For the past two years, motorists couldn't really see construction of the new Woodrow Wilson Bridge as much as feel and hear it through the relentless pounding of pile drivers carving out a new foundation for the 12-lane span.

Now, the visual -- and inevitable traffic -- impact begins. This month, the Virginia Department of Transportation awarded a contract worth more than $54 million for work to begin in about two weeks.

A wrecking ball is gradually reducing one of the nine-story Hunting Towers apartment buildings along South Washington Street in Alexandria to rubble. In the spring, the street will undergo construction to accommodate widening the Capital Beltway as part of the bridge project.

The Washington Street project, which bridge officials hope will cause minimal disruption, is the first of several significant bridge-related projects:

* Work on replacing the rickety Route 1 interchange is scheduled to begin later in the year, adding more lanes and making merges less treacherous.

* Bridges will start rising this year over Cameron Run and Hunting Creek near Route 1, eventually connecting the new Beltway approach to the bridge with the current Beltway.

* Construction of the drawbridge part of the span over the Potomac River will begin this year.

Bridge officials said every effort is being made to minimize inconvenience to motorists.

"There's a commitment to keep all lanes open during peak hours of traffic on the Beltway," said John Undeland, chief spokesman for the $2.5 billion bridge project. "We've got a full-time 'lane guru' who coordinates all this."

For safety reasons, controlling dust from construction is a priority, too, he said.

Undeland said Beltway closures should be limited to late night. But on South Washington Street, one lane will be closed at all times for two years, and after a year's respite, one will be closed again in 2007 and 2008. Alexandria city officials are apprehensive.

"We're uneasy about Washington Street because that reversible center lane has serious implications as far as traffic flow around the city goes," said Reed Winslow, the city's coordinator for the bridge project.

Winslow said that having two lanes open in the peak direction should be adequate, but that any problems could have a ripple effect on nearby arteries. "We know we're going to have to work to tune up our traffic control system," he said, adding that the city's relations with the bridge builders have been amicable.

Converting a congested six-lane highway with a drawbridge into a 12-lane highway with twin drawbridges is like "painting your car when you're driving 55 miles per hour," Undeland said. In addition to logistics, there are safety concerns, neighbors' concerns and environmental concerns.

Undeland said the project plans to spend $50 million on efforts to keep the water and air clean and maintain natural habitats.

Stephanie Spears, an environmental specialist with the project, said she regularly checks air and water quality monitoring stations on both sides of the river. In addition, wildlife has "adapted really well," she said.

Bald eagles have nested and reproduced on the Maryland side of the project and have been spotted snatching fish after launching themselves off the backs of tugboats working in the river, she said. Foxes are regular visitors to the various sites, and some river work has been shifted to winter months so as not to interrupt fish movement, she said.

Although the pong-pong-pong of pile drivers was a constant presence for much of last year, demolition of the Hunting Towers building has been much quieter, some neighborhood residents said. Project managers decided not to use explosives to bring down the building all at once.

Instead, a wrecking ball and crane-mounted grapples are being used to pull it apart gradually. Workers constantly hose the area to minimize dust, even in the biting cold, and Bradbury said the moves have helped to lessen complaints from neighborhood residents.

Winslow said that pile driving in the river on Sundays is the latest hot issue, and that the city is seeking a solution.

"Generally speaking, they've been quite cooperative, and we've been able to negotiate around these things," Winslow said. "I'd say the relationship is good."

When completed in several years, the $2.5 billion Woodrow Wilson Bridge will have 12 lanes and twin spans.A wrecking ball reduces the Hunting Towers apartments to rubble. Soon, work begins in earnest on bridge-related road projects.Bases at Jones Point will hold supports for the Wilson Bridge. Several related road projects are planned this year.