Gates are control devices used for closing and opening water discharge channels. An essential component of hydraulic structures, they can be used to intercept water flow, control water levels, regulate flow rates, and discharge silt and floating debris, etc.

The gate is mainly composed of three parts:
① The main operating section used for closing or opening openings, commonly known as a gate, also referred to as a gate leaf.
② Grouting section;
③ Valves and Shut-off Equipment.
The activity section includes weighing structures such as panel beams, support and walking parts, guiding and water-stop devices, and lifting lugs. The embedded part includes main tracks, guide tracks, hinge seats, lintels, sill plates, and water-stop seats, which are embedded around the openings and securely connected to the concrete of hydraulic structures with anchor rods. They form supports and water-stop surfaces on the door leaves, facilitating the transfer of water pressure and other loads on the door leaf structure to the hydraulic structures and achieving good gate water-stop performance. The operating machinery is connected to the lifting lugs of the door leaves to control the position of the activity section, but some gates also rely on hydraulic automatic control for operation.