Hydrology of the North Saskatchewan River

By Chris Smith

The North Saskatchewan Watershed in Alberta drains approximately 80,000 km2, or 12.5% of all land in Alberta, yet provides water for more than 25% of the population in our province. It begins at the Saskatchewan Glacier in the Columbia Icefields, nestled in Banff National Park. From there, it flows more than 1,000km west to east across Alberta, joining the South Saskatchewan River in Saskatchewan and flowing into Lake Winnipeg in Manitoba, eventually emptying into the Hudson Bay.

In Alberta, the majority of the water flowing in the North Saskatchewan River is provided by its headwaters region, comprised of four subwatersheds: the Cline, Ram, Clearwater and Brazeau, which collectively contribute approximately 88% of the total flow. The headwaters of mountain-fed prairie rivers are often referred to as ‘water towers’ because they tend to provide the largest portion of total annual water within a watershed. This flow comes from precipitation that falls as rain or snow, which slowly filters into the river over time through numerous streams, tributaries and via groundwater infiltration. The North Saskatchewan River is the primary source of drinking water for Edmonton and dozens of other communities across the prairies, supplying water to more than 1.2 million people for human consumption, hydroelectric generation, oil and gas extraction, mining, and agricultural use. Much of the water use in the North Saskatchewan River is returned the the river after being used, either by going through a waste water treatment plant or a waste-water lagoon.

Although glacier melt contributes only a small portion of the overall flow (~1%), it provides much needed minimal flow during the hot and dry summer months. The flow is also affected by the two hydroelectric dams along the length of the river: the Brazeau Dam (1965) and the Bighorn Dam (1972). In order to ensure equitable and fair access to water, the North Saskatchewan River is also subject to the 1969 Master Agreement on Apportionment signed between Alberta, Saskatchewan and Manitoba, which states that Alberta must allow 50% of the natural flow of rivers to flow into Saskatchewan, and which must meet a minimum flow requirement.