Aguasabon Gorge and Falls near Terrace Bay
|Part of||Great Lakes Basin|
|- elevation||395 m (1,296 ft)|
|- location||Terrace Bay|
|- elevation||180 m (591 ft)|
|Length||70 km (43 mi)|
The Aguasabon is 70 kilometres (43 mi) in length, and plunges down 30 metres (98 ft) at the Aguasabon Falls. The river follows fractures in the 2.6 billion-year-old bedrock, and the exposed rock is granodiorite.
In 1945, the Hydro-Electric Power Commission of Ontario began preliminary survey work for a planned hydroelectric facility in the Terrace Bay area. Construction commenced in 1946 and the facility began operating in 1948. The development required five million hours of labour, a network of access roads, and the erection of 25 buildings including staff housing, a hospital, administration office, pump house, machine shops and laundry. The dam enlarged Hays Lake to five hundred times its original size, and forced the relocation of Ontario Highway 17, requiring a new bridge be constructed. As part of the project, the Hydro-Electric Power Commission of Ontario diverted the headwaters of the Kenogami River to flow south into Long Lake and into the Aguasabon River system to Lake Superior, rather than flowing north towards Hudson Bay via the Albany River.