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
Whitesand River (Lake Nipigon) and then another southeast to its mouth at Lake Nipigon, for a total distance from Selassie Lake of . Whitesand River (Lake Nipigon) The Whitesand River is a river in Thunder Bay District, Ontario, Canada, that flows south into the northwest side of Lake Nipigon. Another river in Thunder Bay District with the same name, Whitesand River (Hewitson River), lies further southeast and flows into Lake Superior via the Hewitson River. The river begins at Selassie Lake at an elevation of . Selassie Lake is adjacent to Haile Lake, which also flows into Lake Nipigon, but via the Pikitigushi River