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POL Government Elected Officials Auditor Griffin-Valade Charter, Code & Policies City Code & Charter Online Code & Charter Title 24 Building Regulat Chapter 24.50 Flood Hazard Areas
24.50.030 Flood Related Definitions.

(Amended by Ordinance Nos. 178741, 182370 and 184235, effective November 26, 2010.)  The definitions contained in this Section relate to flood hazard areas and considerations outlined in this Chapter.

 

A.  "Appeal" means a request for a review of the City of Portland’s interpretation of any provision of this ordinance or a request for a variance.

 

B.  "Area of shallow flooding" means a designated AO or AH zone on the Flood Insurance Rate Map (FIRM).  The base flood depths range from 1 to 3 feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and, velocity flow may be evident.  AO is characterized as sheet flow and AH indicates ponding.

 

C.  "Areas of Special Flood Hazard" mean the land in the flood plain within a community subject to a one percent or greater chance of flooding in any given year.  Designation on maps always includes the letters A or V.

 

D.  "Base Flood (100‑year flood)" means the flood having 1 percent chance of being equaled or exceeded in any given year.  Designation on maps always includes the letters A or V.

 

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

 

F.  "City Datum" means the reference datum for the City of Portland maps.  The FIRM maps described in Section 24.50.050 are referenced to the North American Vertical Datum (NAVD) of 1988.  To convert NAVD 1988 level to City datum, subtract 2.125 feet from the elevation referenced to NAVD 1988 level.

 

G.  "Development" means any man‑made change to improved or unimproved real estate, including but not limited to buildings, bridges, other structures, and mining, dredging, filling, grading, paving, excavation, fencing, landscaping, drainage facilities, drilling operations, or storage of equipment or material.

 

H.  "Existing manufactured home park or manufactured home subdivision" means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale for which the construction of facilities for servicing the lot on which the manufactured home is to be affixed (including as a minimum, the installation of utilities, either final site grading or the pouring of concrete pads, and the construction of streets) is completed before the original date of this Chapter.

 

I.  "Expansion to an existing manufactured home park or manufactured home 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, either final site grading or the pouring of concrete pads, and the construction of streets).

 

J.  "FIA" means Federal Insurance Administration.

 

K.  "Flood Hazard Area" means any area which has been identified as subject to flooding. 

 

L.  “Flood Insurance Study” means the official report provided by the Federal Insurance Administration that contains information regarding flooding, discusses the engineering methods used to develop the Flood Insurance Rate Maps (FIRMs), includes flood profiles, and the water surface elevation of the base flood.

 

M.  "Flood Insurance Rate Map (FIRM)" means the official map on which the Federal Insurance Administration has delineated the areas of special flood hazards.

 

N.  "Flood or flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters, and/or the unusual and rapid accumulation of runoff of surface waters from any source.

 

O.  "Flood protection elevation" means the water surface elevation of the base flood plus a freeboard allowance.

 

P.  "Floodplain" means the channel of watercourse and adjacent land areas which are subject to inundation by the base flood.

 

Q.  "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, sanitary, and water facilities, structures, and their contents.

 

R.  "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 actual floodway boundaries are computer activated and approximate.  These boundaries are depicted on the FIRM.  Boundaries for other watercourses may be subject to identification by the Sewage System Administrator.  The width of the floodway for unidentified watercourses should not be less than 15 feet.

 

S.  "Flood fringe area" means any area lying outside the floodway which is subject to flooding by a base flood and for which water surface elevations and floodway and flood fringe boundaries have been determined by a Flood Insurance Study and are shown on the FIRMs.  Boundaries for unidentified watercourses may be subject to identification by the Sewage System Administrator.

 

T.  "Freeboard" means an additional height above the base flood level to account for factors that may contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as filling in the floodway fringe, wave action, effect of urbanization of the watershed, map inaccuracies, irregular stream cross sections, irregular constructions at bridges, and the uncertainties of flood discharge computations.

 

U.  "Lowest Floor" means 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 found at Section 24.50.060 F.2. 

 

V.  "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.  For flood plain 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.  For insurance purposes, the term “manufactured home” does not include park trailers, travel trailers, and other similar vehicles.

 

W.  "New construction" means structures for which the start of construction commenced on or after the effective date of this Chapter.

 

X.  "New manufactured home park or manufactured home subdivision" means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale for which the construction of facilities for servicing the lots on which the manufactured home is to be affixed (including as a minimum, the installation of utilities, either final site grading or the pouring of concrete pads and the construction of streets) is completed on or after the original date of this Chapter. 

 

Y.  “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.  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, walkways, sanitary sewers, storm sewers, and/or drainage facilities; nor does it include excavation for a basement, footings, piers, or foundation 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. 

 

Z.  “Structure or accessory structure” means, for the purposes of this Chapter, a walled and roofed building including a gas or liquid storage tank that is principally above ground.

 

AA.  “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.

 

BB.  "Substantial Improvement" means any repair, reconstruction, 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 improvement or repair is started, or

 

2.   If the structure has been damaged, and is being restored, before the damage occurred.  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

 

b.  Any alteration of a structure listed on the National Register of Historic Places or the State Inventory of Historic Places. 

 

CC.  “Variance” means a grant of relief from the requirements of this ordinance which permits construction in a manner that would otherwise be prohibited by this ordinance. 

 

DD.  “Water surface elevation” means the height of the water surface of the base flood for any point along the longitudinal course of a stream. 

 

EE.  “Watercourse” means a channel in which a flow of water occurs, either continuously or intermittently, and if the latter, with some degree of regularity.  Watercourses may be either natural or artificial.


Title 24 Building Regulat
Chapter 24.10 Administration and Enforcement
Chapter 24.15 Definitions
Chapter 24.20 Special Inspections
Chapter 24.25 Movings of Buildings
Chapter 24.30 Home Occupations
Chapter 24.35 Historical Buildings
Chapter 24.40 Use of and Projections Over Public Streets and Property
Chapter 24.45 Parking and Driveway Surfaces
Chapter 24.50 Flood Hazard Areas
Chapter 24.51 Wildfire Hazard Zones
Chapter 24.55 Building Demolition
Chapter 24.60 Fences
Chapter 24.65 Sidewalk Vault Openings
Chapter 24.70 Clearing, Grading and Erosion Control
Chapter 24.75 Uniform Building Address System
Chapter 24.80 (Repealed)
Chapter 24.85 Seismic Design Requirements for Existing Buildings
Chapter 24.90 Manufactured Dwelling Installation and Accessory Structures, Manufactured Dwelling Parks, Recreation Parks, Recreational Park Trailer Installation and Accessory Structures
Chapter 24.95 (Repealed)