Underwater Vallinkoski potholes
Potholes began to emerge at the bottom of the Vallinkoski rapids after the outbreak of Vuoksi about 5,700 years ago. Strong water currents gouged them out of the uneven bedrock with the help of transported rock material and cavitation, “excavation force of the water”.
Historical information about the Vallinkoski area is found on the South Karelia Museum’s online exhibition Imperial Travels in Southeast Finland (only in Finnish).
Image: Favorin Ellen, Finnish Heritage Agency’s Picture Collections