Water mills were built on the sides of dammed rivers, and worked in spring, summer, and autumn, when the rivers were free of ice. A water mill was a log structure in whose top part was a running millstone, and in the bottom part, the fixed one secured in a wooden frame. The mechanism was set in motion by a strong head of water. The upper millstone was rotating on the lower one grinding the grain falling between them.
Abstract by O.G. Baranova