It is said, and is probably true, that the American Bottoms can never have an adequate system of drainage without lowering the bed of the Mississippi. The drainage question of the Bottoms has for many years been an unsolved problem, and will probably remain so until some freak of nature shall settle the vexed question.”[i] –St. Clair County History, 1881
It is always good news when a restoration project on the Mississippi floodplain begins to come to fruition, in this case on the American Bottom near East St. Louis, Illinois. The Illinois DNR and Madison County will built riffles in Glen Carbon Creek, to retain water and sediment in the uplands to reduce sedimentation of the Cahokia Canal, Harding Ditch, and Canal #1 in the bottomlands of the American Bottom. If this works, they will move on to Judy Creek and build riffles there. It is the first step in a much larger project to reduce flooding in the American Bottom.
At the beginning of the twenty-first century, the Corps of Engineers, the Illinois Department of Natural Resources, and a host of other conservation agencies were trying the settle the question of the drainage of the American Bottoms by mimicking its drainage before European settlement.
Channelization, urbanization, industrialization, and the need to control flooding disrupted the flow of water across the American Bottom and destroyed much of the ecosystem that existed before European settlement. Before it was channelized across the northern end of the American Bottom, Cahokia Creek was the principal stream flowing out of the uplands onto the floodplain. It entered the bottomland, gathered water from tributary creeks flowing out of the uplands, passed through Horseshoe Lake, approached the Mississippi, and veered south. It carried its load of water and sediment into Cahokia Chute, a side channel of the Mississippi, twenty-one miles to the south. It was slow, sluggish, and meandered in several channels for a total of thirty-eight miles. And, it was prone to flooding. Nicholas Jarrot, who settled in Cahokia, built one mill after another on Cahokia Creek at the beginning of the eighteenth century, only to see each washed away in a flood. By the end of the twentieth century 62% of Cahokia Creek had been filled for industrial or agricultural development. Of the tributaries to Cahokia Creek, 72% had been filled or converted to drainage ditches.
Once the railroad came to the American Bottom in 1837, Cahokia Creek backed up against the trestles and embankments–mini-levees–that carried trains across the bottom. In 1861 the City of East St. Louis, made the first diversion of Cahokia Creek to accommodate the railroad. Additional diversions came throughout the nineteenth century to make room for railyards. In 1903 the newly established East Side Levee and Sanitary District began construction of a levee along the Mississippi. The final diversion of Cahokia Creek came in 1909 with the construction of the Cahokia Diversion Canal at the northern end of the American Bottom. Later, other creeks were also diverted to the Mississippi.
In all, three canals–the diversion canal, Cahokia Canal, and Harding Ditch, each bracketed by levees–carried Cahokia Creek and all other creeks to the Mississippi, eliminating the presettlement drainage system forever. Harding Ditch entered the Mississippi twenty miles south of the Cahokia Diversion Canal. Engineers tied the levees of both to the bluff and integrated them into the Mississippi levee, turning the East Side Levee and Sanitary District into a catch basin for storm water. Flooding in the basin was a problem throughout the twentieth century. In August 2007 the Federal Emergency Management Agency declared the levees, which lacked relief wells to control seepage under them, inadequate and removed them from the flood control maps, further eroding the East St. Louis housing values, insurance rates, and prospects for economic development.
Upland streams, filled with sediment eroded from farm fields and urban sites, cascaded through hollows in the bluffs into bottomland drainage canals and slowed down. They deposited their load of mud and sand in the slow-moving canals, which were incapable of carrying it to the Mississippi. Sediment built up. For most of the twentieth century, the solution to sediment build-up was to remove it with backhoes. What couldn’t be removed filled wetlands and lakes. Come a big summer rain, stormwater overflowed the leveed ditches and canals close to the bluff line.
Interior flooding became severe from 1993 through 1996. For four years, the Federal Emergency Management Agency and the Natural Resource Conservation Service poured tens of millions of dollars into flood relief in the district, cleaned out canals and ditches, and purchased flood-prone properties.
In 1997 Congress authorized the Corps of Engineers to re-evaluate the flooding problem. Earlier efforts to deal with the problem had failed to meet the cost-benefit ratio required by Congress to justify a flood control project. The region was poor, its housing impoverished, its industry of low value, and the land outside its cities devoted to agriculture.
A year later the St. Louis District of the Corps, working with the Waterways Experimental Station and a host of other state and federal agencies*, decided to integrate stream and wetland restoration with flood control in the district. The agencies developed a Hydrogeomorphic Model to determine how wetlands in the district were formed, where they sat in the landscape, and how water flowed through them–their hydrology. They combined their model with a multi-species Habitat Evaluation Procedures analysis to determine the impact of changes in the landscape on aquatic, wetland, and terrestrial systems.
In November 2003 the St. Louis District of the Corps of Engineers issued its final report on its East St. Louis and Vicinity Interior Flood Control/Ecosystem Restoration Project. It included restoration of parts of Cahokia Creek and other creeks and wetlands to mimic pre-settlement conditions. Complete restoration was impossible.
The engineers proposed building reservoirs on the uplands to catch water and sediment before it flowed to the American Bottom, and converting old meanders in the bottomland to retention pools for floodwater. They aimed to restore up to four miles of Cahokia Creek where it emerged from the bluff to approximate presettlement conditions by clearing sediment out of the old creek bed and excavating parts of the channel that had been completely filled in. Forest managers would plant a riparian forest up to three hundred feet wide along the banks of the restored creek, and add a berm on the west side of the forest to retain flood water between the berm and the bluff. The newly restored section of Cahokia Creek would flow to County Ditch, which would carry it to Cahokia Canal and the Mississippi. They scheduled two other sections of the creek for restoration with riparian forests planted along their banks.
In all the partners would restore 10.4 miles of Cahokia Creek and plant 1705 acres of riparian forest along its banks, revive 843 acres of marsh and shrub swamp habitat, 460 acres of lakes, 1,111 acres of prairie, and 379 acres of upland forest in seven areas along the old course of Cahokia Creek. They would place 651 wood duck boxes and 870 prairie bird perches throughout the district. Finally, they would construct 131 tributary stream detention basins in the uplands, riffle and pool complexes along 178 miles of streams in the bluffs, 15.5 miles of stream embankments, and culverts, flap gates, and new channels as needed to control the flow of water through the system. The total cost of the project would be just short of $190 millon dollars, shared by the Federal government, the State of Illinois, and Madison and St.Clair Counties.[ii]
While Horseshoe Lake, an important stop for migrating ducks and the first great Mississippi oxbow , is not included in the project, it will benefit from it. Reducing sedimentation in the creeks and canals, will reduce the amount of sediment that is filling the lake.
For more information about Horseshoe Lake and the wetlands along the Mississippi River north of East St. Louis, download the Riverlands tour from TwoTankTours.com. The tour covers Horseshoe Lake, the Chain of Rocks, the Columbia Bottoms, Riverlands, and Dresser Island.
[i] St. Clair County History, Philadelphia: Brink, McDonough and Company, 1881, 330.
[ii] Hajic, 1991; Yarbough, Ronald E., “The Physiography of Metro East,” in Illinois Geographical Society Bulletin, vol. 16, no. 1, 23; University of Illinois, East St. Louis Action Research Project, “Railroads and Cahokia Creek,” http://www.eslarp.uiuc.edu/ibex/archive/IDOT/idot20.htm; Illinois Department of Natural Resources, Office of Water Resources, Metro East Projects, “Sand Road Watershed,” http://dnr.state.il.us/owr/OWR_MetroEast.htm; U.S. Army Corps of Engineers, St. Louis District, “East St. Louis & Vicinity Interior Flood Control and Ecosystem Restoration Project,” http://www.mvs.usace.army.mil/pm/E_St_Louis/alternatives.htm; U.S. Army Corps of Engineers, St. Louis District, East St. Louis and Vicinity, Illinois Ecosystem Restoration and Flood Damage Reduction Project, General Reevaluation Final Report with Intetrated Environmental Impact Statement, II-4-5, B-18, 2-33, 8-8.
[iii] Schwartz, John, “East St. Louis Levees Fail Test,” New York Times, August 23, 2007, http://www.nytimes.com/2007/08/23/us/23levees.html.