See animation on how the Glines Canyon Dam will be removed: http://interactive-earth.com/resources/science-visualizations/7-glines-canyon-dam-removal-process.html
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OLYMPIC NATIONAL PARK — Lake Mills will be closed to recreational boating, fishing and swimming at sundown Monday to allow work that prepares for the removal of the Elwha River dams.
The lake is expected to be closed until Oct. 4.
A $743,708 contract for the work was awarded to Cherokee Construction of Vancouver, Wash., Barb Maynes, Olympic National Park spokeswoman, announced Thursday.
On Tuesday, workers with the company will begin moving large heavy equipment to the boat launch at the north end of the Lake Mills reservoir.
After Labor Day, they will begin digging a giant channel for sediment through which millions of yards sediment will flow once the dams are taken down, said Brian Winter, Elwha River Restoration Project manager.
Workers will establish a pilot channel, remove trees from the Lake Mills delta and reposition logs within the river and reservoir to help redirect the river towards the new pilot channel, the park said.
“Now that the contract has been awarded we are able to provide a more definite work schedule” than was available last week, said Karen Gustin, park superintendent, in a prepared statement.
“We are happy to say that boaters and anglers will have one more weekend to enjoy Lake Mills before the work begins,” she added.
The entire Lake Mills reservoir and the Elwha River between Goblins Gate and Lake Mills will be closed to boating.
Kayakers using the river are directed to leave the river at Goblins Gate and hike out the Rica Canyon Trail and Elwha River Trail to the Whiskey Bend Trailhead.
The two-mile West Lake Mills Trail, which begins at the lake’s boat launch parking area, and Upper Lake Mills Trail also will be closed.
Lake Mills will be lowered 5 feet, its waters emptying over the dam’s spillways to expose the delta and allow workers to dig with heavy equipment on drier ground, Brian Winter, Elwha River Restoration Project manager, has said.
Lake Mills is a fishing and recreational boating reservoir that sits behind Glines Canyon Dam, sister to the Elwha Dam, both of which will be torn down beginning in September 2011 and ending in March 2014.
As the Glines Canyon and Elwha dams are torn down, sediment will gradually coat the riverbed of the Elwha River.
Redistribution of sediment, which will take from three to five years to settle, is the crux of the Elwha River Restoration Project, Winter has said.
The Lake Mills delta, created by the river’s sediments as they flow downstream, has become overgrown in recent years by a large number of alder trees, Maynes said.
As the trees and root systems have grown, the delta has become more stable and less easily eroded by the river.
“This project will help maximize erosion through the delta before, during and after dam removal,” she said.
In addition to removing trees and creating a pilot channel through the middle of the delta, workers will reposition logs within the river and reservoir to help redirect the river towards the new pilot channel.
The likelihood of floating and submerged logs within the existing river channel and reservoir, along with heavy equipment at work, necessitate the boating closure, Maynes said.
At least 18 million cubic yards of gravel and dirt is piled behind the dams — 13 million behind Glines and 5 million behind Elwha.
The project must be completed before the rainy fall season “so we can maximize winter erosion, accomplish the work safely and be prepared for the dam removal to begin next year,” Gustin has said.
