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Category Archives: Riverine Health

Canada’s Freshwater in the 21st Century, 2014, Dr. David Schindler

Freshwater is widely recognized as the most pressing environmental issue of the coming century, as roughly 2 billion humans suffer from scarcity of water for drinking or sanitation. Despite its abundance of freshwater, Canada is experiencing great pressure on both its quality and quantity. Despite impending problems, the Canadian government is de-emphasizing freshwater research, both in its funding for university research and its support for federal departments with a freshwater mandate. This lecture describe some of the current threats to Canadian water, and outlines what we must do to solve them.
This is an excellent presentation and it is beneficial to listen to it all; however, if you have specific interest in hydroelectric or pipelines:
Hydroelectric: go to 34:56
Pipelines and the tar sands:  go to 50:00

June 18, 2014 — Water Institute Lecture Series and Faculty of Science Public Lecture Series
Dr. David W. Schindler, Killam Memorial Professor of Ecology, University of Alberta, retired.

Jellification of our Lakes a Troubling Sign

Studies by Jon Smol and colleagues at Queens University on lakes in Nova Scotia and Ontario reveal a very worrisome trend – a change in the phytoplankton species associated with declining calcium levels. “Without calcium entering the lakes in run-off, some crustaceans at the base of the aquatic food chain, which make their exoskeletons from the mineral, are at a disadvantage, and they’re being displaced by species that have an jelly-like coating. These jelly-organisms are inedible to many predators, and disruptive to the lakes’ ecological balance.” (CBC report). Acid rain combined with inherently poorly buffered soils, especially in SW Nova Scotia, is the major driver; clearcutting is also cited as a factor. View references on our Water Quality Page.

More information:

The Jellification of North Temperate Lakes, Study by Smol et al.

Queen’s University – Paleoecological Environmental Assessment and Research Laboratory (PEARL) – Lakes Turning to Jelly?

‘Jellification’ in Muskoka, Haliburton may affect fish, by Kate Allen, The Star

Principles of Riverine Health, by Frederick Schueler

One of the triumphs of the 2014 Ontario Rivers Alliance (ORA)  Annual General Meeting was the realization that, while the fight against the misguided Feed in Tariff (FIT) meso-scale hydro projects was an ongoing struggle, we could see light at the end of the tunnel.  We needed to begin to implement a broader consideration of the health of rivers that we’re mandated to address, perhaps working towards a publication on criteria of health for Ontario rivers.

Googling riverine health brings up two sets of criteria. These either suggest that “minimally altered watersheds are intrinsically healthy, because their key process regimes are, by definition, within the natural range of variation,”[1] or they tend to emphasize the services the “healthy” stream can provide to human observers or exploiters.

Ever since I had my mind blown by the density of ideas in Valerius Geist’s classic Life strategies, human evolution, environmental design: toward a biological theory of health,[2] I’ve valued his definition of organic health as phenotypic development that maximizes the expression of the characteristics that distinguish a species from its relatives (in the case of humanity including large brain, high capacity for exercise due to evaporative cooling, manual & bodily dexterity, highly developed intellect & language, music, tool manufacture & use, dance, visual mimicry, role playing, altruism, humor, self-control, complex traditions, and long life span).

If we import Geist’s biological criterion into the “health” of rivers, it’s clear that  what makes them different from other habitats is that they are lentic (flowing) rather than lotic (standing). This means that what we’re looking for in a healthy stream is expressions of the consequences of water moving downstream. On this basis, I’ve come up with a 3-point conceptualization. The first two points are consequences of the flow itself, and the third is about differentiation among rivers:

1) Continuity (channel, flow regimes, migration, long-lived species) – The connectedness of rivers can be broken in either time or space. In its early years ORA has mostly been defending continuity, since dams break dispersal and flow in diverse ways (and by creating impoundments, reduce the difference between the river and standing water). Lakes, the alternative kind of water, are geologically temporary, since they fill in with sediment or drain when their sills are eroded down, but as long as rain falls, rivers will flow, and almost always in the channels that they have flowed in before. All our lakes date from the recent retreat of the Ice, but at least north to the Arctic Watershed, Ontario rivers are geologically confluent with streams which have been flowing south across North America since the Paleozoic. Another aspect of healthy continuity – or indication that continuity has been preserved – is long-lived stream creatures with complex life histories, such as Unionid mussels, Sturgeon, Eels, Turtles, and Mudpuppies.

2) Oligotrophy (net watershed ombrotrophy, filter-feeding, wetlands) –  One of the primary goals of conventional river conservation has been preventing organic and nutrient pollution, whether from point sources or through runoff or groundwater. The reason such nutrient loading is unnatural is that mature  terrestrial plant communities characteristically strip most of the mineral nutrients out of the water they process, so the biota of a river is adapted to water that has a lower concentration of nutrients than precipitation – what I’ve called ‘net ombrotrophy.’[3] Another consequence of flow is that there’s minimal nutrient recycling in any particular reach of a river – photosynthetic production and filter-feeding both depend on extracting nutrients from the thin broth that’s flowing downstream, and anything that gets up into the current is lost downstream unless it’s moved back upstream in the body of some current-breasting creature.

3) Endemicity (biogeographic integrity, biodiversity, native rather than alien species) – Because they flow for so long in constrained channels, which many of their creatures either can’t or won’t leave, rivers and streams provide venues for evolutionary adaptation to local conditions. South of the limits of glaciation the number of species of locally endemic fish, Unionid mussels, Crayfish, and Salamanders is astonishing.  In Ontario we don’t have species-level differentiation, but we do have different faunas dependent on how species colonized through post-glacial lakes, and every local population is specially adapted to its situation, and every twist and reach of a stream has its own community. Maintaining the distinctiveness of a river means working to prevent extinction of local populations, and avoiding the introduction of alien species that will make all invaded streams more similar to each other.

All of this converges on the conventional idea that “minimally altered watersheds are intrinsically healthy, because their key process regimes are, by definition, within the natural range of variation,” and the resulting idea that a measure of “health” would “appropriately be based on the extent to which watershed process regimes are modified relative to the baseline, or their natural ranges of variation,”[4] but I think it helps to think about riverine health in these three categories, just as we conventionally think of human health as being determined by the physical conditions of life, social environment, and exposure to pathogenic organisms.

So the lesson for river lovers is to rejoice in whatever you’ve got, but when there’s a chance, move towards a healthier state. This is just a first sketch of  these ideas: if this approach and these points stand up to scrutiny we’ll need to expound them and find ways to make nontechnical readers comfortable enough with the language that they can assimilate the meaning of the points and apply them in practical conservation.

You can contact Fred at


[1]    Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency. 2011. Healthy Watersheds Integrated Assessments Workshop Synthesis. contribution AED-11-051, December 2011, 81 pp.\zyfiles\Index%20Data\11thru15\Txt\00000003\P100DXBV.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=p|f&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1&SeekPage=x&ZyPURL
[2]   1978, New York, Springer-Verlag, 495 pp
[3]   Schueler, Frederick W. 1989. Feeding from the clouds: Net ombrotrophy as a measure of the health of landscapes. Trail & Landscape 23(3):122-125 –
[4]   link to the same document as #1

Anecdotes of Winter Rivers devoid of Oxygen, by Frederick Schueler

In 1982 I taught freshwater ecology for a sabbaticalling professor at the University of Ottawa (U of O). Having collected frogs all across Canada, I thought I was perfectly qualified, but at the U of O freshwater ecology was  limnology, a deepwater sport, more akin to oceanography than it was to dipnetting frogs from roadside ditches. I stayed about a week ahead of the students in Robert G. Wetzel’s Limnology,[1] which was a great textbook, but with a significant tadpole in its lemonade: Wetzel affirmed that, under their ice cover, streams remained well oxygenated through the winter.

The problem with this was that in the winter before I’d been studying Leopard Frogs hibernating in Kemptville Creek, cutting holes in the ice and setting nets in the current to catch frogs and fish that were swept downstream. It had turned out that thousands of  fish and frogs had died, and in the winter of 1982-83 I borrowed an oxygen meter from the course to confirm that it was the lack of oxygen in the water which was killing them.

It was easy to reason that this anoxia occurred when solid ice kept the air from the water. It was also easy to infer that the difference between Kemptville Creek, with a gradient of 14 cm per kilometre, and New York and Wisconsin, where most of Wetzel’s material seemed to be sourced, was that the topographic relief in those hilly States allowed their babbling brooks more access to the air  than our Beaver-flattened creek obtained under 40 cm of ice liberally buried in snow. In the years since we’ve had various confirmations that in areas of low topographic relief, and increasingly to the north where winters are longer, anoxia, and the resulting deaths of gill- or skin-breathing animals, is widespread.

Throughout the winter, Mudpuppy Night in Oxford Mills is our weekly visit to Kemptville Creek below the dam at Oxford Mills.[2]  In some winters we experience the organic and hydrogen sulphide “cat farts” odor of anoxia, when murky brown oxygen-depleted water comes over the spillways, obliging the Mudpuppies to retreat into the rocky creek downstream, where the water has picked up some oxygen. There are no Mudpuppies above the dam.

In the polar-vortex winter of 2013-14, episodes of anoxia began in December, causing a kill of frogs below the dam that were seen to be eaten by Mudpuppies in the following weeks. Large numbers of ‘puppies were seen until the high water of a mid-January thaw, then through February, and into March, the oxygen was on and off, with many nights when no Mudpuppies were seen.

While anoxia was just an inconvenience to Mudpuppies, when spring finally came the usual mass movements of Leopard Frogs across the roads from hibernating to breeding sites above the dam just did not occur. We went out again and again without seeing any frogs on the road and heard no Leopard Frog choruses. Through the later spring there was not much calling by other aquatic-hibernating frogs, and through the summer very few frogs of water-hibernating species were on the roads, leaving us to conclude that there had been massive winter mortality along with, or caused by, the anoxia.

The classic cause of anoxia is organic pollution from sewage. Oxygenation is regarded as “good water quality,” and the conventional conservationist’s role is to prevent  it. Winter anoxia happens while academics are in their classrooms, government employees are in their offices, and the water is under ice, making it harder to study than something that happens in the summer. Natural anoxia is an important factor in understanding our rivers: it will often determine which species live in low-gradient rivers, amplify the biological breaks caused by dams, and cause wide swings in abundance of species depending on the character of winters.

How can you tell if and when your stream is anoxic? There’s the ‘cat farts’ smell – an organic enhancement of whiffs of the hydrogen sulphide released by reducing conditions – the water is often cloudy with humic acids that have been loosened by the change in water chemistry, and dead animals, such as frogs and fish, are a good sign that anoxia has occurred. Meters for measuring oxygen directly are cheaper every year, and can sometimes be borrowed from office-bound institutions which wouldn’t be using them during the winter.

One of the precautionary strategies of river conservation is to know things that will make a potential exploiter’s job more difficult, and “episodes of hibernal  anoxia” is one of these, because many disturbances can be surmised to enhance it, and the proponent of exploitation is unlikely to have a glib reply. To really assess “the effects of  [a potential disturbance] on patterns of occurrence of hibernal anoxia,” a proponent would need to spend several winters measuring under-ice oxygen levels, and by that time the political climate might have changed, or the proponent might have run out of money.

Contact Fred Schueler at


[1]    Wetzel, Robert G. 1975. Limnology. 743 pp. Thomson Learning & W.B. Saunders (Philadelphia, London, Toronto).
[2] – this page includes links to field notes from all Mudpuppy Nights