Devils Gate Dam, Forth River, 1969-
Description
This 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. The horizontal and vertical curvatures are chosen to ensure that virtually all the concrete is in compression. Otto Vettiger wrote a computer program to calculate the stresses in the arch, one of the first such programs in the world. Frank Kinstler was the principal designer, reporting to Jack Fidler and Bill Mitchell. Ted Hofto was in charge of construction.
The spillway is the crest of the dam in two stages. The overhanging crest allows flood water to freefall 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 is severe, so that concrete slab protection on both abutments is 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.
Devils Gatwe Dam and power station are part of the Mersey Forth Power Development This scheme develops the hydro-electric resources of the Mersey, Forth and Wilmot rivers. There are seven dams and power stations. Devils Gate Power Station is located at the foot of the dam and contains a 63 MW Francis turbine.
Division
Marker Type
- HEM: Historic Engineering Marker (to 2008)