Northern Prairie Wildlife Research Center
|46d. Glacial Lake Deltas||Level IV Ecoregion|
|The Northern Glaciated Plains
ecoregion is characterized by a flat to gently rolling landscape
composed of glacial drift. The subhumid conditions foster a grassland
transitional between the tall and shortgrass prairie. High concentrations
of temporary and seasonal wetlands create favorable conditions for duck
nesting and migration. Though the till soil is very fertile, agricultural
success is subject to annual climatic fluctuations.
The Glacial Lake Deltas were deposited by rivers entering glacial lake basins (e.g., Glacial Lake Souris, Devils Lake, and Lake Dakota). The heaviest sediments, mostly sand and fine gravel, formed delta fans at the river inlets. As the lake floors were exposed during withdrawal of the glacial ice, wind reworked the sand in some areas into dunes. In contrast to the highly productive, intensively tilled glacial lake plains, the dunes in the delta areas have a thin vegetative cover and a high risk for wind erosion. These areas are used mainly for grazing or irrigated agriculture.
Area (square miles): 1877
Surficial Material and Bedrock
Order (Great Groups)
Precipitation - Mean annual (inches)
Potential Natural Vegetation
Prairie sandreed, little bluestem, indiangrass, switchgrass, sand bluestem.
Land Use and Land Cover
Droughty soils mostly used for native pasture. When tiled, used for small grains, flax and fall-planted rye (north), or small grains, sunflowers, and corn (south). Some irrigation.