region K Area 95B larger picture

Southern Wisconsin and Northern Illinois Drift Plain

81% of area in Wisconsin
19% of area in Michigan.

This area is in the Central Lowland Province of the Interior Plains.
Most of the area is in the Eastern Lake Section of the province.
A narrow strip along the western edge of the area is in the Wisconsin Driftless Section.
The southwestern quarter is in the Till Plains Section.

Total Land Area 10,880 square miles (28,200 square kilometers).

Towns/cities include:
Beloit, Madison, Waukesha, West Bend, and Beaver Dam, Wisconsin,,
Rockford and McHenry, Illinois.

Part of the Wisconsin Dells, numerous other Wisconsin State parks, and many Illinois State parks are in this area.


This area is almost entirely covered with glacial drift. The eastern extent of the 'Driftless Area' in southwest Wisconsin occurs in the western part of the area. Where glacial deposits are on the surface, the higher areas are moraines that appear as arc shaped ridges representing the retreat of the ice from south to north. Most of the bedrock in the southern half of this area consists of Ordovician shale, limestone, and dolomite. A sequence of Cambrian sandstone, limestone, and shale beds underlies the glacial deposits in the northern half of the area. These bedrock units are exposed in the 'Driftless Area' along the southwest margins of the area.

This area is characterized by gently sloping ground moraines, lake plains, outwash plains, drumlin fields, end moraines, flood plains, swamps, and marshes. Most of the area has belts of morainic hills and ridges and nearly level outwash terraces. Drumlins (steep-sided, elongated or oval hills) are prominent features in the north-central part of the area.

The area is dissected by numerous streams and rivers.

Topography -

Elevation ranges from 660 to 980 feet (200 to 300 meters). Local relief is mainly 25 feet (8 meters).
Moraines, drumlins, and bedrock escarpments rise 80 to 330 feet (25 to 100 meters) above the adjacent lowlands.


The average annual precipitation in this area is 30 to 38 inches (760 to 965 millimeters).
Most of the rainfall occurs as high-intensity, convective thunderstorms during the summer.
The average annual temperature is 43 to 48 degrees F (6 to 9 degrees C).
The freeze-free period averages about 170 days and ranges from 150 to 190 days.

Major Hydrologic Unit Areas

Name Code Extent*
Rock (0709) 56%
Northwestern Lake Michigan (0403) 21%
Upper Illinois (0712) 10%
Wisconsin (0707) 7%
Southwestern Lake Michigan (0404) 6%

* this is the percent of area drained by each named hydrologic unit

A short reach of the Wisconsin River is in the western part of this area. The Fox River in Wisconsin, the Kishwaukee River in Illinois, and the Pecatonica and Rock Rivers in both States occur in this area.


Estimated withdrawls in this MLRA:
Public supply surface water 10.8% ground water 9.0%
Livestock surface water 0.3% ground water 1.1%
Irrigation surface water 0% ground water 1.2%
Other surface water 74.2% ground water 3.4%

Total Average Daily Withdrawls:
2,280 million gallons per day (8,630 million liters per day)
15% ground water sources
85% surface water sources

The many inland lakes and streams typically have good-quality water. The surface water can be impacted by agricultural and municipal pollution, but it is generally suitable for most uses.

Ground water is abundant in unconsolidated sand and gravel deposits throughout the areas covered by glacial drift. All of the ground water in this MLRA is a calcium-magnesiumbicarbonate type. It is moderately hard to very hard. It has an average of 220 parts per million (milligrams per liter) total dissolved solids in the western part of the area and an average closer to 310 parts per million (milligrams per liter) in the unconsolidated sand and gravel aquifer in the eastern half of the area, nearer Lake Michigan. The levels of iron and manganese can exceed the State drinking water standards and may require treatment for esthetics.

A sandstone, dolomite, dolomite-sandstone, and siltstone aquifer is in the “Driftless Area” and beneath the glacial deposits in the western part of this area. The water in this aquifer is similar in quality to that in the glacial drift, but the levels of iron and manganese do not exceed State standards for drinking water. In the southeast corner of the area, naturally occurring radium and fluoride levels do exceed drinking water standards.

Ground water from the St. Peter and Ironton-Galesville sandstones in Illinois is used extensively. This water is typically low in total dissolved solids (having a median value of less than 500 parts per million, or milligrams per liter). It is very hard, but the levels of iron and manganese do not exceed the State and Federal drinking water standards. The water in this aquifer is polluted with volatile organic contaminants and nitrates from sewage effluent in the Rockford area.

Poorer quality ground water is in the Silurian Dolomite aquifer along the eastern edge of this area. The levels of total dissolved solids commonly exceed the national secondary standard for drinking water of 500 parts per million (milligrams per liter). The water also is high in iron, but manganese levels are not so high as those of the water in the other aquifers.

The moderate precipitation generally is adequate for crops and pasture, but in years of little or no precipitation, some crops on coarse textured soils are damaged by a lack of moisture. Many of the fine textured soils require water management practices that facilitate tillage and harvesting.


  • Dominantly a mesic soil temperature regime.
  • Aquic or udic soil moisture regime
  • Mixed mineralogy.
  • Soils are very deep and can range from well drained to very poorly drained and are generally loamy.

    Dominant Soils:
  • Alfisols
  • Histosols
  • Mollisols
  • Great Group Series Location
    Hapludalfs Casco, Fox, Dodge, Kidder, McHenry, Miami, and St. Charles series formed in alluvium over outwash and loess over outwash on outwash plains, valley trains, and kames, in loess over till on till plains, moraines, and drumlins.
    Haplosaprists formed in organic material in depressions on lake plains, outwash plains, and till plains.
    Endoaquolls Drummer, Pella series formed in loess over outwash, and in silty and loamy sediments on till plains, outwash plains, and stream terraces.
    Argiudolls Elburn, Hochheim, Plano, and Saybrook Griswold series in loess over outwash or till, and till on till plains, outwash plains, and stream terraces.

    Fauna and Flora

    The soils on uplands support natural stands of oak, sugar maple, and hickory and natural prairie vegetation characterized by little bluestem and big bluestem. Scattered oak and hickory trees grow on many of the prairies.

    Lowland areas support sedge and grass meadows and mixed stands of hardwoods and conifers. Elm, ash, cottonwood, soft maple, and white cedar are the major species in the lowland forests.

    Major wildlife species include whitetailed deer, red fox, gray fox, raccoon, muskrat, mink, fox squirrel, pheasant, Wilson’s snipe, and woodcock.

    Fishing occurs in the many lakes and rivers.

    Land Use

    55% - Cropland - private
    8% - Grassland - private
    0 - - Federal
    14% - Forest - private
    1% - - Federal
    12% - Urban development - private
    3% - Water - private
    7% - Other - private

    Agricultural uses include the production of dairy cattle, other livestock, forage, hay, feed grains, sweet corn, snap beans, canning peas, soybeans, winter wheat, barley, and fruit. Much of the hay, feed grain, and forage is fed to dairy cattle and other livestock on the farms where the feed is grown, but cash-grain farming also is important. Canning crops, potatoes, fruits, and other specialty crops are important, especially around urban centers.

    The major soil resource concerns are water erosion on cropland and construction sites, surface water quality, stormwater management, drainage of wet soils, and protection and restoration of wetland wildlife habitat.

    Conservation practices on cropland generally include systems of crop residue management, such as mulch-till, no-till, and strip-till systems; cover crops; conservation cropping systems; and crop rotations.

    Grassed waterways, grade-stabilization structures, surface and subsurface drainage systems, and filter strips help to control concentrated runoff and protect water quality. Nutrient management and pest management also are important conservation practices in this area.

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