Lake Sevan

Lake Sevan ("Սևանա լիճ" in Armenian), formerly called Gokcha or Goktscha, is Armenia's largest lake, the largest lake in Transcaucasia and one of the largest high altitude lakes in the world. The entire lake is situated inside the eastern Armenian province of Geghark'unik'. It is fed by 28 rivers and drained by the Hrazdan (Razdan) river. Only 10% of the outgoing water is drained by the Hrazdan; the remaining 90% evaporates. Along with lake Van and lake Urmia it was one of the three great lakes of the Armenian Kingdom, referred to as the seas of Armenia, and it is the only one that lies within today's Republic of Armenia.

Before human intervention 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 was located at an altitude of 1,950 m.

In 1910 Soukias Manasserian (also the mastermind behind the interventions that spelled disaster for the Aral Sea) published a study Evaporating billions and stagnation of the Russian Capital, suggesting to lower the lake to 45 metres and use the water for irrigation and hydroelectricity purposes. In the Stalin 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 of lake water would decline 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 by ten times.

The Armenian Supreme Soviet approved the plan without consulting the local people and the major works started in 1933. The river bed of the Hrazdan was deepened and construction of a tunnel 40 metres below the original water level started. The work was delayed due to World War 2 and was only finished in 1949 when the water level began to fall by more than one metre per year.

An ecological disaster compared to that of the Aral Sea was avoided when the Stalinist era came to an end in 1956 and the project and its consequences were reviewed thoroughly. As there were troubles with planting of oaks and nuts and also with fishery, the Sevan committee was established with the mission "to raise the level as much as possible". It was decided that hydro-electrical power stations on the Hrazdan would be replaced with thermal power stations. The water level stabilised at 18 metres below the original level in 1962, but two years later the lake started to "bloom" due to eutrophic algae. In 1981, a 49 km tunnel was constructed that diverted water from the Arpa river (from a reservoir near Kechut) to the lake near Artsvanist. The water level rose, however, only by 1.5 metre, so another 22 km tunnel from Vorotan (further south from Kechut) was begun, but only 18 km were constructed because in 1988 Azerbaijan imposed an economic blockade over Armenia due to the Nagorno-Karabakh conflict and the works had to be stopped.

The current Armenian government has completed the Vorotan tunnel in 2003, but water inflow into the lake has not yet begun. The water level is currently stabilised at 20 metres below the original level, and the lake's area is now 940 km².

Sevan trout (Salmo ischan) was an endemic species of the lake, but it is endangered as some competitors were introduced into the lake, including common whitefish (Coregonus lavaretus) from Lake Ladoga, goldfish (Carrasius auratus), and crayfish (Astacus leptodactylus). If the Sevan trout is likely to become extinct in its "home" lake, it seems that it will survive in Issyk-Kul lake (Kyrgyzstan) where it was introduced.

There are numerous beaches along the entire lake shore. 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 Hayrivank, and further south, near Noratus, there is a field of khachkars, a cemetery with approximately 900 khachkars of different styles. When the water level fell, many archaeological artefacts were found, 2000 years old or older. Most of them are now displayed in Yerevan.da:Sevansøen fa:سوان nl:Sevanmeer pl:Sewan sl:Sevan ru:Севан