By ALAN J. ORTBALS
Restoration work on the levee system protecting the American Bottom is behind schedule and no one knows when the entire system will be completed.
Some of the projects are being carried out by the Southwest Illinois Flood Protection District and are fully funded and underway. Those projects were scheduled for completion by May of this year but have been delayed due to problems acquiring easements from private property owners and the high river levels on the Mississippi River this summer, according to Chuck Etwert, the district’s chief engineer.
“Everything is under construction right now,” said Etwert. “We’ve already completed three of the projects and we expect another to be completed by the end of September; two more by the end of the year; one should be finished in March, and the last by May of next year. We hope to have the FEMA accreditation by the end of 2016. We were hoping to have it done by the end of 2015 but with the delays we’ve gotten pushed back.”
More troubling, however, is work on a stretch of the levee that is the full responsibility of the U.S. Army Corps of Engineers. That 8,000-foot portion of the Wood River Levee runs from the Mel Price Locks and Dam upstream to the Alton Marina. In 2009, Col. Thomas O’Hara Jr., then-commander of the Corps’ St. Louis District, held a meeting with local elected officials to explain the problem and the Corps’ proposed solution. The area suffers from under seepage due to design flaws when the dam was moved downstream in 1990. While some under seepage is not unusual with levees, this was different, according to the Corps.
“This is the only levee we’re aware of within the Mississippi Valley Division that under normal operating conditions is moving both water and material,” Chris Wilson, the Corps’ program manager for the Metro East Levees Program, was quoted as saying at that meeting. “That condition compels urgency. The levee is not at imminent risk of failure today, but it does require immediate attention. It’s a problem that won’t fix itself.”
The planned solution was to install a cut off wall as deep as 140 feet to prevent under seepage. The plan was initially approved by the Corps’ regional headquarters, said Corps spokesperson Mike Petersen, but had to be nixed when exploratory drilling discovered large boulders in the way.
“We had a plan approved to construct a deep cut off wall with relief wells along that segment of the levee,” Petersen said. “It was planned to go as deep as 140 feet. We got our funding in 2013 and started doing the exploratory drilling necessary to do a complete design. During the exploratory drilling we discovered that there were boulders as big as a Volkswagen Beetle in this stretch of the levee. When we discovered those boulders, we decided we needed to talk to people in the construction industry who specialize in deep cut off walls. Through workshops with people in the industry, we determined that cut off walls would not be a viable option. That sent us back to the drawing board.”
And the Corps is still at the drawing board. Petersen said that Corps engineers are currently working on a permanent solution that would restore that section of the levee to the 500-year flood protection standard, but they don’t expect to be able to complete that plan and get headquarters approval for another year.
In the meantime, the Corps has installed instrumentation to better understand the under seepage problem and has developed an interim solution that can be employed when high water levels require it.
“In 2014 we had a pretty serious flood and we used air compressors to push water through the relief well system more quickly,” Petersen said. “The effect on the pressure on the levee is about the same as reducing the water level 4 feet. By making the relief wells work at a faster rate, it reduces the pressure of under seepage. They run an air hose down into the relief well and percolate the water up at a faster rate, reducing the pressure on the system. It’s a very innovative approach. We put it into effect twice in 2014. This year we had the compressors on standby and ready to go but didn’t need to use them. It’s expensive but it’s effective in reducing pressure on the levee. The instrumentation that we’ve installed shows us how well this system performs and it performs really well.”
That interim solution may have to work for quite a while. Once the Corps develops its permanent solution and gets it approved by headquarters, there is no money to fund construction—an amount that has not yet been determined. Funding, Petersen said, would depend on the budgeting cycle.
“We want to make sure that we can reduce risk,” Petersen said. “There’s a huge value behind that levee in human lives plus more than $7 billion in property and infrastructure. There’s a lot to protect. While we’re waiting for the permanent fix, the interim operating plan really does deliver that risk reduction.”
Etwert does not expect the lack of a permanent fix on the upper Wood River levee to hold up FEMA accreditation, however.
“The Corps is doing the certification for that portion of the levee system,” Etwert said, “and FEMA is willing to accept their certification which includes the Corps of Engineers providing an interim flood-fighting operation plan during periods of high water until the Corps can build a permanent solution. It’s one federal agency accepting that another federal agency will take care of the situation.”