Chapter 11.58
FLOOD DAMAGE PREVENTION

Sections:

11.58.010    Statement of purpose.

11.58.020    Methods of reducing flood losses.

11.58.030    Definitions.

11.58.040    Lands to which this chapter applies.

11.58.050    Adoption of Flood Insurance Study—Establishing areas of special flood hazard.

11.58.060    Compliance.

11.58.070    Abrogation and greater restrictions.

11.58.080    Interpretation.

11.58.090    Warning and disclaimer of liability.

11.58.100    Development permit required.

11.58.110    Designation of the director of community and economic development.

11.58.120    Duties and responsibilities of the director of community and economic development.

11.58.130    Variance procedure.

11.58.140    General standards.

11.58.150    Specific standards.

11.58.160    Floodways.

11.58.170    Standards for shallow flooding areas (AO zones).

11.58.180    Wetlands management.

11.58.010 Statement of purpose.

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

(1)    To protect human life and health;

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

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

(4)    To minimize prolonged business interruptions;

(5)    To minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, streets and bridges located in areas of special flood hazard;

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

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

(8)    To ensure that those who occupy the areas of special flood hazard assume responsibilities for their actions.

(B)    The city’s enactment or enforcement of this chapter shall not be construed for the benefit of any individual person or group of persons other than the general public. In the event of a conflict between the intent of this subsection and any other provision of this chapter, this subsection shall govern insofar as applicable. (Ord. 2560 § 1 (part), 1981).

11.58.020 Methods of reducing flood losses.

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

(1)    Restricting or prohibiting uses which are dangerous to health, safety, and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;

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

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

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

(5)    Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. (Ord. 2560 § 1 (part), 1981).

11.58.030 Definitions.

Unless specifically defined below, words or phrases 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. The following words, phrases, and terms as used in this chapter shall have the following meaning ascribed to them, unless a different meaning clearly appears from the context:

“Appeal” means a request for a review of the interpretation by the director of community and economic development 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 depth 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 equalled or exceeded in any given year. Also referred to as the “one-hundred-year flood.” Designation on maps always includes the letters A or V.

“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.

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

“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-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 in Section 11.58.150(2).

“Habitable floor” means any floor usable for living purposes, which includes working, sleeping, eating, cooking or recreation, or a combination thereof. A floor used only for storage purposes is not a “habitable floor.”

“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 one hundred eighty 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.

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

“Shall” means:

1.    With respect to the functions and powers of the director of community and economic development, any agents and employees of the city of Yakima authorized hereunder, direction and authorization to act in the exercise of sound discretion and good faith.

2.    With respect to the obligation upon owners and occupants of premises and their agents, a mandatory requirement to act in compliance with this chapter at the risk of civil and criminal liability upon failure so to act.

“Start of construction” includes substantial improvement, and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement or other improvement was within one hundred eighty days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading, and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers, or 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 or roofed building or manufactured home, including a gas or liquid storage tank that is principally above ground.

“Substantial improvement” means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds fifty percent of the market value of the structure 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 the 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. 3344 § 1, 1991: Ord. 3052 § 1, 1987: Ord. 2560 § 1 (part), 1981).

11.58.040 Lands to which chapter applies.

This chapter shall apply to all areas of special flood hazards within the jurisdiction of the city of Yakima. (Ord. 2560 § 1 (part), 1981).

11.58.050 Adoption of Flood Insurance Study—Establishing areas of special flood hazard.

A.    “The Flood Insurance Study for the City of Yakima,” dated March 2, 1998, or as amended and the “Flood Insurance Study: Yakima County Washington Unincorporated Areas,” dated December 5, 1984, or as amended, for the county of Yakima for areas annexed into the city of Yakima after December 1, 1981, (three copies of which are filed with the office of the Yakima city clerk) are adopted as an official study and official maps of the city of Yakima; and as by this reference declared to be a part of this chapter and incorporated in this subsection.

B.    The areas of special flood hazard identified by the official study and maps adopted by subsection A of this section are designated and established as special flood hazard areas for the purpose of interpreting and administering this chapter. (Ord. 98-5 § 1, 1998: Ord. 3344 § 2, 1991: Ord. 3052 § 2, 1987; Ord. 2560 § 1 (part), 1981).

11.58.060 Compliance.

No structure or land hereafter shall be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable laws, rules, and regulations. In addition to any other penalty or remedy available by law, a civil penalty of not more than five thousand dollars per violation may be imposed upon any person, firm, or corporation which violates the provisions of this title, and in addition, the city of Yakima shall be entitled to its costs and expenses including a reasonable attorney fee. The city attorney is authorized to collect the civil penalty by appropriate legal remedies. Nothing herein contained shall prevent the city of Yakima from taking such other lawful action as is necessary to prevent or remedy any violation. (Ord. 3344 § 3, 1991: Ord. 2560 § 1 (part), 1981).

11.58.070 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. 2560 § 1 (part), 1981).

11.58.080 Interpretation.

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

(1)    Considered as minimum requirements;

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

(3)    Deemed neither to limit or repeal any other powers granted under state statutes. (Ord. 2560 § 1 (part), 1981).

11.58.090 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 man-made 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 of Yakima, 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. 2560 § 1 (part), 1981).

11.58.100 Development permit required.

A development permit shall be obtained before construction or development begins within any area of special flood hazard established in Section 11.58.050. The permit shall be for all structures including manufactured homes, as set forth in the “definitions” (Section 11.58.030 of this chapter), and for all other development including fill and other activities, also as set forth in the “definitions.” Application for a development permit shall be made on forms furnished by the director of community and economic development 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 11.58.150(2);

4.    Description of the extent to which any watercourse will be altered or relocated as a result of proposed development. (Ord. 3052 § 3, 1987: Ord. 2560 § 1 (part), 1981).

11.58.110 Designation of the director of community and economic development.

The director of community and economic development is appointed to administer and implement this chapter by granting or denying development permit applications in accordance with its provisions. (Ord. 2560 § 1 (part), 1981).

11.58.120 Duties and responsibilities of the director of community and economic development.

Duties of the director of community and economic development shall include, but not be limited to:

1.    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 11.58.160(1) are met.

2.    Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 11.58.050, the director of community and economic development 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 11.58.150 and 11.58.160(2).

3.    Information to be Obtained and Maintained.

(1)    Where base flood elevation data is provided through the Flood Insurance Study or as required in subsection (2) of this section, obtain and record the actual elevation (in relation to mean sea level) of the lowest habitable floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.

(2)    For all new substantially improved floodproofed structures:

(a)    Verify and record the actual elevation (in relation to mean sea level); and

(b)    Maintain the floodproofing certifications required in Section 11.58.100(3).

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

4.    Alteration of Watercourses.

(1)    Notify adjacent communities and the Washington State 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.

5.    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 11.58.130. (Ord. 3052 § 4, 1987: Ord. 2560 § 1 (part), 1981).

11.58.130 Variance procedure.

For the purpose of this section, hearing examiner shall have the same meaning as in Section 15.02.020 of the city of Yakima Municipal Code.

A.    Appeal.

1.    The hearing examiner of the city shall hear and decide appeals and requests for variances from the requirements of this chapter.

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

3.    Those aggrieved by the decision of the hearing examiner or any taxpayer, may appeal such decision to the council following the appeal procedures outlined in Chapter 1.43 of the city of Yakima Municipal Code.

4.    In passing upon such applications, the hearing examiner shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:

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

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

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

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

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

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

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

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

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

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

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

5.    Generally, variances may be used 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 subsection (A)(4)(a)—(k) of this section has been fully considered. As the lot size increases beyond the one-half acre, the technical justification required for issuing the variances increases.

6.    Upon consideration of the factors of subsection (A)(4) of this section and the purpose of this chapter, the hearing examiner may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter. The director of community and economic development shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration upon request.

B.    Conditions for Variances.

1.    Variances may be used 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 the remainder of this section.

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

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

4.    Variances shall only be issued upon:

(a)    A showing of good and sufficient cause;

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

(c)    A determination that the granting of a variance will not result in increased flood height, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public as identified in subsection (A)(4) of this section or conflict with existing local laws or ordinances.

5.    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.

6.    Variances may be used for nonresidential buildings in very limited circumstances to allow a lesser degree of floodproofing than watertight or dry-floodproofing, where it can be determined that such action will have low damage potential, complies with all other variance criteria except subsection (B)(5) of this section, and otherwise complies with Section 11.58.140.

7.    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. 3344 § 4, 1991: Ord. 3052 § 5, 1987: Ord. 2560 § 1 (part), 1981).

11.58.140 General standards.

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

1.    Anchoring. Notwithstanding the provisions of Section 11.06.010 of this code:

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

(2)    All manufactured homes shall be anchored to resist flotation, collapse or lateral movement by providing over-the-top and frame ties to ground the anchors. Specific requirements shall be that:

(a)    Over-the-top ties be provided at each of the four corners of the manufactured home, with two additional ties per side at intermediate locations, with mobile homes less than fifty feet long requiring one additional tie per side;

(b)    Frame ties be provided at each corner of the home with five additional ties per side at intermediate points, with manufactured homes less than fifty feet long requiring four additional ties per side;

(c)    All components of the anchoring system be capable of carrying a force of four thousand eight hundred pounds; and

(d)    Any additions to the manufactured home be similarly anchored.

(3)    An alternative method of anchoring may involve a system designed to withstand a wind force of ninety miles per hour or greater. Certification must be provided to the director of community and economic development that his standard has been met.

2.    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 the conditions of flooding.

3.    Utilities.

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

(2)    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; and

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

4.    Subdivision Proposals.

(1)    All subdivision proposals shall be consistent with the need to minimize flood damage;

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

(3)    All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and

(4)    Where base flood elevation data has been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed development which contain at least fifty lots or five acres (whichever is less).

5.    Review of Building Permits. Where elevation data is not available, either through the Flood Insurance Study or from another authoritative source (Section 11.58.120(2)), 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. 3052 § 6, 1987: Ord. 2560 § 1 (part), 1981).

11.58.150 Specific standards.

In all areas of special flood hazards where base flood evaluation data has been provided as set forth in Section 11.58.050 or Section 11.58.120, the following provisions are required:

1.    Residential Construction.

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

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

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

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

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

2.    Nonresidential Construction.

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

(a)    Be floodproofed so that below one foot above 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; and

(c)    Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with the 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 11.58.120 3(2).

(2)    Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection 1 (2) of this section.

(3)    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 one foot above the base flood level will be rated at the base flood level).

3.    Critical Facility.

(1)    Construction of new critical facilities shall be, to the extent possible, located outside the limits of the base flood plain. Construction of new critical facilities shall be permissible within the base flood plain if no feasible alternative site is available. Critical facilities constructed within the base flood plain shall have the lowest floor elevated to three feet or more above the level of the base flood elevation 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 floodplain shall be provided to all critical facilities to the extent possible.

4.    Manufactured Homes.

(1)    Manufactured homes to be placed or substantially improved within zones A1-30, AH, and AE on the community’s FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is one foot or more above the base flood elevation; and be securely anchored to an adequately anchored foundation system in accordance with the provisions of Section 4.58.140(1). (Ord. 3440 § 1, 1992: Ord. 3344 § 5, 1991: Ord. 3052 § 7, 1987: Ord. 2560 § 1 (part), 1981).

11.58.160 Floodways.

Located within areas of special flood hazard established in Section 11.58.050 of this chapter 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 erosions potential, the following provisions apply:

(1)    Encroachments, including fill, new construction, substantial improvements, and other developments are prohibited unless certification by a registered professional engineer or architect demonstrates to the code administration manager that such encroachments shall 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 (i) repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and (ii) repairs, reconstruction, or improvements to a structure, the cost of which does not exceed fifty percent of the market value of the structure either, (A) before the repair, reconstruction, or repair is started, or (B) if the structure has been damaged, and is being restored, before the damage occurred. Work done on structures to comply with existing health, sanitary, or safety codes or to structures identified as historic places shall not be included in the fifty percent determination.

(3)    If Section 11.58.160(1) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Sections 11.58.140, 11.58.150, and 11.58.160 of this chapter. (Ord. 3344 § 6, 1991: Ord. 3093 § 1, 1988: Ord. 3058 § 1, 1987: Ord. 2560 § 1 (part), 1981).

11.58.170 Standards for shallow flooding areas (AO zones).

Shallow flooding areas appear on FIRM’s as AO zones with depth designations. The base flood depths in these zones range from one to three feet above ground where a clearly defined channel does not exist, or where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is usually characterized as sheet flow. In these areas, the following provisions apply:

1.    New construction and substantial improvements of residential structures within AO zones shall have the lowest floor (including basement) elevated above the highest adjacent grade of the building site one foot or more above the depth number specified on the FIRM (at least two feet if no depth number is specified).

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

a.    Have the lowest floor (including basement) elevated above the highest adjacent grade of the building site, one foot or more above the depth number specified on the FIRM (at least two feet if no depth number is specified); or

b.    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 11.58.150.

3.    Required adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures. (Ord. 3344 § 7, 1991: Ord. 3052 § 8, 1987).

11.58.180 Wetlands management.

To the maximum extent possible, avoid the short 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 should be implemented:

1.    Review proposals for development within base flood plains for their possible impacts on wetlands located within the floodplain.

2.    Ensure that the development activities in or around wetlands do not negatively affect the public safety, health, and welfare by disrupting the wetlands’ ability to reduce flood and storm drainage. (Ord. 3344 § 8, 1991).