d. Forebay tank
Maintaining a constant water height (level) is the main function of the forebay tank. In addition, it also
helps further reduce any foreign solid particles entering the penstock and stops any air getting into the
penstock. To achieve this, the forebay tank must hold a considerable volume of water and maintain it.
Forebay tanks are designed with different shapes and sizes by the designers.
Section of Forebay Tank
e. Penstock
Sending the water from the forebay tank to the turbine with minimum losses is the main function of the
penstock. It appears like a big pipe that brings down water from a higher elevation to a lower elevation.
Penstocks can be made out of uPVC (Ultraviolet PVC), steel or any other piping material recommended
by the designer. Inside the penstock, the potential energy of water transforms into pressure energy. By
constructing the penstock to have the minimum number of bends and to be of the shortest length, the
energy loss in the penstock can be minimised.
18