type of walls, whether solid or lattice, and whether constructed of concrete, masonry, wood, metal, plastic or any other suitable building materials, which are not part of the structural support of the building and which are so designed as to break away, under abnormally high tides or wave action, without damage to the structural integrity of the building on which they are used or any buildings to which they might be carried by floodwaters.

“Coastal high hazard area” means the area subject to high-velocity waters, including but not limited to storm surge or tsunamis. The area is designated on a FIRM as V and VE.

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

“Flood” or “flooding” means a general and temporary condition of partial or complete inundation of normally dry land areas from:

1. The overflow of inland or tidal waters; and/or

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

“Flood Insurance Rate Map” (“FIRM”) means the official map on which the Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

“Flood insurance study” means the official report provided by the Federal Insurance Administration that includes flood profiles, the Flood Boundary and Floodway Map, and the water surface elevation of the base flood.

“Floodway” means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.

“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 this chapter found at LCMC 15.16.290(B).

“Manufactured home” means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term “manufactured home” also includes park trailers, travel trailers and other similar vehicles placed on a site for greater than 180 consecutive days. For insurance purposes, the term “manufactured home” does not include park trailers, travel trailers and other similar vehicles.

“Manufactured home park or subdivision” means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale.

“Mean sea level” means the average height of the sea for all stages of the tide.

“New construction” means structures for which the start of construction commenced on or after the effective date of the ordinance codified in this chapter and includes any subsequent improvements to a structure that already meets the definition of “new construction.”

“Permanent foundation” refers to a natural or manufactured support system to which a structure is anchored or attached. A permanent foundation is capable of resisting flood forces and may include posts, piles, poured concrete or reinforced block walls, properly compacted fill or other systems of comparable flood resistivity and strength.

“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 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 foundation 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.

“Structure” means a walled and roofed building, including a gas or liquid storage tank, that is principally above ground.

“Substantial damage” pertains to flood-related damage where the cost of restoring the structure would equal or exceed 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 50 percent of the market value of the structure either (1) before the improvement or repair is started, or (2) if the structure has been damaged and is being restored, before the damage occurred. For the purpose 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 comply with existing state or local health, sanitary or safety code specifications which are solely 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 which permits construction in a manner that would otherwise be prohibited by this chapter. (Ord. 98-9 §§ 1, 2; Ord. 91-6 §§ 1, 2; Ord. 87-5 § 2.0)

15.16.070 Basis for establishing areas of special flood hazard and floodways.

The areas of special flood hazard identified by the Federal Insurance Administration in a scientific and engineering report entitled “The Flood Insurance Study for Lincoln City, Oregon,” revised August 17, 1998, with accompanying Flood Insurance Rate Maps, are adopted. The area of floodway identified by the Federal Insurance Administration in a scientific and engineering report entitled “The Flood Insurance Study for Lincoln County, Oregon,” dated September 30, 1980, with accompanying Flood Boundary and Floodway Map, panel 3, are adopted. The flood insurance studies shall be maintained on file at the planning and community development department at City Hall. (Ord. 98-9 § 3; Ord. 94-21 § 1; Ord. 87-5 § 3.2)

15.16.080 Compliance with chapter required.

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. (Ord. 87-5 § 3.3)

15.16.090 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. 87-5 § 3.4)

15.16.100 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. 87-5 § 3.5)

15.16.110 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 city, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder. (Ord. 87-5 § 3.6)

15.16.120 Establishment of development permit.

A development permit shall be obtained before construction or development begins within any area of special flood hazard established in LCMC 15.16.070. The permit shall be for all structures, including mobile homes, as set forth in LCMC 15.16.060, and for all other development, including fill and other activities, also as set forth in LCMC 15.16.060. Application for a development permit shall be made on forms furnished by the planning and community development director or designee 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.

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

B. Elevation, in relation to mean sea level, to which any structure has been floodproofed;

C. Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria in LCMC 15.16.300; and

D. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development. (Ord. 98-9 § 4; Ord. 87-5 § 4.1)

15.16.130 Designation of planning and community development director.

The planning and community development director is appointed to administer and implement this chapter by granting or denying development permit applications in accordance with its provisions. (Ord. 98-9 § 5; Ord. 87-5 § 4.2)

15.16.140 Planning and community development director – Duties generally.

The duties of the planning and community development director shall include, but not be limited to, those set forth in LCMC 15.16.150 through 15.16.190. (Ord. 98-9 § 6; Ord. 87-5 § 4.3)

15.16.150 Permit review.

The planning and community development director shall:

A. Review all development permits to determine that the permit requirements of this chapter have been satisfied;

B. 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;

C. Review all development permits to determine whether the proposed development is located in the floodway. If located in the floodway, he shall ensure that the encroachment provisions of LCMC 15.16.320 are met. (Ord. 98-9 § 7; Ord. 87-5 § 4.3-1)

15.16.160 Use of other base flood data.

When base flood elevation data has not been provided in accordance with LCMC 15.16.070, the planning and community development director 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 LCMC 15.16.280 through 15.16.320. (Ord. 98-9 § 8; Ord. 87-5 § 4.3-2)

15.16.170 Information to be obtained and maintained.

A. Where base flood elevation data is provided through the flood insurance study or required as in LCMC 15.16.160, the planning and community development director shall obtain and record the actual elevation in relation to mean sea level of the lowest floor, including basement, of all new or substantially improved structures, and whether or not the structure contains a basement.

B. For all new or substantially improved structures, the planning and community development director shall:

1. Verify and record the actual elevation in relation to mean sea level; and

2. Maintain the floodproofing certifications required in LCMC 15.16.120(C).

C. The planning and community development director shall maintain for public inspection all records pertaining to the provisions of this chapter. (Ord. 98-9 § 9; Ord. 87-5 § 4.3-3)

15.16.180 Alteration of watercourses.

The planning and community development director shall:

A. Notify adjacent communities and the Oregon Department of Land Conservation and Development prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration;

B. Require that maintenance be provided within the altered or relocated portion of such watercourse so that the flood-carrying capacity is not diminished. (Ord. 98-9 § 10; Ord. 87-5 § 4.3-4)

15.16.190 Interpretation of FIRM boundaries.

The planning and community development director shall 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 LCMC 15.16.200. (Ord. 98-9 § 11; Ord. 87-5 § 4.3-5)

15.16.200 Appeal board.

A. The city planning commission as established by the city shall hear and decide appeals and requests for variances from the requirements of this chapter.

B. The city planning commission shall hear and decide appeals when it is alleged there is an error in any requirement, decision or determination made by the planning and community development director in the enforcement or administration of this chapter.

C. Those aggrieved by the decision of the city planning commission, or any taxpayer, may appeal such decision as provided by law.

D. In passing upon such applications, the city planning commission shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:

1. The danger that materials may be swept 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 city planning commission may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

F. The planning and community development director shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration upon request. (Ord. 98-9 §§ 12, 13; Ord. 87-5 § 4.4-1)

15.16.210 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 the items set forth in LCMC 15.16.200(D) 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.

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 as identified in LCMC 15.16.200(D), or conflict with existing local laws and 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 the general standards set forth in LCMC 15.16.230 and 15.16.240.

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. 87-5 § 4.4-2)

15.16.220 Provisions for flood hazard reduction – Generally.

In all areas of special flood hazards, the standards set forth in LCMC 15.16.230 through 15.16.340 are required. (Ord. 87-5 § 5.1)

15.16.230 Anchoring.

A. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.

B. All manufactured homes must likewise be anchored to prevent flotation, collapse or lateral movement, and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but 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), except for single-wide manufactured homes which must comply with the requirements of OAR 814-23-065. (Ord. 87-5 § 5.1-1)

15.16.240 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. (Ord. 87-5 § 5.1-2)

15.16.250 Utilities.

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

B. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters.

C. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. (Ord. 87-5 § 5.1-3)

15.16.260 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 so constructed as to minimize flood damage.

C. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage.

D. Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain at least 50 lots or five acres, whichever is less. (Ord. 87-5 § 5.1-4)

15.16.270 Review of building permits.

Where elevation data is not available either through the flood insurance study or from another authoritative source (LCMC 15.16.160), applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet above grade in these zones may result in higher insurance rates. (Ord. 87-5 § 5.1-5)

15.16.280 Specific standards – Generally.

In all areas of special flood hazards where base flood elevation data has been provided as set forth in LCMC 15.16.070 or 15.16.160, the provisions set forth in LCMC 15.16.290 through 15.16.310 are required. (Ord. 87-5 § 5.2)

15.16.290 Residential construction.

A. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, one foot or more above base flood elevation.

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 must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:

1. A minimum of two openings 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.

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

3. Openings may be equipped with screens, louvers or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters. (Ord. 98-9 § 14; Ord. 87-5 § 5.2-1)

15.16.300 Nonresidential construction.

New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, one foot or more above the base flood elevation; or, together with attendant utility and sanitary facilities, shall:

A. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

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

C. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this section 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 LCMC 15.16.170(B);

D. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in LCMC 15.16.290(B); and

E. Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building constructed to the base flood level will be rated as one foot below that level). (Ord. 98-9 § 15; Ord. 87-5 § 5.2-2)

15.16.310 Manufactured homes.

All manufactured homes to be placed or substantially improved within Zones A, AH, and AE shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at one foot or more above the base flood elevation and securely anchored to an adequately anchored system in accordance with the provisions of LCMC 15.16.230(B). (Ord. 98-9 § 16; Ord. 87-5 § 5.2-3)

15.16.320 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. 87-5 § 5.3)

15.16.325 Floodways.

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

A. Encroachments, including fill, new construction, substantial improvements, and other development, are prohibited unless certification by a registered professional engineer or architect is provided, demonstrating that encroachments will not result in any increase in flood levels during the occurrence of the base flood discharge.

B. If the certification required by subsection (A) of this section is provided, then all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions set out in LCMC 15.16.220 through 15.16.340. (Ord. 94-21 § 2)

15.16.330 Standards for shallow flooding areas (AO zones).

Shallow flooding areas appear on FIRMs as AO zones with depth designations. The base flood depths in these zones range from one to three feet 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 within AO zones shall have the lowest floor, including basement, elevated one foot or more above the depth number specified on the FIRM (at least two feet if no depth number is specified), as measured from the highest grade adjacent to the building site.

B. New construction and substantial improvements of nonresidential structures within AO zones shall either:

1. Have the lowest floor, including basement, elevated one foot or more above the depth number specified on the FIRM (at least two feet if no depth number is specified), as measured from the highest grade adjacent to the building site; 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 LCMC 15.16.300(C).

C. Adequate drainage paths shall be required around structures on slopes to guide floodwaters around and away from proposed structures. (Ord. 98-9 §§ 17, 18; Ord. 87-5 § 5.4)

15.16.340 Coastal high hazard areas.

Located within areas of special flood hazard established in LCMC 15.16.070 are coastal high hazard areas, designated as VE and/or V. These areas have special flood hazards associated with high-velocity waters from tidal surges and, therefore, in addition to meeting all provisions of this chapter, the following provisions shall also apply:

A. All new construction and substantial improvements in zones VE (V if base flood elevation data is available) shall be elevated on pilings and foundations so that:

1. The bottom of the lowest horizontal structure member of the lowest floor, excluding the pilings or columns, is elevated one foot or more above the base flood level; and

2. 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).

B. 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 this section.

C. The elevation, in relation to mean sea level, of the lowest floor, excluding pilings and columns, of all new and substantially improved structures in zones V and VE shall be obtained; and it shall be ascertained whether or not such structures contain a basement. The planning and community development director shall maintain a record of all such information.

D. All new construction shall be located landward of the reach of mean high tide.

E. All new construction and substantial improvements shall 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:

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

2. 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).

F. 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.

G. The use of fill for structural support of buildings is prohibited.

H. Manmade alteration of sand dunes which would increase potential flood damage is prohibited. (Ord. 98-9 §§ 19 – 21; Ord. 87-5 § 5.5)

15.16.350 Flood Insurance Rate Maps and Flood Boundary and Floodway Map.

The Flood Insurance Rate Map for the city (Community Panel Number 410130-0001-C, Map Revised August 17, 1998), is adopted and shall be maintained on file at the planning and community development department at City Hall. The Flood Boundary and Floodway Map (Panel 3 of 21) for the county (Community Panel Number 410129-0003-B, Effective Date: September 3, 1980), is adopted and shall be maintained on file at the planning and community development department at City Hall. (Ord. 98-9 § 22; Ord. 94-21 § 3; Ord. 87-5 § 6.0)