Originally Posted By: LukeJavan8

Here in the Northern Plains, a channel of water runoff, similar
to a canal, can be called a slough.

Here we would perhaps call that a 'sluice' (rhymes with juice). Maybe where you are it is a corruption of sluice rather than coming from the word for a marshy bog, slough, by dropping off the sibilant sound from the end? (More often though we would call such a thing an irrigation canal or table drain, or race (if associated with mining)).