Flume

n. artificial ditch; ravine, gully

A flume is an open artificial water channel, that leads water from a diversion dam or weir completely aside a natural flow, often an elevated box structure (typically wood) that follows the natural contours of the land. These have been extensively used in hydraulic mining, for the transportation of logs in the logging industry, electric power generation and to power various mill operations by the use of a waterwheel.
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Noun
1. a narrow gorge with a stream running through it
(synonym) gulch
(hypernym) gorge
2. watercourse that consists of an open artificial chute filled with water for power or for carrying logs
(hypernym) watercourse, waterway

A natural or man-made channel that diverts water.

Synonyms and related words:
abysm, abyss, aqueduct, arroyo, avenue, bed, blowhole, box canyon, breach, break, canal, canyon, cavity, channel, chap, chasm, check, chimney, chink, chute, cleft, cleuch, clough, col, coulee, couloir, crack, cranny, creek bed, crevasse, crevice, culvert, cut, cwm, debouch, defile, dell, dike, ditch, donga, door, draw, dry bed, egress, emunctory, escape, estuary, excavation, exhaust, exit, fault, fissure, flaw, floodgate, fracture, furrow, gap, gape, gash, gorge, groove, gulch, gulf, gully, gullyhole, headrace, hole, incision, irrigation ditch, joint, kloof, leak, loophole, moat, notch, nullah, opening, out, outcome, outfall, outgate, outgo, outlet, pass, passage, pore, port, race, ravine, rent, rift, rime, river bed, riverway, runnel, rupture, sally port, scissure, seam, slit, slot, sluice, spillbox, spillway, spiracle, split, spout, stream bed, streamway, swash, swash channel, tailrace, tap, trench, valley, vent, ventage, venthole, void, vomitory, wadi, water carrier, water channel, water furrow, water gap, water gate, watercourse, waterway, waterworks, way out, weir