Definition: 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.
Definition: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
