From WordNet (r) 2.0 (August 2003) [wn]:
flume
n 1: a narrow gorge with a stream running through it [syn:
gulch]
2: watercourse that consists of an open artificial chute filled
with water for power or for carrying logs
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Flume \Flume\ (f;[=u]m), n. [Cf. OE. flum river, OF, flum, fr.
L. flumen, fr. fluere to flow. [root]84. See Fluent.]
A stream; especially, a passage channel, or conduit for the
water that drives a mill wheel; or an artifical channel of
water for hydraulic or placer mining; also, a chute for
conveying logs or lumber down a declivity.
[1913 Webster]