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The following definitions are specific to the regulations for the frequently flooded areas in the Land Use Code and shall have the following meanings:

Alteration of watercourse” means any action that will change the location of the channel occupied by water within the banks of any portion of a riverine waterbody.

Area of special flood hazard means the land in the floodplain within the City subject to a one percent or greater chance of flooding in any given year. It is shown on the Flood Insurance Rate Map (FIRM) as Zone A, AO, AH, A1-30, AE, A99, or AR (V, VO, V1-30, VE). “Special flood hazard area” is synonymous in meaning with the phrase “area of special flood hazard”.

Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year. Also referred to as the 100-year flood.

Base flood elevation (BFE)” means the elevation to which floodwater is anticipated to rise during the base flood.

Basement” means any area of the building having its floor subgrade (below ground level) on all sides.

Development” means any manmade change to improved or unimproved real estate in the frequently flooded areas, including, but not limited to, building or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations, or storage of equipment or materials.

Encroachment” means any alteration or development within the regulatory floodway that would result in any increase in the flood levels during the occurrence of the base flood discharge.

Flood” or “flooding” means:

1. A general and temporary condition of partial or complete inundation of normally dry land areas from:

a. The overflow of inland waters; or

b. The unusual and rapid accumulation or runoff of surface waters from any source; or

c. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in subsection 1.b of this definition and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current.

2. 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 by some similarly unusual and unforeseeable event which results in flooding as defined in subsection 1.a of this definition.

Flood elevation study” means an examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation and determination of mudslide (i.e., mudflow) and/or flood-related erosion hazards. Also known as a Flood Insurance Study (FIS).

Flood Insurance Rate Map (FIRM)” means the official map delineating both special flood hazard areas and the risk premium zones applicable to the City that was prepared by the Federal Insurance Administrator for the City or as subsequently revised by the Federal Emergency Management Agency. A FIRM that has been made available digitally is called a Digital Flood Insurance Rate Map (DFIRM).

Floodplain or flood prone area” means any land area susceptible to being inundated by water from any source. Floodplains are usually defined geographically on the basis of that area flooded by the most intense storm occurring during a certain period of years. Although floodwaters usually drain rapidly after precipitation has ceased, when floodwaters flow into wetland areas, they may be impounded for some time, due to the poor drainage characteristics of wetlands. See “Flood or flooding.”

Floodplain Administrator” means the Director of the Development Services Department, or the designee thereof, responsible for administering and enforcing the floodplain management regulations, and granting or denying development permits on the basis thereof.

Floodproofing” means any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate risk of flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents. Floodproofed structures are those that have the structural integrity and design to be impervious to floodwater below the Base Flood Elevation.

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 a designated height. Also referred to as “Regulatory Floodway.”

Highest adjacent grade” means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

Historic structure” means any structure that is:

1. Listed individually in the National Register of Historic Places (a listing maintained by the Department of the Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;

2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;

3. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of the Interior; or

4. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:

a. By an approved state program as determined by the Secretary of the Interior, or

b. Directly by the Secretary of the Interior in states without approved programs.

Hyporheic zone” means the saturated zone located beneath and adjacent to streams that contains some portion of surface waters, serves as a filter for nutrients and maintains water quality.

Lowest floor” means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood-resistant enclosure, usable solely for parking 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 part found in LUC 20.25H.180.C.1.a.

Manufactured home” means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term “manufactured home” does not include “recreational vehicle.”

Mean sea level” means, for purposes of the National Flood Insurance Program, the vertical datum to which Base Flood Elevations shown on the City’s Flood Insurance Rate Map are referenced.

New construction” means, for the purposes of determining insurance rates, structures for which the “start of construction” commenced on or after December 1, 1978, and includes any subsequent improvements to such structures. For floodplain management purposes, “new construction” means structures for which the “start of construction” commenced on or after December 1, 1978, and includes any subsequent improvements to such structures.

One-Hundred-Year Flood. See “Base flood elevation (BFE).”

Pre-FIRM building” means a building constructed prior to December 1, 1978.

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 a temporary living quarters for recreational, camping, travel, or seasonal use.

Regulatory floodway” means the floodway delineated on the Flood Insurance Rate Map (FIRM).

Start of construction” includes substantial improvement and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within 180 days from the date of the permit. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading, and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

Structure” means a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a mobile home.

Substantial damage” means damage of any origin sustained by a structure where the cost of restoring the structure to its before damage condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.

Substantial improvement” includes the following: Any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the “start of construction” of the improvement. This term includes structures which have incurred “substantial damage,” regardless of the actual repair work performed. The term does not, however, include either (1) any project for improvement of a structure to correct previously identified existing violations of state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions; or (2) any alteration of a “historic structure”; provided, that the alteration will not preclude the structure’s continued designation as a “historic structure.”

Variance” means a grant of relief by the City from the terms of a floodplain management regulation. (Ord. 6521, 7-27-20, § 4; Ord. 6417, 5-21-18, § 43; Ord. 6013, 8-1-11, § 2; Ord. 5680, 6-26-06, § 3)