Biodiversity Canada Sask.
Biodiversity 2
Living Fossil??
Identification, Taxonomy papers
Environmental Laws, Canada
Species of Concern
Oldman Dam Alberta
Alberta Update 2010
Saskatchewan Update
Saskatchewan River
Saskatchewan River Detail Descriptive
Background Concepts of River Ecology
 Communities, species, origins, distribution
 Rare and Endangered Accounts
Additional species of interest
Current status and conditions
Mystery of St. Louis 06
The River at Saskatoon
Lemsford Ferry
Communities Natural and Altered River
Dams,Research Thermal
 Research Nutrients and Eutrophication
Blackfly Research
undisturbed sites, a comparison
Aquatic Insects
Oregon Winter Ponds
Oregon Rivers Intro
Willamette River
Columbia River
Missouri River
China Yangtze River
Arctic Canada, Rankin
MacKenzie River Canada
Fish- Rivers
Teaching Materials

Recent developments have made it necessary for me to make the following statement:  -Copyright is claimed to  all unpublished data, information, and images.  Not for commercial or related use.    Use without permission and proper credit is restricted  to personal  and limited student use. Thank you.

Summary-  (See Map on Home)  The South Saskatchewan River is quite normal at Lemsford Ferry, at the Alberta border.  Diefenbaker Lake  destroys the river by converting it into a lake from Outlook to a position north of Swift Current, Sask.  Cool hypolimnion waters destroy the river community from the Gardiner Dam outlet at Outlook as far as Saskatoon, where sewage and industrial output have, and continue to alter the river downstream from Saskatoon, with plant growths and community changes visible all the way to the Confluence with the North Saskatchewan River.  A new dam (plus many weirs) are  proposed and will probably be built soon at the Confluence and other places, thus, if done,  completing the destruction of aquatic communities in the South Saskatchewan River.  Large dams have been constructed upstream and downstream from Nipawin, on the Main Sask. River.   Thus, almost all ot the S. Sask. River plus the Main River past the confluence have  been altered or completely destroyed.  The North Saskatchewan River upstream from the Confluence and Prince Albert are apparently little altered by human activity, having relatively small amounts of city sewage, and a now non-operating pulp mill.

The following pages give many details on the above.  We have samples from spring to fall at 10 stations taken in 2006, plus about 40 years of data, studies, and reports on the river-  these are too voluminous to record here in complete form.

Click here for a  pdf  which gives a quick overview of the Saskatchewan River, some environmental problems, and the unique mayfly fauna. See discussion and comments at the bottom of this page for some context regarding this presentation.

See also the River at Saskatoon, See Table 1 for the effect of Gardiner Dam- zero insects at the outlet of the dam.

See also Communities Natural and Altered

click here for a discussion and description of some specialized habitats and  more on the unusual species found there.

Click here for Rare and Endangered Species Accounts


The Government of Canada and the Saskatchwan government spend many hundreds of thousands of dollars and employ dozens of Ph. D. scientists and consultants regarding rivers such as the Saskatchewan and other river systems.  I find that these studies are almost always lacking in detail regarding identifications, and are limited regarding sampling methods.   Websites often stress bureaucratic structure and popular objectives but have no scientific content.   These shortcomings, combined with environmental laws, mean that biodiversity and ecological structure and function of the rivers are poorly known (e.g., species -not Genera or Families, in relation to  RCC).  As a result the rivers are not well protected because they are more or less unknown as ecological systems (see MacKenzie for example, or Google the Old Man River, which forms the Saskatchewan) and try to find information on species level biodiversity -or rare and endangered species, -or RCC structure, etc).  



Here I am standing in the South Saskatchewan River at Lemsford Ferry, where the river flows through a treeless and arid prairie.  Here, near the Alberta/Saskatchewan border, the river  is wide and in some places shallow enough to wade to mid-river, but deep channels as well as a number of other habitat types are are almost always present.

A couple hundred miles to the northeast of Lemsford Ferry, this is LaColle Falls, on the North Saskatchewan River, east of Prince Albert, where there is an unfinished dam from many years ago (above).  In this area the Boreal Forest, of White Spruce, Black Spruce, and Jack Pine extends for hundreds of miles to the north, east and west.  The prairies and grasslands are a few miles to  the south, and extensive areas of aspen parkland are present as a transition between the Boreal Forest and the grasslands.


            The Saskatchewan River System considered here has characteristics that are strikingly different when compared with nearby drainages such as the Missouri to the south.  The Missouri system is known as the “Big Muddy” for obvious reasons, while the Saskatchewan system, by comparison, has relatively clear water with a low load of suspended clays and mud,  and  it has clean substrates of boulders, rubble, sand, branches, and roots.  Each of these habitats has unique and specialized species, notably for example the sand loving mayflies Ametropus and Pseudiron.

       Biomass of aquatic insects in the prairie rivers such as the Saskatchewan system is usually very high.  During blackfly control studies, I  found that as a result of treatment with methoxychlor in the 1980’s, the entire insect community was killed or displaced for up to 150 km from the point of injection (Cecil Ferry near Prince Albert  to Nipawin, Sask.).  Samples from the benthos after treatment yielded no insects, but in drift nets facing upstream with an opening of 50 cm by 50 cm, a solid liter  of packed  larvae of dozens of species would be collected each two hour period, for many hours (Lehmkuhl 1981).  The drifting  larvae after treatment were evenly distributed the width and depth of the river, and it can be calculated that the biomass moving downstream in the form of dead and dying insects over a period of nearly 12 hours was huge.  Surprisingly, each spring, recovery of biodiversity seemed to be almost complete (based on comparison with upstream controls), probably from recolonization from upstream (Lehmkuhl 1981), and recovery was  also remarkable in the several week time periods between treatments (usually 4 per summer)  presumably also from drift from upstream, plus hatching of new larvae.


      Research drift nets in the river.

 Large areas of the river system are affected by dams and sewage (Lehmkuhl 1970. 1972, Mason 1983)   and biodiversity and aquatic communities are totally destroyed in many areas (Lehmkuhl 2001).  However, some areas have a very diverse fauna that may be near the original conditions (Lehmkuhl 1979,1980).  Laws to protect rare species and flowing water environments are very weak (Boyd 2003).

Our summary and conclusions are that the river at Saskatoon shows many signs of pollution and ecological stress.  It has about 50-60 % of the diversity found in the normal river.  The river at Saskatoon is characterized by the lack of many unique species such as those found at Lemsford Ferry; it is characterized by pollution tolerant groups such as Oligochaetae and Chironomidae; it is also characterized by  pollution tolerant species of mayflies such as Baetis tricaudatus, and  stress-indicating caddisflies, namely members of the Hydropsychidae.   The water and substrates at Clarkboro Ferry are very unpleasant esthetically.  Details and data to support  these conclusions are given on the link above.  See photos on the Homepage.

Collecting research drift nets in the river during blackfly control studies.

General Area of Interest

               The flowing waters considered here are mostly  the Saskatchewan portion of the  Saskatchewan River System. The whole system  forms a quadrangle about 800 km from west to east and about 500 km from north to south.  It is bounded by the Rocky Mountains in Alberta to the west, boreal forests in Manitoba to the east, Boreal forest to the north, and the arid landscape and muddy Missouri drainage  in North Dakota and Montana to the south.  Some rivers from the north in the boreal forest enter the Saskatchewan River itself, but the Boreal contributions to the prairie fauna are relatively small and the overlap in species between the two is surprisingly low.  This is probably because the ecology of Boreal streams is different from true prairie rivers, the latter of which are much affected by floods from mountain and local runoff  in the spring and mid-summer, and by weather and climate in the hot summers, in contrast to the shaded streams of the Boreal that are often more stable and  fed mainly by cool groundwater.

            Prairie flowing waters considered here also include streams in the Cypress Hills near the United States-Saskatchewan-Alberta borders, the Milk and Souris Rivers which are part of the Missouri and Red River systems.  These are all unique in their own way,  an example being the Cypress hills streams, which share species with the Black Hills of South Dakota and both have a definite unique Rocky Mountain component in the insect communities,  for example mayflies in the genera Epeorus and Ameletus.

Under Construction beyond this point, Please be patient


Add North American Map with Saskatchewan

Add Climate, Boreal, Grasslands, Cypress Hills Glaciation

Aquatic Insects

Rare and Endangered Species Accounts 

Duplicate     The diversity of aquatic insects in prairie flowing waters is very high as a result postglacial recruitment of species from as far away as the Colorado River System and Eurasia, plus the nature of waterways such  as the  Saskatchewan River, which is ecologically a large stream with clear cool water, a variety of rubble, gravel, sand, fallen branch and log habitats, along with submerged vegetation and roots.  This is in contrast to the muddy waters and mucky substrates found in many prairie rivers such as the Missouri to the south.   Over 1000 aquatic and semiaquatic species inhabit prairie  habitats,  and at least half  this number  are found in streams and rivers, where they contribute to nutrient cycles and energy flow.  Aquatic insects often represent a large biomass with great biodiversity in pristine prairie rivers, but dams, sewage, and agricultural runoff and other pollution have destroyed suitable habitat and favorable  environmental conditions  in large areas, thus eliminating natural biodiversity in large portions of prairie flowing waters.  Fortunately, some areas show minimal damage and appear to be in a near original state in terms of biological communities and water quality. 

On the other hand, laws protecting flowing waters are weak, (Boyd)  and large areas of flowing waters have not been studied in detail to gain an understanding of ecological functions or biodiversity, especially the changes in function and biodiversity from midstream regions back to the sources in the mountains in the west, and downstream changes into the deltas and lakes to the east-


THE RIVER AS A SPECIALIZED HABITAT   (see also)- background concepts of River Ecology

Some essential features

What is so special about Rivers as a biological system?  I am often asked the question of whether  rare and unusual species  in the Saskatchewan river can escape from pollution  in the Main River by inhabiting and surviving in tributary streams, or escape to adjacent Boreal Forest streams, or even to nearby ponds.  The data show that the answer is no, and there are reasons.  Samples from small entering  steams such as the Little Red River, at Prince Albert, show that river species do not inhabit  these small tributary streams. and stream species do not live in the river. This is because the river is a special habitat, different in significant physical and chemical ways from the surrounding habitats, to be discussed in detail below.Some local details are that in the case of the Saskatchewan River,  some unusual species thrive in the relatively large Battle River, but they are not in.  The Torch and other medium sized rivers should be studied more to be sure about them.  In the case of the numerous ponds in the region, overlap is almost nil (possibly some Chironomidae,incidental Trichoptera, etc.)

What are the significant Physical and Chemical  Features of Rivers in general?

Whereas small streams and ponds are unstable, dynamic, perhaps dry seasonally, and subject to solid freezing in the winter, all features that can be lethal to many species,
rivers provide a large, reliable, constant flow in at least some portion of the channel for the entire year, and this habitat is available even at times of low water or extreme cold. This water is always well oxygenated, and natural rivers are typically free of noxious gases, toxins, or stressing levels of heavy metals or other pollutants. Rivers are usually well buffered by calcium and other minerals from the surrounding soils, and are usually basic to neutral in pH (in west and central North America). River organisms are not adapted to low oxygen conditions, they are sensitive to toxins and organic pollution, and they do not experience drastic changes in water chemistry.  The river community contains many sensitive species, which can serve as very good indicators of water quality and pollution.


Click here  for a PDF  (a duplicate of the link at the top of this page)  which is a  small introduction to the Saskatchewan River.  The pdf was originally prepared as a basis for discussion in one of my University classes. I would like to point out that, on pages 21-23, there is a report published by Environment Canada, which concludes that the city of Saskatoon has little effect on the river, and that the ecological conditions in the river downstream from the city of 250,000 are quite good.  Of course, my photos and other  material, based on 40 years of experience show that there are community changes in the river, and there is much evidence of organic enrichment, and of local extinctions.  Such  differences in conclusions are common in science, and the reader is invited to draw their own conclusions.