Charlotte Hall can already count the dollars.

The riverboat tour operator foresees hundreds of tourists and conventioneers at the peak of the season filling her boats at the Potomac River dock of Opryland Hotel Potomac, just south of the Woodrow Wilson Bridge in Prince George's County.

"Oh, my!" Hall said, getting a bit carried away imagining it all. "It's going to be endless possibilities. They could take one of my boats over to Old Town Alexandria, shop and eat, walk around, and then go back. It's so exciting. It's just a natural to use the river."

Groundbreaking on the $560 million Opryland project won't take place until 2002 at the earliest. That is the target date for construction of an interchange to serve the new span replacing the Wilson Bridge.

Nevertheless, tourism operators like Hall and area restaurateurs, hoteliers and event promoters already are cooking up ways to cash in on--or compete with--Gaylord Entertainment Co.'s mammoth project.

The development would change the competitive dynamic of the local lodging industry, potentially bringing in new business but also taking away some business from established venues. In the District alone, annual revenue from tourism is $4 billion.

The Nashville-based media and entertainment company, which also owns the Grand Ole Opry, plans to build a lavish 2,000-room hotel and a 400,000-square-foot conference center, including a large exhibition hall and two 50,000-square-foot ballrooms, on 40 acres in Oxon Hill.

Opryland's biggest competitor will be the $685 million convention center under construction in the District at Mount Vernon Square. The new convention center will be twice as large as the current center and will span six city blocks, complete with 725,000 square feet of exhibit space and 150,000 square feet of meeting space. It is set to open in March 2003, a year before Opryland Hotel Potomac is scheduled to open.

"Opryland has high-powered marketing; it's not going to sit there empty," said Dan Mobley, president of the Washington, D.C., Convention and Visitors Association. "They've got a name people recognize and a history of top-quality service to really large groups.

"It will become a destination unto its own," he said. "It's certainly going to be a competitor for us."

Some of the District's larger hoteliers, who typically can accommodate groups of up to 1,000, said they are preparing to feel squeezed.

"They're talking about having two 50,000-square-foot ballrooms," said Ed Rudzinski , general manager of the Marriott Wardman Park Hotel on Connecticut Avenue. His hotel is one of the largest hotels in the District, with 1,348 rooms, 122 suites and 178,000 square feet of meeting space. "That's the edge they're going to have. It's going to take business from me."

Rudzinski joked, "I'll probably have buses taking people out there to Opryland, just to see it."

But whether Opryland can help generate higher demand for large conventions--reversing a decade-long decline in the bookings of major events here--remains to be seen.

In 1990, the existing Washington Convention Center was the site of about 30 shows, compared with about 10 last year, organizers said. Groups outgrew the small convention center and went to other major cities, such as New York, Chicago and Atlanta, organizers and meeting planners said.

They hope groups will come back to the Washington area for conferences with the new center, which is expected to generate $1.1 billion in revenue for the region in its first year. But consultants warned that even the new center may be too small, that it would begin to approach full capacity a little more than a decade after it opens, and that the site has no room for expansion.

"There's a lot of demand to have conferences in Washington," said Emily Vetter, president of the Hotel Association of Washington, D.C. "It's the nation's capital, and every four years, when an elected official takes office, groups want to get in here and do their business and meet near where the power is."

The Opryland Hotel Potomac will have to design its own themes and entertainment to attract visitors, Rudzinski said, adding that the complex can't expect to attract business that normally goes to the District.

"You can't re-create what D.C. has," Rudzinski said. "You can't move these monuments. Some conventions aren't going to want to book rooms that far outside of the city. There's going to be a certain convention-type goer who wants to go there."

But that's not how Hall sees Opryland. She sees dollars for her Potomac Riverboat Co.--which has 100,000 customers from April to October--if she can land a deal with Gaylord to provide boat service from their doorstep and across the river to Old Town Alexandria.

Hall's hopes aside, the future for the convention and meeting business isn't all bright. In recent years, cities across the country have engaged in a kind of gold rush to build huge convention facilities and hotels, usually with taxpayer help. While the convention and meeting industry has been a growing juggernaut in the last decade, gobbling up supply as fast at it is made available, some worry that this will only last as long as the economy is good. After that, all bets are off.

"If the economy keeps growing, they'll be able to find a niche," said H.A. "Skip" Hartman, general manager of Loews L'Enfant Plaza Hotel. "If not, it will make one heck of a condominium."

CAPTION: Visiting the site of the future Opryland Hotel Potomac are David Jones, left, president of Gaylord Entertainment's hospitality group; Gaylord chief executive Terry E. London; and Milt Peterson, president of Fairfax-based co-developer Peterson Cos.

CAPTION: David Jones, president of the hospitality group at Gaylord Entertainment, in the Delta atrium of the Opryland Hotel in Nashville, the world's largest hotel-conference complex.