This area straddles the borders of five different physiographic regions.
The northern one-fifth of the area in Missouri is in the glaciated Dissected Till Plains Section of the Central Lowland Province of the Interior Plains.
The western end in Missouri is in the Osage Plains Section of the same province and division.
The southern four-fifths of the area in Missouri is in the Springfield-Salem Plateaus Section of the Ozark Plateaus Province of the Interior Highlands.
The northeast part of the area in Illinois is in the Till Plains Section of the Central Lowland Province of the Interior Plains.
The southeast corner of the MLRA is in the Highland Rim Section of the Interior Low Plateaus Province of the Interior Plains.
78% of this area within Missouri.
22% of this area within Illinois.
Total Land Area 8,085 square miles (20,955 square kilometers).
Cape Girardeau, Columbia, Fayette, Fulton, Jackson, Jefferson City (the capital of Missouri), Ste. Genevieve, St. Louis, and Washington, Missouri.
East St. Louis, Edwardsville, and Chester, Illinios.
The Cahokia Mounds historical site are along the banks of the part of the Mississippi River, Daniel Boone
Memorial State Forest is in the part of the MLRA in Missouri.
The Shawnee National Forest is in the part in Illinois.
The glacial deposits are underlain by several bedrock systems. The Mississippian System is the most extensive. Cherty dolostone and limestone are the most common rock types in this system. The Ordovician System is most common in more dissected areas and consists mostly of sandstone, dolostone, and limestone. Shale, sandstone, limestone, and coal in the Pennsylvanian System occur in the northeastern part of both Illinois and Missouri. Bedrock outcrops are common on the bluffs along the Mississippi River and its major tributaries. Karst areas have formed where Mississippian or Ordovician limestone is near the surface. Many limestone and dolomite quarries are throughout the MLRA, and silica sand is mined from the Ordovician St. Peter Sandstone Formation in Missouri.
The uplands in this area are covered almost entirely with Wisconsin loess. The loess is thick on stable summits. The loess in the northeastern part is underlain by Illinoian glacial drift, the dominant drift in Illinois. Wisconsin outwash deposits, alluvium, and sandy eolian material are on some of the stream terraces along the major tributaries in the area.Topography -
Elevation ranges from 320 to 1,020 feet (100 to 310 meters). Relief is typically 10-50 feet (3 - 15 meters). The bluffs along the Mississippi River are generally 200 to 350 feet (60 to 105 meters) above the floor of the river valley.
Karst topography is common in this MLRA. The well developed karst areas have hundreds of sinkholes, caves, springs, and losing streams.
The average annual precipitation in this area is 38 to 48 inches (965 to 1,220 millimeters).
Most of the rainfall occurs as high-intensity, convective thunderstorms.
The average annual temperature is 53 to 57 degrees F (12 to 14 degrees C).
The freeze-free period averages about 205 days and ranges from 185 to 230 days.
* this is the percent of area drained by each named hydrologic unit
The Mississippi River flows through this area, forming the boundary between Illinois and Missouri.
|Public supply||surface water||18.4%||ground water||1.8%|
|Livestock||surface water||0.4%||ground water||0.1%|
|Irrigation||surface water||0%||ground water||0.2%|
|Other||surface water||77.3%||ground water||1.8%|
Total daily withdrawls average 1,685 million gallons per day 6,380 million liters).
4% Ground water sources
96% Surface water sources
Abundant ground water exists in deposits of unconsolidated sand and gravel along the Mississippi River, the lower reaches of the Meramac River, and the Missouri River. The average values of total dissolved solids are close to 500 parts per million (milligrams per liter), and the water may have high levels of iron.
Away from the river valley deposits in Illinois, ground water can be obtained from the Pennsylvanian-Mississippian and Shallow Dolomite aquifers.
In Missouri, ground water can be obtained from the Ozark aquifer, which is south of the Missouri River, and the Kimmswick-Potosi aquifer, which is north of the river. Both of these aquifers consist of dolomite with some sandstone beds. Their water has median levels of total dissolved solids that are less than 500 parts per million (milligrams per liter).
Because of the karst topography, contaminated water from surface activities has created some local water-quality problems in these bedrock aquifers.
The soils are very deep, poorly drained to excessively drained and loamy, silty, or clayey.
|Albaqualfs||Marine, Mariosa, Pierron series||formed in loess on broad upland summits and flats.|
|Hapludalfs||Marion series||formed in loess on broad upland summits and flats.|
|Endoaqualfs||Caseyville series||formed in loess on broad upland summits and flats.|
|Hapludalfs||Winfield, Menfro, Hatton, Wrengart, and Stookey series||formed in loess on uplands.|
|Hapludalfs||Freeburg series||formed in silty alluvium on terraces.|
|Endoaqualfs||Moniteau series||formed in silty alluvium on terraces.|
|Hapludalfs||Minnith, Neotoma, Pevely, and Wellston series||formed in siltstone or sandstone residuum.|
|Paleudalfs||Holstein series||formed in siltstone or sandstone residuum.|
|Endoaquolls||Booker, Fults, Ambraw, Beaucoup, Darwin series||formed in alluvium on nearly level, broad flood plains.|
|Hapludolls||Landes, Tice, and Medway series||formed in alluvium on nearly level, broad flood plains.|
|Endoaquepts||Karnak series||formed in alluvium on nearly level, broad flood plains.|
There are many other soil series listed in the USDA information.
Oak, hickory, and sugar maple are the dominant species. Big bluestem, little bluestem, and scattered oak and eastern redcedar trees grow on some upland sites.
The lowlands support mixed forest vegetation, mainly elm, cottonwood, river birch, ash, silver maple, sweetgum, sycamore, pin oak, pecan, and willow. Sedge and grass meadows and scattered trees are on some lowlands.
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.
|32% -||Cropland||- private|
|18% -||Grassland||- private|
|1% -||- Federal|
|28% -||Forest||- private|
|1% -||- Federal|
|15% -||Urban development||- private|
|3% -||Water||- private|
|3% -||Other||- private|
Corn, soybeans, and other feed grains are the principal crops. Specialty crops include vegetables, Christmas trees, grapes, apples and peaches.
The major resource concerns include water erosion, flooding, wetness; maintenance of the content of organic matter in the soils and productivity of the soils and surface water quality.
Conservation practices on cropland generally include crop residue management (no till), cover crops, terraces and grassed waterways, windbreaks, vegetative wind barriers and nutrient and pest management. Woodland management practices, such as exclusion of grazing and timber stand improvement, are important for timber production.