Europe’s second-largest lake hides a wooden World Heritage isle
Lake Onega in northwestern Russia covers 9,891 square kilometres without its islands—Europe’s second-largest lake and the world’s seventeenth by area. About 1,650 islands include Kizhi, whose wooden churches form a UNESCO World Heritage ensemble.
Finns call it Ääninen and the Veps Änine. Glacial-tectonic carving left a young remnant of a larger Ice Age water body across Karelia, Leningrad, and Vologda oblasts. Length near 245 kilometres and width about 90 hold 291 cubic kilometres; average depth is 30 metres with a 127-metre northern hole. The Verhnesvirskaya plant stabilizes levels within about 0.9–1.5 metres. A spring flood lasting six to eight weeks lifts the water to its peak in June to August, and the lowest stage comes in March and April. Fifty-eight rivers and over 110 tributaries feed a 51,540-square-kilometre catchment; only the Svir leaves toward Ladoga.
Summer surface water reaches 20 to 24 °C in the open lake and up to 27 °C in the bays, yet the depths stay between 2 and 6 °C year-round, and air temperatures sit below freezing for half the year. About forty-seven fish species from thirteen families include glacial relicts such as lamprey, landlocked salmon, and sturgeon. Swampy reed banks shelter waterfowl beneath dense conifer forest. Conifers dominate the virgin forest, mixed with lime, elm and alder.
Eastern shores host roughly 1,200 petroglyphs. The islands together cover some 250 square kilometres. Big Klimenetsky is the largest island at 147 square kilometres, while Kizhi packs eighty-nine Orthodox wooden structures spanning the fifteenth to twentieth centuries. The White Sea–Baltic Canal and Volga–Baltic Waterway thread the lake; the Onega Canal (1818–1820 and 1845–1852) skirts the stormy south shore.
Quarries have worked the basin’s granite, marble and black schist since the early eighteenth century, and Petrozavodsk alone turns out about a quarter of Karelia’s industrial output. Once clean, the water is growing dirtier in the north and north-west, where Petrozavodsk, Kondopoga and Medvezhyegorsk hold most of the basin’s people and industry.
Source: Lake Onega
