Mackenzie River Great Slave Lake, at Fort Resolution, Northwest Territories. The Slave is by far the largest river flowing into the lake, with an annual flow of 108 km (87 million acre-feet). It contributes about 77% of the overall inflow, and forms a large delta where it enters the lake. Other rivers entering Great Slave Lake area the Taltson, Lockhart and Hay Rivers, the latter of which also extends into Alberta and BC. The Mackenzie River issues from the western end of Great Slave Lake about south-west of Yellowknife. The channel is initially several kilometres wide but narrows to about at Fort
Besa River Granger Creek also flows in the Besa River west of Klingzut Mountain. Shortly after, Besa River flows into the Prophet River as a right tributary, at an elevation of . Its waters are carried via the Prophet River, Muskwa River, Fort Nelson River, Liard River and Mackenzie River, ultimately into the Arctic Ocean. Besa River Besa River is a river in northern British Columbia, Canada. It is a tributary of the Prophet River. The river flows through the Muskwa Ranges, and is the backbone of the Redfern-Keily Provincial Park, part of the larger Muskwa-Kechika Management Area. It gives the name