Artificial log jam designed to protect roads and fish

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by GLENN FARLEY / KING 5 News

Bio | Email | Follow: @GlennFarley

KING5.com

Posted on March 7, 2014 at 8:05 PM

Updated Friday, Mar 7 at 9:43 PM

SKAGIT COUNTY, Wash. -  A stretch of U.S. Highway 20 that runs right along the Skagit River east of the community of Rockport has been undermined and heavily damaged by rapidly flowing water three times in the last decade.

Each time the Washington State Department of Transportation has had to come out with boulders, more dirt, gravel and pavement to fix it.  But is there a better way?

Now WSDOT thinks it has the solution, and construction of a 1,300-foot long artificial log jam is expected to be a permanent repair.

The structure is made up of real logs, and 1,500 so-called dolosse, giant concrete pieces that look like giant jacks from the childhood game.  They've been used around the world in marine applications, hardening shorelines and jetties.

But according to Jack Bjork, a river engineer with Cardno Entrix, this is by far the largest application on a river.  Several years ago WSDOT constructed about 100 feet of artificial log boom on the Puyallup River near Fife. This one runs a quarter mile.

WSDOT could have resorted to pilings or making a wall to divert the energy from the river away from the bank, but the agency says the artificial log book has the added benefit of becoming a sanctuary for fish, particularly salmon fry trying to get their start before heading down stream to the ocean.

In fact, we saw five or six fry swimming in just a small area of the log jam that's only been in place for a few weeks. 

The transportation agency also says the log jam is being constructed in a way to keep the area safe for people, so boaters or someone falling into the water would not be trapped underneath it.
 

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