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
Cass River (Mackenzie District) Cass, Chief Surveyor of Canterbury Province from 1851 to 1867. Cass River (Mackenzie District) The Cass River is an alpine river in the Canterbury Region of the South Island of New Zealand. It rises in the Hall Range immediately below Rankin Pass, and also receives water from the nearby Huxley Glacier. After dropping very rabidly the river flows south with braided channels along a flat-bottomed valley for . The Leibig Range and Gamack Range are to the west, and the Haszard Range to the east. The river flows into the west side of Lake Tekapo where it has built up