Mississippi River water began rushing across tens of thousands of acres of Missouri farmland on Tuesday after the U.S. Army Corps of Engineers intentionally blew up a large section of a levee in hopes of preventing catastrophic flooding in Illinois.

The Army Corps exploded the Birds Point levee near Wyatt, Mo., after nightfall Monday, potentially sacrificing 130,000 acres of rich farmland and about 100 homes in Missouri to spare the town of Cairo, Ill., with its 2,800 residents, located at the confluence of the Ohio and Mississippi rivers.

But even as the Corps carried out its bid to save the city, floodwaters were rising downriver, including in Memphis, Tenn. And the breach in the Birds Point levee wasn’t expected to ease those flooding concerns.

Army Corp of Engineers Maj. Gen. Michael Walsh, who made the decision to blast, said it was a heart-wrenching but necessary move.

“Making this decision is not easy or hard,” Walsh said. “It’s simply grave, because the decision leads to loss of property and livelihood, either in a floodway or in an area that was not designed to flood.

“Right now, the system is under tremendous stress and the Cairo gauge continues to rise, and it’s just going to continue to rise until we operate it,” he said.

Walsh said the move should lower the river levels by 4 feet or more upriver by early Wednesday, but warned that the historic flooding in the region was far from over. More rain was in the forecast, and the Corps might need to do the same thing downriver to prevent flooding farther south.

Farmers and residents of Wyatt, close to the levee, gathered just after dawn Tuesday to survey the several feet of murky brown water that had spilled into their fields. A small cluster of cattle stood grazing on the slope of the levee, and National Guard soldiers patrolled the area.

Travis Williams, 34, a farmer who owns more than 1,000 acres now under water, said his home is safe because it is on “the good side of the levee.”

“It’s a life-changing event,” Williams said. “My heart goes out to all the farmers who lost their land and homes.”

Billy and Tammy Suggs, who live in Wyatt, opened up the town’s tiny city hall so people would have a place to gather and mourn together as the blast occurred Monday night. They said it was a lot stronger than expected, knocking out windows in several homes.

“We went around putting boards up to keep the rain out,” Billy Suggs said.

The National Weather Service said the initial blast had a dramatic effect on the water level in Cairo. Before the breach, the river was at 61.72 feet and rising. As of Tuesday morning, the river was at 60.62 feet and was expected to fall to 59.4 feet by Saturday, it said on its website.

Flooding concerns also are widespread in western Tennessee, where tributaries have been backed up due to heavy rains and the bulging Mississippi River. Streets in suburban Memphis were blocked, and some 175 people filled a church gymnasium to brace for potential record flooding.

Walsh has said he might also make use of other downstream “floodways” basins surrounded by levees that can 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. The Morganza has been pressed into service just once, in 1973. The Bonnet Carre, which was christened in 1932, has been opened up nine times since 1937, the most recent in 2008.

The corps has said about 241 miles of levees along the Mississippi River between Cape Girardeau, Mo., and the Gulf of Mexico need to be made taller or strengthened. George Sills, a former Army Corps engineer and levee expert in Vicksburg, Miss., said the volume of water moving down the river would test the levee system south of Memphis into Louisiana.

“It’s been a long time since we’ve seen a major flood down the Mississippi River,” Sills said. “This is the highest river in Vicksburg, Miss., since 1927. There will be water coming by here that most people have never seen in their lifetime.”

Engineers carried out the blast on the Missouri levee after spending hours pumping liquid explosives into the floodwall. The blast allowed water to pour into the river basin like a bathtub. Two subsequent blasts further south on the levee, both scheduled for Tuesday morning, were intended to allow some of that water to escape back into the Mississippi.

The destruction of the levee became necessary after another onslaught of rain Sunday and Monday. Parts of southern Missouri have received more than 20 inches of rain in the past 11 days.

Missouri officials fought hard to stop the plan, filing court actions all the way to the U.S. Supreme Court. Rep. Jo Anne Emerson, a Republican from nearby Cape Girardeau, stood beside Walsh as he announced his decision Monday, but she was clearly unhappy.

“We’re uprooting families that have been here six generations and you don’t even know if it’s going to work,” Emerson said.

The explosion came just before 10 p.m., lasting only a few seconds, with reporters watching from about a half mile off the river.

In largely evacuated Cairo, police Chief Gary Hankins watched the orange flashes and was hopeful. “We had periods here where there were lulls, but it seems like lately we couldn’t catch a break,” he said. “Maybe it seems now like we might be at a turning point. This sort of makes it easier to be optimistic.”

On the other side of the river, Mississippi County, Mo., commissioner Robert Jackson said farewell to his family’s 1,500 acres of farmland. But he also tried to stay positive.

“We can’t start drying up until we finish getting wet,” he said. “I hope this mission accomplishes what they wanted it to and the sun will shine again.”

NPR’s David Shaper reported from Chicago for this story, which contains material from The Associated Press. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.