An estimated 9.2 square miles, or 1,300 blocks, were flooded in Cedar Rapids, fire department spokesman Dave Koch said. Early estimates put property damage at $736 million, Koch said.
But, as CBS News correspondent Dean Reynolds reports, some residents were intent on getting back to work and some semblance of a normal life. Outside office buildings in Downtown Cedar Rapids, people eager to get back to their businesses had to bring flash lights to gain entry to their buildings.
"I need contracts. I need payroll," one woman told Reynolds.
Elsewhere in the city, some residents tried to assess damage to their homes while others, like 91-year-old Julia Bennett, remained in shelters set up by the city.
"We have to help each other," Bennett told Reynolds. "We can't be isolated."
The drenching has also severely damaged the corn crop in Iowa, America's No. 1 corn state, and other parts of the Midwest at a time when corn prices are soaring and food shortages have led to violence in some poor countries. But officials said it was too soon to put a price tag on the damage.
While the Cedar River ebbed in hard-hit Cedar Rapids, a levee breach in the state capital of Des Moines flooded a neighborhood of more than 200 homes, a high school and about three dozen businesses.
More than 200 homes were evacuated in Iowa City, home of the University of Iowa, as a flood crest headed down the Iowa River. The Iowa City crest is not expected until Monday or early Tuesday.
At least three deaths in Iowa have been attributed to the storms and subsequent flooding, and 12 more have died in two recent tornadoes. The storms have prompted the governor to issue disaster proclamations for 83 of the state's 99 counties.
Elsewhere, Illinois emergency authorities said a levee along the Mississippi River in far western Illinois burst Saturday morning and voluntary evacuations were under way in Keithsburg, a town of about 700 residents.
"The levee broke in two places," said Keithsburg Alderman George Askew, 76. "We're getting under water."
Democratic presidential candidate Sen. Barack Obama toured Quincy, Illinois, and helped fill sandbags Saturday.
"Since I've been involved in public office we've not seen this kind of devastation," Obama said of the Midwest flooding. He vowed to push the federal and state governments to provide needed aid to the stricken areas.
Parts of southern Wisconsin have been dealing with flooding for days, and President George W. Bush declared disasters in five counties there Saturday. West of Milwaukee in Summit, authorities on Saturday found a man's body near his vehicle on a flooded road, but it was unclear whether the death was flood-related.
Iowa's worst damage so far was in Cedar Rapids, a city of more than 120,000. The Cedar River crested there Friday night at nearly 32 feet, 12 feet higher than the old record set in 1929. City Engineer Dave Elgin said the Cedar River was dropping at a rate of about 2 inches an hour Saturday.
Murky, petroleum- and garbage-choked water inundated three collection wells and threatened the fourth before several hundred volunteers staged a last-ditch sandbagging operation.
Water lapped to within 3 feet of the improvised, 4-foot-high wall surrounding the brick pumping station before it began to recede. Two portable generators, one as big as a semitrailer, roared around the clock to keep the three pumps inside running.
"It's the little engine that could," said Ron Holtzman, one of several people who came to watch the operation Saturday from a nearby foot bridge.
Residents not forced to leave their homes took the warnings to conserve seriously.
Kathy Wickham, 65, was collecting water from the dehumidifier in her basement and has been bathing from the enamel washbasin she used as a child on the farm.
"I grew up without any running water, so I'm going back to my childhood," she said.
About 100 miles to the west in Des Moines, a levee ruptured early Saturday and the Des Moines River poured into the Birdland neighborhood near downtown. A mandatory evacuation was ordered for 270 homes; many of those residents had left after a voluntary evacuation request Friday.
Des Moines city crews and National Guard units started to build a temporary berm in a bid to stop the water, but by midmorning the water had cut through mounds of dirt and sandbags and inundated the homes.
Authorities knew the aging levee near Birdland, a working-class, racially diverse neighborhood, was the weakest link among the city's levees. A 2003 Corps report called for nearly $10 million in improvements across Des Moines, but there was not enough federal money to do all the work.
"This was the first to fail, and we felt it was the one likely to fail," said Bill Stowe, the city's public works director.
Some residents were upset that other areas of city have received more flood-control improvements than Birdland since massive floods hit the area in 1993.
Just south of Cedar Rapids in Iowa City, the Iowa River is expected to crest at 33 feet to 34 feet late Monday or early Tuesday, far above the 25-foot flood stage.
At the University of Iowa, students, faculty, townspeople and National Guard units filled thousands of sandbags in the area known as the Arts Campus.
"We've pretty much just abandoned any effort to try and protect the Arts Campus because we are just overwhelmed by the amount of water," university spokesman Steve Parrott said. "It's just too unsafe."
Valuable paintings have been removed from the art museum, Parrott said.
Elsewhere at the university, reports CBS News correspondent Hari Sreenivasan, the sandbagging effort has brought students and alumni together to help as best they can.
"You know what this is," asked Jane Meyer, an athletic coordinator at the university. "The hawkeye spirit, people volunteering to help the university that they love."
Iowa has had a wet spring and at least 8 inches of rain since June 6. More thunderstorms are possible in the Cedar Rapids area during the weekend, but next week is expected to be sunny and dry.