The weakest spot left along the Mississippi River may be the Pin Oak levee, a barrier so tenuous that soil slides down its slope. Only National Guard soldiers and firefighters in life vests were allowed to stack sandbags, because volunteers and heavy equipment could sink. A muskrat recently created a geyser of river water by digging into the berm.
But the earthen levee is all that's still protecting 100 houses, a city park, several businesses and 3,000 acres of agricultural land in east Winfield, one of the last towns where the upper Mississippi was expected to crest.
For days, emergency management officials in Lincoln County have focused on the 21/2-mile-long levee about 45 miles north of St. Louis. A storm with thunder and lightning Tuesday was only the latest impediment to the desperate attempts to shore up the Pin Oak.
“This storm is not a good thing,” said Jeff Stamper, a structural engineer with the Army Corps of Engineers. “It pulled everyone off. You can work on a levee in the rain, but not in lightning.”
While levees in the nearby communities of Elsberry and Old Monroe held strong, an urgent call went out this week for volunteers to fill up to 50,000 sandbags in Winfield.
The Mississippi was expected to crest at Winfield late Tuesday night and to flow at its high-water mark – more than 11 feet above flood stage – for two more days. A disturbance as minor as a passing boat could lead to disaster.
“A 2-inch wake could be the difference between saving the levee and catastrophic failure,” said Andy Binder, Lincoln County emergency management spokesman.
Overnight and into Tuesday morning, the porous and heavy soil inside the levee created what's called a slide, or a run of soil sinking down the slope of the levee's dry side.
At first light Tuesday, workers used heavy sheet plastic and about 5,000 sandbags to create a 15-by-160-foot “mattress” to add weight and pressure to the weak spot.
“Do we expect more slides? Absolutely,” Binder said.
Officials spent nearly six hours choking off the leak caused by a muskrat burrowing in the soft ground early Monday.
Several miles down the river, the Elm Point levee in St. Charles succumbed Tuesday. But the breach there swamped only a soccer field and a sod farm, and officials said residents of a nearby mobile home park would likely stay dry.
The river continued to recede Tuesday from the Iowa line down through the lock and dam at Saverton, about 90 miles north of St. Louis.