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Project description
On November 5, 2012 a beaver dam failure at the outlet of an unnamed Lake caused flooding over the roadway at 269th Way Northeast and Northeast 124th Street near Carnation-Duvall Road in Duvall. King County installed flood protection barriers to prevent and reduce flooding over Northeast 124th Street. On November 21, 2012 King County installed a flexible pond leveler pipe at the outlet of the unnamed Lake.

Project goals
To reduce flooding over roadway at 269th Way Northeast and Northeast 124th Street and nearby properties by developing alternative solutions and implementing cost effective measures.

Photos

Beaver dam failure on November 5, 2012 caused flooding over Northeast 124th Street
Beaver dam failure on November 5, 2012 caused flooding over Northeast 124th Street
Flooding over guardrail at 269th Way Northeast
Flooding over guardrail at 269th Way Northeast
Flood protection barriers are installed to prevent and reduce flooding over Northeast 124th Street
Flood protection barriers are installed to prevent and reduce flooding over Northeast 124th Street
Flexible pond leveler pipe installed at outlet of unnamed lake draining to Deer Creek
November 21, 2012 a flexible pond leveler pipe is installed at outlet of unnamed Lake

Frequently asked questions

What should I do if I notice roadway drainage problems in this area?
Call the King County Road 24/7 Helpline at 206-296-8100 to report roadway drainage problems.

Does King County or anyone have the ability to destroy a beaver dam and when?
Yes, provided legal access and the proper permit can be obtained. To remove or modify a beaver dam you must have a Hydraulic Project Approval (HPA)—a permit issued by WDFW for work that will use, obstruct, change, or divert the bed or flow of state waters (RCW 77.55). A permit application can be obtained from your Washington Department of Fish and Wildlife Regional Office or from the Hydraulic Project Approval (HPA) web page. Permission of the property owner to access the beaver dam is also necessary. For more information on living with beaver read King County wildlife: beavers.

What monitoring and maintenance will be done to ensure the flexible pond leveler pipe functions properly?
The flexible pond leveler will be monitored at least once a month. A water level monitoring gauge is installed at the unnamed Lake. The maintenance of the flexible pond leveler is as needed.

What is the basin area contributing to Deer Creek?
According to the USGS – Washington StreamStats application, the contributing basin area is approximately 0.54 square miles.

There is a new beaver dam approximately 100 feet downstream of the beaver dam with the flexible pond leveler pipe. Will a flexible pond leveler pipe at the new dam help? What is the adequate level of the pond for public safety risk?
Another flexible pond leveler approximately 100 feet downstream was installed December 2013. King County has produced a beaver dam response protocol November 2014.

NE 124th Street has a downhill slope with a ravine next to the road that is hazardous. What is King County’s plans for a guardrail in this area?
NE 124th Street is listed on King County Roads Guardrail Priority Array as an upcoming candidate for new guardrail. When its priority number comes up, King County Roads will review the entire roadway corridor for guardrail, obstruction hazards, and other safety needs. It's currently ranked 37th on this array and King County Roads typically address 8 to 10 roadways each year.

What can home owners do to reduce the surface water that goes to Deer Creek?
There are Low Impact Development Best Management Practices that home owners can install to reduce surface water to Deer Creek; please refer to:

Thresholds for requiring a Clearing and Grading Permit are cited in Bulletin 28 (pdf) on the King County Department of Permitting site.

Can the 269th Way NE culvert be improved?
The 269th Way NE culvert currently meets the current 2009 King County Surface Water Design Manual and 2007 King County Road Design and Construction Standards. King County does not plan on improving the 269th Way NE culvert at this time.

For more information about the Deer Creek Beaver Dam Flood Risk Reduction Project, please contact Claire Jonson, Project Manager, WLR Capital Services Unit.