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Dump trucks and moving vans crowded the streets of Dakota Dunes on Wednesday, hauling in dirt to build up miles of levees protecting the small southeast South Dakota town and carrying away belongings for hundreds of residents leaving before what could be a prolonged summer of Missouri River flooding.

The carefully planned community of 2,500, which sprang up just a few decades ago with an 18-hole Arnold Palmer-designed golf course and a mix of corporate headquarters that includes Tyson Fresh Meats, is among the early trouble spots as the U.S. Army Corps of Engineers releases excess water from Missouri River dams after record rainfall across the northern Plains.

Heavy runoff from melting Rocky Mountains' snow could soon compound the problem, and officials are planning possible mandatory evacuations in Dakota Dunes as well as the state capital of Pierre and neighboring Fort Pierre far upstream.

Protective levees were expected to reach above river levels in all three cities, but about 2,000 people and 800 homes and businesses remained threatened by flooding in Pierre, with several hundred more people in Fort Pierre's flood zone.

South Dakota Gov. Dennis Daugaard asked residents in threatened areas of Pierre and Fort Pierre to evacuate their homes by 8 p.m. Thursday. Daugaard said it was not a mandatory evacuation, but law enforcement officials were going door-to-door Wednesday evening to tell residents about the request.

The governor has urged residents of Dakota Dunes in southeastern South Dakota to move their possessions and be out of their homes by late Thursday. He says 800 of the 1,100 homes in Dakota Dunes could be subject to flooding.

"As the water flow increases, we want to make sure we protect human life as we evaluate how the levees are doing, how fast the water is being released and whether the areas are going to be safe," he said.

Much of Montana, where the Missouri River hit hardest before rolling down to the Dakotas, caught its breath Wednesday and looked to make repairs as floodwaters at least temporarily receded. The state also braced for more to come as heavy winter snowpack dissipates, and Big Horn County — where the Crow Indian Reservation suffered substantial flooding — ordered 50,000 sandbags for the next round. But mild forecasts pushed fears of more serious flooding further into June.

The city of Minot, N.D., meanwhile struggled with a different waterway. The Souris River's swift rise had about 10,000 people, a quarter of the city's population, searching for places to stay after the mayor issued a mandatory evacuation order a day earlier. Still, residents got a bit of good news Wednesday when the National Weather Service predicted the fast-moving Souris would crest slightly lower than expected.

It's the Army Corps' plans to increase the rate of water being released from Gavins Point Dam upstream of Dakota Dunes that is causing concern for the community situated at the junction of South Dakota, Nebraska and Iowa. The corps plans to gradually increase releases through this week before peaking in mid-June.

Dakota Dunes was born in 1988 as a 2,000-acre venture by an Iowa developer, and swelled by drawing people and business attracted to the state's absence of personal and corporate income taxes. Employees of companies like computer maker Gateway eventually made their homes there and the area ranked as one of South Dakota's wealthiest. The nicest homes sport manicured lawns nearly as impeccable as the golf course, set near streets that carry names such as Augusta Circle, Royal Troon and Pebble Beach Drive.

Retirees Larry and Connie Chapman said they were among the first to move in. On Wednesday, they loaded belongings into trailers and vehicles, unsure when they would be back. The governor had cautioned people to be prepared to be out as long as two months due to all the water that has to come down the Missouri.

"There's nothing to say other than what's happened and why is history and there's no point dwelling on it," Connie Chapman said. "We'll move forward. We have a lot of faith."

Like many of the town's residential streets, the Chapmans' was crowded with cargo trailers, moving trucks, pickups and large semi-trailers. Traffic in and out was brisk as Highway Patrol troopers manned the main intersection to keep everyone moving, including the 70 trucks being used to bring dirt and manpower to work on the levee system. Two Blackhawk helicopters placed half-ton sandbags in areas that couldn't be reached by the vehicles.

Officials hope to have levee construction completed by Saturday, said Beth Hermanson, a spokeswoman at the state incident command center.

"That doesn't mean we'll be buttoned up and done ... but it's a target and we have a significant plan in place," she said.

Homeowners removed furnaces and other basement equipment that could be damaged by water. Plumbers plugged basement floor drains to prevent sewage backups. Only a few homes were fully ringed with sandbags, but many had them protecting ground-level windows to the basement. Some 200 National Guard members and 80 prison inmates helped fill them up.

Nancy Ebert was among residents who stashed household goods in a large semi-trailer to be hauled away and parked on a lot. She and her two adult children, ages 20 and 17, had just moved into their duplex in January and many possessions remained boxed up, so loading the truck didn't take long. Ebert still had the "For Sale" sign, and stuck it back in her yard as a joke.

But she had no intention of fleeing.

"We're not leaving," she said. "They shouldn't stop us from coming back if there's no risk."

Ebert said she can't afford a motel, and can't pay her mortgage unless she works. So she kept a small refrigerator, microwave oven, inflatable air mattresses and patio furniture on hand.

"The only thing we'll miss is a shower," she said. "We've got water, but it's cold because we took the heater out of the basement."

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Associated Press writers Chet Brokaw in Pierre, S.D., James MacPherson in Minot, N.D., and Stephen Dockery in Helena, Mont., contributed to this report.