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Article Dans Une Revue Silnews Année : 1997

What happened to Lake Sevan ?

M. Akopian
  • Fonction : Auteur
Vazken Andréassian

Résumé

Lake Sevan, in Little Caucasus, is one of the few ancient lakes of the world and share some rare peculiarities with some other great lakes. However Sevan characteristics and fate are still poorly known to western scientists and to environmentalists. In classical western limnology text books Sevan (1416 km2, 58.4km3) is rarely mentioned, mostly for its endemic fishes including Salmo ischchan and two cyprinidae species. Sevan is one of the few lakes of the world beeing continuously studied since 1923 when a limnological station was created. It is now known as the Sevan Institute of Hydroecology and Ichthyology, part of Armenia Academy of Science since 1932. In 1993 a major scientific conference was held on Lake Sevan (Oganessian, 1993) but was attended only by scientists from Armenia and other former USSR republics. Another conference organised in October 1996 by the newly created Armenia Ministry of Nature and Environmental Protection, UN Development Programme, and the French Embassy allowed the exchange of information with few foreign experts and with some NGOs from Armenia and from the Armenian diaspora. Sevan water balance is unusual: evaporation over the water body (800 mm.year-1) largely exceeds direct precipitation (360 mm.year-1) (Hovhannissian, 1994). As a result the lake outlet, the Razdan River, a tributary of the Araxe has an average natural discharge of 2m3/s or only 3.6% of all outputs while seepage is estimated to 6.4% and evaporation to 90%. The very restricted lake basin area and the dry continental climate result in very slow renewal of the lake waters, around 50 years at its natural stage.

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Dates et versions

hal-02581216 , version 1 (14-05-2020)

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Michel Meybeck, M. Akopian, Vazken Andréassian. What happened to Lake Sevan ?. Silnews, 1997, 23, pp.7-10. ⟨hal-02581216⟩
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