The destruction of the 125-foot tall Condit Dam allows the White Salmon River to run free for the first time in nearly a century.
With a massive charge of TNT detonated at the base of Condit Dam, the White Salmon River roared back to life Wednesday,
Penned up and drowned under a reservoir since the 125-foot-tall dam was completed in 1913, the White Salmon quickly found its natural channel. Engineers had predicted it could take up to six hours to drain Northwestern Lake, which covered 92 acres and stretched 1.8 miles upstream. But the river was free flowing within two hours of blasting through a drain tunnel at the base of the dam at 12:11 p.m.
Thomas Hickey, senior hydro engineer for PacifiCorp, said all went as planned in the breach. And while the river was a muddy mess, sluicing out some of the 2.4 million cubic yards of sediment behind the dam, scientists had expected that to occur. They planned ahead, salvaging 679 adult tule fall chinook from below the dam last month, and carrying the fish above the dam to spawn.
By then, scientists hoped winter storms will have rinsed out much more of the sediment left behind, and salmon will recolonize the upper river.
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Built with fish ladders, the dam’s fish passage equipment nonetheless was rudimentary and blew out in floods, leaving the dam without any fish passage since 1918.
When the dam came up for re-licensing in 1991 before the Federal Energy Regulatory Commission, it became clear to PacifiCorp that taking the dam out for $33 million would be a lot cheaper than bringing it up to modern environmental standards at three times the cost.
Located three miles from the river’s confluence with the Columbia, taking out the dam is expected to reopen about 33 miles of habitat for steelhead and about 14 miles for chinook, depending on how well different runs of fish contend with natural falls in the river. Power from the dam, enough for about 6,259 homes, will be replaced with PacifiCorp’s other resources, which include wind, hydropower, and coal.
The moment of detonation was memorable. “Fire in the hole, fire in the hole, fire!” was the command to push the proverbial button, said Tom Gauntt, company spokesman.
In seconds, roostertails of water were kicking down the canyon below the dam. But in just hours the white water had subsided, and the river’s flow was smooth and steady, as if nothing historic had just happened.
But the 125-foot tall dam was the second tallest to be breached in U.S. history, after Glines Canyon Dam, the world record holder, on the Elwha River at 210 feet tall. Elwha Dam follows in third place at 108 feet, making Washington booming in dam removal with three of the largest dam removals ever under way at the same time. Nowhere have larger projects ever been undertaken to restore runs of salmon, steelhead and other native fish at risk or already lost to extinction.
Now that Condit is breached, beginning next spring, contractors will take the rest of the dam out, then tackle revegetation of the mud flats.
By this time next year, the dam is expected to be completely gone — and the first run of salmon in nearly a century will head up river to spawn.
Lynda V. Mapes: 206-464-2736 or firstname.lastname@example.org