Devils Gate Dam
Background
The Devils Gate Dam was completed by the Hydro Electric Commission in 1969 forming part of a series of seven dams and hydro electric power stations that comprise the Mersey Forth Power Development.
Devils Gate is a high concrete arch dam and is one of the thinnest concrete arch dams in the world. Arch dams require sound rock abutments on both sides of the valley to carry the thrust from the arch.
Innovative design involving the writing of a computer program by Otto Vettiger to calculate the stresses in the arch. This was one of the first such programs in the world.
Equipment and Subsequent History
The horizontal and vertical curvatures were chosen to ensure that virtually all of the concrete is in compression. The narrowness of the gorge and the computer aided design of its double curvature shape enabled engineers to minimise the volume of concrete and hence the cost of the dam.
The overhanging crest of the dam wall allows flood water to free fall to the river bed. With up to 2000 tonnes of water falling every second during an extreme flood, the potential for eroding the dam foundation was severe, so the provision of concrete slab protection on both abutments was essential. Using hydraulic model tests, the slabs on the two abutments are designed to deflect the falling water into two colliding jets to destroy most of the energy in mid air.
The dam is 84m high and the water feeds a power station at the foot of the dam. The power station contains a single 63MW Francis turbines.
There are a further six power stations utilising the waters of the Mersey, Forth and Wilmot Rivers to generate power.
Engineering Heritage Recognition Program
| Marker Type | National Engineering Marker (NEM) |
| Award Date | 2001 |
| Heritage Significance | One of 25 Australian dams with the highest heritage value. One of the thinnest concrete arch dams in the world. |
| Nomination Document | Nomination document |
