Oakville, Iowa ? Even before the Iowa River used this town as a shortcut to the Mississippi, there wasn’t much here: A post office, a convenience store, a tavern and a little restaurant.

The largest employer was a pork-and-grain producer called TriOak Foods. The company’s towering grain elevator was the tallest structure for miles around.

Then the floodwaters soaking much of the Midwest turned their force on the region’s small communities – most with skylines that consist only of a water tower and maybe a couple of church steeples.

As the rivers rise, these modest towns survive because neighbor helps neighbor, and the people reinforcing the levees are business owners, farmers and fellow church members who have lived there for years.

“My house is past help. So we’re trying to save everybody else’s,” said Bethany Frank as she helped fill sandbags in a church parking lot in Oakville, about 40 miles southwest of Davenport. Her home on the outskirts of town was flooded up to the roof.

On Wednesday, Iowans assessed their losses from flooding that inundated Des Moines and Iowa City. But small towns up and down the Mississippi still awaited the worst of the flooding. Some rivers were not expected to crest until Thursday.

Storms and flooding across six states this month have killed 24 people, injured 148 and caused more than $1.5 billion in estimated damage in Iowa alone – a figure that’s likely to increase as river levels climb in Missouri and Illinois.

Federal officials predicted as many as 30 levees could overflow this week, leaving industrial and agricultural areas vulnerable but sparing major residential centers. So far this week, 20 levees have overflowed.

At least 10 levees have been topped in Illinois and Missouri in recent days, including two south of tiny Gulfport, Ill., that threatened to swamp 30,000 acres of farmland near the evacuated town of Meyer, Ill.

A 280-mile stretch of the Mississippi River remained closed between Fulton, Ill., and Winfield, Mo., because of flooding, and is expected to remain closed for at least 10 more days. Lynn Muench, of the towboat and barge trade group The American Waterways Operators, said as many as 10 tows – each with as many as 15 barges – were stuck on the upper Mississippi River.

Missouri Gov. Matt Blunt sent 600 members of the National Guard to the northeastern part of the state, plus another 100 to the St. Louis area to help towns further downstream. In Illinois, 1,100 Illinois National Guard troops have been sent to help flooded communities.

“My property is right on this street. I’ve got a lot to lose,” said Tony Dye, whose home in Canton, Mo., stands beneath the levee and well below the river’s expected crest. The river was projected to crest at Canton Thursday at nearly 14 feet above flood stage.

Even if population hubs are spared, some fear entire communities may be lost forever, possibly wiping off the map names such as Columbus Junction, Fredonia, Palo and New Hartford.

About 70 percent of Iowa towns have populations of less than 1,000. Just over half of those places have fewer than 500 inhabitants.