CEDAR RAPIDS, Iowa (CNN) -- Floodwaters inundated Iowa City and the University of Iowa arts campus on Sunday despite what one official called a "Herculean effort" to hold back the water with sandbags. Residents surround Lt. Tobey Harrison at a Cedar Rapids checkpoint as they wait to see their homes Sunday. "We've had the [National Guard] working next to prisoner inmates, sandbagging," said David Jackson, the university's facilities manager. "Students, faculty and staff, leaders of the university, the president of the university -- out sandbagging." Some 500 to 600 homes were ordered to evacuate and others faced a voluntary evacuation order through the morning, said Iowa City Mayor Regenia Bailey.
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About 500-600 homes evacuated in Iowa City on Sunday
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Some 36,000 Iowans, most in Cedar Rapids, have been evacuated
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Agricultural damage estimated at $1 billion or more
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