ST. LOUIS (AP) -- The Army Corps of Engineers is monitoring a major Mississippi River levee near St. Louis after discovering a problem that could cause it to fail.
Corps officials said Thursday that the Wood River Levee is not in imminent danger, but it needs to be fixed before the next big flood. A repair plan and cost estimate have not been determined."It is an urgent situation, and it does need to be addressed as soon as possible," said Chris Wilson, program manager for the corps office in St. Louis.
The levee protects thousands of homes, businesses and industrial sites in the Illinois communities of Alton, East Alton and Wood River. If it broke, flooding would cause damage estimated at $350 million.
Corps officials met Wednesday with county and community leaders. Calls to several officials were not returned.
The corps first became concerned in July when water was found seeping through the levee near the Melvin Price Locks and Dam, near Highway 143.
It was in an area where water that naturally seeps in and rainfall collect for draining or pumping back into the river. While some seepage is normal, the amount in July was enough that the corps began frequent monitoring.
Then, about three weeks ago, "sand boils" were discovered. Sand boils occur when river water on the outside of the levee creates enough hydrostatic pressure to push soil, and water, to the surface on the inside. Eventually, the flow can erode the levee foundation and cause failure.
Corps officials said the problem is even more pronounced during periods of high river levels. Heavy rain has occurred throughout the fall in the Midwest, and the river rose above flood level last month -- unusual for this time of year. More rain this month has pushed the Mississippi above flood stage again in Alton.
On Thursday, the river was a half-foot above flood stage and expected to stay at that level or slightly higher until Monday.
Corps spokesman Alan Dooley said engineers have short-term solutions in mind if the river should suddenly rise to significant flood levels.
The corps believes the problem is partly due to relocation of the locks and dams about 25 years ago, when Lock and Dam 26 was moved about two miles downstream. The move caused a significant and permanent increase in the pool of water that sits against the levee, putting more pressure on the structure.
As a result, the repairs will be funded entirely with federal money. Wilson said the corps expects to have a cost estimate, repair plan and request for funding before Congress by the end of the year.
(Copyright 2009 by The Associated Press. All Rights Reserved.)
