Lake Sevan is the largest lake in Armenia and the Caucasus region. It is one of the largest fresh-water high-altitude lakes in the world. Lake Sevan is situated in the central part of the Republic of Armenia, inside the Gegharkunik Province, at the altitude of 1,900m above sea level. The total surface area of its basin is about 5,000 km2, the lake itself is 940 km2, and the volume is 34.0 bln cubic metres. It is fed by 28 rivers and streams. Only 10% of the outgoing water is drained by the Hrazdan (Razdan) river, while the remaining 90% evaporates. Before human intervention dramatically changed the Lake Sevan ecosystem, the lake was 95 metres deep, covered an area of 1,360 km² (5% of Armenia's entire area), had a volume of 58 km³ and a perimeter of 260 km. The lake surface was at an altitude of 1,916 m above sea level. Along with Lake Van and Lake Urmia, Sevan was considered one of the three great lakes of the historical Armenian Kingdom, collectively referred to as the Seas of Armenia; it is the only one within the boundaries of today's Republic of Armenia. The Sevanavank peninsula (formerly an island) is the historic area of the lake at its northern shores. During the past decades, the ecological condition of Lake Sevan has undergone tangible changes and vast degradation due to the following reasons: a) reduced water level, b) increased eutrophication c) detrimental impact of human activity on the biological diversity of the lake. Lowering of the water level had a variety of negative consequences. The biological mass of macrophyte plants fell, resulting in lack of adaptability of the plants changes, namely the weeding and pollution of the water in the newly emerged waterless area of the shore, as a result of growing erosion of this area. Dangerous reduction of Hypolimnion is another problem. Hypolimnion is the internal section of Sevan, in which the organic substances alochtone and autochtone mineralize. If this section is well developed (for example, in Lake Geneva it is 85% of the whole mass) then mineralization process is active, without discarding the oxygen, dissolved in water. There are numerous beaches along the entire lake shore. The most popular of them is a 2.5 kilometre stretch on the northern shore, extending northwest from the peninsula. Resorts include Harsnaqar Hotel, Best Western Bohemian Resort, and numerous smaller facilities. Activities include swimming, sunbathing, jet skiing, windsurfing, and sailing. The area also includes numerous campgrounds and picnic areas for daytime use. A less developed beach destination stretches along the eastern shore from Tsovagyugh to Shorzha, with numerous small cabins at Shorzha. The Avan Marak Tsapatagh Hotel, a Tufenkian Heritage Hotel, is a luxury resort on the undeveloped southeastern shore of the lake near Tsapatagh. The most famous cultural monument is the Sevanavank monastery near the town of Sevan at the northwestern shore. Initially the monastery was located on an island, but the fall of the water level turned it into a peninsula. Another monastery at the western shore is Hayravank Monastery, and further south, in the village of Noraduz, there is a field of khachkars, a cemetery with approximately 900 khachkars of different styles. Additional khachkars are found at Nerk'in Getashen on the south coast. When the water level fell, many archaeological artifacts were found, 2000 years of age and older (some as old as the early Bronze Age). Most of them are now displayed in Yerevan. The lake is an important breeding ground for the Armenian Gull (Larus armenicus) with about 4,000--5,000 pairs. Other birds which visit the lake include Bewick's swan (Cygnus columbianus), lesser white-fronted goose (Anser erythropus), red-crested pochard (Netta rufina), ferruginous duck (Aythya nyroca) and great black-headed gull (Larus ichthyaetus). The mouflon are suffering a great population decline due to poaching and habitat loss. The Sevan trout, which made up thirty percent of the fish in Lake Sevan, have virtually disappeared. Another endangered visitor to the lake is the Armenian leopard or panther (Panthera pardus tullianus). In 1910 Soukias Manasserian, one of the civil engineers behind the interventions that caused the Aral Sea disaster, published a study Evaporating billions and stagnation of the Russian Capital, which suggested the lowering of the lake's surface to 45 metres and the use of the water for irrigation and hydroelectricity. In Joseph Stalin's era the plan was slightly modified: the water level would be reduced by 55 metres (5 metres more than suggested by Manasserian), the perimeter would shrink to 80 km and the volume to only 5 km³. Nut and oak trees would be planted on newly acquired land, and introducing some trout species into the remainder of the lake would increase fishery production tenfold.

• published: 08 Sep 2013
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