Barges soon will float massive concrete spans, each weighing more than some commercial airliners, to the new St. Croix River bridge two miles south of Stillwater. From there, cranes will drop them into place to form Minnesota's newest link to Wisconsin.

In coming months, hundreds of sightseers on excursion boats will look on with interest at the completion of a bridge that's already transforming a woodsy river valley by its colossal size.

Never has a public works project put its stamp so dramatically on the nationally protected river: It's a $646 million monument, including new connecting highways in both states, that 35 entities warred over for four decades.

Now, with the 20-story bridge beginning to span the river and halfway to completion, it's inspiring a variety of reactions, from admiration over its physical presence to confirmation that it stains a pristine river valley as opponents long feared.

"The engineering side of it is an absolute marvel. To see it from the air is awe-inspiring," said Mike Demulling, airport manager in New Richmond, Wis. "It reminds me of flying into New York City and seeing the George Washington Bridge. These are monuments that last hundreds of years."

New projections cast doubt on both the hopes of proponents and the fears of opponents of a land rush in western Wisconsin.

Stillwater residents, meanwhile, wonder what the transformation will bring. Will motorists now race past their historic river town? Will the St. Croix Valley's rural personality vanish overnight? Or will the bridge bring a new calm — an eco-paradise of river walks and looping bike trips to replace constant traffic backups?

As the bridge rises after years of bitter warfare, there's a new push for reconciliation but also a profound sense of fatigue: "People," said Stillwater resident and historian Don Empson, "are sick of hearing about it."

Halfway home

Although the bridge won't open until late 2016, growing evidence of how it will look will appear this summer, said Michael Beer, the Minnesota Department of Transportation manager overseeing the project.

The bridge's driving surface will begin to take shape later this spring with the arrival of those 180-ton concrete spans — called box girders — from a casting yard on Grey Cloud Island on the Mississippi River.

They'll be assembled, side by side, to bridge the 600-foot distance between piers. A webbing of steel will support the girders — which form the bridge deck — along with giant cables strung from towers 67 feet above the driving surface.

As it all goes in, tour boats will head to the work site on MnDOT-sponsored tours, offering as many as 350 people per ride a close-up look.

"It took so long to get it done, and now it's finally being done, and you don't get to see bridges built very often," said MnDOT spokeswoman Kristin Calliguri.

The bridge, projected to carry 80,000 vehicles a day within 20 years, is expected to erase geographic buffers that gave Stillwater its independent identity. It also will stretch the boundaries of the metro area far into farm fields and villages in lightly populated northern St. Croix County, Wis.

Stillwater's historic Lift Bridge has about 16,800 crossings a day — many of them commuters driving to and from work.

"I think there's a chance that the quiet character of Stillwater and Bayport and Oak Park Heights could change," said Stillwater Mayor Ted Kozlowski, whose city fought hard to push interstate commuter traffic from the Lift Bridge.

Civic leaders on the Wisconsin side, meanwhile, welcome potential prosperity.

"There's tremendous excitement here," said Rob Kreibich of the New Richmond Area Chamber and Visitors Bureau. "People have to pinch themselves to make sure it's actually happening after such an extended battle to make it a reality. We're expecting this bridge to deliver tremendous economic growth and business expansion."

Minnesota cabin-goers will pour through New Richmond en route to places like Hayward and Spooner, he said.

"There is a perception that we're far away and unreachable, but that bridge will change that in a hurry."

Shaking heads

Opponents still mourn.

"The new bridge is so far removed from the river that it is just another piece of highway," said Deb Ryun of the St. Croix River Association. "Now that highway is imposing itself on what historically has been a beautiful little river town. That will be emotionally hard for a lot of people to get over."

Kozlowski, Stillwater's new mayor, said that even though efforts to stop the project failed, the river still needs vigorous protection.

"I don't want anyone to think that it's still not a precious and treasured resource," he said. "Just because we lost this battle with the bridge doesn't mean it's no longer a wild and scenic river."

Stillwater resident Dana Jackson described the view from a city park close to her house: "I can see the bridge and the [power plant] smokestack, all together, big urban structures on a national scenic river and that bothers me. I just can't see them as compatible."

Still, she said, many residents are now talking about positive changes in Stillwater.

"This is now getting an exciting feeling," she said. "There's a fascination with bridges."

Others are downright spellbound. A Facebook rendering of the lighted bridge at night, posted by state officials, drew praise: "Hypnotic!" "OMG how beautiful is that!"

Jill Greenhalgh, a past president of the Stillwater Foundation, said it's time to heal old wounds. A long stretch of the riverfront, bought recently for public use, is a "fantastic enhancement" that will link nicely with the new biking loop, she said.

"Will people forget about Stillwater?" she asked recently. "Or come back here? Who knows?" Civic leaders, though, need to see that "we're at a point of incredible future opportunities."

Tom Gillaspy, Minnesota's retired chief demographer who has been hired to study what could happen, isn't so sure.

"The expectation was, as soon as the bridge got built, people are going to flood over there," he said. "If the bridge were built in 1990, that may have been the case. Here, we've got the bridge opening in about a year, and the question becomes 'what the heck will happen then?' "

Gearing up for fast growth costs tens of millions of dollars, he said.

"High schools, roads, sewers, water treatment, these are expensive things. You don't want to overbuild or underbuild. It's expensive both ways. I don't envy decisionmakers in places like St. Croix County. It shouldn't be driven by emotion or what you wish to have happen, but by what you think is actually going to happen."

Ryun, meanwhile, said people should turn their attention to the St. Croix National Scenic Riverway — a national park — and put the bridge debate behind them.

"You're not going to stop it, so you make the best of it and try to raise awareness that we have a national park here, folks," she said. "People will adjust. People adjust to about everything."

Kevin Giles • 651-925-5037

David Peterson • 651-925-5039