Lake Sevan
Sevan was used for irrigation of the Ararat plain and creating hydroelectric power during the Soviet period. This causes the level of water to decreaseby around . Its volume was reduced by more than 40%. Later two tunnels were built to move water from highland rivers. This stopped the decrease and its level began rising. Before people begane changing the lake's ecosystem, the lake was at an altitude of 1,916 m (6,286 ft) above sea level, 95 m (312 ft) deep, covered an area of 1,416 km2 (547 sq mi) (5% of Armenia's entire area), and had a volume of 58.5 km3 (14.0 cu mi).