Chapter 7.50
FLOODPLAIN MANAGEMENT OVERLAY DISTRICT1
Sections:
7.50.010 Authorization, findings and purpose of floodplain management overlay district.
7.50.020 Methods of reducing flood losses.
7.50.060 Provisions for flood hazard reduction.
7.50.010 Authorization, findings and purpose of floodplain management overlay district.
A. Statutory Authorization. The Legislature of the state of California has in California Government Code Sections 65302, 65560, and 65800 conferred upon local government units authority to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the city council of the city of Aliso Viejo does hereby adopt the following floodplain management regulations.
B. Findings of Fact.
1. 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.
2. These flood losses are caused by uses that are inadequately elevated, floodproofed, or protected from flood damage. The cumulative effect of obstructions in areas of special flood hazards that increase flood heights and velocities also contributes to the flood loss.
C. Purpose of Floodplain Management Overlay District. It is the purpose of these regulations 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:
1. Protect human life and health;
2. Minimize expenditure of public money for costly flood control projects;
3. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;
4. Minimize prolonged business interruptions;
5. 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;
6. 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 blighted areas caused by flood damage;
7. Ensure that potential buyers are notified that property is in an area of special flood hazard; and
8. Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-010)].
7.50.020 Methods of reducing flood losses.
In order to accomplish its purposes, this chapter includes methods and provisions to:
A. Restrict or prohibit 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. Require that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;
C. Control the alteration of natural floodplains, stream channels, and natural protective barriers, which help accommodate or channel floodwaters;
D. Control filling, grading, dredging, and other development which may increase flood damage; and
E. Prevent or regulate the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-020)].
7.50.030 Definitions.
Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application.
“Accessory use” means a use of a portion of land or building that is customarily and clearly incidental to the principal use of the land or building that is located on the same lot as such principal use. Accessory uses typically are very minor in proportion to the principal use.
“Alluvial fan” means a geomorphologic feature characterized by a cone- or fan-shaped deposit of boulders, gravel, and fine sediments that have been eroded from mountain slopes, transported by flood flows, and then deposited on the valley floors, and which is subject to flash flooding, high velocity flows, debris flows, erosion, sediment movement and deposition, and channel migration.
“Apex” means the point of highest elevation on an alluvial fan, which on undisturbed fans is generally the point where the major stream that formed the fan emerges from the mountain front.
“Appeal” means a request for a review of the floodplain administrator’s interpretation of any provision of this chapter.
“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. Such flooding is characterized by ponding or sheet flow.
Area of Special Flood Hazard. See “Special flood hazard area.”
“Base flood” means a flood which has a one percent chance of being equaled or exceeded in any given year (also called the “100-year flood”). “Base flood” is the term used throughout this chapter.
“Basement” means any area of the building having its floor subgrade – i.e., below ground level – on all sides.
Building. See “Structure.”
“Development” means any manmade change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials.
“Encroachment” means the advance or infringement of uses, plant growth, fill, excavation, buildings, permanent structures or development into a floodplain which may impede or alter the flow capacity of a floodplain.
“Expansion to an existing manufactured home park or subdivision” means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).
“Flood,” “flooding,” or “floodwater” means:
1. A general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters; the unusual and rapid accumulation or runoff of surface waters from any source; and/or mudslides (i.e., mudflows); and
2. The condition resulting from flood-related erosion.
“Flood boundary and floodway map (FBFM)” means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazards and the floodway.
“Flood hazard boundary map” means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated the areas of flood hazards.
“Flood hazard development permit” means the permit issued by the floodplain administrator which authorizes subject to findings and conditioned development in an area of special flood hazard as defined by this chapter.
“Flood insurance rate map (FIRM)” means the official map on which the Federal Emergency Management Agency or 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 insurance rate map, the flood boundary and floodway map, and the water surface elevation of the base flood.
“Floodplain” or “flood-prone area” means any land area susceptible to being inundated by water from any source – see “Flooding.”
“Floodplain administrator” is the director of public works or his or her designee.
“Floodplain management” means the operation of an overall program of corrective and preventive measures for reducing flood damage and preserving and enhancing, where possible, natural resources in the floodplain, including but not limited to emergency preparedness plans, flood control works, floodplain management regulations, and open space plans.
“Floodplain management regulations” means this chapter and other zoning ordinances, subdivision regulations, building codes, health regulations, special purpose regulations (such as grading and erosion control) and other application of police power which control development in flood-prone areas. This term describes federal, state or local regulations in any combination thereof which provide standards for preventing and reducing flood loss and damage.
“Floodproofing” means any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures, and their contents.
“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. Also referred to as “regulatory floodway.”
“Floodway fringe” is that area of the floodplain on either side of the “regulatory floodway” where encroachment may be permitted.
“Fraud and victimization” as related to AVMC 7.50.070, Variance procedure, means that the variance granted must not cause fraud on or victimization of the public. In examining this requirement, the city council will consider the fact that every newly constructed building adds to government responsibilities and remains a part of the community for 50 to 100 years. Buildings that are permitted to be constructed below the base flood elevation are subject during all those years to increased risk of damage from floods, while future owners of the property and the community as a whole are subject to all the costs, inconvenience, danger, and suffering that those increased flood damages bring. In addition, future owners may purchase the property, unaware that it is subject to potential flood damage, and can be insured only at very high flood insurance rates.
“Functionally dependent use” means a use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, and does not include long-term storage or related manufacturing facilities.
“Hardship” as related to AVMC 7.50.070, Variance procedure, means the exceptional hardship that would result from a failure to grant the requested variance. The city council requires that the variance be exceptional, unusual, and peculiar to the property involved. Mere economic or financial hardship alone is not exceptional. Inconvenience, aesthetic considerations, physical handicaps, personal preferences, or the disapproval of one’s neighbors likewise cannot, as a rule, qualify as an exceptional hardship. All of these problems can be resolved through other means without granting a variance, even if the alternative is more expensive, or requires the property owner to build elsewhere or put the parcel to a different use than originally intended.
“Highest adjacent grade” means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
“Historic structure” means any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the Department of the Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;
2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of the Interior; or
4. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either by an approved state program as determined by the Secretary of the Interior or directly by the Secretary of the Interior in states without approved programs.
“Levee” means a manmade structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control or divert the flow of water so as to provide protection from temporary flooding.
“Levee system” means a flood protection system which consists of a levee, or levees, and associated structures, such as closure and drainage devices, which are constructed and operated in accord with sound engineering practices.
“Lowest floor” means the lowest floor of the lowest enclosed area, including basement (see “Basement” definition).
1. An unfinished or flood resistant enclosure below the lowest floor that is 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 it conforms to applicable nonelevation design requirements, including, but not limited to:
a. The wet floodproofing standard in AVMC 7.50.060(A)(3).
b. The anchoring standards in AVMC 7.50.060(A)(1).
c. The construction materials and methods standards in AVMC 7.50.060(A)(2).
d. The standards for utilities in AVMC 7.50.060(B).
2. For residential structures, all subgrade-enclosed areas are prohibited as they are considered to be basements (see “Basement” definition). This prohibition includes below-grade garages and storage areas.
“Manufactured home” means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term “manufactured home” does not include a “recreational vehicle.”
“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.
“Market value” shall be determined by estimating the cost to replace the structure in new condition and adjusting that cost figure by the amount of depreciation which has accrued since the structure was constructed. The cost of replacement of the structure shall be based on a square foot cost factor determined by reference to a building cost estimating guide recognized by the building construction industry. The amount of depreciation shall be determined by taking into account the age and physical deterioration of the structure and functional obsolescence as approved by the floodplain administrator, but shall not include economic or other forms of external obsolescence. Use of replacement costs or accrued depreciation factors different from those contained in recognized building cost estimating guides may be considered only if such factors are included in a report prepared by an independent professional appraiser and supported by a written explanation of the differences.
“Mean sea level” means, for purposes of the National Flood Insurance Program, the National Geodetic Vertical Datum (NGVD) of 1929 or other datum, to which base flood elevations shown on a community’s flood insurance rate map are referenced.
“Mudslide” describes a condition where there is a river, flow or inundation of liquid mud down a hillside, usually as a result of a dual condition of loss of brush cover and the subsequent accumulation of water on the ground, preceded by a period of unusually heavy or sustained rain.
“New construction,” for floodplain management purposes, means structures for which the “start of construction” commenced on or after the effective date of the floodplain management regulations set forth in this chapter, and includes any subsequent improvements to such structures.
“New manufactured home park or subdivision” means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of the floodplain management regulations set forth in this chapter.
“Obstruction” includes, but is not limited to, any dam, wall, wharf, embankment, levee, dike, pile, abutment, protection, excavation, channelization, bridge, conduit, culvert, building, wire, fence, rock, gravel, refuse, fill, structure, vegetation or other material in, along, across or projecting into any watercourse which may alter, impede, retard or change the direction and/or velocity of the flow of water, or due to its location, its propensity to snare or collect debris carried by the flow of water, or its likelihood of being carried downstream.
One-Hundred-Year Flood or 100-Year Flood. See “Base flood.”
“Public safety and nuisance” as related to AVMC 7.50.070, Variance procedure, means that the granting of a variance must not result in anything which is injurious to safety or health of an entire community or neighborhood, or any considerable number of persons, or unlawfully obstructs the free passage or use, in the customary manner, of any navigable lake, or river, bay, stream, canal, or basin.
“Recreational vehicle” means a vehicle that is:
1. Built on a single chassis;
2. Four hundred square feet or less when measured at the largest horizontal projection;
3. Designed to be self-propelled or permanently towable by a light-duty truck; and
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.
“Regulatory 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.
“Remedy a violation” means to bring the structure or other development into compliance with state or local floodplain management regulations, or, if this is not possible, to reduce the impacts of its noncompliance.
“Riverine” means relating to, formed by, or resembling a river (including tributaries), stream, brook, etc.
Sheet Flow Area. See “Area of shallow flooding.”
“Special flood hazard area (SFHA)” means an area in the floodplain subject to a one percent or greater chance of flooding in any given year. It is shown on the FIRM as Zone A, AO, A1-A30, AE, A99, AH.
“Start of construction” includes substantial improvement and other proposed new development and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within 180 days from the date of the permit. The “actual start” means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading, and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the “actual start of construction” means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.
“Structure” means a walled and roofed building that is principally above ground; this includes a gas or liquid storage tank or a manufactured home.
“Substantial damage” means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
“Substantial improvement” means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the “start of construction” of the improvement. This term includes structures which have incurred “substantial damage,” regardless of the actual repair work performed. The term does not, however, include either:
1. Any project for improvement of a structure to correct existing violations or state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or
2. Any alteration of a “historic structure”; provided, that the alteration will not preclude the structure’s continued designation as a “historic structure.”
“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.
“Violation” means the failure of a structure or other development to be fully compliant with this chapter. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this chapter is presumed to be in violation until such time as that documentation is provided.
“Water surface elevation” means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929 (or other datum, where specified), of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas.
“Watercourse” means a lake, river, creek, stream, wash, arroyo, channel or other topographic feature on or over which waters flow at least periodically. Watercourse includes specifically designated areas in which substantial flood damage may occur. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-030)].
Cross-reference: definitions generally, AVMC 1.02.010.
7.50.040 General provisions.
A. Lands to Which This Chapter Applies. The provisions of this chapter shall apply to all areas of special flood hazards within the city limits of the city of Aliso Viejo.
B. Basis for Establishing the Areas of Special Flood Hazard. The areas of special flood hazard identified by the Federal Emergency Management Agency (FEMA) in the flood insurance study (FIS) for Orange County, CA and Incorporated Areas, dated February 18, 2004, with accompanying flood insurance rate maps (FIRMs), and all subsequent amendments and/or revisions, are hereby adopted by reference and declared to be a part of this chapter. This FIS and attendant mapping is the minimum area of applicability of this chapter and may be supplemented by studies for other areas which allow implementation of this chapter and which are recommended to the city council by the floodplain administrator. The FIS, FIRMs and FBFMs are on file at the Aliso Viejo City Hall in the department of public works.
C. Compliance. 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. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Nothing herein shall prevent the city council from taking such lawful action as is necessary to prevent or remedy any violation.
D. Abrogation and Greater Restrictions. This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and other ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.
E. Interpretation. In the interpretation and application of this chapter, all provisions shall be:
1. Considered as minimum requirements;
2. Liberally construed in favor of the city; and
3. Deemed neither to limit nor repeal any other powers granted under state statutes.
F. Warning and Disclaimer of Liability. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This 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, the state of California, or the Federal Insurance Administration, Federal Emergency Management Agency, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-040)].
7.50.050 Administration.
A. Establishment of Development Permit. A flood hazard development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in AVMC 7.50.040(B). Application for a flood hazard development permit shall be made on forms furnished by the floodplain administrator and may include, but not be limited to: plans in duplicate drawn to scale showing the nature, location, dimensions, and elevation 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. Site plan, including but not limited to:
a. For all proposed structures, spot ground elevations at building corners and 20-foot or smaller intervals along the foundation footprint, or one-foot contour elevations throughout the building site; and
b. Proposed locations of water supply, sanitary sewer and utilities; and
c. If available, the base flood elevation from the flood insurance study and/or flood insurance rate map; and
d. If applicable, the location of the regulatory floodway;
2. Foundation design detail, including but not limited to:
a. Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures; and
b. For a crawl-space foundation, location and total net area of foundation openings as required in this chapter; and
c. For foundations placed on fill, the location and height of fill, and compaction requirements (compacted to 95 percent using the standard proctor test method);
3. Proposed elevation in relation to mean sea level to which any nonresidential structure will be floodproofed, as required in this chapter and this subsection;
4. All appropriate certifications listed in this section; and
5. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.
B. Designation of the Floodplain Administrator. The director of public works is hereby appointed to administer, implement, and enforce this chapter by granting or denying flood hazard development permits in accord with its provisions.
C. Duties and Responsibilities of the Floodplain Administrator. The duties and responsibilities of the floodplain administrator shall include, but not be limited to, the following:
1. Permit Review. Review all flood hazard development permits to determine that:
a. Permit requirements of this chapter have been satisfied;
b. All other required state and federal permits have been obtained;
c. The site is reasonably safe from flooding; and
d. The proposed development does not adversely affect the carrying capacity of areas where base flood elevations have been determined but a floodway has not been designated. For purposes of this chapter, “adversely affects” means that the cumulative effect of the proposed development when combined with all other existing and anticipated development will increase the water surface elevation of the base flood more than one foot at any point.
2. Review and Use of Any Other Base Flood Data. When base flood elevation data has not been provided in accordance with AVMC 7.50.040(B), the floodplain administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal or state agency, or other source, in order to administer AVMC 7.50.060. Any such information shall be submitted to the city council for adoption.
3. Notification of Other Agencies. In alteration or relocation of a watercourse:
a. Notify adjacent communities and the California Department of Water Resources prior to alteration or relocation;
b. Submit evidence of such notification to the Federal Insurance Administration, Federal Emergency Management Agency; and
c. Assure that the flood carrying capacity within the altered or relocated portion of said watercourse is maintained.
4. Documentation of Floodplain Development. Obtain and maintain for public inspection and make available, as needed, the following:
a. Certification required by AVMC 7.50.060(A)(3)(c) (lowest floor elevations);
b. Certification required by AVMC 7.50.060(A)(3)(b) (elevation or floodproofing of nonresidential structures);
c. Certification required by AVMC 7.50.060(A)(3) (wet floodproofing standard);
d. Certification of elevation required by AVMC 7.50.060(C) (subdivision standards); and
e. Certification required by AVMC 7.50.060(F) (floodway encroachments).
5. Map Determinations. Make interpretations, where needed, as to the exact location of the boundaries of the areas of special flood hazard, 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 AVMC 7.50.070.
6. Remedial Action. Take action to remedy violations of this chapter as specified in AVMC 7.50.040(C).
D. Appeals. The city council shall hear and decide appeals when it is alleged there is an error in any requirement, decision, or determination made by the floodplain administrator in the enforcement or administration of the provisions of this chapter. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-19-050)].
Cross-reference: appeal procedures generally, Chapter 1.10 AVMC.
7.50.060 Provisions for flood hazard reduction.
A. Standards of Construction. In all areas of special flood hazards the following standards are required:
1. Anchoring.
a. All new construction and substantial improvements shall be adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
b. All manufactured homes shall meet these anchoring standards.
2. Construction Materials and Methods. All new construction and substantial improvement shall be constructed:
a. With materials and utility equipment resistant to flood damage;
b. Using methods and practices that minimize flood damage;
c. With electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding; and
d. If within Zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.
3. Elevation and Floodproofing. (See AVMC 7.50.030 definitions for “basement,” “lowest floor,” “new construction,” “substantial damage” and “substantial improvement.”)
a. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement:
i. In an AO zone, elevated two feet above the highest adjacent grade to a height equal to or exceeding the depth number specified in feet on the FIRM, or elevated at least four feet above the highest adjacent grade if no depth number is specified.
ii. In an A zone, elevated two feet to or above the base flood elevation, as determined by this community.
iii. In all other zones, the lowest floor shall be elevated at least two feet above the base flood elevation.
Upon the completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the city building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.
b. New construction and substantial improvement of any nonresidential structure shall either be elevated to conform with subsection (A)(3)(c) of this section or together with attendant utility and sanitary facilities:
i. Be floodproofed below the elevation recommended under subsection (A)(3)(c) of this section so that the structure is watertight with walls substantially impermeable to the passage of water;
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 standards of this subsection (A)(3)(b) are satisfied. Such certification shall be provided to the floodplain administrator.
c. All new construction and substantial improvement with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement must exceed the following minimum criteria:
i. Be certified by a registered professional engineer or architect; or
ii. Have 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. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves or other coverings or devices; provided, that they permit the automatic entry and exit of floodwater.
d. Manufactured homes shall also meet the standards of this section.
B. Standards for Utilities.
1. All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate:
a. Infiltration of floodwaters into the systems; and
b. Discharge from the systems into floodwaters.
2. On-site waste disposal systems shall be located to avoid impairment to them, or contamination from them during flooding.
C. Standards for Subdivisions.
1. All preliminary subdivision proposals shall identify the flood hazard area and the elevation of the base flood.
2. All subdivision plans will provide the elevation of proposed structure(s) and pad(s). If the site is filled above the base flood elevation, the lowest floor and pad elevations shall be certified by a registered professional engineer or surveyor and provided to the floodplain administrator.
3. All subdivision proposals shall be consistent with the need to minimize flood damage.
4. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.
5. All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.
D. Standards for Manufactured Homes.
1. All manufactured homes that are placed or substantially improved, within Zones A1-A30, AH, and AE on the community’s flood insurance rate map, on sites located:
a. Outside of a manufactured home park or subdivision;
b. In a new manufactured home park or subdivision;
c. In an expansion to an existing manufactured home park or subdivision; or
d. In an existing manufactured home park or subdivision on a site upon which a manufactured home has incurred substantial damage as the result of a flood, shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated at least two feet above the base flood and be securely fastened to an adequately anchored foundation system to resist flotation collapse and lateral movement.
E. Standards for Recreational Vehicles.
1. All recreational vehicles placed on sites within Zones A1-A30, AH, and AE on the city’s flood insurance rate map will either:
a. Be on the site for fewer than 180 consecutive days, and be fully licensed and ready for highway use – a recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions; or
b. Meet the permit requirements of AVMC 7.50.050 and the elevation and anchoring requirements for manufactured homes in subsection (D)(1) of this section.
F. Floodways. Located within areas of special flood hazard established in AVMC 7.50.040(B) are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial improvement, and other new development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge.
2. If subsection (E) of this section is satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of this section. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-060)].
7.50.070 Variance procedure.
A. Nature of Variances. The variance criteria set forth in this chapter are based on the general principle of zoning law that variances pertain to a piece of property and are not personal in nature. A variance may be granted for a parcel of property with physical characteristics so unusual that complying with the requirements of this chapter would create an exceptional hardship to the applicant or the surrounding property owners. The characteristics must be unique to the property and not be shared by adjacent parcels. The unique characteristic must pertain to the land itself, not to the structure, its inhabitants, or the property owners. The focus of this chapter is to implement alterations that reduce flood loss with the granting of a variance to occur only after all other feasible alternatives are considered and it is concluded that they are not capable of being implemented.
There is a need to help protect citizens from flooding. This need is so compelling and the implications of the cost of insuring structures built below flood level are so serious that variances from the flood elevation or from other requirements in this chapter are quite rare.
B. Appeal Board.
1. The city council shall hear and decide requests for variances from the requirements of this chapter. The city council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:
a. Danger that materials may be swept onto other lands to the injury of others;
b. Danger to life and property due to flooding or erosion damage;
c. Susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the existing individual owner and future owners of the property;
d. Importance of the services provided by the proposed facility to the community;
e. Necessity to the facility of a waterfront location, where applicable;
f. Availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;
g. Compatibility of the proposed use with existing and anticipated development;
h. Relationship of the proposed use to the general plan and floodplain management program for that area;
i. Safety of access to the property in time of flood for ordinary and emergency vehicles;
j. Expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters expected at the site; and
k. 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 system, and streets and bridges.
2. Any applicant to whom a variance is granted shall be given written notice by the floodplain administrator that:
a. The issuance of a variance to construct a structure below the base flood level may result in increased premium rates for flood insurance; and
b. Such construction below the base flood level increases risks to life and property. A copy of the notice shall be recorded by the floodplain administrator in the office of the Orange County recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.
c. The floodplain administrator shall maintain a record of all variance actions, including justification for their issuance, and report such variances issued in its biennial report submitted to the Federal Insurance Administration, Federal Emergency Management Agency.
C. Conditions for Variances.
1. Generally, variances may be issued for new construction, substantial improvement, and other proposed new development 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 that the procedures of AVMC 7.50.050 and 7.50.060 have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases.
2. Variances may be issued for the repair or rehabilitation of “historic structures” (as defined in AVMC 7.50.030) upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as an historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.
3. Variances shall not be issued within any mapped regulatory floodway if any increase in flood levels during the base flood discharge would result.
4. Variances shall only be issued upon a determination that the variance is the “minimum necessary” to afford relief, considering the flood hazard. For purposes of this section, “minimum necessary” means to afford relief with a minimum of deviation from the requirements of this chapter.
5. Variances shall only be issued upon a:
a. Showing of good and sufficient cause;
b. Determination that failure to grant the variance would result in exceptional “hardship” (as defined in AVMC 7.50.030) to the applicant; and
c. Determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, or extraordinary public expense, create a nuisance (as defined in AVMC 7.50.030 – see “Public safety and nuisance”), cause fraud or victimization (as defined in AVMC 7.50.030) of the public, or conflict with existing local laws or ordinances.
6. Variances may be issued for new construction, substantial improvement, and other proposed new development necessary for the conduct of a functionally dependent use; provided, that the provisions of subsections (C)(1) through (5) of this section are satisfied and that the structure or other development is protected by methods that minimize flood damages during the base flood and does not result in additional threats to public safety and does not create a public nuisance.
7. Upon consideration of the factors of subsection (B) of this section and the purposes of this chapter, the city council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter. [Ord. 2010-126 § 1 (Exh. A); Ord. 2006-082 § 1 (7-10-070)].
Cross-references: buildings and construction, AVMC Title 13; subdivision floodplain standards, AVMC 14.10.190; zoning code, AVMC Title 15.