region M Area 114 B larger picture

Southern Illinois and Indiana Thin Loess and Till Plain, Western Part

This area is within the Till Plains Section of the Central Lowland Province of the Interior Plains.

66% of this area within Illinois.
34% of this area within Indiana.

Total Land Area 7,005 square miles (18,150 square kilometers).

Towns/cities include:
Brazil, Bloomfield, Cloverdale, and Spencer, Indiana.
Carlyle, Nashville, Hillsboro, Greenville, Vandalia, and Pinckneyville, Illinios.

The numerous State parks in the MLRA include Eldon Hazlet, South Shore, and Pyramid State Parks in Illinois and Cagles Mill and McCormick’s Creek State Parks in Indiana.

Geology

Middle and Late Mississippian bedrock occurs in the eastern part of the area, and Early and Middle Pennsylvanian bedrock occurs in the western part.

Bedrock outcrops are common on the bluffs along rivers and the major tributaries. They also are evident at the base of steep slopes along minor streams and drainageways.

This area is covered dominantly with loess and Illinoian till. The loess ranges from about 4 to 7 feet (1 to 2 meters) in thickness on stable summits. On the steeper slopes, it is 1 foot or less (0.1 to 0.3 meter) thick or does not occur. Meltwater outwash and lacustrine and alluvial deposits are along some of the streams and on terraces along the major tributaries.

Well defined valleys with broad flood plains and numerous stream terraces are along the major streams and rivers. The flood plains along the smaller streams are narrow. Broad summits are nearly level to gently sloping.

Topography -

Elevation ranges from 350 to 1,190 feet (105 to 365 meters). Relief is typically 10-50 feet (15-30 meters).

Climate

The average annual precipitation in this area is 37 to 46 inches (940 to 1,170 millimeters).
Most of the rainfall occurs as high-intensity, convective thunderstorms.
The average annual temperature is 52 to 56 degrees F (11 to 14 degrees C).
The freeze-free period averages about 210 days and ranges from 190 to 225 days.

Major Hydrologic Unit Areas

Name Code Extent*
Upper Mississippi-Kaskaskia-Meramec (0714) 45%
Wabash (0512) 34%
Lower Illinois (0713) 18%
Upper Mississippi-Salt (0511) 3%

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

Water

Estimated withdrawls in this MLRA:
Public supply surface water 91.9% ground water 1.8%
Livestock surface water 0.4% ground water 1.8%
Irrigation surface water 0.6% ground water 3.4%
Other surface water 0% ground water 0%

Total daily withdrawls average 79 million gallons per day (300 million liters).
7% Ground water sources
93% Surface water sources

The larger rivers and reservoirs provide water for industrial and municipal uses and some limited irrigation. Surface waters are suitable for almost all uses.

Abundant ground water occurs only in deposits of unconsolidated sand and gravel along the East and West Forks of the White River in Indiana and along the Kaskaskia River in Illinois. The average values of total dissolved solids are 546 and 500 parts per million (milligrams per liter) in Indiana and Illinois, respectively.

Away from the river valley deposits, the only source of ground water in Illinois is the Pennsylvanian-Mississippian aquifer. The level of total dissolved solids is 500 to 3,000 parts per million (milligrams per liter).

In Indiana, the only other source of ground water is in isolated lenses of sand and gravel buried in older glacial till outside the river valleys.

Soils

  • Mesic soil temperature regime.
  • Aquic or udic soil moisture regime.
  • Mixed or smectitic mineralogy
  • Dominant Soils:

  • Alfisols
  • Inceptisols
  • The MLRA also has small areas of Mollisols, Ultisols, and Entisols.

    Great Group Series Location
    Albaqualfs Cowden, Marine serieson broad, loess covered till plains.
    Endoaqualfs Iva, Oconee serieson broad, loess covered till plains.
    Epiaqualfs Hoosierville serieson broad, loess covered till plains.
    Glossaqualfs Vigo serieson side slopes on till
    Argiudolls Herrick serieson side slopes on till
    Hapludalfs Hickory serieson side slopes on till
    Hapludalfs Parke, Pike seriesformed in outwash deposits on high stream terraces, kames, and moraines.
    Epiaqualfs Hurst, McGary seriesformed in lacustrine sediments on lacustrine terraces and lake plains.
    Hapludalfs Colp, Shircliff, Markland seriesformed in lacustrine sediments on lacustrine terraces and lake plains.

    There are many other soil series listed in the USDA information.

    Fauna and Flora

    Pin oak, shingle oak, hickory, sweetgum, and black oak are the dominant species on the wetter sites. Silver maple, cottonwood, sycamore, pin oak, elm, and sweetgum grow along rivers and streams. Sedge and grass meadows and scattered trees are on some lowland sites.

    White oak, black oak, red oak, hickory, yellow-poplar, ash, sugar maple, and black walnut grow on the better drained sites.

    Some of the major wildlife species include whitetailed deer, gray and red fox, beaver, mink, raccoon, opossum, great horned owl, bobwhite quail, and wood duck.

    Land Use

    47% - Cropland - private
    11% - Grassland - private
    1% - - Federal
    27% - Forest - private
    1% - - Federal
    7% - Urban development - private
    1% - - Federal
    2% - Water - private
    2% - Other - private

    Winter wheat, corn, soybeans, grain sorghum, and other feed grains are the principal crops. Some surface coal mining.

    The major resource concerns include wind and water erosion, flooding, wetness; maintenance of the content of organic matter in the soils and productivity of the soils.

    Conservation practices on cropland generally include surface and subsurface drainage systems, crop residue management, filter strips, cover crops, and nutrient and pest management. Woodland management practices, such as exclusion of grazing and timber stand improvement, are important for timber production.


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