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Lake Sevan
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Lake Sevan is the largest lake in Armenia and one of the largest high-altitude lakes in the world.
Former names of the lake include Gegharkunik , Gegham Sea , Lychnitis (Latin) and Gokcha (Turkish for Blue Lake).
Lake Sevan is sisutated in the central part of the Republic of Armenia, inside the Gegharkunik Province, at the altitude of 1900m above sea level.
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Encyclopedia
Lake Sevan is the largest lake in Armenia and one of the largest high-altitude lakes in the world.
Former names of the lake include Gegharkunik , Gegham Sea , Lychnitis (Latin) and Gokcha (Turkish for Blue Lake).
Lake Sevan is sisutated in the central part of the Republic of Armenia, inside the Gegharkunik Province, at the altitude of 1900m above sea level. The total surface area of its basin is about 5000 sq. km, the lake itself is 1200 sq. m, and the volume is 34.0 bln cubic meters. 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 this 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 1,950 m above sea level.
Along with Lake Van and Lake Urmia, Sevan was one of the three great lakes of the historical Armenian Kingdom, collectively referred to as the Seas of Armenia, and it is the only one within the boundaries of today's Republic of Armenia. Sevanavank is the historic area near the lake.
Intervention
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 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 tenfold.
The Armenian Supreme Soviet approved the plan without consulting the local people, and major work started in 1933. The river bed of the Hrazdan was deepened, and construction of a tunnel 40 metres below the original water level was begun. The work was delayed due to World War II and was only finished in 1949. The water level then began to fall by more than one metre per year.
As a result of these activities, the level of the lake fell by 19.01m, from its original of 1,915.9m. Currently, the lake is 1,896.86 meters high; the volume has declined from 58.5 billion cubic meters to about 34.0, and the surface area has shrunk from 1,416.2 sq. km to 1,238.1 sq. km.
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 difficulties with planting oaks and nut trees, 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 water level stabilized 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 in the lake rose only 1.5 metres, so another 22 km tunnel was begun from Vorotan River (further south from Kechut). Eighteen kilometers of this tunnel were completed before the collapse of the Soviet Union, but 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 stabilized 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).
Fauna
Ichtyofauna
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 in the 1970s.
Due to anthropogenic impact, changes have occured in all the biologycal components of the lake, including bacteria, benthos, and of course fish. Thus, the benthic mass increased 10-fold in 1940, due to oligochetes and chrinomices. Today, the former prevail and multiply the oxygen-rich residue at the bottom of the Lake.
The bojak and winter bakhtak species of the Sevan-endemic trout have already disappeared. The summer bakhtak occurs rarely; the gegharkuni is still capable of reproducing naturally. In 1980s, the quantity of Sevan koghak significantly decreased. There are numerous reasons for this:
- The level of the water lowered, the patches of rivers changed, the trout (gegharkuni and Aestivalis species) lost its natural sp?wning place. Changes in the areas near the shore (mossing, disappearance of macrophyte plants) also had a negative impact on the trout lays. The trout spawns only in certain areas, where there is oxygen-rich underground water at the depth of 25-30 meters.
- Deoxidization of the bottom is extremely detrimental for salmon, which are used to more than 4 mg O2 per liter.
-In the last 10 years, poaching rapidly increased, which significantly reduced the amount of fish in the lake.
Other Species
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). 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).
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 to function until the 20th century; the last monk left in 1930. Today the monastery is maintained by the Church, which maintains a summer retreat for seminarians on the peninsula.
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, 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.
Gallery
External links
- all about the lake
- - Armeniapedia article with information and photos
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- World Summit on Sustainable Development. 2002. National Assessment Report.
See also
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