region K Area 92 larger picture

Superior Lake Plain

This area is in the Superior Upland Province of the Laurentian Upland

Area in Wisconsin is 48%
Area in Michigan is 39%
Area in Minnesota is 13%

Total Land Area 2,920 square miles (7,570 square kilometers).

Towns/cities include:
Superior, and Ashland, Wisconsin
Duluth, Minnesota
Ontonagon, Michigan,

A large part of the Ottawa National Forest is in the eastern half of this area.

The Ontonagon, Bad River, and Red Cliff Indian Reservations are in the area.

Numerous State parks and State forests are throughout the area.
The Apostle Islands National Lakeshore is in this MLRA..


This area has been glaciated, and most of the surface deposits are fine textured till derived from glacial lake sediments. The bedrock in the area is a mixture of late Precambrian and Cambrian sandstones and shales and mafic igneous rocks. It is known as the Keweenawan Group in Wisconsin and Minnesota.

The bedrock units in Michigan are known as the Freda and Jacobsville sandstones, Nonesuch shale, the Portage Lake volcanics, and the Copper Harbor conglomerate.

The area is characterized by a till plain mixed with lake plains, lake terraces, beaches, flood plains, swamps, and marshes. Some rocky knobs, hills, and low mountains make up part of this nearly level lake plain.

Topography -

Elevation ranges from 600 to 1,400 feet (185 to 425 meters). Local relief on the lake plain is only 3 to 6 feet (1 to 2 meters) Adjoining hills and low mountains rise sharply from 85 feet (25 meters) to more than 330 feet (100 meters) above the plains.


The average annual precipitation in this area is 27 to 37 inches (685 to 940 millimeters).
Most precipitation occurs as high-intensity, convective thunderstorms in summer.
The average annual temperature is 38 to 42 degrees F (4 to 6 degrees C).
The freeze-free period averages about 155 days and ranges from 125 to 190 days.

Major Hydrologic Unit Areas

Name Code Extent*
Western Lake Superior (0401) 60%
Southern Lake Superior-Lake Superior (0402) 40%

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

Some of the streams crossing this area and emptying into Lake Superior are the Bois Brule, Nemadji, Whittlesey, Montreal, Black, Presque Isle, and Ontonagon Rivers in Wisconsin and Michigan.
Numerous steep-gradient streams empty into Lake Superior along the north shore of Minnesota.


Estimated withdrawls in this MLRA:
Public supply surface water 3.4% ground water 0%
Livestock surface water 0.7% ground water 0.4%
Irrigation surface water 0% ground water 0%
Other surface water 95.5% ground water 0%

Total Average Daily Withdrawls:
Total daily withdrawls averages 155 million gallons per day (585 million liters per day).

Almost 100 percent is from surface water sources.

Precipitation is adequate for crops and pasture. Drainage of level areas of wet soils is needed for good growth of crops.

The surface water is of good quality. It is hard but is suitable for most uses with little or no treatment.

Two sources of ground water occur in this area. One is the isolated pockets of unconsolidated sand and gravel in the glacial drift. The other is the Lake Superior Sandstone and Precambrian Lava Flows aquifer.

Water from both of these aquifers is moderately hard to very hard and is typically very low in total dissolved solids, having less than 300 parts per million (milligrams per liter).

About 30 percent of all the wells tested in these aquifers had iron and manganese concentrations that exceeded the national secondary standards for drinking water. These standards are for esthetics and do not affect human health.


  • Soils have a frigid soil temerature regime.
  • Udic or aquic soil moisture regime and mixed or isotic mineralogy.
  • The major soils formed in clayey to loamy till in some areas with a sandy mantle. Some soils along the edges of the MLRA, have stratified silty and clayey lacustrine deposits. The soils in some areas along the shore of Lake Superior formed in organic material or in sandy beach deposits.

    Dominant Soils:

  • Alfisols
  • Entisols
  • Inceptisols
  • Spordosols
  • Great Group Series Location
    Glossudalfs Miskoaki, Amnicon, Cuttre, Odanah, Sanborg, Badriver, Watton, Flintsteel, and Big Iron series on till plains formed in very deep clayey or loamy till
    Haplorthods Superior, Ubly, and Belding seriesManistee, Kellogg, and Ashwabay series in clayey till or loamy till mantled with sandy material
    Epiaquepts Bergland, Pickford, and Munuscong series formed in very deep clayey or loamy till
    Haplohemists Rifle series formed in organic deposits in marshes along Lake Superior
    Haplosaprists Seelyeville, Cathro, Lupton, Dorval, and Tawas series formed in organic deposits in inland swamps and in side-hill seep areas.
    Udipsamments Grayling, Wurtsmith, and Meehan series formed in sandy beach and dune deposits on active beaches.

    Fauna and Flora

    This area supports deciduous and evergreen trees. Boreal forests (aspen, white birch, balsam fir, white spruce, white pine, red pine, white cedar, and tamarack)
    Mixed deciduous and coniferous forests (hemlock, sugar maple, yellow birch, red pine, and white pine) are dominant.
    Swamp conifers and lowland brush commonly grow on the wetter soils.

    Major wildlife species in this area include black bear, white-tailed deer, coyote, snowshoe hare, timber wolf, ruffed grouse, tree squirrel, bald eagle, and Canada goose.

    Land Use

    10% - Cropland - private
    4% - Grassland - private
    0% - - Federal
    68% - Forest - private
    12% - - Federal
    3% - Urban development - private
    1% - Water - private
    2% - - Federal
    6% - Other - private

    More than three-fourths of this area is forested, and about two-thirds is privately owned forestland used for timber production and recreation.

    14% agricultural use; cropland used mainly for small grains and hay for dairy cattle and other livestock. Apples, blueberries, trefoil seed, and other specialty crops are important cash crops in some areas. Only a small part of the land is used for pasture.

    Major soil resource management concerns are water erosion, wetness, soil fertility, and soil tilth.

    Major resource concerns are water erosion, wind erosion, wetness, soil fertility, soil tilth, water quality.

    Conservation practices on cropland generally include crop rotations, conservation tillage systems, and grassed waterways. Surface drainage systems are needed to remove surface water from wet areas.

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