Manicouagan Reservoir (mănĬkwäg´ən), annular artifical lake, 750 sq mi (1,942 sq km), SE Que., Canada, in a heavily forested area of the Canadian Shield. It has a maximum depth of 1,150 ft (300 m). Fed by four rivers, it was created by the Daniel Johnson Dam (1971), 25 mi (40 km) S of the reservoir on the Manicouagan River, and is located in one of the largest impact craters on earth. The crater was produced by a meteorite in the Triassic period, some 214 million years ago. René-Lavesseur Island, 780 sq mi (2,020 sk km), is ringed by the lake.