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
Clearwater River (Saskatchewan) at Fort McMurray. The section of the river in Fort McMurray is affectionately referred to as The Chant. From Broach Lake at an elevation of above sea level, the Clearwater drops about to the confluence at Fort McMurray. Its waters eventually reach the Arctic Ocean via the Athabasca and Mackenzie Rivers. Tributaries of the Clearwater River include Descharme River and McLean River in Saskatchewan and the Christina River in Alberta. In its upper reaches, the Clearwater River flows over the Precambrian rocks of the Canadian Shield. That section of the river is rough, characterized by rapids, small waterfalls, and a