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 . This long tunnel was begun from the Spandarian Reservoir on the Vorotan River further south from Kechut . Due to the Nagorno-Karabakh conflict and the 1988 earthquake in northwestern Armenia construction was halted . The tunnel was inaugurated on 26 April 2004 . The Vorotan – Arpa tunnel brings an additional to the lake annually
1988 earthquake
1988 Armenian earthquake
Lake Sevan