The Broughton Log Flume was constructed between 1913 and 1923 and ceased operation in 1986. The flume was a 9-mile-long trough of flowing water that carried rough cut timber down from a sawmill at Willard, Washington, to a planer mill at Underwood, along the Columbia River (this map link shows the locations of each, but the route shown is that of the road, not the flume). This webpage is chock-full of historic images and information about the flume. Log flumes such as this were once common in the western timber regions (Wikipedia article). The Broughton Flume was the very last of its kind and seems to have been something of a tourist attraction. Its closure in 1986 drew the attention of the New York Times.
Nevermind the history, though--the cool thing about the Broughton Log Flume is that it was twice used to film TV shows that featured animals taking a ride down the flume. First, was Charlie the Lonesome Cougar, in what seems to have been a trippy (and short-lived) 1976 television show:
That same year, Lassie tried her luck on the flume:
In many places in the American West, such nineteenth-century timbering methods as log flumes, splash dams, and driving logs down rivers continued well into the 20th century, and there is a surprising amount of historic film footage of these activities on YouTube. Today the remnants of the structure continue to be a tourist attraction--but you can't ride the flume anymore.