The river on Friday tore a 40-foot hole in the levee in Dardanelle, a city of 4,700 people 100 miles north of Little Rock.
Mayor Jimmy Witt said officials don't believe a temporary levee being constructed will stop water from the Arkansas River from flooding the south side of town. The hope is to buy time for residents of up to 800 homes to prepare, he said.
"We have started a last-ditch effort to try and protect the southern borders of the city," he said at a news conference.
Floodwaters have slowly breached the levee and some homes have already been flooded, officials said. In North Little Rock, just across the river from Little Rock, the state capital, officials were going to home in the Dixe Addition neighborhood to tell residents to consider leaving.
North Little Rock officials believe the river will back up storm drainage areas and cause roads to become impassable in and around the neighborhood.
Gov. Asa Hutchinson said Friday that officials were working to identify higher-risk spots in the Arkansas River's levee system.
"Obviously the breach in Dardanelle is a sign that there could be more of these breaches that will happen as the pressure continues to mount in the coming days," Hutchinson said.
The region is being plagued by a number of floods. In Illinois, residents near rivers were told to prepare for potential evacuations. A mandatory evacuation order was issued to residents in Howard County, Missouri, along the Missouri River, on Friday. A topped levee along the Mississippi River in northeastern Missouri flooded several thousand acres of farmland Thursday.
The Associated Press contributed to this report.