Lake Onega water per year, of which 46% are industrial and household water, 25% is stormwater runoff and 16% is melioration-related drainage. This drainage contains of phosphorus and of nitrogen; respectively of these elements are removed through the River Svir whereas the rest accumulates in the lake. Ships and motor boats (about 8,000 units) bring oil pollution at the level of about per navigation year, as well as phenols (), lead () and oxides of sulfur, nitrogen, and carbon. The lake basin is a major source of granite, marble and black schist in Russia which have been exploited in the area since
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