1. (noun) regulator consisting of a valve or gate that controls the rate of water flow through a sluice

• head gate
• penstock
• sluice valve
• sluicegate
• water gate

1. (noun) something that restrains a flood or outpouring

• restraint

2. (noun) regulator consisting of a valve or gate that controls the rate of water flow through a sluice

• regulator