Irganai Reservoir, reservoir in Russia

Irganai Reservoir is an artificial lake in the mountains of Dagestan, Russia, formed by a dam built on the Avarskoye Koisu River. It sits within a narrow mountain valley, flanked on both sides by steep rocky slopes that drop directly to the water's edge.

The reservoir was created when the Irganai hydroelectric dam was completed in the 2000s, though the project had been planned since the Soviet era. The flooding of the valley permanently changed the landscape and displaced several small communities that once lived there.

The reservoir's fish include trout, salmon, and other species, and the flooded villages of Irganai, Zirani, and Maydanskoye lie beneath the water. Only 30% of the reservoir bed was cleaned before filling, so orchards, houses, farm buildings, and cemeteries were submerged on the night of 13 June 2008.

A road runs along the shore and offers several spots with open views over the water, making it easy to stop and look around without needing to hike. Accommodation is available in nearby villages, and the area is accessible year-round, though spring and autumn tend to offer the most comfortable conditions.

The dam project was first drawn up during the Soviet era but took several decades to complete because construction was repeatedly stopped and restarted. As a result, the remains of old settlements now lie beneath the water, submerged when the valley was finally flooded.