An undammed Elwha River building beaches again: Crab found where it once was too rocky
Copyright © 2013, Tom Roorda. All rights reserved.
This aerial photo by pilot Tom Roorda (http://roordaaerial.com) taken Oct. 1 shows sediment from the Elwha River moving east in the Strait of Juan de Fuca toward Port Angeles and Ediz Hook.
By Jeremy Schwartz
Peninsula Daily News
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Miller, a coastal hazards specialist with Washington Sea Grant, came across a Dungeness crab that had tucked itself into fine-grain sand onto the lowest portion of a beach east of the river mouth, just north of where Sampson Road on the Lower Elwha Klallam reservation ends.
A crab living in this type of habitat on its own is not particularly newsworthy, except for the fact that this sandy area of beach was nothing but cobblestone a year prior.
“It was just one crab, but it was the first time I had seen an organism using that sandy habitat,” Miller said.
To Miller, the crab was another sign that the fine sand and sediment released into the Elwha River from the ongoing dam removal process is having a noticeable effect on the river mouth and the beaches surrounding it.
The 108-foot Elwha Dam was fully demolished in 2012.
Demolition crews on Oct. 5 blew an estimated 800-square-foot hole in the remaining 60 feet of the Glines Canyon Dam, once 210 feet tall, and are next set to clear a passable fish channel before work must stop for a fish window in November.
The remnants of the dam are expected to be gone by September 2014 as part of a $325 million restoration of the Elwha River, the largest such effort in U.S. history, to a wild and fish-spawining state.
Dam deconstruction has sent millions of cubic yards of sediment locked behind the former lakes Mills and Aldwell coursing down the river.
As part of the research portion of the dam removal and restoration project, Miller — part of a team of scientists monitoring different aspects of the project — regularly monitors the beaches surrounding the mouth of the Elwha to see how they are reacting to the millions of cubic yards of sediment flowing down the river out into the Strait of Juan De Fuca.
In his September and October beach surveys, Miller said he has continued to see weekly changes in the shape of the Elwha's mouth as sediment builds up in some areas and is washed away in other.
“Every time we go out things are different,” Miller said.
Most striking, Miller said, is a sediment berm built up just to the east of the mouth that has grown enough to protect an area behind it from salt water at most tide levels.
“It's exposed at most tides, and that's as of [Oct. 7],” Miller said.
Large woody debris, such as logs, and finer wood materials have begun to accumulate in this area, Miller said, with some types of plants taking root in what was beach regularly drenched with salt water last year.
“Our observations are that fine wood material acts like mulch in your garden,” Miller said.
“I think we could see that last through the winter and become a new estuary area.”
Sediment also continues to build up immediately to the north of the mouth, Miller said, former berms and new beach where there was only water.
“I think it's really cool to walk around and remember that a year ago you would have been in 30 feet of water,” Miller said.
“That's essentially 20 to 30 feet of new material.”
While the changes seen so far are dramatic, Miller said the sediment seen so far is between 20 and 30 percent of the material expected to flow down the river as dam removal is completed.
“There's still more to come,” Miller said.
Reporter Jeremy Schwartz can be reached at 360-452-2345, ext. 5074, or at firstname.lastname@example.org.
Last modified: October 13. 2013 6:39PM