Vuoksi River - Geological History

Geological History

Around 5,000 BP the waters of the Saimaa Lake penetrated Salpausselkä and formed the river emptying into Lake Ladoga in its northwestern corner and raising the level of the latter by 1–2 m. Lake Ladoga transgressed, flooding lowland lakes and Vuoksi, and connected with the Baltic Sea at Heinjoki, to the east of present-day Vyborg. Ladoga level gradually sank as the River Neva had originated around 3100–2400 BP, draining its waters into the gulf of Finland, but Vuoksi still had a significant direct outflow connection to the Bay of Vyborg, possibly as late as in the 16th or 17th century AD. The connection disappeared due to ongoing land uplift.

In 1818 a canal, which was dug to drain spring flood waters from Lake Suvanto (now Lake Sukhodolskoye, a 40-km long narrow lake in the eastern part of the Karelian Isthmus) into Lake Ladoga, unexpectedly eroded and turned into Taipaleenjoki (now Burnaya River). Taipaleenjoki started draining Suvanto and decreased its level by 7 m. Originally waters of Lake Suvanto flowed into Vuoksi River through a waterway at Kiviniemi (now Losevo), but as a result of the change, the waterway dried out. In 1857 the channel was dug there, but the stream reversed direction, revealed rapids and rendered navigation at Kiviniemi impossible. Since 1857 Suvanto and Taipaleenjoki have constituted the southern armlet of Vuoksi River, which has decreased the level of the original northern armlet emptying into Ladoga near Kexholm (now Priozersk) by 4 m and become the main stream.