Lake Onega Reservoir has an area of and volume of , i.e. almost the same as those of Onega Lake. Its construction raised the water level of the lake by . The lake contains a well-developed navigation system which is part of the Volga–Baltic Waterway and White Sea – Baltic Canal, connecting the basins of Baltic, Caspian and the northern seas. These canals allow water transport of goods from the lake to the countries from Germany to Iran; most traffic goes to Finland, Sweden, Germany and Denmark. The Onega Canal running along the southern shore of the lake there is not used
Onega River mid-April - May. It was used for timber rafting. The Onega flows among the coniferous forests (taiga of spruce, pine, and larch), mostly among the swamps. There are only four bridges across the Onega: one in Kargopol on the road connecting Kargopol to Nyandoma, one in the village of Sorokinskaya, on "Onezhsky Trakt", the road connecting Kargopol to Plesetsk and Yemetsk, one combined road and railway bridge connecting Oksovsky and Severoonezhsk, and one railway bridge in Porog on the railway from Arkhangelsk to Belomorsk (no road traffic). Elsewhere, including the former district center of Konyovo, the Onega can only be