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
Bistcho Lake Bistcho Lake Bistcho Lake is a large lake in north western Alberta, Canada. Bistcho Lake has a total area of (with islands area and water surface), and lies at an elevation of . It is the third largest lake in Alberta (or fourth if considering Lake Athabasca, which is partly in Saskatchewan). Bistcho Lake is located in the hydrographic basin of the Liard River, to which it is connected by the Petitot River. The waters of the lake drain to the Arctic Ocean through the Petitot, Liard and Mackenzie River. The Jackfish Point and Bistcho Lake indian reserves of the