Article 1 — General Provisions

(a)

The flood hazard areas of the city of Lafayette are subject to periodic inundation which could result 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. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities, and when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed, elevated or otherwise protected from flood damage also contribute to the flood loss.

(b)

Watercourses include valued natural resources and specifically designated areas in which substantial flood damage may occur. The riparian lands and watercourses of the city may be subject to mandatory

compliance with federal and state environmental laws and regulations and any amendments or additions thereto as may be established from time to time.

(c)

Flood hazard areas, riparian lands and watercourses of the city are subject to the applicable goals, policies, requirements and guidelines of the general plan, downtown specific plan, downtown creeks preservation, restoration and development plan, and any amendments or additions thereto as may be established in order to protect the public health, safety and general welfare.

(Ord. No. 684, § 2(Exh. 2), 4-10-2023)

It is the purpose of this chapter to promote the public health, safety and general welfare, to implement compliance with applicable environmental and water quality laws and regulations, to effectuate applicable provisions of the general plan, downtown specific plan, downtown creeks preservation restoration and development plan, and other applicable land use ordinances and guidelines, and to minimize public and private losses due to flood conditions in specified areas by provisions 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 second use and development of areas of special flood hazard so as to minimize future flood blight areas;

(g)

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

(h)

Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions;

(i)

Protect persons and property along creek channels; and

(j)

Preserve and restore the natural environment along creeks, and watercourses and riparian lands in accordance with applicable laws, regulations, plans and guidelines and enumerated in [Section] 6-1801 hereinabove.

(Ord. No. 684, § 2(Exh. 2), 4-10-2023)

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

(a)

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

(b)

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

(c)

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

(d)

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

(e)

Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters or which may increase flood hazards in other areas.

(Ord. No. 684, § 2(Exh. 2), 4-10-2023)

In this chapter, unless the context otherwise requires:

"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 city engineer's interpretation of a provision of this chapter or a request for a variance.

"Area of shallow flooding" means a designated AO or AH Zone on the flood insurance rate map (FIRM). The base flood depths range from one to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

"Area of special flood hazard." See "special flood hazard area."

"Area of special flood-related erosion hazard" means the land within a community which is most likely to be subject to severe flood-related erosion losses. The area may be designated as Zone E on the flood insurance rate map (FIRM).

"Base flood" means the flood having 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 (below ground level) on all sides.

"Breakaway walls" means any walls, whether solid or lattice, and whether constructed of concrete, masonry, wood, metal, plastic or any other suitable building material, which are not part of the structural support of the building and which are designed to break away without causing any damage to the structural integrity of the building on which they are used or any buildings to which they might be carried by floodwaters. A breakaway wall shall have a safe design loading resistance of not less than ten and no more than 20 pounds per square foot. Use of breakaway walls must be certified by a registered engineer or architect and shall meet the following conditions:

(1)

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

(2)

The elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood.

"Building." See "structure."

"Creek channel" means a creek shown on the city geographic information system map.

"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 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.

"Existing 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 before the effective date of the floodplain management regulations adopted by a community.

"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;

(3)

The collapse or subsidence of land along a body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood, or by some similarly unusual and unforeseeable event which results in flooding as defined in this definition.

"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 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 insurance rate map (FIRM)" is 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" is 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.

"Flood-related erosion" means the collapse or subsidence of land along the shore of a lake or other body of water as a result of undermining caused by waves or currents of water exceeding anticipated cyclical level or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as a flash flood or an abnormal tidal surge, or by some similarly unusually and unforeseeable event which results in flooding.

"Flood-related erosion area" or "flood-related erosion prone area" means a land area adjoining the shore of a lake or other body of water, which due to the composition of the shoreline or bank and high water levels or wind-driven currents, is likely to suffer flood-related erosion damage.

"Flood-related erosion area management" means the operation of an overall program of corrective and preventive measures for reducing flood-related erosion damage, including, but not limited to, emergency preparedness plans, flood-related erosion control works, and floodplain management regulations.

"Floodplain" or "flood-prone area" means any land area susceptible to being inundated by water from any source (see definition of "flooding").

"Floodplain administrator" means 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 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 ordinances (such as grading ordinance and erosion control ordinance) and other applications of police power which control development in flood-prone areas. This term describes such federal, state or local regulations in any combination thereof, which provide standards for the purpose of 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. (Refer to FEMA Technical Bulletins TB 1-93, TB 3-93 and TB 7-93 for guidelines on dry and wet floodproofing.)

"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. The floodway is delineated on the flood boundary and floodway map. Also referred to as "regulatory floodway."

"Floodway fringe" means that area of the floodplain on either side of the "regulatory floodway" where encroachment may be permitted.

"Fraud and victimization" as related to Article 6, Flood Hazard Variance Procedure, of this chapter, 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, 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 related to Article 6, Flood Hazard Variance Procedure, of this chapter 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 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 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.

"Improved creek channel" means a creek channel where the Contra Costa County Flood Control District or private parties have constructed and maintain flood and/or erosion protection systems within the channel. These systems consist of bank and channel reinforcement with gabion baskets or concrete structures that are designed to withstand a 100-year flood event. To be considered an improved creek channel the improvements must be maintained in good condition as determined by a licensed geotechnical engineer.

"Invasive plant" means one or more of the following plant species:

Tree-of-heaven (Ailanthus altissima)

Acacia species (Acacia melanoxylon, A. decurrens)

Giant reed (Arundo donax)

Algerian ivy (Delairea odorata)

Blue gum (Eucalyptus globulus)

English ivy (Hedera helix)

Glossy privet (Ligustrum lucidum)

Himalayan blackberry (Rubus armeniacus)

Elm (Ulmus sp.)

Periwinkle (Vinca major)

"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, that such enclosure is not built so as to render the structure in violation of the applicable nonelevation design requirements of this chapter, including, but not limited to:

(A)

The wet floodproofing standard in Section 6-1834(d);

(B)

The anchoring standards in Section 6-1832;

(C)

The construction materials and methods standards in Section 6-1833; and

(D)

The standards for utilities in Section 6-1836.

(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 connected 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 sale or rent.

"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.

"Native riparian plant" means a plant species typical of riparian lands that is indigenous to a Lafayette watercourse and listed in the City of Lafayette Homeowner's Creek Guide or Table 5-2 of the Downtown Creeks Preservation, Restoration and Development Plan or their subsequent amendments or revisions.

"New construction" means, for flood management purposes, structures for which the "start of construction" commenced on or after the effective date of the ordinance codified in this chapter, and includes any subsequent improvements to 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 ordinance codified 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."

"Person" means an individual or his agent, firm, partnership, association or corporation, or agent of the aforementioned groups, or this state or its agencies or political subdivisions.

"Public safety and nuisance" as related to Article 6, Flood Hazard Variance Procedure, of this chapter 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.

"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 this chapter or otherwise deterring future

similar violations, or reducing state or federal financial exposure with regard to the structure or other development.

"Riparian lands" means lands that occur along a watercourse and are delineated by the existence of plant species that differ from adjacent upland vegetation, because more surface or subsurface water is supplied to plants by their proximity to the associated watercourse. Typical examples include floodplains and creek banks. Riparian lands occur along natural watercourses, as well as along constructed water bodies such as ditches, canals and ponds.

"Riverine" means relating to, formed by or resembling a river (including tributaries), stream, creek, 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 an FHBM or FIRM as Zone A, A1-30, AE, AO, A99 or 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 of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of a slab or footings, 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, footing, 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. For a structure (other than a manufactured home) without a basement or poured footings, the "start of construction" includes the first permanent framing or assembly of the structure or any part thereof on its piling or foundation. For manufactured homes not within a manufactured home park or manufactured home subdivision, "start of construction" is the date on which the construction of facilities for serving the site on which the manufactured home is to be affixed (including, at a minimum, the construction of streets, either final site grading or the pouring of concrete pads and installation of utilities) is completed.

"Structure" means (a) a walled and roofed building that is principally above ground; this includes a gas or liquid storage tank as well as a manufactured home; (b) any other roofed building supported by columns, walls, or other foundation systems not intended for housing; or (c) retaining walls, foundations, and systems intended to be load bearing that do not support housing.

"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 comply with existing 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 structure listed on the National Register of Historic Places or a State Inventory of Historic Places or designated by the city as an historical landmark; provided, that the alteration will not preclude the structure's continued designation as a "historic structure."

"Top of bank" means a point or line which is the beginning of a change in the slope of the land surface to a slope greater than 33 percent, then from which the land surface slopes downward toward a watercourse. When two or more slopes are located together or separated by a bench of less than 20 feet, the slope that is highest and farthest away from the toe of slope shall be the slope considered for the top of bank.

"Unimproved creek channel" means those channels that do not meet the definition of "improved creek channels."

"Variance" or "flood hazard 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 the city's floodplain management regulations. 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. No. 684, § 2(Exh. 2), 4-10-2023)