A. Alter. In the context of this Article and the changing of a riverine or drainage channel, shall mean any activity which decreases, increases, or otherwise causes changes to the carrying capacity of said riverine or drainage channel.

B. Appeal. A request for a review of the Floodplain Administrator’s interpretation of any provision of this ordinance or a request for a variance.

C. Area of Shallow Flooding. A designated AO, AH, or VO 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.

D. Area of Special Flood Hazard. The land in the flood plain within a community subject to a one percent or greater chance of flooding in any given year.

E. Base Flood. The flood having a one percent chance of being equaled or exceeded in any given year (also called the “100 year flood”).

F. Basement. Any area of the building having its floor subgrade, i.e., below ground, level on all sides.

G. Breakaway Walls. Any type of wall, whether solid or lattice, and whether constructed on 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 they are used or any buildings to which they might be carried by flood waters. A breakaway wall shall have a safe design loading resistance of not less than ten and no more than twenty pounds per square foot. Use of breakaway walls must be certified by a registered engineer or architect and shall meet the following conditions:

H. Coastal High Hazard Area. The area subject to high velocity waters, including coastal and tidal inundation or tsunamis. The area is designated on a Flood Insurance Rate Map (FIRM) as Zone V1-V30, VE or V.

I. Development. Any man-made change to improved or unimproved real estate including, but not limited to, buildings or other structures, mining, dredging, filling, grading, excavation, drilling operations, permanent storage of equipment and materials (i.e., lumber yards, junk yards, vehicle storage yards, etc.), excluding the improvement or maintenance of public roads.

J. Development Permit. A zoning permit, grading permit or building permit or any other permit, certificate, or license pertaining to the erection, construction, reconstruction, moving, conversion, alteration, or addition to any building or structure and the use of any land, building or premise, per the procedure set forth in Section 6.070(B).

K. Flood or Flooding. A general and temporary condition of partial or complete inundation of normally dry land areas from: (1) the overflow of inland or tidal waters; (2) the unusual and rapid accumulation or runoff of surface waters from any source; and/or (3) 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 flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in this definition.

L. 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.

M. Flood Insurance Rate Map (FIRM). An official map of the City of Petaluma or Sonoma County, on which the Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

N. Flood Insurance Study. The official report provided by the Federal Insurance Administration. The report contains flood profiles, as well as the Flood Boundary-Floodway Map, the Flood Insurance Rate Maps, and the water surface elevation of the base flood.

O. Floodplain or Flood-prone Area. Any land area susceptible to being inundated by water from any source (see definition of flooding).

P. Floodplain Management. The operation of an overall program of corrective and preventive measures for reducing flood damage, including but not limited to emergency preparedness plans, flood control works, and floodplain management regulations.

Q. Floodplain Management Regulations. Zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as floodplain ordinance, grading ordinance and erosion control ordinance), and other applications of police power. The term describes such state or local regulations in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.

R. Floodproofed. Watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

S. Floodproofing. 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.

T. Floodway. Also referred to as regulatory floodway. 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 (1) foot.

U. Functionally Dependent Use. A use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does not include long-term storage or related manufacturing facilities.

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

W. Highest Adjacent Grade. The highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

X. Lowest Floor. The lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement area is not considered a building’s lowest floor; provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this ordinance.

Y. Manufactured Home. A structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term “manufactured home” also includes park trailers, travel trailers and other similar vehicles placed on a site for greater than 180 consecutive days.

Z. Manufactured Home Park or Subdivision. A parcel (or contiguous parcels) of land divided into two or more manufactured home lots for sale or rent.

AA. Mean Sea Level. 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.

BB. New Construction. Structures for which the “start of construction” commenced on or after the effective date of this Ordinance.

CC. No Net Fill. Any material brought on to a project site within a flood plain area that would displace flood waters. All fill shall be offset by the removal of a like amount of material. This material may be removed from a portion of the project site; or it may be removed from a site in the immediate area where the removal of compensating material from the off-site location can be determined, to the satisfaction of the City Engineer and the Sonoma County Water Agency, to result in a reasonable equivalence of hydrology and hydraulics to the situation before the development. For purposes of compliance, one or more individual parcels or an entire reach may demonstrate a “zero net fill” balance.

DD. Petaluma River Basin. All significant flooding sources affecting the City of Petaluma including the Petaluma River, Washington Creek, Lynch Creek, Willow Brook, Thompson Creek, Kelly Creek, Adobe Creek, Capri Creek, Corona Creek, and several minor tributaries thereto.

EE. Person. 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.

FF. Regulatory Floodway. 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.

GG. Remedy a Violation. 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 to a level acceptable to the City. Ways that impacts may be reduced include protecting the structure or other affected development from flood damages, implementing the enforcement provisions of the ordinance or otherwise deterring future similar violations, or reducing Federal financial exposure with regard to the structure or other development.

HH. Riverine. Relating to, formed by, or resembling a river (including tributaries), stream, brook, etc.

II. 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, AO, A1-30, AE, A99, AH, V0, V1-V30, VE or V.

JJ. Start of Construction. Includes substantial improvements, rehabilitations, additions and reconstructions, 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. 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, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or placement of a manufactured home on foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or sidewalks; 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.

KK. Structure. A walled and/or roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home.

LL. Substantial Improvement. Any repair, reconstruction, rehabilitation, addition or improvement of a structure, the cost of which exceeds 50 percent of the market value of the structure, not inclusive of the land value, before the start of construction of the improvement either (1) before the improvement or repair is started; or (2) if the structure has been damaged and is being restored, before the damage occurred. For the purposes of this definition, “substantial improvement” is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimension of the structure. The term does not, however, (1) include 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 (2) any alteration of a structure listed on the National Register of Historic Places or a State of City Inventory of Historic Places provided that the alteration will not preclude the structure’s continued designation as a historic structure.

MM. Variance. A grant of relief from the requirements of this ordinance which permits construction in a manner that would otherwise be prohibited by this ordinance.

NN. Violation. The failure of a structure or other development to be fully compliant with the community’s floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this ordinance is presumed to be in violation until such time as that documentation is provided.