Roof gate

A roof gate is a metallic device that is inserted into a rectangular cutout. A hydraulic jack is used to operate the roof gate.

The downstream section of the roof gate, known as the ‘roof of the valve’, is specially designed to allow the safe passage of watercraft: bottom baffles reduce the speed of surface water.

This type of valve offers the user a great deal of flexibility as the downstream flow rate can be easily adjusted in accordance with the upstream water level. Watercraft may pass regardless of its position.

How does it work?

A roof gate is a metallic structure whose function is to stop and to regulate the flow rate of a whitewater stadium. It must also allow watercraft to pass.

A roof gate comprises two sections :

• A shutter, which is lowered or raised to ensure the leaktightness required by the upstream reservoir and to control the downstream flow rate.
• A roof, whose role is to accompany the blade of water spilled on to the shutter and into the downstream pool. The roof is fitted with deflectors, whose purpose is to generate attractive and safe water movements. This system has been studied on a scale model in our laboratory. Consequently, the roof gate is a part of the whitewater course.

Several applications

It should also be noted that the roof gate can also be used as a fish pass (when open) as the baffles enable fish to migrate upstream. Finally, this type of valve is also found on certain dams.

To ensure the course remains safe, an emergency stop function immediately raises the roof gate in order to stop the flow rate in the whitewater river.