 |
Ecoregions of
|
| 48a. Glacial Lake Agassiz Basin | Level IV Ecoregion |
| Home
48a. Glacial Lake Agassiz Basin |
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The historic tallgrass prairie has been replaced by intensive agriculture.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.
From the Pembina Escarpment (46a), the view of the Glacial Lake Agassiz Basin is of an extremely flat patchwork of cultivated farmland. Because the Red River of the North has a poorly defined floodplain and very low gradient, flooding can be a problem. Outside of channelized areas in the floodplain, turbid valley streams meander within narrow buffer strips of cottonwood, elm, ash, and willow. Soils range from silty to clayey in texture. Most have high water tables and are extremely productive.
Physiography Area (square miles): 5137 Geology Surficial Material and Bedrock Soil Order (Great Groups) Climate Precipitation - Mean annual (inches) Potential Natural Vegetation Tallgrass prairie: big and little bluestem, switchgrass, and indiangrass. Cottonwood, willow, green ash, burr oak and American elm in riparian areas and on the Pembina Delta. Land Use and Land Cover Intensive row crop agriculture. Potatoes, edible beans, and wheat in the north; soybeans, corn, and wheat in the south. Farmland with woodlot or shelterbelt plantings. Urban and rural residential development. |
