Lake Sevan (Armenian: Սևանա լիճ, romanized: Sevana lich) is the largest body of water in both Armenia and the Caucasus region.

[8] Sevan was heavily exploited for irrigation of the Ararat plain and hydroelectric power generation during the Soviet period.

[9] In the 19th and early 20th centuries, Russian and European sources sometimes referred to the lake as Sevanga or Sevang,[16] Per folk etymology, Sevan is either a combination of sev ("black") and vank’ ("monastery"),[17] sev ("black") + Van (i.e., Lake Van),[18][19] or originates from the phrase sa ē vank'ə ("this is the monastery").

[20] The scholarly explanation, first suggested by Mikhail V. Nikolsky [ru] in 1896,[21][9] is that Sevan originated from the Urartian word suinia, usually translated as "lake".

[25] It is attested on an 8th-century BC cuneiform inscription by the Urartian king Rusa I, found in Odzaberd, on the southern shore of the lake.

[35] The Turkic name Gokcha[36][37][38][39] or Gökche,[40][41][42] which means "blue lake" was also used in Russian and British sources from the 17th to early 20th centuries.

"[56] Chardin in 1673 noted the "extraordinary sweetness of the water", the "small Island in the middle of it; where stands a Monastery built about 600 years ago, of which the Prior is an Archbishop", and "nine sorts of fish which are there taken; the fairest trouts and carps which are eaten at Erivan being caught in this Lake".

[57] Naturalist and traveler Friedrich Parrot, best known for ascending Mount Ararat in 1829 for the first time in history, wrote: It is important for the Armenian economy: being the main source of irrigation water, Sevan provides low-cost electricity, fish, recreation, and tourism.

[7] Sevan originated during the early Quaternary when tectonic formation created a Palaeo-Sevan, ten times larger than the present lake.

Its high altitude location relative to the fertile Ararat plain and limited energy resources attracted engineers to explore ways of usage of the lake's water.

In his 1910 book, Armenian engineer Sukias Manasserian proposed using Sevan's water for irrigation and hydroelectric power generation.

The tunnel was completed in 1949 and thereafter the Sevan's level began to drop significantly, at a rate over 1 metre (3 ft) per year.

[61] According to Babayan et al. "by the 1950s it had become evident that the ecological and economic consequences of extensive exploitation of the water of Lake Sevan were too undesirable to continue in the same way.

"[59] In 1964 a project began to divert the Arpa River (from a reservoir near Kechut) through a 49 km (30 mi) long tunnel to the lake near Artsvanist.

[65] Since the water level in the lake did not rise as fast and as much, on 20 April 1981 the Council of Ministers of the Soviet Union made a decision for the construction of the Vorotan–Arpa tunnel.

[71] The Gegharkunik Province, which roughly corresponds to the lake's basin, had a de facto population of 211,828 according to the 2011 Armenian census.

The largest settlements in the province are: Gavar (20,765), Sevan (19,229), Martuni (12,894), Vardenis (12,685), Vardenik (9,880), Yeranos (6,119), Chambarak (5,660), Lchashen (5,054), Tsovagyugh (4,189).

The beaches have free parking space, children's and sports playgrounds, toilets, medical aid stations, and rescue services.

Due to anthropogenic impact, changes have occurred in all the biological components of the lake, including bacteria, benthos, and of course fish.

During migration the Lake is visited by wide variety of birds including raptors, such as Montagu's harrier (Circus pygargus) and Steppe eagle (Aquila nipalensis), waterbirds such as red-crested pochard (Netta rufina) and ferruginous duck (Aythya nyroca), while during the wintering period the lake hosts another set of species such as Bewick's swan (Cygnus columbianus) and great black-headed gull (Larus ichthyaetus).

The rivers feeding Lake Sevan flow through densely populated settlements which produce agricultural, domestic, and industrial waste.

According to the researchers it "may have posed health risks to aquatic life as well as to humans (at least in the case of river water used for drinking purposes).