Chapter 15.28 — FLOODPLAIN MANAGEMENT

The legislature of the State of California has in Government Code Sections 65302, 65560, and 65800 conferred upon local governments the authority to adopt the regulation designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the City Council of the City of Palmdale does hereby adopt the following flood plain management regulations.

• (Ord. 1563 § 1 (Exh. A), 2021)

• (A) The flood hazard areas of City of Palmdale 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 uses that are inadequately elevated, floodproofed, or protected from flood damage. The cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities also contributes to flood losses.

• (Ord. 1563 § 1 (Exh. A), 2021)

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 legally enforceable regulations applied uniformly throughout the community to all publicly and privately owned land within flood prone, mudslide (i.e., mudflow) or flood related erosion areas. These regulations are designed to:

• (A) Protect human life and health;

• (B) Minimize expenditure of public money for 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 blighted areas caused by flood damage;

• (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.

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.003

§ 15.28.010

• (Ord. 1563 § 1 (Exh. A), 2021)

In order to accomplish its purposes, this chapter includes regulations 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. 1563 § 1 (Exh. A), 2021)

Unless specifically defined in this Section, words or phrases used in this Chapter shall be interpreted according to their common usage and to give this Chapter its most reasonable application to further its purpose.

"Accessory structure" means a structure that is either:

• (1) Solely for the parking of no more than two cars; or

• (2) A small, low-cost shed for limited storage, less than 150 square feet and $1,500 in value.

"Accessory use" means a use which is incidental and subordinate to the principal use of the parcel of land on which it is located.

"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 or a request for a variance.

"Area of shallow flooding" means a designated AO, or AH (no AH in City) Zone on the Flood Insurance Rate Map (FIRM). Generally, the base flood depths of an area of shallow flooding 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.

Area of Special Flood Hazard. See "Special flood hazard area (SFHA)."

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.010

§ 15.28.010

"Base flood" means the flood having a one percent chance of being equaled or exceeded in any given year (also called "100-year flood"). "Base flood" is a term used throughout this Chapter.

"Basement" means any area of the building having its floor subgrade (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 floodplain which may impede or alter the flow capacity of the floodplain.

"Existing manufactured/mobile home park or subdivision" means a manufactured/mobile home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured/mobile 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 before the effective date (December 10, 1987, Ordinance 711) of the floodplain management regulations adopted by a community.

"Expansion to an existing manufactured/mobile home park or subdivision" means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured/mobile 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" or "flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from:

• (1) The overflow of floodwaters; or

• (2) The unusual and rapid accumulation or runoff of surface waters from any source.

"Flood Boundary and Floodway Map" (FBFM) means the official map on which the Federal Insurance Administration has delineated both the areas of special flood hazards and the floodway.

"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 City.

"Flood Insurance Study" means the official report provided by the Federal Insurance Administration that includes flood profiles, the FIRM, 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.

"Floodplain Administrator" is the individual appointed to administer and enforce the floodplain management regulations.

"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 of the floodplain, including but not limited to emergency preparedness plans, flood control works and floodplain management regulations.

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City of Palmdale, CA § 15.28.010

PALMDALE CODE

§ 15.28.010

"Floodplain management regulations" means this Chapter and other zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances and other applications of the police power which controls development in flood-prone areas. The term describes such Federal, State or local regulations, which provide standards for the purpose of preventing flood 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 PMC § 15.28.185 (Nature of variances) through § 15.28.200 (Conditions for variances) means that the variance granted must not cause fraud on or victimization of the public. In examining this requirement, the City 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 shipbuilding and ship repair facilities, but does not include long-term storage or related manufacturing facilities.

"Governing body" is the local governing unit, i.e., county or municipality, that is empowered to adopt and implement regulations to provide for the public health, safety and general welfare of its citizenry.

"Hardship" as it relates to PMC § 15.28.185 (Nature of variances) through § 15.28.200 (Conditions for variances) means the exceptional hardship that would result from a failure to grant the requested variance. The City 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

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.010

§ 15.28.010

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.

"Lowest floor" means the lowest floor of the lowest enclosed area, including the basement.

• (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 non-elevation design requirements, including, but not limited to:

  • (a) The wet floodproofing standard in PMC § 15.28.120(C)(5) (Standards of construction);

  • (b)

  • The anchoring standards in PMC § 15.28.120(A) (Standards of construction);

• (c) The construction materials and methods standards in PMC § 15.28.120(B) (Standards of construction);

• (d)

  • The standards for utilities in PMC § 15.28.130 (Standards for utilities).

• (2) For residential structures, all subgrade-enclosed areas are prohibited as they are considered to be basements. This prohibition includes below-grade garages and storage areas.

"Manufactured home" as defined in State of California Health and Safety Code Section 18007, shall mean a structure that was constructed on or after June 15, 1976, is transportable in one or more sections, is eight body feet or more in width, or 40 body feet or more in length, in the traveling mode, or, when erected on site, is 320 or more square feet, is built on a permanent chassis and designed to be used as a single-family dwelling with or without a foundation when connected to the required utilities, and includes the plumbing, heating, air conditioning, and electrical systems contained therein.

"Manufactured/mobile home park" shall mean a development designed and occupied by manufactured/mobile housing units or park models including development with facilities and amenities used in common by occupants who rent, lease, or own spaces for mobile/ manufactured/park model housing units through a subdivision, cooperative, condominium, or other form of resident ownership.

"Manufactured/mobile home subdivision" shall mean an area of land where lots are divided for sale, rent, or lease to accommodate manufactured or mobile homes.

"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

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.010

§ 15.28.010

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, North American Vertical Datum (NAVD) of 1988, or other datum, to which base flood elevations shown on the City of Palmdale's Flood Insurance Rate Map are referenced.

"New construction" means structures for which the "start of construction" commenced on or after the effective date (December 10, 1987, Ordinance 711) of floodplain management regulations adopted by the City, and includes any subsequent improvements to such structures.

"New manufactured/mobile home park or subdivision" means a manufactured/mobile home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured/mobile 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 (December 10, 1987, Ordinance 711) of floodplain management regulations adopted by this community.

"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" means a flood which has a one percent annual probability of being equaled or exceeded in any given year. It is identical to the "base flood," which will be the term used throughout this Chapter.

"Public safety and nuisance" as related to PMC § 15.28.185 (Nature of variances) 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 which 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.

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.010

§ 15.28.010

"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. Ways that impacts may be reduced include protecting the structure or other affected development from flood damages, implementing the enforcement provisions of the chapter, or otherwise deterring future similar violations, or reducing State and Federal financial exposure with regard to the structure or other development.

"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 of the floodplain subject to a one percent or greater chance of flooding in one given year. It is shown on an FHBM or FIRM as Zone A, AO, A1-30, AE, A99 or AH.

"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. If the actual start of construction, repair, reconstruction, placement or other improvement is not within 180 days of the permit date, then "start of construction" shall mean the actual start. 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/mobile home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; 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, including a gas or liquid storage tank, that is principally aboveground, as well as a manufactured/mobile 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 repair, reconstruction, rehabilitation, addition, 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 "start of construction" of the improvement; or

• (2) If the structure has been damaged, and is being restored, before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either:

  • (a) 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

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City of Palmdale, CA § 15.28.010

PALMDALE CODE

§ 15.28.050

• (b) Any alteration of a "historic structure" listed on the National Register of Historic Places or a State Inventory of Historic Places; 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, North American Vertical Datum (NAVD) of 1988 (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. 1563 § 1 (Exh. A), 2021; Ord. 1614 § 4 (Exh. I), 2023)

This chapter shall apply to all areas of special flood hazards within the jurisdiction of the City. (Ord. 1563 § 1 (Exh. A), 2021)

The areas of special flood hazard identified by the Federal Insurance Administration (FIA) of the Federal Emergency Management Agency (FEMA) in the Flood Insurance Study (FIS) for the City of Palmdale dated March 30, 1998, and accompanying Flood Insurance Rate Maps (FIRM), dated March 30, 1998, and all subsequent amendments and/or revisions are hereby adopted by reference and declared to be a part of this chapter. This Flood Insurance Study and attendant mapping are the minimum area of applicability for this chapter and may be supplemented by studies for other areas that allow implementation of this chapter and are recommended to the City Council by the Floodplain Administrator. The Flood Insurance Study and FIRM are on file in the office of the City Engineer.

(Ord. 1563 § 1 (Exh. A), 2021)

No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of the provisions of this chapter by failure to comply with any of its requirements (including violations of conditions and safeguards established in connections 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. (Ord. 1563 § 1 (Exh. A), 2021)

This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants or

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.050

§ 15.28.090

deed restrictions. However, where this chapter and another chapter, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail. (Ord. 1563 § 1 (Exh. A), 2021)

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

• (A) Considered as minimum requirements;

• (B) Liberally construed in favor of protecting persons and property from flood hazards; and

• (C) Deemed neither to limit nor repeal any other powers granted to the City under state statutes. (Ord. 1563 § 1 (Exh. A), 2021)

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 damage. 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. 1563 § 1 (Exh. A), 2021)

A development permit shall be obtained before construction or development begins within any area of special flood hazards. Application for a development permit shall be made on forms furnished by the Floodplain Administrator and may include, but need 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:

• (A) Site plan, including but not limited to:

  • (1) Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures, ground elevations shown at one-foot contour elevations throughout the building site; and

  • (2) Proposed locations of water supply, sanitary sewer and utilities; and

  • (3) For foundations placed on fill, the location and height of fill, and compaction requirements (compacted to 95 percent using the Standard Proctor Test Method); and

  • (4) If available, the base flood elevation from the Flood Insurance Study and/or Flood Insurance Rate Maps; and

  • (5) All appropriate certifications listed in PMC § 15.28.110(D); and

  • (6) Description of the extent to which any watercourse will be altered or relocated as a

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.090

§ 15.28.110

result of proposed development. (Ord. 1563 § 1 (Exh. A), 2021)

The City Engineer is appointed to administer and implement this chapter by granting or denying development permits in accordance with its provisions and is referred to in this chapter as the "Floodplain Administrator."

(Ord. 1563 § 1 (Exh. A), 2021)

The duties and responsibilities of the Floodplain Administrator shall include, but not be limited to:

• (A) Permit Review. Review of all development permits to determine that:

  • (1) The permit requirements of this chapter have been satisfied, including a determination of substantial improvement and substantial damage of existing structures;

  • (2) All other required state and federal permits have been obtained;

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

  • (4) 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 affect" means that the cumulative effect of the proposed development when combined with all other existing and anticipated development will not increase the water surface elevation of the base flood more than one foot at any point.

• (B) Use of Other Base Flood Data. When base flood elevation data has not been provided in the Flood Boundary and Floodway Map, the Flood Insurance Rate Map, or the Flood Insurance Study, the Floodplain Administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, in order to administer PMC § 15.28.120.

• (C) Notification of Other Agencies. Whenever a watercourse is to be altered or relocated:

  • (1) Notify adjacent communities and the California Department of Water Resources prior to such alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Emergency Management Agency;

  • (2) Assure that the flood-carrying capacity of the altered or relocated portion of said watercourse is maintained.

• (D) Base Flood Elevation Changes Due to Physical Alterations.

  • (1) Within six months of information becoming available or project completion, whichever comes first, the Floodplain Administrator shall submit or assure that the permit applicant submits technical or scientific data to FEMA for a letter of map revision (LOMR).

  • (2) All LOMRs for flood control projects are approved prior to the issuance of building

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.110

§ 15.28.120

permits. Building permits must not be issued based on conditional letters of map revision (CLOMRs). Approved CLOMRs allow construction of the proposed flood control project and land preparation as specified in the "start of construction" definition.

Such submissions are necessary so that upon confirmation of those physical changes affecting flooding conditions, risk premium rates and floodplain management requirements are based on current data.

• (E) Notify FEMA in writing whenever the corporate boundaries have been modified by annexation or other means and include a copy of a map of the community clearly delineating the new corporate limits.

• (F) Documentation of Floodplain Development. Obtain and maintain for public inspection and make available as needed:

  • (1) The certification required in PMC § 15.28.120(C)(1) (lowest floor elevations);

  • (2) The certification required in PMC § 15.28.120(C)(4) (elevation of floodproofing of nonresidential structures);

  • (3) The certification required in PMC § 15.28.120(C)(2) (elevations in areas of shallow flooding);

  • (4) The certification required in PMC § 15.28.120(C)(5)(a) (wet floodproofing standard);

  • (5) The certified elevation required in PMC § 15.28.140 (subdivision standards).

  • (6) Maintain a record of all variance actions, including justification for their issuance, and report such variances to the Federal Emergency Management Agency.

• (G) Make interpretations where needed, as to the 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 PMC § 15.28.190.

• (H) Take action to remedy violations of this chapter as specified in PMC § 15.28.040. (Ord. 1563 § 1 (Exh. A), 2021)

In all areas of special flood hazards the following standards are required to be met to the satisfaction of the Floodplain Administrator:

• (A) Anchoring.

  • (1) All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;

  • (2) All manufactured homes shall meet the anchoring standards of PMC § 15.28.150.

• (B) Construction Materials and Methods.

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.120

§ 15.28.120

• (1) All new construction and substantial improvements, including manufactured homes, shall be constructed with materials and utility equipment resistant to flood damage below the base flood elevation;

• (2) All new construction and substantial improvements, including manufactured homes, shall be constructed using methods and practices that minimize flood damage;

• (3) All new construction and substantial improvements, including manufactured homes, shall be constructed 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;

• (4) All new construction and substantial improvements, including manufactured homes, within Zones AH or AO shall be required to have adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

• (C) Elevation and Floodproofing.

  • (1) In an AO Zone, new residential construction and substantial improvement, including manufactured homes, of any residential lowest floor, including basement, elevated to a height equal to or exceeding the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade if no depth number is specified;

  • (2) In an A and AE Zone, new residential construction and substantial improvement, including manufactured homes, of any residential structure shall have the lowest floor, including basement, elevated to or above the base flood elevation;

  • (3) In all other special flood hazard area zones, new residential construction and substantial improvement, including manufactured homes, of any residential structure shall have the lowest floor, including basement, elevated to or above the base flood elevation;

  • (4) Upon completion of the residential structure, the elevation of the lowest floor, including basement, shall be verified by a registered professional engineer or surveyor, and verified by the City Building Inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator;

  • (5) Nonresidential construction, new or substantial improvement, shall either be elevated in conformance with subsection (C)(1), (2) or (3) of this section or together with attendant utility and sanitary facilities:

• (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, and

  • (c) Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator;

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.120

§ 15.28.120

• (6) All new construction and substantial improvements, that have fully enclosed areas below the lowest floor (excluding basements) and are usable solely for parking of vehicles, building access or storage that are subject to flooding 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 meet or exceed the following minimum criteria:

  • (a) Have a minimum of two openings on different sides 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 floodwaters, or

  • (b) Be certified by a registered professional engineer or architect to comply with a local floodproofing standard approved by the Federal Insurance Administration;

• (7) Manufactured homes shall also meet the standards in PMC § 15.28.150.

• (D) Garages and Low-Cost Accessory Structures.

  • (1) Attached Garages.

    • (a) A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry of floodwaters. Areas of the garage below the BFE must be constructed with flood resistant materials.

    • (b) A garage attached to a nonresidential structure must meet the above requirements or be dry floodproofed. For guidance on below grade parking areas, see FEMA Technical Bulletin TB-6, as it may be amended from time to time.

  • (2) Detached Garages and Accessory Structures.

    • (a) "Accessory structures" used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in PMC § 15.28.010, may be constructed such that its floor is below the base flood elevation (BFE), provided the structure is designed and constructed in accordance with the following requirements:

      • (i) Use of the accessory structure must be limited to parking or limited storage;

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

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

• (iv) Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the BFE;

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.120

§ 15.28.150

• (v) The accessory structure must comply with floodplain encroachment provisions in PMC § 15.28.160; and

• (vi) The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with subsection (C)(6) of this section.

(b) Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in this section. (Ord. 1563 § 1 (Exh. A), 2021)

• (A) All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and to eliminate discharge from the systems into floodwaters.

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

• (Ord. 1563 § 1 (Exh. A), 2021)

Subdivisions and other proposed development, including proposals for manufactured home parks or subdivisions, greater than 50 lots or five acres, whichever is the lesser, shall meet the following requirements to the satisfaction of the Floodplain Administrator:

• (A) Shall identify any special flood hazard area and the elevation of the base flood.

• (B) Will provide the elevation of proposed structure(s) and pads on the final plans. If the site is filled above the base flood elevation, the lowest floor final pad elevations shall be certified by a registered professional civil engineer or surveyor as part of an application for a FEMA letter of map revision based on fill (LOMR-F) to the Floodplain Administrator.

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

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

• (E) All subdivisions shall provide adequate drainage to reduce exposure to flood hazards. (Ord. 1563 § 1 (Exh. A), 2021)

• (A) All manufactured homes that are placed or substantially improved, within Zones A1-30, AH, and AE on the City's Flood Insurance Rate Map, shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist floatation, collapse or lateral movement on sites located:

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

  • (2) In a new manufactured home park or subdivision;

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.150

§ 15.28.160

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

• (4) 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 to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse or lateral movement.

• (B) All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-30, AH, and AE on the community's Flood Insurance Rate Map that is not subject to the provisions of subsection (A) of this section will be elevated so that either the:

  • (1) Lowest floor of the manufactured home is at or above the base flood elevation; or

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

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 verification shall be provided to the Floodplain Administrator.

• (Ord. 1563 § 1 (Exh. A), 2021)

All recreational vehicles placed on sites within Zones A1-30, AH, and AE on the City's Flood Insurance Rate Map will either:

• (A) Be on the site for fewer than 180 consecutive days, 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 PMC § 15.28.090 through 15.28.110 and the elevation and anchoring requirements for manufactured homes in PMC § 15.28.150.

• (Ord. 1563 § 1 (Exh. A), 2021)

Located within areas of special flood hazards established in PMC § 15.28.030 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters, which carry debris, potential projectiles and erosion potential, the following provisions apply:

• (A) Encroachments into floodways within Zones A1-30 and AE shall be prohibited, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating that the proposed encroachments shall not result in any increase in (the base) flood levels within the community during the occurrence of the base flood discharge.

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.160

§ 15.28.190

• (B) Where the floodway has not been determined, no construction, substantial development, or other development including fill shall be permitted within Zones A1-30 and AE, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other development, will not increase the water surface elevation of the base flood more than one foot at any point within the City of Palmdale.

• (C) If subsections (A) and (B) of this section are satisfied, all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions of PMC § 15.28.120.

• (Ord. 1563 § 1 (Exh. A), 2021)

The variance criteria set forth in this section 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.

It is the duty of the Floodplain Administrator to help protect its 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 the flood chapter are quite rare. The long-term goal of preventing and reducing flood loss and damage can only be met if variances are strictly limited. Therefore, the variance criteria are designed to screen out those situations in which alternatives other than a variance are more appropriate. (Ord. 1563 § 1 (Exh. A), 2021)

• (A) The City Council shall hear and decide appeals from decisions made by the Floodplain Administrator and requests for variances from the requirements of this section.

• (B) 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 this chapter.

• (C) In passing upon such applications, the City Council 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 of 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 and future owners of the property;

  • (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

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.28.190

§ 15.28.200

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 time of flood for ordinary and emergency vehicles;

• (10) The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters 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 system, and streets and bridges.

• (D) Any applicant to whom a variance is granted shall be given written notice over the signature of a City official that:

  • (1) The issuance of a variance to construct a structure below base flood level will result in increased premium rates for flood insurance up to amounts as high as $25.00 for $100.00 of insurance coverage; and

  • (2) Such construction below the base flood level increases risks to life and property. It is recommended that a copy of the notice shall be recorded by the Floodplain Administrator in the office of the County Recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

• (E) The Floodplain Administrator will 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.

• (Ord. 1563 § 1 (Exh. A), 2021)

• (A) Generally, variances may be issued for new construction, substantial improvement, and other proposed new developments 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 elevation; provided, that the procedures of PMC § 15.28.090 through 15.28.160 have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases.

• (B) Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed in the National Register of Historic Places or the State Inventory of Historic Places, upon a determination that the proposed reconstruction, rehabilitation or restoration will not preclude the structure's continued designation as an historic structure as defined in PMC § 15.28.010 and the variance is the minimum necessary to preserve the historic character and design of the structure.

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

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City of Palmdale, CA

PALMDALE CODE

§ 15.28.200

§ 15.28.300

• (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" as defined in PMC § 15.28.010 to the applicant; and

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

• (F) Variances may be issued for new construction and substantial improvements and for other development necessary for the conduct of a functionally dependent use; provided, that the provisions of subsections (A) through (D) 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 create no additional threats to public safety.

• (G) Upon consideration of the factors of PMC § 15.28.190 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.

• (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 regulatory flood elevation and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation. A copy of the notice shall be recorded by the City in the office of the Los Angeles County Recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

• (Ord. 1563 § 1 (Exh. A), 2021)

To the extent the provisions of this chapter are substantially the same as previous provisions of the Palmdale Municipal Code, these provisions shall be construed as continuations of those provisions and not as new enactments.

(Ord. 1563 § 1 (Exh. A), 2021)

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City of Palmdale, CA

BUILDINGS AND CONSTRUCTION

§ 15.30.010

§ 15.30.010