Burrowing muskrat brings down Pin Oak levee at Winfield, Mo.

WINFIELD, Mo. -- Defiant residents of this eastern Missouri community lost one brave struggle against the relentless Mississippi River Friday, but quickly began another.

Residents and flood fighters were saddened after a burrowing muskrat brought down the saturated Pin Oak levee shortly before dawn. But within hours, a new defense was in the works -- a hurriedly constructed sandbag levee to protect the 100 homes in harm's way.

"We're not quitting -- the Army doesn't quit," said National Guard Col. Michele Melton, who was coordinating the sandbagging effort. "That's why we're here -- to try and save these people."

The struggle to save the levee has been a round-the-clock effort for the past several days. Many of the 720 residents of Winfield and people from surrounding communities joined the National Guard in patching one trouble spot after another.

In the end, all that effort was undone by an animal that weighs no more than 5 pounds. Officials said holes dug by a muskrat that was either seeking food or building a den led to the levee's downfall.

"How bad do I feel? You have no idea," said Travis Tutka, the Corps of Engineers' dam safety expert who has helped coordinate the effort to save the levee. "The challenge we met for so long out here -- I can't come up with the words for the feeling. The levee did as well as it did because of the resolve of the people who worked on it."

Resident Linda Wilmesherr was heartbroken. She operates a horseback riding school and essentially suspended the business so she and her workers could bring in equipment and help save the levee.

"It's so disappointing," Wilmesherr said, peering through binoculars at the water pouring through what appeared to be about a 30-foot gap in the levee. "With all the guns in this county, couldn't we kill a muskrat?"

The only bright spot was the site of the breach -- at the far southern corner of the levee. About 3,000 acres flooded before the water made its way to the cluster of homes at the north edge of the flood plain.

By afternoon, with water quickly approaching the homes, a convoy of military trucks and Humvees carried National Guard members, sandbags and equipment to the site. Already, a 4-foot-tall levee was in place. Dozens of volunteers filled sandbags at the high school while some 300 members of the National Guard worked on the levee.

The quick-built levee involves more than throwing sandbags onto a pile. Four-foot-tall Hesco walls -- connected walls of steel frame and cloth material filled with dirt -- are first placed down. More dirt is placed around them, then wrapped in plastic. Sandbags -- thousands of them -- go on top of the plastic to weigh it down and add height.

All told, the makeshift levee will stand 5 feet tall and more sandbags can be added to the top if needed, National Guard Col. Wendell Hagler said.

Gov. Matt Blunt got a look at the breach from a helicopter and called the effort to save the homes "a race against time."

"It really is just a reminder of how powerful a force the Mississippi River is as you watch it flow into the field," he said.

The muskrat holes were first discovered on Monday. Sandbags were placed at the spot.

"We thought we had that area controlled," Tutka said.

In fact, other areas of the levee had become more concerning. The constant pressure from the river turned the relatively small, private levee to mush. By midweek, mudslides were forming. Levee workers described the walk atop the levee akin to walking on a waterbed.

Officials were constantly patrolling the levee to check for weak spots. At 4 a.m. Friday, three corps officials visited the south end of the levee and all was fine. At 5:03 a.m., when members of the National Guard did a walk-by, they saw the break -- water was already violently pushing sandbags off the levee. It was too late to save it.

A siren sounded and sheriff's deputies went door to door to get everyone out of the homes in harm's way, yelling, "The levee broke! Get out!"

Winfield resident Debbie Halcomb, 52, was sleeping in a bed elevated on milk crates to protect it from potential floodwaters when the siren sounded.

"Oh my God. I was hoping it would hold, but it didn't," Halcomb said. "I think we probably lost it on this last bunch of rain."

Lincoln County authorities put out an emergency call for sandbagging volunteers to meet at Winfield High School. Only National Guard troops and emergency responders were allowed in the area around the homes.

Elsewhere in Missouri, the flood news was improving. Canton in far northeast Missouri lifted its voluntary evacuation, with officials saying the levee protecting the town of 2,500 residents was sound and the river level was dropping.

Still, Emergency Management Director Jeff McReynolds said residents and merchants who have moved furnishings to a secure area may not want to put them back just yet. With the river so high, heavy rain in the wrong place could still cause problems, he said.

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Associated Press Writer Betsy Taylor in St. Louis contributed to this report.