Iowa DNR
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River & Stream Biological Monitoring
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Physical Habitat Assessments

Ecoregion 47a : Northwest Iowa Loess Prairies

Ecoregion Map

Ecoregion Characteristics

Landform Description
Irregular plains. Elevation 1200-1600 ft.
Surficial Materials
Moderate to thick loess over clay loam.
Soils
Mollisols (Hapludolls) {Galva-Primghar-Sac}
Climate
Annual precipitation 27-29 in. Freeze free: 140-150 days.
Potential Vegetation
Bluestem prairie
Predominant Land Use
Cropland
The Northwest Iowa Loess Prairies ecoregion is a gently undulating plain with a moderate to thick layer of loess. It is the highest and driest region of the Western Corn Belt Plains, as it rises to meet the Northern Glaciated Plains of the Dakotas. Although loess covers almost all of the broad upland flats, ridges, and slopes, minor glacial till outcrops occur near the base of some of the side slopes. Silty clay loam soils have developed on the loess. The area is mostly treeless, except for the more moist areas along some stream corridors and on farmstead windbreaks. The dominant land use is cropland agriculture with some pasture and cattle feedlots.