News Releases

Corps considers plan to reduce Detroit Reservoir maximum pool elevation

Portland District, U.S. Army Corps of Engineers
Published March 15, 2021
Detroit Dam, 45 miles southeast of Salem, Ore. sits across the North Santiam River. It has six spillway gates that are 42 feet wide by 31 feet tall. 

In 2020, as a part of Portland District's comprehensive dam safety program, staff completed an updated seismic hazard
analysis for Detroit Dam to better understand the potential earthquake ground motions at the site.

Corps engineers used this his hazard study to analyze the performance of the spillway gates and found the risk to be higher than we previously assessed. Structural analysis of the spillway gates has shown there is a possibility for buckling of the spillway gates' supporting arms, which could result in an uncontrolled release of water from the dam. 

Because Detroit Dam is located upstream of many communities including the state capital of Salem, Oregon, there is potential for devastating flooding to affect large portions of the narrow North Santiam River canyon and urban areas.

Detroit Dam, 45 miles southeast of Salem, Ore. sits across the North Santiam River. It has six spillway gates that are 42 feet wide by 31 feet tall. In 2020, as a part of Portland District's comprehensive dam safety program, staff completed an updated seismic hazard analysis for Detroit Dam to better understand the potential earthquake ground motions at the site. Corps engineers used this his hazard study to analyze the performance of the spillway gates and found the risk to be higher than we previously assessed. Structural analysis of the spillway gates has shown there is a possibility for buckling of the spillway gates' supporting arms, which could result in an uncontrolled release of water from the dam. Because Detroit Dam is located upstream of many communities including the state capital of Salem, Oregon, there is potential for devastating flooding to affect large portions of the narrow North Santiam River canyon and urban areas.

Portland District, U.S. Army Corps of Engineers considers a plan to reduce Detroit Reservoir’s maximum pool elevation by five feet beginning this summer to reduce the likelihood of overstressing the spillway gates during a large earthquake, which might impact boat ramp access in some years.

Portland District invites members of the public to join a virtual informational briefing via WebEx Monday, March 22, 2021 from 5-7 p.m. on a plan to restrict Detroit Dam’s maximum pool elevation to 1558.5 feet (from 1563.5 feet) in order to reduce the life-safety risk associated with large seismic events.

In 2020, the District completed a seismic hazard analysis for Detroit Dam. The hazard study found the risk to be higher than Corps officials previously thought. Structural analysis has shown a possibility of the spillway gates buckling under the force of a full reservoir during a large earthquake. Even though the probability of breach is low, the Corps wants to take immediate action to reduce risk to acceptable levels because the potential impacts of a breach of the spillway gates are high with Detroit Dam located upstream of many communities including the state capital of Salem. The reservoir spans the Linn County–Marion County border in the Oregon Cascades on the North Santiam River near the city of Detroit.

The Corps has a public safety responsibility, when a project has known safety issues, to take appropriate interim risk reduction measures including reservoir releases. Corps responsibilities require operation of dams in a manner that reduces the project’s probabilities of failure when there are known issues with the integrity of the project.

The pool restriction may affect a few boat ramps in some years at the end of the recreation season. However, the proposed plan should have little-to-no impact on recreation such as fishing, non-motorized boating, swimming, camping, hiking, nature viewing, and picnicking.

The public and media are invited to find out more during a live presentation, which is for informational purposes only. Public comments on the proposed action will not be taken for the record during the meeting and anyone interested in submitting a comment on the proposed action or the Environmental Assessment must submit them via email or by mail. All comments, whether by conventional mail or email, must be received no later than the expiration date of this public notice to ensure consideration.

When: March 22, 2021: 5-7 p.m.

Where: https://usace1.webex.com/meet/PDXCorps.publicmeetings

Call in number: 1-844-800-2712

Access Code: 199-430-8599

The U.S. Army Corps of Engineers released for public comment a draft Environmental Assessment evaluating alternatives for the Corps’ proposed seismic risk reduction. The EA is currently available for a 15-day public review here.

Submit Public Comments Here: DetroitPoolRestrictions@usace.army.mil. The Corps will review all comments received and all comments, whether by conventional mail or email, must be received no later than the expiration date of this public notice to ensure consideration. The report will be available for download.  

Willamette Valley Project: The U.S. Army Corps of Engineers operates 13 dam and reservoir projects in the Willamette River drainage system. Each dam contributes to a water resource management system that provides flood damage reduction, power generation, irrigation, water quality improvement, fish and wildlife habitat and recreation on the Willamette River and many of its tributaries. Since their completion, the dams have cumulatively prevented over $25 billion in flood damages to the Willamette Valley. For more information, visit: www.nwp.usace.army.mil/.


Contact
Tom Conning
504-403-9378
edward.t.conning@usace.army.mil
or
John Morgan
503-808-4510
john.l.morgan@usace.army.mil

Release no. 21-015

How to Subscribe to RSS

Use Edge Browser
How to follow feeds in Microsoft Edge

  1. Visit the Microsoft Edge Add-on store: https://microsoftedge.microsoft.com/addons/Microsoft-Edge-Extensions-Home. ...
  2. Search for “rss feed reader”: ...
  3. Click “Get” Next to “Feeder – RSS Feed Reader”, then Confirm by clicking “Add Extension”
  4. ​ Setup your feeds: Search for feeds one-by-one, browse the library of sites or import feeds with OP
    Use Outlook
 
  1. In Outlook, right-click the RSS Feeds folder and choose Add a New RSS Feed.

  2. In the New RSS Feed dialog box, enter the URL of the RSS Feed.

    Enter the URL for the RSS Feed

    Tip: If you need help finding the RSS feed URL on a website, look for an RSS icon.
     Button image Right-click that icon, and then copy the shortcut to the Clipboard.
    Press Ctrl+V to paste the information from the Clipboard into the RSS Feed location box.

    Choose Add > OK.                                                                

    Additional Subscription Information: Microsoft How to Subscribe to RSS feed in Outlook

Use Internet Explorer

Open Internet explorer and open any USACE website. Look for the small RSS icon and click on that icon as show in this image:

Once it opens in Internet Explorer, it will have an option at the top to subscribe to this RSS feed as show here:

 

 

 

 

 

 

Use Google Chrome
Chrome Extension allows RSS Feed Subscriptions

Free RSS Feed Readerhttps://feeder.co