Enguri Dam

Enguri Dam, sixth-highest dam in the world and once the world’s highest arch dam when it was completed in 1980. The primary dam is 892 feet (272 meters) tall and is a double-curvature arch with a crest length of 2,231 feet (680 meters). It is located on the Enguri River in northwestern Georgia in Jvari town near the point at which the river leaves the Caucasus Mountains on its way to the Black Sea.

History

The idea of harnessing the Enguri River for hydroelectric power was first proposed in the early 20th century by the Georgian intellectual Niko Nikoladze, before Georgia became part of the Soviet Union. Although the hydrolectric potential of the Enguri River was recognized early, the scale, cost, and technical difficulty of constructing a high arch dam in a seismically active mountain gorge made the project unfeasible for both pre-Soviet and early Soviet authorities. Only in the late 1950s did advances in dam engineering and changes in Soviet energy policy shift priorities enough for the project to be reconsidered.

Construction for the Enguri Dam began in 1961 as part of the Soviet Union’s centrally planned electrification program. The Enguri Dam was built between 1961 and 1987. The project’s underground power plant was put into operation in 1978 while the primary arch dam was still being erected to its present height.

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With the collapse of the Soviet Union in 1991, Georgia witnessed a secessionist movement from the region of Abkhazia, which had previously functioned as an autonomous administrative territory under Soviet authority. These tensions led to Abkhazia formally declaring itself an independent state in 1999. Only a few countries—most notably Russia, which maintains a military presence in Abkhazia—recognize its independence. The Enguri Dam is in Georgia-controlled Jvari, but some of the project’s important power stations are in Abkhazia-controlled Gali across the Enguri River. The two sides continue to be divided by unresolved territorial and political disputes. Though the two countries do not have a formal treaty governing the use of the dam and power stations, operation of the facility has been maintained through an informal arrangement. Many of the workers who operate the dam and the power station belong to the same regional ethnic community from both sides of the border, which minimizes scope for conflict at the site. In exchange for continued access to the power station infrastructure, Georgia shares the power generated by the Enguri Dam with Abkhazia: 40 percent of the energy goes to Abkhazia and 60 percent to Georgia.

Specifications

The Enguri HPP covers almost 390 square miles (1,000 square km) from Jvari to the Black Sea and forms a reservoir 810,700 acre-feet (1 billion cubic meters) in volume. Works in the Enguri HPP complex on both the Georgian and the Abkhazian side of the Enguri River include the arch dam, a low-level water intake, and a high-pressure power tunnel about 9 miles (15 km) long and 31 feet (9.5 meters) in diameter. The dam was built using interlocking stacks of concrete monoliths laid over reinforced limestone bedrock. The power plant associated with the dam has five Francis turbines, in which water enters such that it turns the blades of the turbine but exits through an outlet at the center of the turbine body. The turbines together account for a planned power capacity of 1,300 megawatts.

The Enguri Dam is located in a seismically active region, which prompted engineers to install a monitoring system designed to detect earthquakes and vibrations affecting the structure. This system uses sensors placed on and around the dam to record ground motion and the dam’s own movements. If unusual movement is detected, operators can take preventive action.