A final explosion Aug. 26 removed the remains of 12-MW Glines Canyon Dam, fully opening the Elwha River to salmon passage in Washington’s Olympic National Park.
Congress passed the Elwha River Ecosystem and Fisheries Restoration Act in 1992, requiring the Secretary of Interior to restore the Elwha River ecosystem and native anadromous fisheries. The Interior Department determined that removal of the 12-MW Elwha and 12-MW Glines Canyon dams was the only option that would accomplish full restoration.
The National Park Service acquired the dams in 2000 from paper manufacturer Daishowa America. In September 2010, the park service awarded a $26.9 million contract to Montana-based Barnard Construction Co. Inc. to remove the two dams.
The removal also is intended to protect and restore treaty fishing rights for affected Indian tribes. Removal, to cost $40 million to $60 million, began in 2011. The National Park Service took bids in August for operation and maintenance of water treatment and pumping facilities made necessary by removal of the dams.
In the wake of Elwha Dam, which already had been removed, engineers blasted away the last remains of Glines Canyon Dam, whose crest had been gradually reduced until the final portion could be blown into rubble that will be removed in the coming days. The event took on a festive atmosphere as dam opponents posted celebratory comments on a National Park Service Facebook page.
“From my little corner of the world, we see a glimmer of hope that more decisions will be made to save parts of Earth rather than destroy it,” one poster wrote.
The Elwha River flows through Olympic National Park. Its restoration opens more than 70 miles of river to salmon and steelhead habitat. At 210 feet tall, Glines Canyon is the largest dam ever removed.
Elwha Dam construction was completed in 1913 and Glines Canyon in 1927. Neither had a fish ladder, which prevented native anadromous salmon and trout from advancing above the lower five miles of the river.
Dam removal also frees about 18 million cubic yards of rock, gravel, sand and sediment that have been captured since the dams were built. Sediment now is expected to accumulate in areas that have eroded since the dams were built, increasing river elevations in some areas an average of two feet.