Penstock

n.	1.	A close conduit or pipe for conducting water, as, to a water wheel, or for emptying a pond, or for domestic uses.
	2.	The barrel of a wooden pump.

Noun	1.	penstock - regulator consisting of a valve or gate that controls the rate of water flow through a sluice Synonyms: head gate, sluice valve, sluicegate, water gate, floodgate
	2.	penstock - conduit that carries a rapid flow of water controlled by a sluicegate Synonyms: sluice, sluiceway

aboideau, air lock, chute, dock gate, eaves trough, flood-hatch, floodgate, gate, guide, gutter, head gate, lock, lock gate, pentrough, shoot, sluice, sluice gate, tide gate, trough, water gate, weir