Why are Alberta’s trout species threatened?

5 per cent.

That’s what’s left of the once-thriving population of cutthroat trout in Alberta. Combine that with a 70 per cent loss of habitat for Alberta’s provincial fish, the bull trout, and things aren’t looking too positive for our freshwater fishes. Both cutthroat and bull trout are now restricted to high elevations, when they were once abundant through the Oldman and Bow river basins.

Facing multiple pressures

So why the dramatic decline? The biggest threat might not be what you think: off-highway vehicles. Quads, 4x4s, dirt bikes, and other off-highway vehicles tear up the stream bottom, compromise important habitat, and increase the amount of silt and sediment being deposited into important spawning grounds.1

But it’s not just our off-roading friends to blame. The creation of logging roads, expansion of energy development, effluent runoff from feedlots, and draining of watersheds to meet irrigation needs are all part of the problem. Together, these pressures create an ecosystem that is heavily disturbed, and its estimated that the disturbance density of the Oldman watershed are ten times the recommended maximum to ensure the long-term health of cutthroat and bull trout.

But why is silt and sediment a problem?

We used to think silt and sediment would just be washed away when it entered our waterways, but this actually isn’t the case: these tiny particles of sand and dirt become trapped in the bigger stones and gravel that make up the stream bed, where it solidifies. Eventually, the sediment and silt becomes so concentrated in the seafloor that water can’t permeate through it, creating what is referred to as a “hardpack streambed.” This makes it extremely difficult for trout to carve out redds (nests) – and hardpacks aren’t expected to go anywhere soon.

Echoed all over the province

In order to see real, lasting change for all of our native species of fishes and freshwater species, Alberta will need to address its land-use policies and make considerable changes.2 Some of these would include better protection for headwaters, more control of industrial activity, and improved water quality monitoring.

What can you do?

The biggest thing we can do to ensure the long-term health of our freshwater species is to limit the impact we have on our waterways directly. When you’re out camping, leave some distance between your site and the water. Don’t use your off-highway vehicle in or near the water. And make sure you use caution down on the waterfront.



CBC News. (June 13, 2015). Alberta trout threatened, say anglers and environmentalists. Retrieved from: http://www.cbc.ca/news/canada/calgary/alberta-trout-threatened-say-anglers-and-environmentalists-1.3112452.


Bob Weber. (July 12, 2015). Most Alberta trout streams threatened: survey. The Canadian Press. Retrieved from: http://globalnews.ca/news/2106366/most-alberta-trout-streams-threatened-survey/.


How clean is the North Saskatchewan River?

When you ask someone about the quality of the North Saskatchewan River, clean might not be the first word they respond with. But saying the North Saskatchewan River is “dirty” isn’t correct. The early history of our river and its muddy brown appearance are both partly responsible for misconceptions about the health of the river today.

The river’s quality has improved significantly in the last half-century, and bacterial levels have lowered to those measured in the 1920s, despite a 10-fold increase in population.1 Improvements in water quality are primarily due to improved sewage and wastewater treatment, though a better understanding of how to protect and manage our watershed have also contributed to increased health. Yet misconceptions about its health are still widespread, and this challenges our community’s connection to the watershed. We’re hoping to change the perception of our watershed through outreach and education.


Just because its brown, doesn’t mean it’s dirty.

The appearance of the North Saskatchewan River is mainly due to natural processes. In the spring, the river is a muddy-brown colour because of sediments and silts, which are washed into the river as snowmelt and rainfall increases.The colour of the water changes in early to mid-summer, when water flow is reduced and sediments settle.3 The river is particularly prone to this muddy colouration when it flows through Edmonton due to natural topography and high levels of erosion.

Today, a few sources of pollution do threaten our water, primarily in the form of discharge from storm sewer outfalls and combined sewer overflows (CSOs). Urban and agricultural runoff deposit heavy metals, nutrients, and other contaminants into our waters. However, these only pose a threat to human health during heavy rainfall and snowmelt.

Discharges into the river continue to be reduced, and stormwater is being better treated. There is also a trend towards wastewater reuse. All of these are contributing to increasing health of our watershed.4


Our river wasn’t always clean, and that’s a big reason we think it’s dirty today.

Standing in the river valley today, you wouldn’t know that this beautiful urban escape was once a dumping ground for toxic industrial waste. But it was: in the early 20th century, downtown Edmonton was a booming industrial landscape, and the river valley was populated with coalmines, brickyards, garbage dumps, and slaughterhouses.The North Saskatchewan River was a natural effluent for all of these. On top of this, logging operations used the river as a float for log booms, and dredging equipment cluttered the river. Combined with untreated human waste that was routinely discharged into the river, the North Saskatchewan endangered those who dared to drink or come into contact with it with real threat of disease and infection. 3

In the early 1950s, an assessment of the water was done and results were chilling: by the time the river reached the Saskatchewan border, there was no dissolved oxygen left, and no life could be found in the river. These findings were pivotal to our understanding of the watershed – and we began to take steps to protect and manage our watershed.4


Today, the North Saskatchewan River is (mostly) clean and safe to swim in.

But there’s always more we can do, and we need to continue to protect and maintain our watershed to ensure it stays that way.



  1. Bunner, Paul. (October 23, 2014). I swam in the North Saskatchewan River and lived to tell this tale. Retrieved from: http://www.rivervalley.ab.ca/2014/swam-north-saskatchewan-lived-tell-tale/.
  2. City of Edmonton. (2015). North Saskatchewan River – Water Quality. Retrieved from: http://www.edmonton.ca/city_government/environmental_stewardship/north-saskatchewan-river-water-quality.aspx.
  3. Marcellin, Josh. (May 2015). River Valley Alliance.The North Saskatchewan River has killer angling right in Edmonton. Vue Weekly.Retrieved from http://www.vueweekly.com/the-north-saskatchewan-river-has-killer-angling-right-in-edmonton/.


WWF assessed half of Canada’s watersheds, and the results are pretty much what you’d expect.

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This month, WWF released the first half of a Canada-wide assessment of our 25 most prominent watersheds. The assessment focused on four indicators of watershed health and seven key threats. Measures of health included hydrology, water quality, fish, and benthic macro-invertebrate communities. The seven key threats assessed were pollution, climate change, alteration of water flows, invasive species, water use, fragmentation, and habitat loss.


How did our watershed do?


The North Saskatchewan River watershed ranged in overall threat level from moderate to very high. You can see the data for our watershed here.


Edmonton and area received a rating of “high.” The biggest threats to our watershed were pollution and fragmentation, which were assessed at “very high”; this was closely followed by habitat loss. Climate change posed a moderate risk, while overuse of water and invasive species were listed as low risk.


The main source of pollution to our watershed is agricultural runoff. Fragmentation was largely driven by roads and rail infrastructure as well as dams.


What’s threatened in our watershed?


More than 1.2 million people live within our watershed, the majority of which are located in the greater Edmonton area. We share this important habitat with moose, elk, woodland caribou, and the endangered burrowing owl. Our river contains 27 native fish species, including massive Lake Sturgeon, a species dating back to prehistoric times that is increasingly being threatened by urban development and expansion.


How was health assessed?

This section is meant to summarize the health indicators used in the WWF assessment. You can find WWF’s detailed methodology here.



Hydrology accounts for changes in a river’s flow, or the amount of alteration from its natural flow regime. WWF’s assessment measured trends in monthly and annual flows over time.


If large dams (ie. greater than 10m in height) were present, hydrology was assessed between pre- and post-dam conditions. If no large dams were present, the test was completed comparing monthly flow with a benchmark or related historical time period.


Water Quality

Water quality is often monitored for its consequences to aquatic life and relevance for humans, primarily for drinking water and recreation. The assessment focused on chemical components rather than biological (eg. E. coli or other bacteria, viruses and protozoa). This section focused on aquatic life, though future iterations may focus on other indicators more related to or specifically related to human health and wellbeing.



Fish are an important part of aquatic health. Not only are they integral in aquatic food webs, but also are of high commercial and recreational value to humans.


Fish – and all life – can be assessed at different levels. For example, species richness can be assessed coarsely, where it provides a snapshot of overall health; species abundance can be studied to show population-level health; and size and weight can be measured for individual analysis. Most publicly availably data is based on species presence or absence or focused on individual species of commercial or recreational value.


Benthic Macrocommunity

WWF used the Hilsenhoff Biotic Index (HBI) to determine the health of benthic macro invertebrate communities. The HBI accounts for sensitivity of benthic invertebrates to disturbance and indicates degree of disturbance of the sampling location (based on their relative abundance in the sample).


WWF aims to have the assessment complete by our country’s 150th birthday in 2017. To learn more about the assessment and see how your watershed is doing, visit the site here.