Hay River (Canada) border, the annual discharge is . Hay River (Canada) The Hay River (in South Slavey: "Kátå’odehche") is a large river in northern Alberta and southern Northwest Territories, Canada. It originates in the muskeg of north western Alberta, flows west to British Columbia, then curves northward and returns to Alberta, where it follows a north-northeast course towards the Northwest Territories. After passing over two main waterfalls, the Alexandra Falls and Louise Falls, it flows through the town of Hay River and discharges into the Great Slave Lake. From there, its waters are carried to the Arctic Ocean by the Mackenzie River.
Mackenzie River Lakes are remnants. Today's Mackenzie River is very young in geologic terms – its channel formed over a period of no more than several thousand years as the ice sheet retreated. Prior to the ice ages, only the Peel River tributary flowed through what is now the Mackenzie Delta into the Arctic Ocean. The other tributaries of the Mackenzie combined into the "Bell River" which flowed east into Hudson Bay. During glaciation the weight of the ice sheet depressed northern Canada's terrain to such an extent that when the ice retreated, the Mackenzie system was captured to lower elevations in