David Finch ~ (a january article in the calgary herald):
"If not for the rapids, large ocean vessels could ascend up the Mackenzie River, cross Great Slave Lake, and continue up the Slave and Athabasca rivers to the geographical centre of Alberta."
 

a forty-km portage road bridges four sets of violent rapids in one 25 km stretch ~ linking Bell Rock (just north of Fort Smith) NWT and Fort Fitzgerald AB (in 2006 a 150,000-ton barge and tugboat portaged in two hours)
 

from ramp-alberta
The Mackenzie River system extends over 4,241 km from its most distant source to its delta on the Beaufort Sea. The river drains an area of 1.8 million sq km, a fifth of Canada's land, and has an average annual discharge of 9,910 m3/s. It is the 10th largest river basin in the world, extending over 20 degrees of longitude and 15 of latitude from the Rocky Mountains to the Arctic lowlands.
The Mackenzie River system played an important role in the fur trade, and is still an important transportation route for northern communities. While the northern part of the basin is still sparsely populated, demand for its resources is increasing.