After reaching major flood stage last week, the Mississippi River continues a steady decline of more than one foot per day in St. Louis and Monroe County.

On Tuesday, the river measured at 33.3 feet in St. Louis, down significantly from last Tuesday’s crest of 40.52 feet. Barring any major rainstorms here and throughout the Upper Midwest, the river is expected to drop to 30.9 feet on Friday — just barely above minimum flood stage.

The only slight flood-related hiccup reported in Monroe County last week was the detection of several sand boils Thursday near the levee at Riechmann Road and Merrimac Road north of Valmeyer.

The U.S Army Corps of Engineers received assistance from area fire departments, emergency management personnel, and other city and county officials in tending to the sand boils.

A local farmer first observed the sand boils bubbling in a field and notified emergency officials.

Corps members stressed that the situation was not uncommon with such a high river elevation. Sand boiling is a result of hydrostatic pressure of the high water on the outside of the levee. This forces water through the ground and it rises to the surface. Left undetected, sand boils can eventually lead to a levee collapse.

“We’re just gonna try and take care of them. No need to panic,” Brian Mehrtens of the Columbia Levee and Drainage District said at the scene on Thursday.

And take care of them, they did.

Corps sector engineer Keith McMullan joined fellow Corps officials David Gordon, Janet Ulivi and Mario Guerrero in overseeing a plan to surround the most serious of the sand boils closest to the levee by using a ring of sandbags.

One by one, volunteers passed sandbags in a line from a county highway department truck to the sand boil area in a muddy field.
The first sandbags used Thursday were leftovers from the Flood of 1993, trucked in from a county storage yard adjacent to Rock City in Valmeyer. Once those were used up, volunteers were put into action and more bags were filled with sand to be trucked to the affected area.

Other smaller sand boils in the area were treated with “stand-pipes,” or portions of metal culverts used to apply pressure.
McMullan assessed the situation Friday morning, and told the Republic-Times it appears Thursday’s efforts to contain the sand boils were successful.

“All of them have shut down, so that’s great,” he said. “They are stagnant, with no movement of materials. We believe we have it under control.”

McMullan added that with the continued river recession, the risk of similar incidents is diminishing day by day.

Some much smaller “nickel and dime” sized sand boils were also detected near the Prairie du Pont levee northwest of Columbia last week, McMullan said, but they were deemed so minor that no action was required.

Many county roadways located in or near the bottoms, including Bluff Road, have reopened as standing water is no longer a concern.

Other related articles:

• Sand boils detected near levee north of Valmeyer
• River reaches major flood stage, but no problems locally