Lake Sevan

From Wikipedia, the free encyclopedia

Lake Sevan
A view from the Sevanavank monastery
Coordinates	40°19′N 45°21′ECoordinates: 40°19′N 45°21′E
Primary sources	28 rivers
Primary outflows	evaporation (90%), Hrazdan
Basin countries	Armenia
Max-length	78 km (2005)
Max-width	56 km (2005)
Surface area	940 km² (2005), 1360 km² (1949)
Water volume	58 km³ (1949)

Lake Sevan (Armenian: Սևանա լիճ, named Gegham Sea (Գեղամա ծով) in ancient times; Russian: Озеро Севан; Azeri: Göyçə gölü; Turkish: Gökçe Gölü) is the largest lake in Armenia and one of the largest high-altitude lakes in the world. The entire lake is situated inside the eastern Armenian province of Gegharkunik. It is fed by 28 rivers and drained by the Hrazdan (Razdan) river. Only 10% of the outgoing water is drained by the Hrazdan, while the remaining 90% evaporates. Along with Lake Van and Lake Urmia, Sevan was one of the three great lakes of the Armenian Kingdom, referred to as the seas of Armenia, and it is the only one within today's Republic of Armenia. Sevanavank is the historic area near the lake.

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 surface was at an altitude of 1,950 m above sea level.

1 Intervention
2 Fauna
3 Beaches
4 The Island Monastery
5 External links
6 See also

[edit] Intervention

View of the lake from space

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, suggesting to lower the lake to 45 metres and use the water for irrigation and hydroelectricity.

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 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 II and was only finished in 1949 when the water level began to fall by more than one metre per year.

An ecological disaster like that in the Aral Sea was avoided when the Stalinist era ended in 1956 and the project and its consequences were reviewed thoroughly. As there were troubles with planting oaks and nuts and with fishery, the Sevan committee was established with the mission "to raise the level as much as possible". Hydro-electric power stations on the Hrazdan would be replaced with thermal power stations. In 1962 the level stabilised at 18 metres below the original level, but two years later the lake started to "bloom" due to eutrophic algae.

In 1981, a 49 km tunnel was constructed, diverting water from the Arpa river (from a reservoir near Kechut) to the lake near Artsvanist. The water level rose only 1.5 metres, so another 22 km tunnel was begun from Vorotan (further south from Kechut). 18 km were constructed before the collapse of the Soviet Union, because in 1988 Azerbaijan imposed an economic blockade on Armenia due to the Nagorno-Karabakh conflict and the work had to be stopped.

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

Due to recent rain and other changes, the water level is again slowly rising (as of 2005).

[edit] Fauna

Sevan trout (Salmo ischchan) 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.

The lake is an important breeding ground for the Armenian Gull (Larus armenicus) with about 4000-5000 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).

Another endangerd visitor to the lake is the Armenian leopard or panther (panthera pardus tullianus).

Churches at Sevanavank

[edit] Beaches

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. 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.

[edit] The Island Monastery

Originally made from three churches, the monastery was built on an island. Receding waters in the 20th century created the current peninsula. The island was uninhabited until the end of the 8th c. CE, when monks built a chapel and a group of cells. The monastery was founded in 874 by King Ashot I, the founder of the Bagratid Dynasty, and his daughter Mariam. Two churches remain, St. Arakelots and Astvatsatsin. The island monastery was, according to historians of the time, used both for worship and pilgrimage, and as a place of exile for Armenian noblemen who had fallen into disgrace. It also was the residence and headquarters for King Ashot, from which he led a battle against invading Arabs beginning in 859 CE.

During the battles monks and clergy fought alongside the army to defeat the Arabs, but repeated Arab and Ottoman invasions continued. The monks on the island continuously led battles to protect the monastery, and such was the life in and around the monastery for almost 500 years until the Persians and the Ottomans divided the Armenian kingdom. The monks in Gegham-kiunik specialized in medicine, and some of their natural cures are still used, based on herbs that grow in the wild around the lake. The monastery continued until the 20th century, when the last monk left the in 1930. Today the monastery is maintained by the church, which has a summer retreat for seminarians on the peninsula.