North Albany Floodplain Study Overview
- About this page:
- Last Updated: June 20, 2016 June 20, 2016
FEMA’s Letter of Final Determination dated June 8, 2016 arrived setting the final stages of this project in motion. The letter states that FEMA completed their internal review and revised the map panels where needed. Other important information in the letter:
- The flood maps will become effective on December 8, 2016
- A final list of LOMAs or LOMR-Fs that have been revalidated or superseded is attached
In early 2010 the City retained Pacific Water Resources (now AMEC Earth and Environmental) to model the floodplain of the Willamette River in North Albany. The study was initiated because the current Federal Emergency Management Agency (FEMA) floodplain maps for North Albany appeared to be inaccurate. The most significant inaccuracy was an unmapped floodway, which was identified through review of past development proposals that were either ultimately denied or have since expired. In order to adequately review future development proposals the City believed it was important to have a more accurate understanding of floodplain characteristics throughout North Albany. In addition, by having this study completed in advance of future development proposals the development community will know what challenges might exist on an existing parcel prior to investing in predevelopment activities.
AMEC concluded their study in July 2011. The study verified that there was a significant unmapped floodway through North Albany. This floodway is essentially an overflow channel from the Willamette River. It is estimated that during a 100-year flood event that approximately 5,600 cubic feet per second (cfs) of water flows through this floodway at a maximum speed in excess of five feet per second. To put that amount of water in perspective, it is typically what flows in the Willamette River itself in September. At five feet per second, water with very little depth can apply enough force to push a car off of the road.
The study also unexpectedly identified significant differences in the amount of flooding throughout the study area. These differences were seen in both the extents and depths of flooding. When compared to FEMA’s most recent (2010) DFIRM floodplain maps, the study identified approximately 102 acres of property mapped as being in the floodplain that shouldn’t be and approximately 104 acres of property that should be shown in the floodplain, that is not. Differences in the depths of flooding ranged from more than four feet less than the 2010 FEMA maps to around two feet more than the 2010 FEMA maps.
Preliminary results were presented to the community in 2011 at an Open House in North Albany. Every property potentially impacted by the study received a letter describing the project and letting them know where to find information and inviting them to the Open House. Since then, FEMA has accepted the study results and issued preliminary FIS/FIRM documents.
The City and FEMA hosted another open house on February 17, 2015. The format was similar to that of the 2011 open house where residents learned about the study, the risks of flooding on their property, potential flood insurance impacts, and anticipated time frame for FEMA’s adoption of new maps. The Open House was announced in the newspaper and in another letter sent to each property in the North Albany study area.
FEMA’s preliminary maps can be reviewed at www.fema.gov/preliminaryfloodhazarddata. Be sure to view Linn and Benton County.
FEMA announced a 90-day appeal period to FEMA’s proposed revisions to the floodplain maps in North Albany. This public notification was published in the Albany Democrat-Herald and Corvallis Gazette-Times on July 8, 2015, and again on July 15, 2015. The appeal period ran from July 15, 2015 through October 13, 2015. During this period one appeal was received. The appeal period is now closed.
Following the close of the appeal period, FEMA completed their internal review, revised flood elevations, flood extents, and flood maps and announced that the flood maps will become effective on December 8, 2016.
In addition to this general overview, this website contains:
- Definitions of floodplain terminology,
- Aerial photos of past flood events,
- Maps that compare the old and new FEMA maps,
- A question and answer section,
- Technical information on the floodplain modeling approach, and
- A description of potential flood insurance rate implications.
Albany’s current floodplain development regulations are found in Article 6 of the Albany Development Code. This study doesn’t change the floodplain development regulations in the Albany Development Code, but could result in changes to the floodplain data that would be used to evaluate a given development proposal.