Irganai Dam
Location of the Irganai Dam in Dagestan Show map of Republic of Dagestan Irganai Dam (Russia) Show map of Russia
Country	Dagestan, Russia
Location	Untskul region
Coordinates	42°44′42.72″N 46°49′53.76″E / 42.7452000°N 46.8316000°E / 42.7452000; 46.8316000
Status	Operational
Construction began	1979
Opening date	1998
Owner(s)	RusHydro
Dam and spillways
Impounds	Avar Koisu
Height	111 m (364 ft)
Length	317 m (1,040 ft)
Reservoir
Creates	Irganai reservoir
Total capacity	705,000,000 m3 (2.49×1010 cu ft)
Surface area	18 km2 (6.9 sq mi)
Power Station
Turbines	4 x 200 MW
Installed capacity	400 MW 800 MW (max. planned)
Annual generation	1,280 GWh

Irganai Dam is a hydroelectric dam in the Untskul region of Dagestan, Russia. It is located on the river Avar Koisu.

Construction of the dam and power station started in 1979. The first generation unit of the Irganai hydropower station was launched in 1998.^[1] The second generation unit was launched in 2001.

The dam is 111 metres (364 ft) high and 317 metres (1,040 ft) long at the crest. It is filled of gravel with asphalt-concrete diaphragm. The complex includes tunnel spillway, intake structure, two diversion tunnels 5.2 kilometres (3.2 mi) each, underground surge tanks, steel-reinforced concrete penstocks, and a powerhouse.^[1]

Irganai is the largest derivational hydroelectric power station in Russia, with two radial-axial hydraulic units with a capacity of 200 MW each.^{[citation needed]} The power station has a total installed capacity of 400 megawatts (MW) and projected capacity of 800 MW.^[1][2] Its mean annual electric energy output is 1,280 GWh.

The dam creates the Irganai reservoir. The reservoir has a surface area of 18 km² (6.9 sq mi). Its full capacity is 705,000,000 cubic metres (2.49×10¹⁰ cu ft) and alive storage capacity is 397,000,000 cubic metres (1.40×10¹⁰ cu ft).^[1]

The dam and power station is projected by Lenhydroproject and operated by RusHydro.

On 7 September 2010, fire broke out at power station's hall. On 9 September 2010, Russian security forces defused an explosive device equivalent to 3 kilograms (6.6 lb) of trinitrotoluene in the room.^[3][4] On 31 January 2011, a stick of dynamite was discovered at the power station.^{[citation needed]}