Officials warn that the Coralville Reservoir could top its spillway and flood Iowa City by Tuesday.

Levels for the Iowa River are predicted to be similar to those seen in the flood of 1993. Officials say that people whose property was affected in 1993 should assume that situation will repeat itself.

They are urging people to take protective measures and prepare to vacate the area if necessary.

"It's within the realm of possibility we meet or exceed '93 levels," Iowa City Police Sgt. Troy Kelsay said. "This is not going to go away this weekend. This is not going to go away this week.

"The community needs to be prepared for an extended event."

Officials said Friday that the U.S. Army Corps of Engineers will increase the release rate of water this weekend. But water could still reach the reservoir spillway by Tuesday.

Iowa City Public Works Director Rick Fosse says he expects the river level to rise three feet this weekend and five feet by Tuesday. Forecasters believe that as much as four inches of rain could hit the area in the next five days.

The engineers will increase the outflow levels twice this weekend to drop the water level in the reservoir. They need to release water from the reservoir quickly to make room for the expected inflow.

About 1.67 trillion gallons of water flowed through the Coralville Dam from March to October in 1993. That was 11 times the amount of water that Coralville Lake can hold, up to the spillway. Iowa City closed 14 streets that summer.

According to Kelsay, current water levels are just below those in 1993, and the Iowa River hasn't been this high since. Fosse and Coralville City Engineer Dan Holderness said that measures were put in place after the 1993 flood to help abate the affects of flooding. But Holderness says this event will be the first test for those improvements.

Engineers also said that they plan to increase outflows of the Saylorville and Red Rock Reservoirs. At Saylorville, the outflow will increase from 15,000 to 16,000 cubic feet per second on Sunday to 21,000 by Thursday. Red Rock Reservoir releases will increase from 25,000 to 30,000 cubic feet per second on Sunday to 37,000 by next Saturday.

Saylorville Lake was at 876 feet and is expected to rise to 886 feet -- two feet above the emergency spillway -- by next weekend. But the U.S. Army Corps of Engineers installed an inflatable dam following the 1993 floods. When inflated, it raises the spillway elevation to 890 feet.

Saylorville reached its highest stage on July 11, 1993 at 892 feet.

Numerous roads across the state were closed on Saturday due to flooding, the Iowa Department of Transportation said. DOT officials say the additional rainfall predicted for the area will likely cause further river and small stream flooding and flash flooding in localized areas.