Skip to Main Content View Text-Only

The City of Portland, Oregon

Charter, Code and Policies

City of Portland



More Contact Info

17.38.020 Definitions.

(Replaced by Ordinance No. 185397; Amended by Ordinance Nos. 186902 and 187904, effective August 19, 2016.)  For the purposes of this Chapter, the following definitions apply:

A.  "Approved Drainage System" means a system approved by BES which adequately collects, conveys, treats or disposes of stormwater runoff or other site discharge.  Approved systems must meet all requirements and specifications laid out in this code, BES design manuals and documents, and any applicable plumbing code provisions relating to the piped portions of any system.

B.  "Capacity"  means the flow volume or rate for which a specific facility is designed to safely contain, receive, convey, infiltrate, or reduce pollutants from sanitary sewage, stormwater, wastewater, or other discharge in order to meet a specific performance standard. 

C.  "Combination Facilities"  means stormwater management systems that are designed to meet two or more of the objectives detailed in the Stormwater Management Manual

D.  “Conveyance” means the transport of sanitary sewage, stormwater, wastewater or other discharge from one point to another point.

E.  "Director" means the Director of the Bureau of Environmental Services, or the Director’s designee.

F.  “Discharge” means any disposal, injection, dumping, spilling, pumping, emitting, emptying, leaching, leaking or placing of any material so that such material enters or is likely to enter a waterbody, groundwater, or a public sewer and drainage system.

G.  “Discharge Point” means the connection point to a public sewer or drainage system or destination for a discharge leaving a site.

H.  “Discharge Rate” means the rate of flow expressed in cubic feet per second (cfs).

I.  "Drainageway" means an open linear depression, whether constructed or natural, which functions for the collection and drainage of surface water.  It may be permanently or temporarily inundated.

J.  “Green Street” means a vegetated stormwater management facility located within a public or private right-of-way.

K.  “Groundwater” means subsurface water that occurs in soils and geological formations that are fully saturated.  Groundwater fluctuates seasonally and includes perched groundwater.

L.  “Groundwater Discharge” means a discharge of water pumped or directed from the ground. Groundwater discharges include but are not limited to subsurface water from site remediation and investigations, well development, Brownfield development, discharges from footing and foundation drains, and subsurface water associated with construction or property management dewatering activities.

M.  "Impervious Surface" means any surface that has a runoff coefficient greater than 0.8 (as defined in the City’s Sewer and Drainage Facilities Design Manual).  Types of impervious surfaces include rooftops, traditional asphalt and concrete parking lots, driveways, roads, sidewalks and pedestrian plazas. Slatted decks and gravel surfaces are considered pervious unless they cover impervious surfaces or gravels are compacted to a degree that causes their runoff coefficient to exceed 0.8.

N.  “Infiltration” means the percolation of water into the ground.  Infiltration is often expressed as a rate (inches per hour) which is determined through an infiltration test.

O.  "Pollutants of Concern" means constituents identified by DEQ or BES as having the potential to have a negative impact on the receiving system, including surface waters, groundwater, the wastewater collection system or the wastewater treatment plant.  Pollutants of concern can include suspended solids, metals, nutrients, bacteria and viruses, organics, volatiles, semi-volatiles, floatable debris and increased temperature.

P.  "Practicable" means available and capable of being done as determined by the Director, after taking into consideration cost, resources, existing technology, and logistics in light of overall project purpose.

Q.  “Public Right-of-Way” means the area within the confines of a dedicated public street, an easement owned by the City, or other area dedicated for public use for streets or public utilities. 

R.  "Redevelopment" means any development that requires demolition or complete removal of existing structures or impervious surfaces at a site and replacement with new impervious surfaces. Maintenance activities such as top-layer grinding,  re-paving (where the entire pavement is not removed) and re-roofing are not considered redevelopment.  Interior remodeling projects and tenant improvements are also not considered to be redevelopment. 

S.  "Site Map"  means a map showing the stormwater management facility location in relation to buildings, structures or permanent survey monuments on the site. A site map shall depict location of sources of runoff entering the stormwater management facility and the discharge point and type of receiving system for discharge leaving the facility.

T.  “Source Control” means a structural or operational measure to prevent or control the release or potential release of pollutants generated by certain site characteristics and uses.

U.  “Stormwater” means water that originates as precipitation on a particular site, basin, or watershed.

V.  “Stormwater Management" means techniques used to reduce pollutants from, detain, retain, or provide a discharge point for stormwater runoff. Stormwater management reduces combined sewer overflows and basement sewer backups, and helps meet the capacity needs of the existing infrastructure.

W.  "Stormwater Management Facility” means a facility or other technique used to reduce volume, flow rate or pollutants from stormwater runoff. Stormwater facilities may reuse, collect, convey, detain, retain, or provide a discharge point for stormwater runoff.

X.  “Temporary Structure” means a structure that is separate and distinct from all other structures and is created and removed in its entirety within three years, including all impervious area associated with the structure.

Y.  "Tract" means a parcel of land designated as part of a land division per Title 33  that is not a lot, lot of record, or a public right-of-way .

Z.  "Wetland" means an area that is inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands include swamps, marshes, bogs, and similar areas except those constructed as pollution reduction or flow control facilities.