Work is expected to begin this summer on a more than $4 million project to protect Nippon Paper Industries’ water supply from tons of sediment that will be released into the Elwha River when two dams on the river are removed.
The National Park Service’s Denver Service Center awarded the $4,092,700 contract to protect the water supply for the mill on Ediz Hook to Erick Ammon Inc. of Anderson, Calif., and Silverdale on Wednesday, Olympic National Park spokespeople said in a statement.
“This project will provide the mill with increased water treatment capabilities to account for higher levels of sediment expected to occur during and after dam removal,” said Olympic National Park Superintendent Karen Gustin.
The contract includes completion of a new outfall pipe to improve dispersion of sediment from the mill’s incoming water treatment process, improvements to clarifiers and the addition of chemical feed capability for iron and manganese removal from water going to the plant.
Most of the construction will be at the mill, the park service said. Work is expected to be finished early this fall.
When the 105-foot Elwha Dam — which creates Lake Aldwell eight miles upstream from the river’s mouth — and the 210-foot Glines Canyon Dam — which forms Lake Mills 13 miles upstream from the river’s mouth — are removed, tons of sediment now trapped behind the dams will be released into the river and swept out to sea.
In a draft report based on reservoir surveys conducted last year, the U.S. Bureau of Reclamation estimated that 24.3 million cubic yards of sediment have accumulated in the Lake Mills and Lake Aldwell reservoirs combined.
In the past, sediment from the Elwha River formed the sand spit of Ediz Hook, playing a role in the formation of Port Angeles Harbor.
The $308 million National Park Service project to remove the dams is scheduled to begin Sept. 17 and be completed by March 2014.
The National Park Service is funding construction of the Nippon Paper Industries Water Treatment Improvements and Outfall Phase 2 project as part of water quality mitigation for dam removal.
Removal of the two dams is the centerpiece of the $350 million federal project to restore the river’s ecosystem, called the Elwha River Restoration.
Removing the Elwha and Glines Canyon dams will allow fish to access spawning habitat in more than 70 miles of river and tributary stream, most of which is protected inside Olympic National Park.
The 45-mile-long Elwha River is the historic home of all five species of Pacific salmon.
Work stoppages will be built into the dam removal schedule in order to limit the amount of sediment released at any given time, particularly when adult fish are in the river, the park service said.
The dam removal is the largest in the nation’s history.
For more information, visit www.nps.gov/olym or share information on the Elwha River Restoration Facebook page.
