24.50.030 Flood Related Definitions.

1. The definitions contained in this Section relate to flood hazard areas and considerations outlined in this Chapter.
2. A.  "Appeal" means a request for a review of the City of Portland’s interpretation of any provision of this Chapter or a request for a variance.
3. 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.
4. C.  "Areas of Special Flood Hazard" mean the land in the floodplain subject to a one percent or greater chance of flooding in any given year.  Designation on Flood Insurance Rate Maps always includes the letters A or V.  “Special flood hazard area” is synonymous with the phrase “area of special flood hazard.”
5. D.  "Base Flood (100‑year flood)" means the flood having 1 percent chance of being equaled or exceeded in any given year.
6. E.  “Base flood elevation (BFE)” means the elevation to which floodwater is anticipated to rise during the base flood.
7. F.  “Basement” means any area of the building having its floor, including crawlspace, below ground level on all sides.
8. G.  “Building” – See Structure.
9. H.  "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.
10. I.  “Design Flood” means the greater of the base flood or the February 1996 Flood Inundation Area.
11. J.  “Design Flood Elevation” means the greater of the base flood elevation or the February 1996 Flood Inundation Area elevation.
12. K.  "Development" means any human-created 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.
13. L.  "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 October 18, 1979.
14. M.  "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).
15. N.  "FIA" means the Federal Insurance Administration.
16. O.  "Flood Hazard Area" means any area that has been identified as subject to flooding. 
17. P.  “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), and includes flood profiles, and the water surface elevation of the base flood.
18. Q.  "Flood Insurance Rate Map (FIRM)" means the official map on which the Federal Insurance Administration has delineated the areas of special flood hazards.
19. R.  "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, or the unusual and rapid accumulation of runoff of surface waters from any source.
20. S.  "Flood protection elevation" means the design flood elevation plus a freeboard allowance.
21. T.  "Floodplain" means the channel of watercourse and adjacent land areas that are subject to inundation by the design flood.
22. U.  “Floodplain Administrator” means the City of Portland official designated by the Director of the Portland Permitting & Development to administer and enforce this Chapter.
23. V.  "Floodproofing" means any combination of structural and nonstructural additions, changes, or adjustments to structures that reduce or eliminate the risk of flood damage to real estate or improved real property, sanitary, and water facilities, structures, and their contents.  Floodproofed structures are those that have the structural integrity and design to be watertight with walls substantially impermeable to the passage of water.
24. W.  "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.  The actual floodway boundaries are computer generated 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 may not be less than 15 feet unless otherwise approved by the Sewage System Administrator.
25. X.  "Flood fringe area" means any area lying outside the floodway that 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.
26. Y.  "Freeboard" means an additional height above the design flood elevation 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 flood fringe, wave action, effect of urbanization of the watershed, map inaccuracies, irregular watercourse cross sections, irregular constructions at bridges, and the uncertainties of flood discharge computations.
27. Z.  “Functionally-dependent use” means a use that cannot fulfill its intended purpose unless it is located or carried out in close proximity to water. For purposes of this Chapter, this definition applies only to docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship-building and ship-repair facilities, and does not include long-term storage or related manufacturing facilities.
28. AA. “High Hazard Area” means the area comprised of and measured to the farthest landward extent of the floodway or the area inundated by a flood event having a 10 percent or greater chance of flooding in a given year as mapped or determined by FEMA.
29. BB. "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 Subsection 24.50.060 F.2. 
30. CC. "Manufactured home" means a structure transportable in one or more sections, that 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.  For insurance purposes, the term “manufactured home” does not include park trailers, travel trailers, and other similar vehicles.
31. DD. "New construction" means structures for which the start of construction commenced on or after October 18, 1979.
32. EE.  "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 October 18, 1979.
33. FF.  “Reasonably safe from flooding” means floodwaters and subsurface waters related to the design flood or other sources identified by the Sewage System Administrator will not damage proposed or existing structures.
34. GG. “Sewage System Administrator” means the person designated by the Bureau of Environmental Services who is responsible for regulating the public sanitary and stormwater facilities. The Sewage System Administrator may delegate their authority for the purpose of implementing these provisions.
35. HH.  “Start of construction” means the date the building permit was issued, provided the actual construction, repair, reconstruction, substantial improvement, placement, or other improvement was commenced within 180 days of the permit issuance 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, or filling; the installation of streets, walkways, sanitary sewers, storm sewers, or drainage facilities; excavation for a basement, footings, piers, or a foundation or the erection of temporary forms; or 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. 
36. II.  “Structure or accessory structure” means a walled and roofed building, including a gas or liquid storage tank, as well as a manufactured home.
37. JJ.  “Substantial Damage” means damage of any origin sustained by a structure whereby the cost of restoring the structure to its pre-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
38. KK. "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. 1.  Before the start of construction of the improvement or repair, or
    2. 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.
    3. The term does not, however, include either:
       1. a.  Any project for improvement of a structure to comply with existing State or local health, sanitary, or safety code specifications that are solely necessary to assure safe living conditions; or
       2. b.  Any alteration of a structure listed on the National Register of Historic Places or the State Inventory of Historic Places. 
39. LL. “Top of Bank” means the largest decrease in slope that is 10 percent or greater between the ordinary high water mark of a water body and a point 50 feet landward from the ordinary high water mark. See Chapter 33.930, Measurements. If there is no decrease in slope that is 10 percent or greater within a distance of 50 feet from the ordinary high water mark, then the top of bank will be the default top of bank location described in Chapter 33.930.
40. MM.  “Variance” means a grant of relief from the requirements of this Chapter that permits construction in a manner that would otherwise not be allowed under this Chapter. 
41. NN.  “Water surface elevation” means the height of the water surface of the design flood for any point along the longitudinal course of a watercourse. 
42. OO. “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.

PP. “Willamette River Central and South Reach” means that portion of the Willamette River Flood Zone south of the Fremont Bridge on the west bank and the Broadway Bridge on the east bank.

QQ. “Willamette River North Reach” means that portion of the Willamette River Flood Zone north of the Fremont Bridge on the west bank and the Broadway Bridge on the east bank.