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
Lake Volta Dam holds back both the White Volta River and the Black Volta River, which formerly converged where the middle of the reservoir now lies, to form the single Volta River. The present Volta River flows from the outlets of the dam's powerhouse and spillways to the Atlantic Ocean in southern Ghana. The main islands within the lake are Dodi, Dwarf, and Kporve. Digya National Park lies on part of the lake's western shore. The lake is formed by the Akosombo Dam, which was originally conceived by the geologist Albert Ernest Kitson in 1915, but whose construction only began in 1961