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Back to spillwaysSpillways & Outlets - Outlet Towers

Construction of outlet tower and shaft spill way

The outlet tower and shaft spillway
under construction for Roadford
Dam in Devon, SW England. The
outlet tower is the one on the left.
The tunnel leading away from the
two towers houses the outlet pipe

Outlet towers are found in reservoirs, usually near to the dam. The tower sits above an outlet pipe or tunnel used to transport water out of the reservoir. It is built to house controls for opening and closing valves or gates that control the flow of water through the outlet. The controls are normally located inside in a room at the top of the tower.

In a reservoir for water supply, a tower will often have a vertical pipe inside with a number of horizontal pipes leading into it from the reservoir. The horizontal pipes are used to draw-off water from different levels in the reservoir. Water is let into them by opening valves at their entrances. The vertical pipe then connects to a horizontal pipe that takes the water away from the tower through a tunnel to the water treatment works.

The vertical pipe in the outlet tower in Wimbleball lake

The vertical pipe in the
outlet tower in Wimbleball
lake in Somerset,
SW England

Cross-section through an outlet tower

Cross-section through an outlet tower

Intake tower

The intake tower in Loch
Glascarnoch in Scotland

Where a tower is used to control water supply to a hydroelectric power station, there is only one inlet for the water. These towers are called intake towers.