Lake Lacha Lake Lacha Lake Lacha () is a freshwater lake, located in the south of Kargopolsky District of Arkhangelsk Oblast in Russia, south of the town of Kargopol. It is the largest lake in Arkhangelsk Oblast, with a surface area of and a basin area of . Lake Lacha is the source of the Onega River, one of the major waterways of the White Sea basin. The etymological origin of the name is unclear. The river basin of Lake Lacha includes the southern and western parts of Kargopolsky District of Arkhangelsk Oblast, as well as north-west of Vologda Oblast. In particular,
Lake Onega the early 18th century. Also advanced is metallurgy, especially in the Petrozavodsk area which produces about 25% of industrial products of Karelia. Water level of the lake is controlled by the Nizhnesvirskaya (, "Lower Svir") and Verkhnesvirskaya (, "Upper Svir") hydroelectric power plants. The former was built between 1927 and 1938 and has a peak power of 99 MW. The construction of Verkhnesvirskaya plant started in 1938, but was interrupted by World War II and could only be resumed in 1947. The plant was completed in 1952 and provided 160 MW of electric power. The associated with the plant Verkhnesvirsk