The Army Corps of Engineers now expects water to go over the spillway at the Coralville Reservoir on Tuesday. Water output at the dam is being incrementally increased to a maximum of 20,000 CFS, which will cause flooding in Iowa City.

This afternoon the Johnson County Board of Supervisors plans to vote on whether to declare a civil emergency, which would give emergency crews clearance to conduct mandatory evacuations this weekend, if needed. Chairperson Janelle Rettig said a conversation with Emergency Management convinced her evacuations would be necessary.

“I actually think the public’s taking this too calmly. People haven’t been getting sandbags yet, they’re a little slow to react, government’s been trying to tell them trouble is coming,” Rettig says. “And I think people need to begin to make preparations for their homes and businesses.”

The water is expected to crest on June 4th, but officials say rainfall along the river system will affect the flood forecast. Officials has said earlier that they expected the water to crest just below the spillway.