For the purpose of this article, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
APPEAL. A request for a review of the Floodplain Administrator's interpretation of any provision of this article or a request for a variance.
AREA OF SHALLOW FLOODING. A designated AO 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.
AREA OF SPECIAL FLOOD HAZARD. See “special flood hazard area.”
BASE FLOOD. A flood having a 1% chance of being equalled or exceeded in any given year (also called the “100-year flood”).
BASEMENT. Any area of the building having its floor subgrade (below the ground level) on all sides.
BREAKAWAY WALL. Any type of wall, whether solid or lattice, and whether constructed of concrete, masonry, wood, metal, plastic, or any other suitable building material, which is not part of the structural support of the building and which is designed to break away under abnormally high tides or wave action without causing any damage to the structural integrity of the building on which the wall is used or any building to which it might be carried by floodwaters. A breakaway wall shall have a safe design loading resistance of not less than 10 and no more than 20 pounds per square foot. The use of breakaway walls shall 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 a base flood.
DEVELOPMENT. Any man-made change to improved or unimproved real estate, including, but not limited to, buildings or other structures or mining, dredging, filling, grading, paving, excavation, drilling operations, storage of equipment or materials.
FEDERAL INSURANCE ADMINISTRATION (FIA). An agency of the United States Department of Housing and Urban Development, an agency recently reorganized into the Federal Emergency Management Agency (FEMA). The agency names are used interchangeably.
FLOOD OR FLOODING. A general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of floodwaters, the unusual and rapid accumulation or runoff of surface waters from any source, and/or the collapse or subsidence of land along the shore of a lake or other 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 a flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in this definition.
FLOOD BOUNDARY AND FLOODWAY MAP. The official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of flood hazard and the floodway.
FLOOD ELEVATION. The elevation of the water surface of the 100-year flood, U.S.G.S. mean sea level datum, also referred to as base flood (see “flood height”).
FLOOD FRINGE AREA. That area within the 100-year flood boundary which is not otherwise identified as a floodway. The boundaries of the flood fringe area are defined by the flood insurance maps. The boundaries may be expanded based on projec-tions, hydrographic analyses, and actions taken by the Contra Costa County Flood Control District. No reduction in the flood fringe area shall occur contrary to the appeal and amendment procedures established by the Federal Insurance Administration.
FLOOD HEIGHT. The depth of the floodwater during a 100-year flood which is computed as the difference between the elevation of the 100-year floodwater surface and the elevation of the ground surface at a given point in the flooded area.
FLOOD INSURANCE RATE MAP (FIRM). The official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazard and the risk premium zones applicable to the community.
FLOOD INSURANCE STUDY. The official report provided by the Federal Insurance Admini-stration which 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. Any land area susceptible to being inundated by water from any source (see “flooding”).
FLOODPLAIN COMBINING DISTRICTS, FP-1 (FLOODWAY) AND FP-2 (FLOOD FRINGE). These are established to regulate land uses within areas subject to inundation as designated on the FIRM. The regulations in such districts shall apply in addition to the regulations of the zone district with which the FP District is combined. The provisions of the FP Districts shall govern in such cases where the regulations conflict and cannot be reasonably reconciled between an FP District and the district with which it is combined.
FLOODPLAIN MANAGEMENT. The operation of an overall program of corrective and preventive measures for reducing flood damages, including, but not limited to, emergency preparedness plans, flood control works, and floodplain management regulations.
FLOODPLAIN MANAGEMENT REGULA-TIONS. The zoning provisions, subdivision regulations, building codes, health regulations, special purpose regulations (such as the floodplain regula-tions, grading regulations, and erosion control regulations) and other applications of police power. FLOODPLAIN MANAGEMENT REGULATIONS describes such state or local regulations, in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.
FLOODPROOFING. Any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damages to real estate or improved real property, water and sanitary facilities, or structures and their contents.
FLOODWAY. The channel of a river or other watercourse and the adjacent land areas which 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.”
FP-1 DISTRICT (FLOODWAY). This shall be applied to floodways and is intended to prevent new uses or the expansion of existing uses which require structures, fill, dikes, dumping of materials or waste, or the storage of materials or equipment which, in the event of a flood, may create obstructions within a floodway or become floating material which will increase hazards downstream.
FP-2 DISTRICT (FLOOD FRINGE). This shall be applied to flood fringe areas and is intended to provide supplemental regulations in addition to those of the existing district in order to mitigate potential flood damages and flood hazards.
FUNCTIONALLY DEPENDENT USE. A use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. FUNCTIONALLY DEPENDENT USE shall include only docking facilities, port facilities which are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but shall not include long-term storage or related manufacturing facilities.
HIGHEST ADJACENT GRADE. The highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
HISTORIC STRUCTURE. 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 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.
INCREASE IN FLOOD ELEVATION. An increase of more than one foot at any one point.
LOWEST FLOOR. The lowest floor of the lowest enclosed area (including the basement). An unfinished or flood resistant enclosure, usable solely for the parking of vehicles, building access, or storage in an area other than a basement area, is not considered a building's lowest floor provided such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this article.
MANUFACTURED HOME. A structure, trans-portable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, MANUFACTURED HOME shall also include park trailers, travel trailers, and other similar vehicles placed on a site for greater than 180 consecutive days.
MANUFACTURED HOME PARK OR SUB-DIVISION. A parcel (or contiguous parcels) of land divided into two or more manufactured home lots for sale or rent.
MEAN SEA LEVEL. 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.
NEW CONSTRUCTION. Structures for which the “start of construction” commenced on or after May 12, 1988.
ONE HUNDRED-YEAR FLOOD or 100-YEAR FLOOD. A flood which has a 1% annual probability of being equalled or exceeded. The boundaries of the 100-year flood area include both the floodway and the flood fringe areas. ONE HUNDRED-YEAR FLOOD is identical to “base flood,” which will be the term used throughout this article.
PERSON. An individual, or his agent, firm, partnership, association, or corporation, or agent of such, or the state or its agencies or political subdivisions.
RECREATIONAL VEHICLE. A vehicle 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.
REMEDY A VIOLATION. To bring the structure or other development into compliance with state or local floodplain management regulations, or, if such is not possible, to reduce the impacts of its noncompliance. Ways impacts may be reduced include protecting the structure or other affected development from flood damages, implementing the enforcement provisions of this article or otherwise deterring future similar violations, or reducing federal financial exposure with regard to the structure or other development.
RIVERINE. Relating to, formed by, or resembling a river (including tributaries), stream, brook, or the like.
SPECIAL FLOOD HAZARD AREA (SFHA). An area having special flood or flood-related erosion hazards and shown on an FHBM or FIRM as Zone A, A1-A30, AE, AO, A99, or AH.
START OF CONSTRUCTION. This shall mean and include substantial improvement, and shall mean the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement, or other improvement was within 180 calendar days of the permit date. ACTUAL START shall mean either the first placement of the permanent construction of a structure on a site, such as the pouring of slabs or footings, the installation of piles, the construction of columns, any work beyond the stage of excavation, or the placement of a manufactured home on a foundation. PERMANENT CONSTRUCTION shall not include land preparation, such as clearing, grading, and filling; nor shall it include the installation of streets and/or walkways; nor shall it include excavations for basements, footings, piers, or foundations or the erection of temporary forms; nor shall it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not a part of the main structure.
STRUCTURE. A walled and roofed building, including a gas or liquid storage tank, which is principally above the ground, as well as a manufactured home.
SUBSTANTIAL DAMAGE. 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% of the market value of the structure before the damage occurred.
SUBSTANTIAL IMPROVEMENT. Any repair, reconstruction, rehabilitation, addition or other improvement of a structure, the cost of which equals or exceeds 50% of the market value of the structure either before the improvement or repair is started, or if the structure has been damaged and is being restored, before the damage occurred. For the purpose of this definition, SUBSTANTIAL IMPROVEMENT is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of a building commences, whether or not such alteration affects the external dimensions of the structure. SUBSTANTIAL IMPROVEMENT, however, shall not include either any project for the 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 any alteration of a "historic structure," provided that the alternation will not preclude the structure's continued use as a "historic structure".
VARIANCE. A grant of relief from the requirements of this article which variance permits construction in a manner which would otherwise be prohibited by this article.
VIOLATION. 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 by this article shall be presumed to be in violation until such time as such documentation is provided.
WATERCOURSE. Any stream, river, creek, ditch, channel, canal, slough, conduit, culvert, drain, waterway, gully, or swale.
('66 Code, § 9-4.2003) (Ord. 708-C-S, passed 5-12-88; Am. Ord. 2025-C-S, passed 5-12-09)