Early in September an explosion leveled a 30-foot dam on a tributary of the Kilchis River in Tillamook County. That's a good thing. The blast, so powerful it destroyed two remote cameras set up to record it, was intentional -- set to remove the unneeded dam that for nearly six decades blocked Coal Creek, a key salmon stream. It worked perfectly.
What has since impressed biologists is how quickly the coastal stream has bulldozed the river back into its natural shape. Chris Knutsen, the Oregon Fish and Wildlife Department's district biologist in Tillamook, thought it might take a few years after the dam demolition before the stream was suitable for fish again.
But biologists found even more chum salmon in the stream after the dam came down last year than in the year before. That underscores observations on the Sandy River east of Portland, where Portland General Electric removed a dam in 2007 and scientists watched with surprise as the river digested 150 Olympic-size swimming pools worth of sediment within months. "It doesn't take long for these streams to retake their own path," Knutsen said. "This is great progress. It was a win-win for everybody."
The creek supports coho, chinook, steelhead and cutthroat and is one of the biggest producers of chum salmon in Tillamook County, with biologists counting more than 800 chum some years in less than two miles of stream. Gordon Grant, a research hydrologist at the U.S. Forest Service's Pacific Northwest Research Station said as more and more older dams are removed to benefit fish, it's become clearer that rivers rework themselves quickly. "Where the dam is relatively small, it's a quick response," he said. "The river quickly forgets."
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