IOWA CITY, Iowa (AP) -- Record-high floodwaters that brought misery to some of Iowa's smaller river towns may have helped spare Iowa City from cataclysmic flooding, but the lingering high level of the Iowa River is giving the city's flood protections a marathon test.
The river's crest arrived early and lower than expected, possibly because of a number of levee breaches downstream that opened the channel, the National Weather Service said. But it still posed a lingering threat, and wasn't expected to begin receding until Monday night.
Hundreds of homes were evacuated near the river Sunday, though it wasn't immediately clear how many suffered damage. More than a dozen buildings on the University of Iowa campus had taken on water, but school officials said they believed others were protected.
As Iowa City hoped to elude the worst damage, the state had a multi-front battle on its hands. State officials warned of problems ahead for a string of towns in southeast Iowa along the Mississippi River, led by Burlington, a key railroad hub.
"It's likely that we will see major and serious flooding on every part of the southeastern border of our state from New Boston and down," Gov. Chet Culver said. "We are taking precautionary steps, we are evacuating where necessary, but that is going to be the next round here."
Early Monday, more than 36,000 residents in 26 communities had been evacuated from their homes, said Kevin Baskins of the state Emergency Operations Center. Most of those — 25,000 — were in Cedar Rapids, and another 5,000 in Iowa City, he said.
Sandbagging was under way in Ottumwa to protect the city's water treatment plant from the Des Moines River. Sandbagging was also being done in Burlington to build the city's levee system and protect it from the Mississippi River. Baskins said 350 people had been evacuated from their home in Burlington.
Also on the Mississippi River, the Army Corps of Engineers said Lock 12 at Bellevue, south of Dubuque, was reopened to river traffic on Sunday. But locks 13-25 remained closed, making 281 miles of the Mississippi from Winfield, Mo., to Fulton, Ill., inaccessible to commercial river traffic.
About 30 inmates from the Iowa State Penitentiary helped to sandbag in Burlington, a city of about 27,000. Already the city's four-story Memorial Auditorium was surrounded by water and some evacuations were under way.
In Iowa City, a town of about 60,000 where the Iowa River bisects both the school and the town, residents were cheered by the lower crest.
Donna Dubberke, a meteorologist with the National Weather Service in Davenport, said one reason that Iowa City's troubles may have eased was levee bursts down river.
"Downstream there are some levees that have broken and we believe that some of that water is able to go off in those areas so that just provides a little more storage," Dubberke said.
The University of Iowa said 16 buildings had been flooded, including one designed by acclaimed architect Frank O. Gehry. Some buildings have as much as 8 feet of water inside.
"I'm focused on what we can save," University of Iowa President Sally Mason said as she toured her stricken campus. "We'll deal with this when we get past the crisis. We're not past the crisis yet."
All elective and non-emergency procedures were canceled at the university hospital, and non-critical patients were discharged, Mason said. Nurses were brought in from elsewhere to ensure all emergency shifts would be covered.
Iowa City Mayor Regenia Bailey said 500 to 600 homes were ordered to evacuate and hundreds of others were under a voluntary evacuation order through Monday morning. The city had no estimate of the number of homes that had actually flooded.
Bailey said homeowners will not be allowed back until the city determines it's safe.
Culver said cities big and small were getting adequate support in their efforts to survive the flooding.
"While we are having challenges in our urban centers we have multiple ongoing battles in the smaller communities," he said. "And we are doing just as much to help those rural, more remote areas of the state."
The governor called word of Iowa City's crest "a little bit of good news." But he cautioned that the situation was still precarious.
The threat to southeast Iowa was already taking shape, though the Mississippi River is days from cresting. State officials girded for serious flooding threats, sending 500 National Guard troops to Burlington.
In Illinois, National Guard soldiers expected to fill about 500,000 sandbags by Monday as they worked to fortify levees along a 15-mile stretch of the swollen Mississippi River near Quincy.
"We're just biding the raising of the water and helping people who have to get their stuff out," said George Askew, an alderman in Keithsburg, where multiple levee breaks prompted voluntary weekend evacuations.
Askew said water sat as high as 3 or 4 feet in some parts of the small Mississippi River community of 700 residents. The National Weather Service said the river was expected to crest there Tuesday just above 25 feet. Flood stage in the area is 14 feet.
The Iowa River breached levees in the town of Columbus Junction on Saturday evening, leaving much of the downtown, including a medical center, senior center, water plant and a couple dozen other businesses, under about 10 feet of water.
"So we ended up losing the battle, but there are a lot of good things that come out of an effort like that," said Mayor Dan Wilson. "The community spirit has been phenomenal."
In Cedar Rapids — where flooding had forced the evacuation of about 24,000 people from their homes — residents waited hours to get their first up-close look since flooding hammered most of the city earlier this week.
Some grew angry after long waits to pass through checkpoints. Cedar Rapids officials also were inspecting homes for possible electrical and structural hazards.
"It's stupid," said Vince Fiala, who said he waited for hours before police allowed him to walk five blocks to his house. "People are down on their knees and they're kicking them in the teeth."
The city's municipal water system was back to 50 percent of capacity Sunday, a big victory after three of the city's four drinking water collection wells were contaminated by murky, petroleum-laden floodwater. That contamination had left only about 15 million gallons a day for the city of more than 120,000 and the suburbs that depend on its water system.
Meanwhile, flood waters receded in parts of western Michigan as the state tried to recover from a second straight weekend of severe weather.
The latest flooding followed rain that totaled 11 inches in less than 12 hours Thursday and Friday near Scottville, east of Ludington. The Pere Marquette River that enters Lake Michigan at Ludington in the western Lower Peninsula receded to 4.87 feet over flood stage Sunday afternoon, according to the National Weather Service.
About 29 roads in Mason County remained closed Sunday because of flooding. A sewage main that served about 90 percent of Ludington broke as a result of the rains, and repairs were completed Sunday afternoon. Drinking water in the city of 8,400 was safe, the officials said.