Mon, 10 Jun 2013 16:45 UTC
Gramling said as the waters of the Mississippi River rose to above flood stage for the second time this spring, the problem worsened. He said one of the sinkholes on South Sprigg Street is about 50 feet in diameter and about 15 feet deep. A second sinkhole near the end of the bridge over the creek is 20 to 25 feet in diameter and is roughly 6 to 8 feet deep.
"And it's growing as we're talking," he said.
The water erodes the soil, causing more sinkholes.
Gramling said employees from Buzzi Unicem are working to address the creek sinkhole. He said the company is damming the creek by the bridge, attempting to isolate the water and keep down the flow into the quarry.
"They're not shut down, but they're trying their best to keep the water down," he said.
City employees are monitoring the creek bridge.
"It hasn't been affected," Gramling said. "We keep an eye on it."
The city and Buzzi Unicem have attempted in the past to fill the sinkholes with rock and concrete, to no avail.
"You can put stuff in them and it just disappears and we've done that for several years," Gramling said. "If we filled the holes up, by tomorrow [the fill] would be gone."
While the crest of the Mississippi River at just short of 45 feet on Friday at Cape Girardeau is good news in many ways, Gramling said it isn't much help as far as the sinkholes are concerned.
"When the water goes down, it actually aggravates them," he said. "It could aggravate them and make them worse."
Gramling said Ameren is keeping a close watch on a major natural gas line that runs through the problem area.
Asked if there's much that can be done, Gramling was not optimistic.
"Not really; just keep an eye on it," he said. "Right now the main thing is safety for the public. It's very dangerous; it's very unpredictable; it's random. It's just not a place for people to be walking around, unless they're emergency workers."
As for the future, the permanent closure of Sprigg Street in the area of the creek is a possibility. The city had to change plans to expand its wastewater treatment plant -- the first few sinkholes were noticed south of the plant -- and instead build a new one in another location.
Gramling said not to expect the closed portion of Sprigg Street to reopen any time soon.
"It will probably be closed now for a while," he said.