noun (n)

• conduit that carries a rapid flow of water controlled by a sluicegate(noun.artifact)

  Synonym:
  penstock, sluice
  

  source: wordnet30
• An artificial channel into which water is let by a sluice; specifically, a trough constructed over the bed of a stream, so that logs, lumber, or rubbish can be floated down to some convenient place of delivery.(noun)

  source: webster1913