Countywide FEMA Floodplain Maps Effective June 2, 2011

North Albany FIRMs updated, Effective December 8, 2016

 ***see bottom of page for Interactive Map of flood hazards***


Principal Flood Problems

Benton Co SFHA

Flooding in Benton County is caused by intense rainfall from large winter storms moving inland from the Pacific Ocean. This condition often results in simultaneous flooding on all streams in the study area. The greatest known flood on the Willamette River occurred in December 1861, before there was stream-gaging network for recording flood heights. Discharges and crest elevations for large Willamette River floods at the U.S. Geological Survey (USGS) Albany gage from 1941 to 2007. The 1964 flood was a result of unusually intense precipitation on frozen topsoil, augmented by snowmelt in the mountains and valley.

Without upstream regulation, the 1964 flood would have been the largest flood of the 20th century, with a peak discharge of 320,000 cubic feet per second (cfs) at the Albany gage. However, upstream regulation reduced the peak discharge to 186,000 cfs. Flood damage caused by the 1964 flood in the unincorporated areas was limited primarily to agricultural lands. However, residential developments near Stewart Lake and North Albany suffered extensive damage. The 1964 flood had a recurrence interval of 80 years. The most recent Willamette River flood occurred in 1997 and had a recurrence interval of about 6 years. default Read more...

Map Changes Since Previous Release

The detailed study area floodplain boundaries of Dixon Creek, South Fork Dixon Creek, Dunawi Creek, Frazier Creek, Jackson Creek, Oak Creek, and approximately 7 miles of the Marys River, from the mouth to the confluence with Muddy Creek, were revised using topographic mapping with a contour interval of 2 feet. Detailed study area floodplain boundaries for the North Fork Alsea River, Newton Creek, Soap Creek, and 8 miles of the Marys River, from the confluence with Muddy Creek to the upstream limit of the detailed study area, were revised using topographic mapping with a contour interval of 5 feet.

Approximately 14 miles of Willamette River floodplain boundaries were revised using topographic mapping with a contour interval of 2 feet. The portion of the Willamette River floodplain redelineation using 2 foot contours were divided into two separate reaches. The first reach is located in the vicinity of Albany, starts from 2,000 feet north of the northern corporate limit of Albany and continues 7.5 miles upstream, to approximately 2000 feet west of the southwest corporate limit of Albany. The second reach begins approximately 1.8 miles downstream of the mouth of Dixon Creek and continues upstream 6.5 miles to approximately 3,000 feet upstream of the confluence with the Boonville channel. The remainder of the Willamette River floodplain boundaries within Benton County were revised using topographic mapping with a contour interval of 5 feet. Approximately 19.6 miles of Marys River and Rock Creek approximate A Zone areas were refined using topographic mapping with a contour interval of 5 feet. Where applicable, the contour data was used to adjust the flood hazard areas to more accurately match the topography.

Community Links:




-Benton County Maps and GIS...

-Benton County Emergency Management...

-Benton County's Hazard Mitigation Plan...


-Corvallis Natural Hazards Map...
-Corvallis's Draft Hazard Mitigation Plan...


Download Products

Current products to download -

- A "KML" is a file that can be downloaded and opened directly in Google Earth, ArcGIS Explorer and other viewing software available on the Internet.  The KML below is for the Special Flood Hazard Area (SFHA), also known as the "100-year" flood.

- A Flood Insurance Study (FIS) is the publication developed in conjunction with the Flood Insurance Rate Map (FIRM) and discusses the engineering methods used to develop the FIRMs.  The study also contains flood profiles for studied flooding sources and can be used to determine Base Flood Elevations for some areas.

Future Mapping

North Albany undergoing a Physical Map Revision (PMR) for new FIRMs.  Public meeting with Preliminary maps Feb. 17th, 2015 in Albany. New Flood Insurance Rate Maps (FIRMs) Effective December 8, 2016.  See FEMA MAP Service Center for for pending FIRMs (Benton County, City of Albany)

Snapshots around the county

 Corvallis-PhilomathCorvallis-Philomath area


***NEW INTERACTIVE MAP for Special Flood Hazard Area ("100-year" flood)***

Note - For general information only - DO NOT use for regulatory purposes, especially for non-modernized areas: see "description" for source information and disclaimer

(hint: once in Viewer select "Basemap" in upper left corner for imagery background)

Interactive Map


Contact for Oregon Risk MAP

The Department of Land Conservation and Development is the lead on the Oregon Risk MAP project. To reach the program coordinator contact:

Dave Lentzner
635 Capitol St. NE, Suite 150
Salem, OR 97301-2540

Phone: 503-934-0010