What time of year do beavers build dams?

A dam erected by beavers on a river or stream serves to protect against predators and to facilitate the extraction of food in winter. Dam construction materials – trees, twigs, leaves, silt, mud, and other materials of natural origin.
Construction begins from mid-summer to autumn, as the water level in the rivers decreases, the beavers take on the construction of dams and excavation of burrows. Moreover, more often fallen trees, previously hidden by water, come across.