SIKESTON, Mo. — The Army Corps of Engineers exploded a large hole in an earthen levee late Monday, unleashing a muddy torrent into empty farm fields in a desperate bid to save an Illinois town from rising floodwaters.
Engineers announced their intention to carry out the blast after spending hours pumping liquid explosives into the Birds Point levee near tiny Cairo, Ill.
But doubts persisted about whether breaking open the levee would provide the relief needed. How much water would the blast really divert from the Mississippi River? And will authorities have to do the same thing at other trouble spots downstream?
Time was running short to find answers. Five more inches of rain fell overnight, further straining the floodwall protecting Cairo. More was in the forecast.
The seemingly endless rain has overwhelmed rivers and strained levees, including one protecting Cairo, at the confluence of the Ohio and Mississippi rivers.
Flooding concerns also were widespread Monday in western Tennessee, where tributaries were backed up due to heavy rains and the bulging Mississippi River. Streets in suburban Memphis were blocked, and about 175 people filled a church gymnasium to brace for potential record flooding.
The intentional breach of the Birds Point levee was expected to do little to ease the flood dangers there, Tennessee officials said.
The Ohio River was expected to crest in Cairo late Wednesday or early Thursday at 63 feet — a foot below the level that Cairo’s floodwall is built to hold back — before starting a slow decline by Friday.
The high water has raised concerns about the strain on the floodwalls in Cairo and other cities. The agency has been weighing for days whether to blow open the Birds Point levee, which would inundate 130,000 acres of Missouri farmland.
Engineers think sacrificing the levee could reduce the water levels at Cairo by about 4 feet in less than two days. Meteorologist Beverly Poole of the National Weather Service put the figure closer to 5 feet.
“These are uncharted territories, but it would be very fast,” she said.
Carlin Bennett, the presiding Mississippi County commissioner, said he was told a 10- to 15-foot wall of water would come pouring through the breach.
“Tell me what that’s going to do to this area?” he said. “It’s a mini-tsunami.”
Maj. Gen. Michael Walsh — the man ultimately responsible for the decision to go through with the plan— has indicated that he might not stop there if blasting open the Missouri levee does not do the trick. In recent days, Walsh has said he might also make use of other downstream “floodways” — basins surrounded by levees that can intentionally be blown open to divert floodwaters.
Among those that could be tapped are the 58-year-old Morganza floodway near Morgan City, La., and the Bonnet Carre floodway about 30 miles north of New Orleans.
