U.S. Army Corps of Engineers photo
The Corps of Engineers St. Louis District and contractors perform embankment work along the Chain of Rocks levee in 2014.
The St. Louis District Corps of Engineers has completed construction on the Chain of Rocks East Canal Levee, making it the first part of the Metro East levees restored to its full level of protection.
The federally owned and operated Chain of Rocks levee is a nine-mile segment of the East St. Louis levee system. The system, located in Madison and St. Clair counties, protects many communities including Edwardsville, Granite City, Pontoon Beach, East St. Louis and Cahokia. Composed of 28.6 miles of levees, pump stations, closure structures and other features, it protects more than 86,000 acres of commercial, industrial and residential properties.
The levee is part of the larger Metro East levee system. Combined, these levees protect more than 250,000 residents and workers, as well as property and infrastructure valued in excess of $7.2 billion. During the flood of 1993 and subsequent floods, sand boils developed along a large portion of the Metro East levees, indicative of underseepage problems.
The completed Chain of Rocks project is the first segment in the Metro East urban levee system restored to provide the congressionally authorized level of protection.
The 100 percent federally funded project addressed the underseepage and assures that the Chain of Rocks levee will withstand a flood to a height of 54 feet on the St. Louis gage — approximately a 500-year flood. The flood of 1993 was approximately a 330-year flood event, reaching a height of 49.5 feet on the gage.
The scope of the problem and several alternatives were studied in 1996 and 1997, culminating in a design deficiency report identifying a recommended plan. The deficiency correction included the installation of relief wells, construction of levee berms, relocations, and mitigation. One of the new features of this levee segment is a new pump station capable of pumping 155 cubic feet of water per second. This new station is in addition to the existing Chouteau, Nameoki and Venice pump stations, which will have no change in operation.
Funding for design and construction began in fiscal year 1999 and continued steadily through the intervening years. The corps was able to make steady progress and was able to accelerate construction when funding from the American Recovery and Reinvestment Act was received in 2009. The federal investment to date is approximately $59 million. In total, more than $170 million in federal and local sponsor funds have been invested in restoring the Metro East levee system since the flood of 1993.
The remaining portions of the East St. Louis levee are operated and maintained by the Metro East Sanitary District. The district and the Southwestern Illinois Flood Prevention District Council are working on levee repairs for the system to be certified to the 100-year level of protection in order to maintain FEMA accreditation. The Corps’ role has been to provide data, analysis and documentation related to the Chain of Rocks levee segment.
“Much has been accomplished to reduce risk to the people and property behind the Metro East levees, but there’s still a lot of work to be done. Flood risk is a shared responsibility, and I look forward to a collaborative effort with our local partners to fully restore the remaining levees in the Metro East system,” said Col. Anthony Mitchell, commander of the St. Louis District. “With a common vision and shared resources, we can fully restore these levees and ensure they perform as designed to save lives, protect investments and strengthen our economy.”