Gates are control devices used to close and open water discharge channels. An essential component of hydraulic structures, they can be used to block 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 activity section, used to close or open apertures, commonly known as a gate, also referred to as a gate leaf.
② Grouted section
③ Shut-off equipment.
The activity section includes weight-bearing structures such as panel beams, support and walking components, guiding and sealing devices, and lifting ears. The embedded part includes main tracks, guide tracks, hinge seats, lintels, sill plates, and sealing seats, which are embedded around the holes and securely connected to the concrete of hydraulic structures with anchor bars. They form supports and sealing surfaces on the door leaves to transfer the water pressure and other loads exerted on the door leaf structure to the hydraulic structures and achieve good gate sealing performance. The operating mechanism is connected to the lifting ears of the door leaf to control the position of the activity section, but some gates also rely on hydraulic automatic control for operation.