Mackenzie River from the Peace-Athabasca system are significantly slowed by the delta area at the western end of Lake Athabasca causing the lake to rise, and the excess water can only flow out after the rivers have receded. The same phenomenon occurs at Great Slave Lake, which naturally regulates the flow from the Slave River into the Mackenzie. There are river gages at several upstream points along the Mackenzie River. The average flow rate at the outlet of Great Slave Lake is . At Fort Simpson, below the Liard River, it is . At Norman Wells it is , and at the
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