American Bottoms

American Bottoms
User:Marcusscotus1 · CC BY-SA 3.0 · source
Name	American Bottoms
Other name	American Bottom
Settlement type	Floodplain
Subdivision type	Country
Subdivision name	United States
Subdivision type1	State
Subdivision name1	Illinois
Subdivision type2	County
Subdivision name2	Madison County, St. Clair County, Monroe County, Clinton County, Jackson County, Madison County, Randolph County, Greene County

American Bottoms is a broad, fertile floodplain of the Mississippi River on the eastern side of the river in southwestern Illinois, stretching roughly from St. Louis south to Cahokia Mounds State Historic Site. The region is bounded by the Mississippi River bluffs and includes major municipalities and industrial centers such as East St. Louis, Illinois, Alton, Illinois, and Collinsville, Illinois. Historically central to prehistoric urbanism, European colonization, steamboat commerce, and modern industry, the floodplain remains a landscape shaped by fluvial dynamics, cultural heritage, and infrastructure.

Geography

The floodplain lies within the larger Upper Mississippi River Basin and encompasses communities including Wood River, Illinois, Goodman Point, Fairmont City, Illinois, Granite City, Illinois, and Belleville, Illinois. Major transportation corridors traverse the area, such as Interstate 55, Interstate 70, U.S. Route 66, and the St. Louis–San Francisco Railway corridors, while crossings like the Eads Bridge and McKinley Bridge link the floodplain to St. Louis, Missouri. The region's landforms include backswamps, natural levees adjacent to the Mississippi River, abandoned meander scars, and oxbow lakes like those near Nature Preserve's and Cahokia Mounds area.

Geology and Floodplain Dynamics

The floodplain developed on alluvium deposited by the Mississippi River during the Holocene following post-glacial adjustments associated with the Wisconsin Glaciation retreat. Thick sequences of sand, silt, and clay overlie bedrock of the Carboniferous and Permian sequences in places, with terraces reflecting episodes of aggradation and incision linked to climate and base-level changes documented in studies by institutions such as the United States Geological Survey and regional universities including Southern Illinois University Carbondale. Fluvial geomorphology here includes active channel migration, levee formation, and periodic avulsions that have produced oxbow lakes near Kaskaskia River confluences.

History

Precontact and historic narratives intersect in the floodplain, where European exploration by figures associated with Jacques Marquette and Louis Jolliet penetrated the region during voyages linked to New France expansion. The area later figured in colonial contests involving Pierre Laclède and August Chouteau enterprises, and in territorial negotiations under the Louisiana Purchase. Nineteenth-century developments included steamboat commerce tied to Mark Twain's era of the Mississippi River and industrialization driven by ironworks and coal associated with companies operating near Alton, Illinois and Granite City, Illinois. Twentieth-century events saw labor conflicts connected to unions such as the United Steelworkers and environmental controversies involving agencies like the Environmental Protection Agency.

Native American Cultures

The floodplain hosted complex pre-Columbian societies, most prominently the urban polity centered at Cahokia Mounds State Historic Site, which features monumental earthen architecture including Monks Mound, plazas, and wooden stockades associated with the Mississippian culture. Archaeological research by scholars and institutions including James A. Brown (archaeologist), Wesley J. A. (Wes) Alt],], and teams from University of Illinois Urbana-Champaign has documented social complexity, long-distance trade networks reaching Hopewell tradition sources, and ceremonial practices connected to regional sites like Emerald Mound and Poverty Point. Epidemics, colonial contact, and displacement involved interactions with tribes recognized today such as the Illiniwek Confederation component peoples and later movements tied to the Treaty of Greenville era dynamics.

Agriculture and Economy

The fertile alluvial soils supported intensive agriculture historically, with crops such as corn, soybeans, and wheat cultivated by landowners and tenant farmers linked to regional markets accessed via St. Louis Mercantile Library era trade routes and railheads like those of the Illinois Central Railroad. Industrialization introduced steelmaking, manufacturing, and petrochemical operations sited near river ports and terminals serving firms with connections to the Union Pacific Railroad and river barge operators. Modern economic activity blends agriculture, manufacturing, logistics, and heritage tourism focused on sites such as Cahokia Mounds State Historic Site and riverfront development in Alton, Illinois.

Ecology and Wildlife

Remnant wetlands, floodplain forests, and backwater habitats support species assemblages including migratory birds along the Mississippi Flyway such as American white pelican, Bald eagle, and waterfowl. Bottomland hardwood species include Baldcypress stands and flood-tolerant oaks and maples documented by botanists at Missouri Botanical Garden and university herbaria. Aquatic fauna include native mussels, catfish, and sportfish important to conservation programs administered by the Illinois Department of Natural Resources, while invasive species concerns involve taxa monitored by the United States Fish and Wildlife Service.

Flood Control and Management

Flood risk has driven construction of engineered levees, floodwalls, pumping stations, and navigation structures developed under the auspices of the United States Army Corps of Engineers and state agencies like the Illinois Department of Natural Resources. Historic floods such as the Great Flood of 1993 and recurring high water events prompted levee breaches, buyout programs administered by Federal Emergency Management Agency initiatives, and restoration projects coordinated with nonprofits like The Nature Conservancy and local conservation districts. Contemporary strategies integrate ecosystem restoration, managed retreat, and infrastructure resilience planning with partners including National Oceanic and Atmospheric Administration and regional planning commissions.

Category:Landforms of Illinois Category:Floodplains of the United States