Arctic Environments/Inland Waters Rivers
Canada's Arctic is laced with rivers large and small, deep and shallow, swift and slow moving. These rivers have served as gateways to the North – Native peoples and explorers paddled them, drank from them, admired their beauty, and occasionally lost their lives in them. Throughout the North, native settlements were first established on or near these waterways and they remain there today.
All Arctic rivers and streams show seasonal variations in the extent of their flow. These shifts are smallest in the larger rivers, like the Mackenzie, which are fed by waters flowing from more southerly regions. However, rivers which are entirely situated in the Arctic show dramatic seasonal shifts in flow because they are starved of a water supply for much of the year – most of the precipitation falls as snow for about eight months. During this period, when the supply of surface water is halted, the rivers are not fed by groundwater because the permafrost layer has refrozen to the surface. However, when the snow melts, it simply runs over the permafrost, flooding the rivers with an intense pulse of meltwater. For a brief time, the rivers and streams become raging torrents, carving out large channels and transporting huge boulders.