Sevan is one of the three large lakes in the Armenian highland.
In ancient times it was called Gegharkunik or Geghama Sea. Sevan is the largest lake in Caucasus as well as one on the largest and highest freshwater lakes of the world.
The lake surface is at an altitude of 1897m above sea level. Its depth is 80m, an area-1260km2, lengh-70km, width-55km and the volume is 58billion cubic metres.
In summer, the middle temperature of lake surface is 18-23 degrees above zero. In winter the lake is partly covered with ice.
Sevan consists of two unequal parts – Big Sevan and Small Sevan. These parts are merged by 5th km length strait which is located between the peninsulas of Artanish and Noradus. The southern and eastern shores are broad and smooth, while the northern and north-eastern shores are narrow and rocky.
The Lake, on the west side, is surrounded by Geghama from the north – Aregunyats from the east – Sevan and from the South – Vardenis mountains.
Sevan is fed by 28 rivers of which Gavaraget, Argithci, Martuni, Karthcaghbyur, Masrik, Dzknaget are the most famous.
The Lake Sevan has tectonic, volcanic origin. From the geological point of view the Great Sevan is an ancient, intermountain concavity, where there was a water basin in the remote past. A separate lake has been existed as well in the place of the Small Sevan.
Young volcanic lava-stream raised the water level blocking the exit of the Small Sevan. Then Big and Small Sevan assembled into the current Sevan .In the northern part of the lake the island of Sevan is situated which has become a peninsula by artificially making water level low.
The lake has a good impact on the surrounding area and preserves the natural equilibrium of the entire basin. The water as well as the fish reserves are of great economic importance. Most of the canals irrigating the Ararat valley as well as the whole 6 electric power stations of cascade of Hrazdan are supplied by the water of Sevan.