As the Mississippi River rises, a spillway in Louisiana will be opened for the third time ever — and only the second time for flood control.

The Army Corps of Engineers plans to begin opening the Morganza Spillway on Sunday. For three days water will rise one foot a day on a 112-square-mile floodway, to let wildlife escape.

After that, officials plan to release enough water to fill the Boston Aquarium’s biggest tank 5½ times every second. That’s one-quarter total capacity.

State wildlife officials say people who live nearby should stay away from displaced wildlife.

Morganza was opened in 2011 for flood control. In 1973, it was used to protect an upriver structure that keeps the Atchafalaya River from capturing the Mississippi.

Unprecedented flood levels are causing problems from the Midwest all the way down to the Gulf of Mexico.

Temporary shelters are housing hundreds of residents who have lost their homes in flooding along the swollen Arkansas River.

Thomas Lindley was waiting out the flooding Thursday at a Red Cross Shelter in Fort Smith, Arkansas’ second-largest city. Floodwaters have submerged his home in nearby Moffett, Oklahoma.

Lindley says floodwaters had reached the roof of his home when he evacuated three days ago. Lindley says he doesn’t have flood insurance and hopes to find relief aid and a job to recover.

Floodwaters forced Kenny Ward from a tent he was living in along the banks of an Arkansas River tributary. The former Marine says he walked around for five days after his tent and all of his possessions were inundated. He says he then helped other residents fill sandbags to protect their homes from flooding.

Officials in Illinois are asking residents in river communities to prepare for potential evacuations due to the threat of rising floodwaters.

The Illinois Department of Emergency Management said Thursday that reports indicate the state is experiencing the longest-lasting flood since 1927. They attribute it to recent heavy rains that have saturated levees along the Illinois River.

State emergency officials are asking residents of flood-prone river areas to create family evacuation plans. State officials say flooding might not affect homes but could cut off roads. That would make routes impassable to places like hospitals and grocery stores.

Data show there have been 49 deaths in Illinois due to flooding since 1995. Most of those deaths involved people in vehicles trying to cross flooded roads.

A substantial sandbagging operation is underway against the rising floodwater of the River Des Peres in south St. Louis near the Mississippi River.

The St. Louis Post-Dispatch reports that the Mississippi is expected to hit a near-historic crest in coming days.

The River Des Peres is rising to near street level on one side. On the other, waters above street level are restrained by a small berm.

The News-Press in St. Joseph reports that flooding has closed part of U.S. Highway 36 in Livingston County east of Chillicothe in north-central Missouri.

The Grand River at Chillicothe on Thursday was less than two feet above the all-time crest there.