© 2024 St. Louis Public Radio
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Five at-risk levees identified along Mississippi

By Adam Allington, KWMU

St. Louis, MO – The Army Corps of Engineers says it knows of at least five levees on the Illinois side of the Mississippi River that need improvements to withstand the kind of flooding the region saw in 1993 and 1995.

They are the Prairie Du Pont, Fish Lake, Chain of Rocks and East St. Louis and Wood River levees.

The Corps has been working with FEMA to find areas that are at a higher risk of flooding.

Terry Reuss Fell, with FEMA, says its part of the agency's effort to publish "risk maps" for the National Flood Insurance Program. "If a levee does not provide protection for a flood with 1% chance of occurring, then we have to show special flood hazard area," Fell said.

In a report to FEMA, the Corps said levees at Prairie Du Pont, Fish Lake, Chain of Rocks and East St. Louis and Wood River could fail a one-hundred year flood event without emergency reinforcement. The corps discussed its findings at a levee summit in Alton on Wednesday.

A Corps of Engineers map of its levees along the Mississippi
(levees are denoted by bold, black lines)

Engineers talk about "100-year levee", that means that in any given year there is a 1% chance the levee could be topped.

Dave Busse, chief of hydraulics for the Corps of Engineers, says over time that risk is actually much higher.

"What I'm saying is, that we're likely to get a hundred year event sometime within a 30 year mortgage and that's a little different then saying a 1%chance," he noted.

Specifically, Busse says the risk rises 26% over 30 years.

In nearly all cases flood levees are reinforced and supported during floods

Still, when inspecting levees the inspectors need to base their inspections on a none-mitigation scenario.

"There are no guarantees that we will have time enough to flood-fight, or that the resources will be available," says Busse.