Levee work along Mississippi River completed on 100-year flood protections

By Bob Pieper For Chronicle Media

Diagram describes seepage undermining Metro East levees
(Image courtesy of Southwestern Illinois FPDC)

A massive restoration of Metro East’s 74-mile system of levees along the Mississippi River, designed to ensure compliance with federal 100-year flood-protection standards, is now complete, according to the Southwestern Illinois Flood Prevention District Council (FPD Council).

Recertification of the levee system by the Federal Emergency Management Agency (FEMA) is anticipated by about Spring of 2019.

Shortly thereafter, the Southwestern Illinois Leadership Council hopes to begin seeing results of its campaign to encourage new business and residential development to the economically downtrodden American Bottom area, protected by the levee system.

But just to make sure the Metro East flood plain remains dry in an era of increasingly high flood levels on the Mississippi, the FPD Council is already preparing for additional improvements to protect the area from 500-year floods.

Renovations are being undertaken by the U.S. Army Corps of Engineers, which built the levee system,  in conjunction with the FPD Council.

Metro East is protected from flooding by a three separate but contiguous levee and groundwater drainage systems:

— The Wood River Drainage and Levee District, extending from the Melvin Price Locks and Dam at East Alton to the Chain of Rocks Canal at Granite City,

— The Metro-East Sanitary District (MESD), formerly the East Side Levee and Sanitary District, extending from the canal to the Cahokia Creeks area near East Carondolet in southern St. Clair County, and

— The Prairie du Pont Levee and Sanitation District and Fish Lake Drainage and Levee District (PdP/FL), extending from Cahokia Creek to the Columbia area south of I-55.

In addition to their levees along the Mississippi River, each district maintains a system of drainage canals and other flood protection infrastructure such as pumping stations.

The FPD Council divided the refurbishing of the Metro East flood protection system into five major renovation efforts; each entailing numerous projects such as levee reinforcement or culver rebuilding.

The FPD Council is now in the process of submitting extensive packages, documenting completion of the work, to FEMA.  

“Four packages have been submitted to FEMA, and the fifth and final package will be submitted to them by the Corps in Spring 2018.  FEMA will approve each package individually.  It will take until Spring 2019 for all to be approved, said Chuck Etwert, the FPD’s Council’s chief supervisor.

The Metro East levee renovation effort has so far not generally centered increasing levee height, which has overall proven adequate to protect the American Bottom from floodwaters, but rather ppreventingn “underseepage,” FPD Council officials explain.

During high-water events, water often seeps through a layer of sand that lies under the levees; causing “sand boils” behind the earthen walls.  Water accumulating behind the levees can result in erosion that could ultimately threaten the structural integrity of the flood walls, FEMA noted in a 2007 analysis of the Metro East flood protection system.

Based on that analysis, the agency threatened to declare virtually all 174 acres of the American Bottom as Special Flood Hazard Area (SFHA). That would have effectively required all property owners in the American Bottoms to purchase expensive federal flood — or face financial ruin in the event of a major flood, the Leadership Council notes.

The area is home to 156,000 people, 4,000 businesses and 56,000 jobs in 25 Madison, St. Clair or Monroe counties communities. Collectively, they would be forced to pay roughly $50 million in federal flood insurance premiums annually, the FPD Council notes.

In addition, any new structure built within the Special Flood Hazard Area would be subject to new building standards, including elevation requirements and construction limits, adding significant cost and likely deterring future development in the region.

While disagreeing FEMA’s dire assessment, area business and civic organizations in 2017 formed the St. Louis Metro East Levee Issues Alliance to pursue flood protection improvements. In 2008, a special .25 percent sales tax for levee improvements was approved by voters in Madison, Monroe and St. Clair counties and Southwestern Illinois Food Protect Districts was formed to oversee renovation of the area’s flood protection system in conjunction with the Army Corps.

The FPD Council in 2016 authorized bonds to finance the second phase of its improvement program; raising levee highest to ensure protect against 500-year floods across Metro East. Timetables for those projects are currently under development.


–Levee work completed on 100-year flood protections–