Metadata: Portland Flood Response Stages

Portland Flood Response Stages

Category Hazard
Feature Dataset Name STAND-ALONE
Item Name flood_response_stages_pdx
Database Type SDE
Originator City of Portland
Bureau Bureau of Planning and Sustainability
Publication Date
Abstract This layer reflects the expected impact and response required for each phase of a flood event.
Purpose To provide a visual estimate of where flooding might geographically occur during each flood response phase.  Flood response phases are based on river gauge heights overlaid over LIDAR topography of the City. The flood phase levels are outlined in the PBEM 2018 FloodResponse Appendix to the Basic Emergency Operations Plan (BEOP).
Supplemental Information
Last Dataset Update 08/04/2020 17:16
Last Source Update 08/04/2020 09:02
Maintenance/Update Frequency n/a
Extent City of Portland
Data Type
Shape Type Polygon
Feature Count 88
Horizontal Position Accuracy
Horizontal Position Accuracy Link
North Bounding Coordinate 732555.357283456
South Bounding Coordinate 650334.220144346
East Bounding Coordinate 7703200.70275591
West Bounding Coordinate 7604005.67158793
Theme Keyword(s) Portland, Flood, Response
Theme Keyword Thesaurus None
Place Keyword(s) Portland, Oregon
Place Keyword Thesaurus None
Access Constraints Available for Public Use
Use Constraints These data are distributed under the terms of the City of Portland Data Distribution Policy. Care was taken in the creation of this data but it is provided "as is".

The City of Portland cannot accept any responsibility for errors, omissions, or positional accuracy.
Source Dataset Type File Geodatabase
Output Geodatabase EGH_Public
Distribution Grid: State plane coordinate system 1983(91).
Units: International feet
Datum: North American Datum of 1983/1991 (HPGN)
Liability: The information in this file was derived from digital databases on the City of Portland GIS. Care was taken in the creation of this file. The City cannot accept any responsibility for errors, omissions, or positional accuracy. There are no warranties, expressed or implied.
Format: Shapefile or File Geodatabase Feature Class - Data will be provided via City of Portland FTP Site.
Online Resource:
Online Instructions: City of Portland Public/Open Data is distributed via the PortlandMaps Open Data Site - Data not available on the PortlandMaps Open Data site can be requested by contacting the City of Portland CGIS Group -
Transfer Size: varies
SPCS Zone Identifier: 5076
This layer was created by data derived from two river gauges: one gauge located on the Willamette River ( and one gauge located on the Columbia River (;gage=VAPW1).
The vertical datum for the river gauge data was converted from the National Weather Service Datum to NAVD88 (Geoid 03) for analysis with 2014 LiDAR digital elevation model (DEM). 
Flood elevation along the rivers was mapped using river elevation cross sections maintained as a part of FEMA's National Flood Hazard Layer (available here: To estimate the flood elevation along the rivers the difference between river gauge elevation and the nearest cross section was applied to all cross sections along the Columbia and Willamette Rivers. Triangulated irregular networks (TINs) representing the river flood elevations were generated for each river based off of the cross sections with the modified elevations. The TINs were then converted to rasters, and cells where the flood raster was greater than the DEM ground elevation were valued as flooded at the particular river gauge elevation phase. Where the flood extents between the Columbia and the Willamette Rivers converged, the highest cell value was used to determine if the elevation was greater or less than the ground elevation. This was done for all phases. The final outputs were then converted from a set of rasters to a single featureclass for ease of use. 

Web Services

Service Description Feature Access Layer
BES_Layers Referecne layers as used by various BES web content Dynamic Flood Response Stages
BDS_Layers Map layers used to facilitate the permitting process Dynamic Flood Response Stages
Hazard Natural Hazards in and around the City of Portland. Dynamic Flood Response Stages
Natural_Hazards Natural Hazards in and around the City of Portland. Dynamic Portland Flood Response Stages

Attribute Tables & Domains

Table Description
Table Jurisdiction
Column Sort Column Name Column Alias Column Type Column Size Domain Value(s) Column Description
1 Phase_name Phase_name String 50
The name of the highest phase of flooding within the record extent
1 Shape_Length Shape_Length Numeric 8
1 Shape_Area Shape_Area Numeric 8
1 Willamette_Gauge_Hts_NWSD Willamette_Gauge_Hts_NWSD String 50
1 Willamette_Gauge_Hts_NAVD88 Willamette_Gauge_Hts_NAVD88 String 50
1 Columbia_Gauge_Hts_NWSD Columbia_Gauge_Hts_NWSD String 50
1 Columbia_Gauge_Hts_NAVD88 Columbia_Gauge_Hts_NAVD88 String 50