flume 
(flm)
(flm)n.
1. A narrow gorge, usually with a stream flowing through it.
2. An open artificial channel or chute carrying a stream of water, as for furnishing power or conveying logs.
3. A very small swimming pool designed with a propeller or pump to generate a current, allowing a swimmer to swim in place.
[Middle English flum, river, from Old French, from Latin flūmen, from fluere, to flow; see bhleu- in the Appendix of Indo-European roots.]