MOORHEAD, MINN. - Five years ago, Brad and Kathy Thom bought a house with a $20,000, 14-inch-thick flood wall to protect them from rises of the Red River.

But last month, the Thoms moved out, pushed not by floodwaters but by a city buyout program.

It's one of many flood mitigation efforts in communities across the region, totaling hundreds of millions of dollars -- soon billions, if a river diversion for Fargo-Moorhead goes forward.

The changes hold promise to lessen -- some believe even end -- the recurring spring ritual of catastrophic flooding in the Red River Valley. This week, residents along much of the Red River are busy sandbagging and nervously watching predictions for a crest expected to move through over the weekend.

"For a lot of us, we're hoping this is the last flood we have to fight," said Steve Jones, city manager in Montevideo, where the Minnesota River has reached three of its five highest recorded crests in the past 13 years.

The Thoms' former home, which the city bought for $270,000, will be jacked up and carted off in an effort to clear flood-prone riverside property. Removing more than four dozen homes from the river's edge and, ideally, plopping them down elsewhere in Moorhead will cost $8.7 million in state money.

Since the 1997 record flood, the city of Montevideo has moved 110 houses and has plans to move 20 more. It has moved its water treatment plant from the lowest to the highest point in town. A new permanent levee system, which will include raising part of Hwy. 212 by 6 feet, will be completed in 2011.

The $13 million worth of work has already had an impact.

This week's crest, the seventh-highest on record, would have required more than a half-million sandbags in the past, Jones said, but only 10,000 will be needed. Only a few minor roads have been closed.

In Breckenridge, where the Otter Tail and Bois de Sioux rivers meet to form the north-flowing Red, a $7.5 million diversion built since 1997 kept the city dry during last year's crest, the third-highest on the books. A levee system worth more than $50 million, designed to protect both Breckenridge and neighboring Wahpeton, N.D., to more than 2 feet above the 1997 level will be completed next year. Mayor Cliff Barth has his fingers crossed in the meantime.

"Once we get the system in place, we're good to go for a long time," Barth said.

Grand Forks and East Grand Forks, Minn., breezed through the 2009 crest thanks to $400 million in levees, walls and pump stations installed since the 1997 flood, which resulted in $2 billion in damages.

All of which has left the region's biggest-ticket item for last: a diversion ditch around Fargo and Moorhead that's projected to cost $1.3 billion, but would cut almost 6 feet off a flood of last year's magnitude.

A flood mitigation task force voted Thursday to dig the ditch on the North Dakota side of the river. The panel's recommendation will be voted on next week by city and county elected officials on both sides of the river, all of whom are expected to ratify it. It will then go to the U.S. Corps of Engineers, which is expected to issue a final decision in December.

The ditch wouldn't be completed for 10 years, however, during which time the cities will likely continue to remove homes, build levees and rely on a steady replenishment of volunteer sandbaggers.

Those measures, including the removal of about 40 homes just in the past several months, have already helped, said Fargo Mayor Dennis Walaker. This year's predicted flood crest of 38 feet, possibly the fourth highest on record, will be "doable," he said.

But a diversion will do far more, he added.

"It's a long ways away, but once it's in place, something like this could probably be our last flood fight."

Thom said that had the diversion been dug already, he and many of his neighbors probably would have stayed in their Horn Park homes, with their back yards sloping down to a wooded river bank, magnets for wild turkeys, deer and other wildlife.

"We didn't want to move," he said. "These were the most beautiful lots in the city of Moorhead. We had a great time together."

By letting their homes be cleared away to make way for a dike, Thom said, he and his neighbors were helping protect 200 other homes.

Thom, who now lives about a mile south of his former home and a mile east of the river, returned to the old neighborhood this week to help those staying behind sandbag their homes. Tuesday they gathered around a small bonfire to celebrate the completion of their personal dikes, talked about the flooding trends they've seen and the possible culprits -- agricultural drainage, nearly 20 years of abnormally heavy rain and snow, even global warming.

A diversion ditch will help, said Ralf Mehnert-Meland, whose home is barely high enough to miss qualifying for the buyout. But it won't bring complete peace of mind.

"This area has never admitted that we live on an untamable river," he said. "Let's be ready for it."

Bill McAuliffe • 612-673-7646