A log flume is an amusement ride consisting of a water flume and artificial hollow logs. Passengers sit in the logs, which are propelled along the flume by the flow of water. The ride culminates with a rapid descent and splashdown into a body of water.
The first log flume is said to be the Timber Mountain Log Ride (formerly Calico Log Ride), built in the 1960s at Knott's Berry Farm. The designer, Bud Hurlbut, drew his inspiration from stories of lumberjacks riding logs down rivers.
Log flumes are a variant on the "Shoot the Chutes" ride at Coney Island's Luna Park, in which a boat slid down a long chute and splashed into a pond.
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A list of amusement ride patents, including water rides, with links to the U.S. Patent Office: