El Atazar Dam
Encyclopedia
Arch dam
An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...
built near Madrid
Madrid
Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
on the Lozoya River
Lozoya River
The Lozoya River is a river flowing near the centre of Spain. It originates at a high altitude in the Sistema Central and cuts downward through steep rocks to flow into the Jarama River, a major tributary of the Tajo, the longest river on the Iberian Peninsula.-Water use:The Lozoya has been...
, very close to where the Lozoya joins the Jarama
Jarama
Jarama is a river in central Spain. It flows north to south, and passes east of Madrid when El Atazar Dam is built on a tributary, the Lozoya River. It flows into the river Tagus in Aranjuez...
. It is the oldest dome dam
Arch dam
An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...
in the world. The curved design of the dam is optimum for the narrow gorge
Canyon
A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...
in which it was built to retain water in the reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
. Arch dams are thin and require less material to construct than other dam types.
When the dam was built, the decision was made to use the dam to store and regulate water only and not to provide energy. Construction started on the dam in 1968 and finished in 1972.
Design
The dam is 440 feet (134 m) high and 171.6 feet (52.3 m) wide at the foundation. The reservoir capacity is 344000 acre.ft. It is a double curvatureCurvature
In mathematics, curvature refers to any of a number of loosely related concepts in different areas of geometry. Intuitively, curvature is the amount by which a geometric object deviates from being flat, or straight in the case of a line, but this is defined in different ways depending on the context...
concrete arch buttress
Buttress
A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall...
design.
Problems
Monitoring of the dam revealed abnormal movement. Although dams normally move, the left side of the El Atazar Dam was moving more than the right because a support built on the dam's right made that side less flexible. In 1977 a crackFracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
was noticed in the dam. By 1979 the crack had grown to 150 feet (45.7 m) and was repaired. Inspection in 1983 revealed that the settling in the foundations and the movements of the dam had caused fracturing in the rock, resulting in significantly increasing the foundation's permeability
Permeability (fluid)
Permeability in fluid mechanics and the earth sciences is a measure of the ability of a porous material to allow fluids to pass through it.- Units :...
. The crack has been treated and since then the problems have abated.