Walsh, president of the Mississippi River Commission, on Sunday directed U.S. Army Corps of Engineers crews to move barges of explosives across the river to Missouri and load the pipes with the blasting agents that, if detonated, would send water flowing over more than 130,000 acres in Mississippi County.
The order came about 3:30 p.m. Sunday and corps officials said loading the pipes with the "slurry" -- a liquid mix of aluminum powder and sodium perchlorate -- would take about 20 hours, meaning the work should be completed by noon today.
Walsh said he would review the situation continuously as conditions change. The next step, and the final one, would be to activate the floodway by artificially breaching the levee. The final decision to activate the floodway has not been made, the corps said.
Nixon said his first priority, if the corps moves forward with its plans to intentionally blow the levee, is safety.
"We're not happy about what's going to occur here, none of us are, but if it's going to be done we're going to do it safely, in an orderly fashion, and we're going to do our best to defend it and we're in it for the long haul," he said.
Nixon pledged state aid to the residents of Mississippi County and others in Southeast Missouri affected by flooding, including Sikeston and Morehouse.
"While this is a dramatic step that will be occurring, most probably here, it's important to know we have folks working, backing up emergency responders, ready to assist," Nixon said.
About an inch and a half of rain was dumped on the region Saturday night and weather forecasters were calling for 3 to 5 inches of rain by Tuesday. The Birds Point New Madrid Floodway plan calls for activation at 61 feet and rising on the Cairo gauge, and it topped 60 Sunday afternoon.
According to the National Weather Service, the gauge at Cairo was at 60.33 at 9 p.m. Sunday. The Ohio is predicted to hit 61.3 -- above the 61 feed needed to activate the flood plan -- Tuesday.
Corps spokeswoman Lisa Coghlan said Walsh opted to pump the slurry into the pipes due to the fast elevation of floodwaters.
"Gen. Walsh will make another determination [today] and, if he says so, we'll be ready to go," she said.
Still, at a news conference Sunday at the Cape Girardeau Regional Port Authority in Scott City, Walsh said blowing the levee was not a foregone conclusion. He flew over the region with Sen. Roy Blunt, R-Mo., and U.S. Rep. Jo Ann Emerson, R-Mo.
Walsh said he suspected that the corps would have to operate the Bonnet Carre Spillway, a similar flood control operation in the Lower Mississippi Valley near St. Charles Parish in Louisiana. They may even have to activate the Morganza Spillway in east-central Louisiana as well, he said.
"[Saturday] night we hit a historic event," he said. "That's when the Cairo gauge went to 59.69. Before that, the highest ever was 59.5. That's a record high at the Cairo gauge."
Walsh said he's still watching forecasts, stresses on an already deluged flood-protection system and will keep the safety of his crews in mind before making a decision to blow the levee. He said he is concerned about sand boil problems in Cairo as well as similar problems further downriver. But, as of now he said, the system is sound and would withstand the pressures of activating the floodway.
"We've been able to stabilize areas that have been degrading, because of the hard work of volunteers and the National Guard," he said. "But we need to be vigilant and continue to do what we're doing -- walking and driving the levees to see if there's any other impacts we have to get to."
Dams holding water upstream, such as those at Kentucky Lake and Lake Barkley, are at capacity. More water may have to be released so those flood-protections don't fail and that would only add to the problem here, he said.
If Walsh decides to activate the levee, he said, he would let the governors of Missouri and Illinois know immediately, and he's already been in daily conversations with them. He hoped to give the public a 24-hour notice, but he stopped short of promising that.
Emerson said at the news conference she was still hopeful that the levee would not have to be breached. Farmers who live in the spillway have said it would cost them financially as well as do irreparable damage to the land. A corps agricultural economists has estimated the impact would top $300 million, though he said not blowing the levee could cost more than $1 billion.
"I'm fortunately not the person who makes this decision," Emerson said. "I think these people know what my decision would be. But I'm also not an engineer."
Southeast Missourian writer Melissa Miller contributed to this report.
SEMO Port Authority, Scott City, MO