Science Spotlight: Watersheds and Their Importance

Guest Blog By Rannee Liu


North Saskatchewan Watershed Alliance 2018

North Saskatchewan Watershed Alliance 2018

Watersheds, or catchment basins, are areas that catch water from rain and snow, which then drains into a river, stream, lake, wetland, groundwater, or the ocean. For example, the North Saskatchewan River and its connecting water corridors, such as Sturgeon River and Whitemud Creek, make up the North Saskatchewan watershed. For Alberta, most of its precipitation starts as clouds in the Pacific Ocean which are intercepted by the Rocky Mountains. In addition to the precipitation we receive throughout the province, rain and snow is collected in the mountains, water is accumulated in glaciers, snowfields, soils and forests and from there, it is slowly released throughout the seasons into areas of lower elevation. Small streams merge to form larger ones, and eventually flow into mighty rivers, all of which make up watersheds.

Major watersheds, like the North Saskatchewan, are made up of subwatersheds as shown in the picture above. Almost all of the Edmonton and Area Land Trust lands can be found in the subwatersheds Sturgeon, Strawberry and Beaverhill. The exception is the Pipestone Creek Conservation Land which resides in the Battle River watershed.

The importance of watersheds cannot be overstated. Catchment basins provide essential-for-life places for recreation and wildlife habitat. A healthy watershed produces good quality drinking water. Water is cleansed and oxygenated to support aquatic life when fast moving headwater streams tumble over rocks and plummet down waterfalls. During this time, water is put into contact with ozone and ultraviolet light in the air, which kills parasites and bacteria.    

Alberta is divided into seven major watersheds: Hay River, Peace/Slave Rivers, Athabasca River, Beaver River, North Saskatchewan River, South Saskatchewan River and the Milk River. Edmonton is within the North Saskatchewan River watershed, which has its headwaters at the Saskatchewan Glacier in the Columbia Icefields in Banff National Park.

It’s Not Just About Water

Land, and how it is used, is just as important to a watershed as the water itself. What happens on the land, happens to the water too. Vegetation, including forests and grasslands, as well as other components of the landscape, from wetlands to the soil, all influence the health of a watershed. Forests perform the important tasks of storing, cleansing and slowly releasing water in the upper portion of watersheds. Trees, shrubs, mosses, and soils retain and cycle nutrients, and purify water as it passes through their systems. The land acts as a sponge that contributes to flood prevention by holding onto large quantities of water. All these natural processes are integral to maintaining good water quality, and reduce the cost of water treatment for human use. The American Water Works Association estimates that every 10% increase in forest cover in a watershed results in a 20% reduction in water treatment costs, up to a forest cover of 60%.  

Climate Change and the Future of Alberta’s Hydrology

Climate change has the potential to severely impact watersheds in Alberta. The Boreal Plains landscape in Alberta, where Edmonton is located, is notable for its many shallow lakes and ponds, large wetland complexes with thick peat deposits and upland aspen forests, which are all influenced by the surrounding hydrology. Climate change research indicates that the Boreal Plains, and other natural regions, are susceptible to climate change, leaving overall reduced water levels in many areas. 

What Can We Do to Protect Watersheds?

  • Reduce personal demands on water through lifestyle changes in sanitation, car washing, lawn watering, consumption, etc. Take shorter showers, and collect rain water for your garden in a rain barrel.

  • Reduce your carbon footprint to take action against climate change. Walk, bike or take transit when possible. Reduce, reuse and recycle. Compost your food scraps and garden waste.

  • Support land and watershed protection through the Edmonton and Area Land Trust by donating and volunteering.

  • Learn more about your watershed, through organizations such as the North Saskatchewan Watershed Alliance.



  • National Research Council. 2008. Hydrologic Effects of a Changing Forest Landscape. National Academies Press, 500 Fifth Street, NW, Washington, D.C. 20001; (800) 624-6242.

  • Ernst C, Gullick R, Nixon K. 2004. Protecting the source: Conserving forests to protect water. Awwa 30(5):1,4-7.