Blogflap gates

What is a flap gate?

A flap gate is a flow control device that functions as a check valve, allowing water to flow through it in only one direction. These special gates are mainly employed to control the flow of water through flood barriers, reservoirs and rivers.


Structure of the gates

The flap gate usually consists of a hinged flat plate that is usually located at the top of a reservoir or waterways. They are a heavy duty structural design consisting of a steel reinforced skin plate located on the outer side, which withstands the water pressure when the gate is in a closed position.

Typically, flap gates or crest gates are made of stainless steel, carbon steel or cast iron. Low friction self-lubricated bearings are used at all connections. Side seal plates are embedded in walls for continuous sealing at all positions.


How do these gates work?

The flap gates are designed to operate in a vertical position whereby they restrict the main flow of water but at the same time create a ‘water jump’ over the top of the gate, from upstream to downstream side of the gate. When the Flap Gates are fully open they are lowered to the bottom level of the river, enabling full water flow to pass over them. The gate is typically operated with a hydraulic cylinder mounted on an adjacent pier.

Gate position sensors can be programmed with operators to modulated or restore gate position.


Different types of Flap Gates

Crest Gates

The crest gate is a spillway style gate used for water level control and trash sluicing. It consists of a reinforced leaf with bottom hinges mounted to the waterway floor. This type of gate is opened and closed by rotating about these hinges and it is typically operated with a hydraulic cylinder mounted on adjacent pier.


Fish-belly & Torsion Flap Gates

Fish-belly and torsion flap gates are flap gates that are pverflowed in open water and canals in order to regulate the water level and volume. These structures are characterised by the most modern methods of construction and drive technology.



To discover more information and more functionalities about these special types of gates, visit our dedicated webpage, where you can find all the information about the accessories that you can supply, and visit our blog to discover all the products and the services offered by Vortex Hydra!