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Ecoregions of
North Dakota
South Dakota

48. Lake Agassiz Plain

48c. Saline Area Level IV Ecoregion


North Dakota Ecoregions

South Dakota Ecoregions

48a. Glacial Lake Agassiz Basin

48b. Sand Deltas and Beach Ridges

48c. Saline Area

  Glacial Lake Agassiz was the last in a series of proglacial lakes to fill the Red River Valley since the beginning of the Pleistocene. The Lake agassiz Plain is composed of thick lacustrine sediments underlain by glacial till. It is extrememly flat and has fewer lakes and pothole wetlands than neighboring ecoregions. The historic tallgrass prairie has been replaced by intensive agriculture. The preferred crops in the northern half of the region are potatoes, beans and wheat; soybeans and corn predominate in the south. Sugar beets are grown throughout the region.

GIF - Feedlot
The concentration of cattle in feedlot operations may contaminate surface and ground water.

In the Saline Area of the Lake Agassiz basin, salty artesian groundwater flows to the surface through glacial till and lacustrine sediments from the underlying beds of Cretaceous sandstone. The regional boundary of ecoregion 48c delineates an area where salt effects are most evident. Other saline areas occur along the tributaries of the Park, Forest, and Turtle rivers in northeast North Dakota. Salt-affected soils in the saline area reduce crop productivity. Many areas are not suitable for fanning, but are used for range or wildlife habitat.


Area (square miles): 348

Elevation/Local Relief (feet): 820-870/3-25

Glacial lake plain with saline ground water welling to the surface.


Surficial Material and Bedrock
Silt and clay lacustrine deposits over Cretaceous shale and sandstone.


Order (Great Groups)
Mollisols (Calciaquolls)

Common Soil Series
Bearden, Antler, Ojata

Temperature/Moisture Regimes


Precipitation - Mean annual (inches)

Frost Free - Mean annual (days)

Mean Temp. - Jan. min/max; July min/max, (°F)

Potential Natural Vegetation

Tallgrass prairie, salt tolerant western wheatgrass, saltgrass.

Land Use and Land Cover

Grazing land on strongly saline soils. Where salinity levels are moderate, sunflowers, barley, sugarbeets, and potatoes are grown. Brackish wetland habitat.

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