Wetlands of the Northern Plains,
United States and Canada

Wetland Environments
James S. Aber

Table of Contents
Introduction Nebraska Sand Hills
Devils Lake, ND Palliser Triangle
Related sites References


For purposes of this overview, the northern Plains includes prairie regions of Nebraska, North and South Dakota, and Montana of the United States, as well as the Canadian Prairie region of southern Manitoba, Saskatchewan and Alberta. A tremendous variety of wetland types exists within this vast territory. Toward the east, precipitation is abundant, and wetlands are mostly perennial and fresh water. In contrast, precipitation declines westward and alkali water chemistry predominates. Western wetlands are also more subject to droughts and periodic dry conditions. Wetlands occur in three main geologic settings.

Wetlands of the northern Plains are particularly important for migrating waterfowl and shorebirds. These birds migrate annually through the region, and many utilize wetlands for summer nesting. This fact, recognized long ago by duck hunters, has given rise to many conservation efforts to maintain and expand wetland habitat conditions throughout the region. Ducks Unlimited, a private hunting and conservation organization, has played a leading role for this effort.

Nebraska Sand Hills

The Nebraska Sand Hills cover an area of ~19,300 square miles (50,000 km²) and encompass the largest area of sand dunes in North America--see Sand Hills (Keech and Bentall 1978). The dunes are largely stabilized by prairie grassland under current climatic conditions. The dunes are situated above the High Plains aquifer, which is particularly deep and receives substantial recharge in central Nebraska. Abundant ground water is evident from the myriad of lakes, wetlands, and perennial streams throughout the sand hills. The types of surface water fall into three general zones.

  1. Perennial streams -- Streams and rivers that have nearly constant flow throughout the years, eastern and southeastern portions. Examples include the North Loop, South Loop, and Dismal rivers. These streams gain their flow from ground water and are rarely subject to either drying up or flooding.

  2. Freshwater lakes -- Numerous freshwater lakes are found throughout the central and west-central portions. These lakes, like the perennial streams, are supported by ground water discharge; they rarely dry up or flood. Such lakes are especially prominent in Grant and Cherry counties, including Valentine National Wildlife Refuge.

  3. Alkali lakes -- A zone of poor surface drainage, located in the western portion in Sheridan and Garden counties, including Crescent Lake National Wildlife Refuge. These lakes depend on surface runoff of enclosed basins. Many are "playa" lakes that contain water in the spring but usually dry up during the summer (Bleed and Ginsberg 1990).

These water zones reflect the general precipitation pattern that ranges from only 40 cm per year on the western edge to more than 60 cm per year on the eastern margin (Keech and Bentall 1978). Winter snowfall and summer thunderstorms are the main forms of precipitation. Wetland conditions are associated with all three water zones. The freshwater lakes of the central Sand Hills are among the most important stopping places for migrating waterfowl and shorebirds, including ducks, geese, and pelicans. Some of these birds spend their summer nesting season in the vicinity.

Lakes in the central Sand Hills vary greatly in size. The largest may be 1½ km wide and up to 5 km long, although most are much smaller. Most are quite shallow, averaging 1 m deep, and have gently sloping floors that merge gradually with the surroundings. This gives rise to transitions in vegetation from aquatic plants, to marsh, to wet meadow, to dryland prairie (Bleed and Ginsberg 1990). Small changes in lake levels result in large changes in lake areas with consequences for adjacent wetlands.

Duck Lake, a typical interdune lake in the Valentine National Wildlife Refuge, south of Valentine, Nebraska. Note the woody vegetation surrounding the lake. Photo date 6/97, © J.S. Aber
Muskrat lodge in Pelican Lake, Valentine National Wildlife Refuge, south of Valentine, Nebraska. Photo date 6/97, © J.S. Aber
Emergent marsh vegetation around the edge of Pelican Lake, Valentine National Wildlife Refuge, south of Valentine, Nebraska. Photo date 6/97, © J.S. Aber

Lake waters of the Sand Hills tend to be alkaline with high pH, although water chemistry is highly variable. Strong wind and wave action are able to stir up bottom sediment, so lakes are often quite turbid. These conditions limit fish populations. However, diverse phytoplanktons and zooplanktons thrive in this environment and contribute to deep organic muck sediment found on the floors of most low alkalinity lakes in the Sand Hills. In lakes with low alkalinity, submerged vegetation includes pondweed, waterweed, and aquatic buttercups. Emergent vegetation consists of common reed, cattails, arrowhead and bulrushes (Bleed and Ginsberg 1990). Wild rice was quite common in the 1800s, but is now scarce.

In the alkali lake region, water chemistry is dominated by potassium, sodium, calcium, magnesium and bicarbonate. Concentrations as high as 90,000 mg/L have been measured (Bleed and Ginsberg 1990). When the lakes dry up, marl (calcium carbonate) and salt (magnesium carbonate) are deposited. In these lakes, invertebrate organisms include large populations of brine shrimp, brine flies, and rotifers. These invertebrates attract large flocks of avocets and phalaropes, which stop to feed during their autumn migration.

Devils Lake, North Dakota

Devils Lake is a series of connected lakes that occupy a complex of large, glacially eroded basins in northeastern North Dakota. The lakes are the terminal point in a large enclosed drainage basin that usually has no surface outlet. As a consequence of climatic cycles, Devils Lake is subject to large changes in water depth, surface area and volume with consequence fluctations in water chemistry (salinity), biomass, and species diversity. During the past four millennia, Devils Lake has completely dried up at times, and has sometimes filled up and overflowed into either the Sheyenne River and/or Stump Lake basin to the east (Bluemle 1996).

Map and introduction to Devils Lake basin.
Historical record for Devils Lake water levels.

View from the top of Sullys Hill looking northwestward over the main bay of Devils Lake. West Bay is visible on the left horizon. Photo date 5/93, © J.S. Aber
Algal mat on shallow water of West Bay, Devils Lake. Algal blooms and mats are common in shallow portions of Devils Lake during late summer and early autumn, when water temperature is highest. Photo date 6/92, © J.S. Aber
Birds feeding on barely submerged mudflats, West Bay, Devils Lake. Photo date 6/92, © J.S. Aber
Shallow lake/marsh complex near Knox, North Dakota with glacial landscape in the background. Photo date 5/93, © J.S. Aber

According to established records, the maximum historical lake level was attained in the early 1800s, when it exceeded 1440 feet (439 m) elevation (Bluemle 1995), toward the end of the Little Ice Age. Between 1826 and 1830, the lake probably overflowed into Stump Lake, and it possibly may have overflowed to the Sheyenne River during part of this time. After the 1860s, lake level declined until 1940, when it fell to its lowest historical elevation of 1400 feet (427 m), at which time the lake was only 1 m deep. The lake subsequently rose and exceeded 1425 feet (434½ m) during most of the 1980s. Between 1973 and 1988, Devils Lake rose by 3 m (10 feet), and its surface area expanded from about 120 km² to >180 km², an increase of more than 50% (Aber et al. 1997).

Rising lake level during the 1980s led to abandonment of the county road at Ziebach Pass. A small boat enters the main bay of Devils Lake from West Bay in the background. Photo date 8/91, © J.S. Aber

In the early 1990s, lake level fell again in response to drought. However, since 1993, Devils Lake has risen dramatically as a result of increased winter snowfall and spring runoff. Flooding of low-lying land around the lake has created serious economic hardships for residents and landowners. Since 2001, Devils Lake has overflowed into Stump Lake, another internal drainage basin to the east. Devils Lake demonstrates the natural history of northern Plains lakes and wetlands, which cycle between dry and overflowing conditions during time periods of decades, centuries and millennia.

Landsat MSS false-color composite of Devils Lake vicinity, ND, 14 May, 1973. This spring scene shows Devils Lake at a low-water stage that existed during the early 1970s. West Bay is a marshy wetland, and East Bay is much reduced in area and depth. Compare with next image. Image taken from Aber et al. (1997).
Landsat MSS false-color composite of Devils Lake vicinity, ND, 23 Sept. 1988. This autumn scene depicts active vegetation in red and pink; Sullys Hill is covered by deciduous forest. Note suspended sediment in West Bay portion of Devils Lake, and many smaller lakes throughout the scene. This image shows Devils Lake at a high-water stage that existed during the mid-1980s. Image taken from Aber et al. (1997).
Landsat TM false-color composite of Devils Lake vicinity, ND, Sept. 8, 2000. This image shows Devils Lake at its highest stage, when water overflows into Stump Lake (to east). Note the tremendous expansion of the West and East Bays as well as a continuous connection to East Devils Lake (EDL). Landsat TM bands 2, 5, 7 color coded as blue, green and red.

East Devils Lake in flood stage, connected with Devils Lake to the west and overflowing eastward to Stump Lake. Road had been raised to connect with farm in the background. Trees on old shore drowned by high water. Views toward north (left) and northwest (right). Blimp aerial photos, Oct. 2003.

Palliser Triangle, Canada

The Palliser Triangle is a semiarid region that is the driest portion of Canada. It is located in southwestern Saskatchewan and southeastern Alberta. This region is characterized by brown soils, temperature extremes, and a water deficit; yet, it is agriculturally one of the most important regions in Canada for production of grain crops. The combination of dry climate and recent glaciation results in poorly integrated drainage with few streams and many internal drainage basins (Sauchyn 1997). Similar conditions exist across the border in adjacent portions of North Dakota and Montana.

Location of Palliser Triangle indicated by distribution of brown soils in Saskatchewan and Alberta.
Taken from Sauchyn (1997, fig. 1).

In spite of relatively dry conditions, the Palliser Triangle supports numerous lakes and wetlands ranging in size from small potholes (< 1 hectare) to large lake basins (100s km²). These wetlands occur in various glacial landforms--moraine potholes, former melt-water drainage channels (ribbon lakes), swales between ice-shoved ridges, depressions of former glacial lake plains, etc. Wetlands also are present in the Great Sand Hills of southwestern Saskatchewan.

Small wetland in a hollow between ice-thrust ridges. From the lake outward to foreground: open water, emergent marsh vegetation, wet meadow, wheat field. Near crest of Dirt Hills, southern Saskatchewan. Photo date 8/91, © J.S. Aber
Nesting ducks in Lake of the Rivers marsh. Nests are built above level of standing water. Near Ardill, southern Saskatchewan. Photo date 8/91, © J.S. Aber
Algal mat on Lake of the Rivers, near Ardill, southern Saskatchewan. Such mats are common in late summer when high water temperature and sunlight combine to produce algal blooms. Photo date 8/91, © J.S. Aber

The continental climate of the Palliser Triangle is subject to wet and dry cycles over periods of decades and longer time intervals. Droughts are common events historically. Thus lakes and wetlands may fill and overflow at times and completely dry up at other times. During the 1970s and early '80s, lakes and marshes generally had abundant water. The late 1980s and early '90s were, in contrast, an interval of drought, and many lakes and marshes dried up.

Landsat MSS false-color composite, southern Saskatchewan. 1 = Old Wives Lake, 2 = Lake of the Rivers, 3 = Cactus Hills, 4 = Dirt Hills, 5 = City of Regina. Image date 21 May 1978; acquired from EROS Data Center, U.S. Geological Survey. Space-shuttle color-visible photograph, southern Saskatchewan. 1 = Old Wives Lake, 2 = Lake of the Rivers, 3 = City of Regina. Notice that Old Wives Lake and Lake of the Rivers are both dry mud and salt flats in this scene. STS28-152-164, date 8/89.

Lake of the Rivers is a "ribbon lake" that occupies a glacial melt-water spillway channel. In this view, near Ardill, Saskatchewan, it contains shallow lakes and marshes during a wet phase. Photo date 10/84, © J.S. Aber
Lake of the Rivers during a dry phase. Approximately same view as previous picture, near Ardill, Saskatchewan. Valley floor is a wet meadow with little open water. Photo date 8/91, © J.S. Aber

Water quality tends to be quite hard (dissolved calcium and magnesium) due to abundant limestone and dolostone in glacial sediments. Many shallow lakes and wetlands become eutrophic during the summer and support large algal blooms, which are enhanced by runoff of fertilizer from agricultural fields. Finally alkali chemistry is found in many lakes of the Palliser Triangle and adjacent United States.

Partly dry alkali lake with salt flat, Cactus Hills, southern Saskatchewan. Photo date 7/84, © J.S. Aber

Sodium-sulfate is present both in the brine and in salt deposits, mainly as the mineral mirabilite (Glauber's salt). Sodium-sulfate has been produced commercially from some of these lakes for various industrial applications--manufacturing pulp and paper, replacement for phosphate in detergent, and other purposes. Few large commercial deposits of such salt exist outside this region in North America (Slezak and Last 1985).

Related sites


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© Notice: Wetland Environments is presented for the use and benefit of students enrolled at Emporia State University. Any other use of text, imagery or curriculum materials is prohibited without permission of the instructor, J.S. Aber (2016).