A Big Dam Difference
Bonneville Dam has made improvements to help adult and young fish pass up and down the river.
// Photo by U.S. Army Corps of Engineers
There aren’t a lot of people who are going to say that the four dams along the Columbia River between Oregon and Washington have done much for healthy salmon populations. Many may also question whether all the money that has been spent helping fish get past the dams in the past couple decades has been all that effective.
Yet at least some of the efforts in recent years by the U.S. Army Corps of Engineers and others connected to the dams appear to be helping. “We have played a big part in that,” says Diana Fredlund, a spokesperson for the Corps, about this year’s larger-than-average Chinook returns.
In addition to improvements made over the years to fish ladders for adult salmon and steelhead coming upstream, the Corps in recent years has been focusing on helping juveniles traveling downstream find their way past the dams. At The Dalles Dam, a new wall guides juveniles coming over the spillway toward deeper areas of the river and away from shallower spots and lurking predators. And a collector originally meant for ice and log debris at Bonneville Dam proved so effective at juvenile fish passage that it became one of the primary bypasses for young salmon in 2004.
In August the Corps was also part of an $800,000 project to remove a small dam on the Sandy River, a tributary of the Columbia, which was expected to improve salmon spawning habitat.