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Banff National Park of Canada

Aquatic Ecosystems

Water: Liquid Gold

Mt. Verendrye, Kootenay National Park
© Parks Canada / L. Horrocks

Humans are drawn to rivers and lakes. Our survival as a species depends on it: we need water for drinking, transportation, irrigation and industry. But we are also drawn to waterways for their beauty and the sense of pristine wilderness they convey. Nowhere is this more evident than in our mountain national parks. Here, lakes set against soaring mountains and glaciers move people to describe their beauty in jewel-like terms.

Henry David Thoreau captured both the beauty of lakes and their ecology in 1854, when he wrote these phrases to describe lakes near his home: great crystals on the surface of the earth . . . their remarkable transparencies, their hues of blue and green, their lack of muck . . . but . . . not very fertile in fish.

His words perfectly describe the lakes of the Rocky Mountains. Such lakes and rivers are called oligotrophic, simply meaning they are naturally low in nutrients like phosphorus and nitrogen. The water is clear, cold, and rich in oxygen. The community of plants, insects and fish that live in the rivers and lakes here are uniquely adapted to this kind of aquatic environment. Any pollution that enters it will affect all life that depends on it, including people.

Parks Canada's priority is to safeguard the health of our national park ecosystems. The mountain national parks contain the headwaters of several major rivers, such as the Bow and North Saskatchewan, which also supply municipal water for people further downstream.

Consequently, human activities within the national parks affect people outside its boundaries. Human waste is the chief source of water pollution in the mountain parks, but toxic substances are also a concern. Through simple actions, all of us can help keep the water clean and conserve it for nature and for future generations.

Human Waste

Human waste contains phosphorus and nitrogen. Sewage treatment plants cannot remove all of these nutrients from wastewater before it is discharged back into our rivers.

Though these nutrients occur naturally in the mountains in very low concentrations and are used by plants and algae for growth, small increases in them from wastewater discharge can cause algae blooms and changes in plant communities. Signs of change may include long strands of algae, presence of weeds and foul odours.

Bugs Tell the Tale

Studies conducted on aquatic insects in the Athabasca, Bow and Kicking Horse Rivers show that effluent from sewage treatment plants has changed these aquatic ecosystems. Excess nutrients in effluent, particularly phosphorus, cause algae blooms below treatment plants where wastewater is discharged back into the river. An increase in nutrients also results in a loss of insect diversity.

Stonefly
© Parks Canada / D. Bjorn / YNP Collection/2002

Aquatic insect samples collected downstream from the treatment plants show more chironomids (midges) and comparatively fewer mayflies, caddisflies and stoneflies. Since chironomids are more tolerant of water pollution than the other insects, their presence indicates a reduction in water quality.

A decrease in mayflies, stoneflies and caddisflies impacts the animals that eat them. For example, harlequin ducks rely largely on stoneflies as a food source. Fewer stoneflies force harlequin ducks to forage for other aquatic insects, which may not be as abundant or nutritious. Consequently, the ducks may have to dedicate more time and energy to foraging to the detriment of reproduction.

Toxic chemicals

Toxins are another source of water pollution in the mountain parks. Some chemicals, such as formaldehyde and ammonia, are used in sewage holding tanks in motor homes. They destroy odours, but they also destroy good bacteria that break down wastes in septic systems and treatment plants. Most treatment plants can't remove these chemicals from wastewater before it is discharged back into the river. In addition to harming aquatic ecosystems, these toxins may end up in someone's drinking glass further downstream.

Some toxins can build up through the food chain, accumulating in the bodies of top predators, such as humans until they reach harmful levels. This process is called biomagnification .

What Parks Canada is doing

Parks Canada is upgrading its sewage treatment systems in the mountain parks to remove excess nutrients from wastewater. To reduce the amount of harmful toxins entering rivers via wastewater, Parks Canada uses environmentally friendly cleaning products wherever possible.

Parks Canada uses low-flow showerheads, timed showers and spring-loaded taps to conserve water in many of its campgrounds.

What you can do: in the frontcountry

Don't dispose of toxic cleaners, solvents or chemicals by throwing them down the drain. Dispose of them at a hazardous waste facility.
Choose environmentally friendly cleaning products.
Use biological control agents in the sewage holding tank of your motor home instead of toxic chemicals.
Conserving water is the best and cheapest way to keep it clean. Avoid wasting it.

What you can do: in the backcountry

Whether you're washing yourself, dishes or clothes, use a washbasin and wash well away from rivers and lakes, and use as little soap as possible.
Strain out those last bits of food from wash water and pack them out. Dispose of grey water at least 100 m (ten bus lengths) from rivers, lakes and campsites. Don't dump it down pit privies: it disrupts the natural biological breakdown in them.
When nature calls, use the pit privies provided. If there aren't any pit privies, select a spot away from trails, campsites and at least 70m (seven bus lengths) from lakes and rivers. Dig a hole, 12-16 cm deep (ankle deep). When you're done, fill the hole loosely with dirt.
Pack out or burn your toilet paper if the fire hazard is not extreme.

Canada's waterways are part of our cultural and natural heritage.

The Big Picture

Respect the needs of plants, animals and natural processes like the water cycle; people are a part of it. Be willing to make a change. Find out how you can conserve water and how you can keep it clean — then teach your children and your friends.