Aerial View north of Prairie Du Pont Levee District and the Mississippi River
Behind more than 200 miles of levees in the metro-east are at least 160,000 residents who would be at risk of losing their properties or even their lives to flooding if water from the rising Mississippi River broke through the embankments.
The U.S. Army Corps of Engineers and the local leaders who maintain the levees say they are in “much better shape” in 2019 than they were in 1993, when the water levels reached a record 49 feet and an overflowing Columbia levee destroyed the village of Valmeyer.
But the Mississippi River brings a new challenge as it is expected to reach its second-highest level over the weekend at 46 feet: An even longer period of high water than during The Great Flood of ’93 saturating the dirt walls of the levees.
They successfully held back water that was above the flood stage for 104 consecutive days in 1993, according to Dave Busse, chief of engineering and construction and the levee safety officer for the Corps of Engineers’ St. Louis District.
He said it will “almost certainly” be longer this time. The river isn’t expected to fall below that level for at least four weeks after the crest, which would mean the levee walls are up against high water for a total of 113 days.
Engineers have made millions of dollars worth of repairs since 1993 that will be put to the test.
“We designed them to be able to be against water for a long time,” Busse said. “They are not built as dams, so it’s not infinite.”
Adding to the concern is the fact that four of the highest eight crests in the Mississippi River’s history have been recorded in the past three years, including just last month on May 6, when the water reached 41 feet.
The National Weather Service meteorologist who works for the Corps of Engineers is predicting a “fairly wet summer,” according to Busse. And the reservoirs that have been holding back even more water from the levees will continue releasing it into the summer and fall, keeping the Mississippi River at a moderate level, he said.
“I think I would have major heartburn if the flood stayed on it through Christmas,” Busse said. “... If by fall the water goes down, we should be in good shape.”
Daily levee monitoring
Engineers, National Guard troops and leaders from levee districts and emergency management agencies have been closely monitoring the levees in Southern Illinois each day.
In the metro-east, a total of 39 levees cover 234 miles. They were built to hold up to 54 feet of water from Alton to East St. Louis and 48 feet from Columbia to Prairie Du Rocher, according to Busse, which is why an overflow like in 1993 isn’t a concern with this near-historic crest of 46 feet.
Instead, officials are looking for any sign the dirt, clay or metal that support the levees are weakening and taking action when they spot trouble.
Water pooling near a levee, for instance, could be a “sand boil,” when water seeps under a levee and comes up through the ground bubbling — or “boiling” — like a natural spring. That movement of water can make the levee’s soil unstable and cause it to fail, according to the Corps of Engineers.
And the consequences of a levee failure could be devastating in the metro-east. They protect thousands of people and $18.5 billion in infrastructure, according to a Belleville News-Democrat analysis of the Corps of Engineers’ National Levee Database.
The database includes the results of the Corps of Engineers’ in-depth inspections of levees, which occur about every 10 years. The assessments of metro-east levees, mostly from 2016 and 2017, showed that the engineers were most concerned about the water seepage causing a failure if left unchecked.
Busse said they assumed there would be sand boils to battle when the water reached 45 or 46 feet.
“I don’t have a great deal of undue concern,” he said. “... Sand boils are not necessarily great for the levee, but they are not occurring at a level we were not expecting.”
Kevin Scheibe, assistant director of the Monroe County Emergency Management Agency, has said it took 1,800 sandbags to contain just two sand boils there recently.
The agency asked for volunteers to help fill sandbags at the end of May, so officials could have at least 15,000 ready for the flood. Sandbags are also used to stack along levees in low-lying areas to increase their height as the water rises.
Busse said more rain in the forecast could mean overflowing becomes more of a risk for the levees that can only hold 48 feet of water in Monroe and Randolph counties, including the Prairie du Rocher and Edgar Lake levee system; the Harrisonville, Stringtown, Fort Chartres and Ivy Landing levee system; and Columbia Drainage and Levee District No. 3, named for the district that maintains it.
Workers from the Columbia Drainage and Levee District No. 3 had tried to use sandbags to increase the height of the Columbia levee in 1993, but it overflowed when they couldn’t keep up with the floodwaters, according to Busse. He said they’ve learned how to control the water coming over the levee through sandbagging from that experience so it flows into the lowest level of district instead and loses momentum.
“There’s a way to raise the levee and do it smartly, and the levee district is all over that,” Busse said.
Monroe County Sheriff Neal Rohlfing said officials have also come up with a back-up plan in case the Columbia levee fails again. If that happens, Rohlfing said they will use a controlled breach in another levee in the Harrisonville, Stringtown, Fort Chartres and Ivy Landing system at Fountain Creek, which cuts off the Columbia basin to the rest of the county.
He said if they had done that in 1993, experts believe they could have saved the rest of the county, including Valmeyer. Most Valmeyer residents have moved out of the floodplain where the village operated in 1993 to the top of the bluffs after the flood wiped it out.
Officials have been encouraging Monroe County residents whose homes could be at risk of flooding to evacuate in recent days until they’re sure that conditions are safe. As of Friday, Rohlfing said most of them had already left.
Past levee repairs and maintenance
Residents and visitors have been paying a higher sales tax on purchases in St. Clair, Madison and Monroe counties for the last 10 years to stabilize some of the metro-east’s levee systems, including the largest one that stretches from Edwardsville to East St. Louis.
The Southwestern Illinois Flood Prevention District Council has used the money to make nearly $75 million in improvements, like adding clay to areas where water was seeping through the soil, as well as new piping, pump stations and relief wells, according to Chuck Etwert, chief supervisor of Construction and the Works for the council.
Etwert described it as “money well spent,” not only because it protects residents and their properties from flooding, but also because it means new infrastructure can be built like an Amazon warehouse constructed in Edwardsville.
“Those type of developments wouldn’t come,” Etwert said. “They’re looking at the area, and they know we’re working on improving the levees.”
More work is planned; Etwert said construction is scheduled to begin in the fall to further strengthen the levees against floodwaters.
Busse, of the Corps of Engineers, said that ongoing maintenance by the council and other local levee districts like the Metro East Sanitary District is important because regular flooding weakens a levee. He lives in Madison County, so he also pays the 0.25% sales tax for flood prevention.
“Every flood takes a little bit out of a levee,” Busse said. “... You don’t build a levee, walk away and say, ‘It’s good forever.’”
Reporter Kavahn Mansouri contributed to this report.