Chirkei hydro power plant is situated on the Sulak river of Dagestan. It is the largest HPP in the North Caucasus, the highest arch dam of Russia. And probably it is also one of the most beautiful dams in the country.
Its construction began in 1964 and finished in 1978. The main structure of the HPP is the dam, of course, the beautiful arch 232,5 meters (763 ft) high and 338 meters (1109 ft) long. The width of the dam is from six (only six!) (19.7 ft) to thirty meters (98.4 ft)!

The width of the Chirkei gorge at the damsite is only thirty meters (98.4 ft). The place was rather difficult for such construction due to geological conditions. Though many problems were quite unexpected.

The narrowness of the gorge made them refuse the underground machine room and led to nonstandard layout solutions. For example, four main tranformers with weight more than 1000 tons, are located on the roof of the machine room. On the photo you can see the administrative building to the left and two reinforced concrete bays to the right for the two transformers.

For the first time in the world practice there was applied a two-row layout of hydraulic units with a two-level placement of suction pipes. On the photo above the headrace is to the left, the downstream – to the right.

The power of the HPP is 1,000 MW, annual output – 2.47 billion kWh.

This is a spiral case of one fo the turbines.

Due to the narrowness of the gorge, the water level in the downstream may vary for fifteen meters. That’s why the machine room is located underground.

The water is supplied to the four pemstocks each 5,5 meters (18 ft) in diameter.

The whole project included the huge complex of undergorund workings.

It’s the general view of the machine room, a transformer substation and the gorge.

In May 1970 the HPP being built turned out to be in the center of the nine point earthquake. The structure of the HPP didn’t suffer though the further works were delayed.

Cable cranes were mounted for concreting the dam.

This is the outdoor switchgear.

The dam is not a solid piece of concrete, it is built by “little” cubes. The length of the section along the dam is fifteen meters (49 ft).

It’s one of the adits.

And this is one of the two vertical pits 250 meters (820 ft) deep.

It’s the service spillway of the tunnel type.

The general view of the downstream.

The open distribution system.

It’s better to observe all the beauty of the dam from the nearest mountains.

The width of the dam is six meters (19.7 ft) only!

Controller’s office.

The first aggregate was launched in 1974 with a temporary wheel. It has been laying unneeded at the warehouse for more than 30 years.

At night it is even more beautiful.

Unfortunately, the pictures cannot convey all the beauty of the structure.

via russos