PORT ANGELES — A huge piece of Glines Canyon Dam was blasted away late Saturday as dam removal on the Elwha River resumed.
Explosive charges set by demolition crews removed almost the entire eastern third of the remaining 60 feet of concrete dam, webcam photos show.
But water did not immediately flow through the new gap because of tons of sediment behind the dam as well as rubble from the explosion that created temporary blockage between the current river channel and the new hole.
With a section of the former 210-foot dam removed nearly to the original riverbed, workers will clear a passable fish channel on the floor of the river canyon before stopping work in November for the next fish window, according to Brian Krohmer, dam removal project manager.
The last remnants of the dam are expected to be completely gone by September 2014.
An estimated 800-square-foot hole was blasted into the dam stub, which stood about 60 feet above the original river bed.
The dam’s demolition process can be monitored by webcam via the PDN website, www.peninsuladailynews.com, and clicking on the link directly below the search engine window.
Glines Canyon Dam and the 108-foot Elwha Dam, demolished in 2012, are part of a $325 million restoration effort to the Elwha River to a wild — and fish-spawning — state in the nation’s largest planned dam-removal project.
Dam-removal work can proceed during the partial federal government shutdown that has closed Olympic National Park to visitors because the project is already appropriated by Congress, according to park officials.
The Glines Canyon Dam spillway, now perched high on a cliff, far above the water level, remains in place and may become an overlook for visitors to view the restoration unfold in the valley that was revealed by the draining of Lake Mills.
Geologists estimated that 34 million cubic yards of sediment were trapped behind the dams.
About 8 million cubic yards have been released as the dams have been dismantled but not all the remaining sediment is expected to flow downstream.
Areas of sediment expected to remain in place are being planted to anchor unstable hillsides and provide cover for migrating and young salmon in riparian areas.
The project was delayed in October 2012 due to sediment clogging the Elwha Water Treatment Plant’s intakes.
Workers from Bozeman, Mont.-based Barnard Construction Co. Inc. started drilling blast holes in Glines Canyon Dam on Oct. 2, after the water plant clog was corrected.
Fish spawning affects removal work in the river channel in October, January to April and July to protect migrating salmon — fingerlings migrating from clear tributaries to the ocean and adult salmon coming upstream to spawn.
Salmon spawning ended in late September, and the only coho and chinook salmon remaining in the river are either naturally dying or dead, Olympic National Park spokeswoman Barb Maynes said last week.
Young salmon live mostly in tributaries unaffected by the sediment.
Clear-water refuge is also is provided by backup facilities such as the state Department of Fish and Wildlife rearing channel and the Lower Elwha Klallam tribe’s fish hatchery, Maynes said.
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Reporter Arwyn Rice can be reached at 360-452-2345, ext. 5070, or at arwyn.rice@peninsuladailynews.com.
