The province of Saskatchewan is located in west central Canada. It covers an area of 651,900 sq km. By comparison Texas is 692,244 sq km and Great Britain is 244,820 sq km. The northern third of the province is generally covered with boreal conifer forests. Lakes and rivers are abundant in this region. The remaining area is parkland and prairie which is now mostly under culivation for crops. In the southwest corner of the province are the Cypress Hills, which is the highest point, 1,392 m, in Canada East of the Rocky Mountains.
The population of the province hovers around 1,000,000 or about 1.6 persons per sq km. Contrast this with Great Britain which has a population of 59,778,000 or 244 people per sq km. Most of the population lives in the southern portion of the province. Almost half live in the two major centers, Saskatoon and Regina (the capital). The economy is agriculture based. But natural resources (potash, gold, uranium, oil, natural gas) are becoming increasingly important to the economy (Fung et al 1999).
Below is a very brief summary of the major features that influence the type of aquatic habitats in Saskatchewan and the aquatic macroinvertebrates that inhabit them. A more detailed account of these topics can be obtained from the Atlas of Saskatchewan (Fung et al 1999).
Generally there are three regions present in SK. The Precambrian shield is the remnants of mountains eroded down over eons of time. The material resulting from this erosion forms the Athabasca Sandstone. The last glaciation scoured the northern part of the province to the bedrock and the melting glaciers deposited the eroded material onto the southern plains. Most of the surface water of the province is found in lakes, rivers, streams and peatlands of the shield. The underlying geological features affect the productivity of the aquatic habitats. Shield lakes and rivers are generally nutrient poor while the lakes and rivers of the plains are usually nutrient rich.
The climate of SK is generally subarctic in the north and north central areas and continental in the remainder. The annual mean temperature in the northern areas is -6 C. Along the southern border it is +4 C. Temperature extremes of -57 C at Prince Albert and +45 C at Yellow Grass have been reported. Saskatchewantonians take pride in being able to survive such weather extremes!! Northern regions receive about 514 mm of precipitation annually. The drier south receives about 300 mm. Most of the precipitation normally falls during Jun to Sep. SK is sunny. Most of the province receives over 2000 hours a year on average. The highest amount of sunshine was recorded at Estevan with 2701 hours in 1980. "Average" and "normal" are fleeting terms in describing SK weather. Periods of atypically dry, cold, wet or hot conditions can occur regularly during any season or over a number of years.
Saskatchewan Biological Zones and Drainage Basins
In the northeastern corner of the province is the Subarctic Woodlands region. It is the transition zone between the boreal forest and tundra. Permafrost is common. The eastern portion drains to Hudson Bay and the western to the Arctic Ocean.
About half of Saskatchewan is covered by boreal forests. The Northern Boreal Forest is dominated by conifers such as black spruce, Jack pine and tamarack. Basins of bedrock contain interconnected lakes, rivers, peat bogs, and fens. The Southern Boreal Forest has an increased appearance of broad-leaved trees and richer soils. Aquatic habitats are similar to Northern Boreal Forest but usually more productive. The eastern half of the Northern Boreal Forest flows to Hudson Bay while the western portion flows to the Arctic Ocean. Most of the Southern Boreal Forest waters flow to Hudson Bay but the extreme northwest portion flows to the Arctic Ocean.
The Aspen Parkland is a transition between the Southern Boreal Forest and Grasslands. In Saskatchewan it is dominated by trembling aspen interspersed with areas of grasslands. Abruptly rolling terrain of glacial moraines etc have resulted in many small wetlands of varying permanencies. The waters of this zone flow to Hudson Bay.
The Grasslands and Prairies are south of the Aspen Parkland. Generally this zone becomes drier toward the south and southwest. Aquatic habitats are sparse. Large slow-moving rivers and saline lakes occur. What rivers and streams that are present in this area flow to Hudson Bay except for a thin strip along the southern border of the province that eventually reach the Gulf of Mexico.
The Cypress Hills are a series of hills in the southwest of SK. These hills were apparently not glaciated during the ice age and acted to some extent as glacial refugia. The flora and fauna of this area has many affinities to the foothills and Rocky Mountains to the west. It is the only area where lodge pole pine is found in SK. Many aquatic insects of the streams, springs and lakes appear to be disjunct populations of the western mountains. Streams and rivers in the northern part of the hills flow to Hudson Bay while the southern part flow to the Gulf of Mexico.
There are also internal drainages around some of the larger saline lakes such as the Quill Lakes, Manitou Lake and Waldsea Lake.
Saskatchewan Aquatic Habitats
About 1/8 of the province is covered by water. Lentic habitats range from the large northern lakes such as Lake Athabasca to mid-sized lakes like Candle Lake and Turtle Lake in the central region. Throughout the northern half of the province are many bogs in shallow, poorly drained basins. In the prairie/parkland region smaller lakes, ponds (sloughs) and wetlands of varying permanencies are common. This area of Saskatchewan is one of the most important nesting zones for waterfowl species in North America. Saline lakes also occur in the prairie region along with smaller "alkaline sloughs". There are a wide variety of tiny habitats such as rock pools, tree holes and even pitcher plants, that are utilized by aquatic insects and other macroinvertebrates.
Two major river systems, the Churchill and the South and North Saskatchewan,flow from Alberta through Saskatchewan into Manitoba and ultimately into Hudson Bay. The majority of the water in these rivers comes from Alberta (98% for the South Saskatchewan River). The North and South Saskatchewan Rivers have their ultimate sources in the Rocky Mountains and the Churchill drains the northern plains of Alberta.
Smaller rivers and streams are common in the shield region and transition zone but are less abundant in the drier southern plains. Many of the major rivers in the prairies flow through large spillways created as the glaciers of the last ice age melted. On hill sides tiny springs and seeps emerge if conditions are right. Along the Qu'Applle River basin the land formations in localized areas are conducive for springs to develop fens (Crooked Lake Fen) along the sides of the valley which are an uncommon features for this area of the province
A number of aquatic habitats in Saskatchewan are man made. Damming of the South Saskatchewan River created Lake Diefenbaker. Two dams on the Saskatchewan River have formed Codette Lake and Tobin Lake. Many smaller rivers and water bodies are either dammed and/or have canal systems or water diverted to them ie Blackstrap Lake. Countless ditches and borrow pits, the result of the provincial grid road and highway system, have created pond-like habitats throughout Saskatchewan. Farm "dugouts'" have been dug to water livestock which provide deep pond habitats for many aquatic macroinvertebrates. Urban parks, golf courses and backyards often have water features as part of their designs. Even eave troughs, bird baths, water troughs, pails, old tires, discarded cups and other litter can provide sufficient water for aquatic macroinvertebrates to colonize and successfully complete their life cycles.
Saskatchewan Aquatic Habitats: Environmental Concerns
In Saskatchewan, especially the southern regions, consistent sources of surface water can be rare, particularly during years of drought. As a result dams were built on many rivers to establish more reliable supplies for human consumption, crop irrigation and to generate electricity. These dams create artificial reservoirs immediately upstream of the dam and change natural flow patterns, water thermal regimes and sediment loads that significantly alter the aquatic community for long distances downstream. Many dams in the province have also been built to regulate lake outflows to abnormally maintain lake levels at consistent levels for recreational purposes.
The North Saskatchewan River is regulated in Alberta by two hydroelectric dams, the Brazeau and Bighorn, in Alberta. All the major tributaries (Bow, Oldman and Red Deer Rivers) of the South Saskatchewan River are regulated by dams in Alberta. Once the South Saskatchewan River flows into the province it is regulated by the hydroelectric Gardiner Dam (completed in 1967). This dam, with the Qu'Appelle Valley Dam creates a 225 km long reservoir, Lake Diefenbaker, that is used for recreation and irrigation. Some of the water from Lake Diefenbaker is diverted into Buffalo Pound Lake and subsequently down the Qu'Appelle River. This diversion also provides the major urban centers of the south with a sustained water supply. After the two branches of the Saskatchewan River meet the Francios-Finlay Dam (completed in 1986) and the E.B. Campbell Dam (completed in 1963) create Codette Lake and Tobin Lake reserviors respectively.
The Saskatchewan River system passes through extensive tracts of agricultural land that are used to grow crops with the aid of chemical fertilizers and pesticides. Intensive cattle feedlots and hog farms are increasing in numbers within the watershed of the rivers. And, a number of urban centers are located on the banks of the rivers. Contaminated runoff from these watershed uses can potentially have deleterious effects on the water quality of the rivers that in turn impact the aquatic organisms.
The parkland and prairie region of Saskatchewan is dotted by millions of shallow depressions, which fill with water for varying periods of time each year. This region of Saskatchewan is also intensively cropped. As a result the vast majority of these ponds have been drained and the surrounding natural emergent vegetation burned to increase agricultural production and make it more efficient for modern, large farm machinery to work the land. The ponds that have not been destroyed are threatened with contamination by agricultural fertilizers and pesticides. In many areas the surviving ponds are now islands of natural, albeit altered, refuges for aquatic organisms in a vast expanse of cropland.
The urban sprawl of larger centers has also "consumed" many wetland habitats as well as highly valued agricultural lands. Near these same urban areas acreage developments have also begun to impact ponds by "improving the aesthetics" of the pond to meet the developer's or owner's needs.
In northern Saskatchewan mining for gold, uranium and other resources has contaminated many lakes and rivers. The recent tar sands developments in Alberta and SK raise water concerns from direct usage and contamination as well as the production of acid rains which could severely impact the land, lakes and waterways of the boreal forest which lack the buffering capabilities to effectively neutralize the lower pH rain water. As well, clear-cut forestry practices have removed or altered the riparian zones of many streams and rivers in the boreal forests of the province.
Potash mine development in the southern parts of the province has salinated many lakes and the land around them. Proposed mine expansions and new mines, ie the Vale request to pump water from Katepwa Lake in the Qu'Appelle Valley, will further increase the degradation and threats to the province's water resources.
Excessive cabin and resort development and other recreational usage around many lakes have started to damage and alter the very lakes the people want to enjoy.
Global climate change will likely seriously impact the aquatic habitats within Saskatchewan. What these changes will be and how rapidly they will occur is unknown.
Fung, K., B. Barry and M. Wilson. Editors. 1999. Atlas of Saskatchewan. University of Saskatchewan, Saskatoon, SK. 336 pp.