D.C. officials are negotiating to purchase more than five acres of additional land in Southeast Washington for a baseball stadium complex, an aggressive move aimed at influencing development that could maximize the return on the city's investment in the ballpark.

The city has planned since last fall to build the stadium by 2008 on a 20-acre plot near South Capitol Street and the Navy Yard. Now officials want to expand their reach in order to produce a "ballpark district" that would feature restaurants, stores, commercial buildings and residential units.

Officials described their strategy as a way to ensure that the $535 million investment generates revenue on more days than just the 81 times each year the Washington Nationals play at home.

"We want more than just a ballpark. Our goal is to create a whole district and a destination," said Andrew Altman, chief executive of the Anacostia Waterfront Corp., a publicly chartered entity overseeing the development process.

"On the destination list of Washington," Altman added, "you'll have the MCI Center area, Georgetown and, now, boom, the South Capitol Street ballpark area."

The additional land would come from parcels totaling 3.2 acres north of the stadium plot that are owned by Metro and at least two acres east of First Street that are owned by the D.C. Water and Sewer Authority. The bid to buy this land had not been previously disclosed.

Metro has a bus garage and other operational facilities on its 3.2 acres. In May, Metro officials were preparing to put the land on the market because the agency plans to move its operations. Two days before the bidding, D.C. officials stopped the proceedings.

In a letter to Metro chief Richard A. White, Mayor Anthony A. Williams (D) noted that Metro's bylaws stipulate that the agency must work with local jurisdictions to foster joint development projects.

"I hereby request to purchase each of the component parcels," the mayor wrote.

Metro's land could be worth about $50 million, developers said. The District could take control in several ways, including trading land in other parts of the city, officials said.

If the city obtains the land, officials would package the Metro and WASA plots and offer development rights to private developers by next month with guidelines on what must be built, said City Administrator Robert C. Bobb.

D.C. Council Chairman Linda W. Cropp (D) said she supports the effort.

"We need to benefit from the economic spinoff of the stadium," she said. "We need to have things around the stadium so that those who attend games will shop and eat and leave their money, which will help with the economic needs of the city. . . . I also believe we need to do it during the same time period as the stadium -- not wait five years before doing this."

Within the next several weeks, the District will open negotiations with the owners of land on the 20-acre stadium site. That process could result in the city seizing the land through eminent domain if the owners refuse to sell.

The city's move to acquire additional land comes as private developers have been snapping up plots near the stadium site, driving up prices and changing the face of some neighborhoods. Monument Realty LLC, for example, recently bought more than two acres next to Metro's land and half an acre on the stadium site for a total of $30 million.

Russell Hines, Monument's executive vice president, said his company plans to build about 750,000 square feet of office space, retail stores and housing.

Herbert S. Miller, a developer who has talked to the city for months about creating a mixed-use "town center" near the stadium, said the city was wise to take a proactive role.

"They have an enormous expense in the stadium and have to turn it into an investment and get something out of it," Miller said. "They have to prove to citizens that this area can be a major pocket of investment. If I were the city, I'd be aggressive. They need to be to sure the stadium is successful."

The experiences of other cities show that new stadiums do not always spark major redevelopment in neglected areas and suggest that cities must carefully plan integrated development strategies.

In Seattle, business owners near Safeco Field have complained that patrons rarely come to the area on non-game days, in part because officials did not include housing units in the area.

Conversely, Coors Field in Denver has won raves for helping to turn around a desolate area that now booms with housing and entertainment. D.C. planners have often cited Denver as a model.

Altman said he would look for a developer who has done similar work.

"This is a very specialized development program and has to be done very carefully," he said.

Arthur Lawson, Metro's D.C. government relations officer, said the agency is "working with the city and our own folks looking at possibilities."

WASA's case is potentially more challenging. The utility owns 11 acres at First and O streets SE and operates a critical pumping station there that is too expensive to move, said WASA General Manager Jerry N. Johnson.

However, some of WASA's operations at the site were being eyed for relocation before the stadium plans were announced last year.

"We're interested in being a development partner with the Anacostia corporation to maximize revenue and working jointly to provide a quality first-class development," Johnson said.

Much of the Metro land near the stadium site is considered particularly valuable because it is along Half Street, which city planners envision as the main entryway to the stadium.

But Altman said he believes it is equally important to get people to the area now owned by WASA, which is east of the stadium and closer to the Anacostia River. Altman is close to unveiling a waterfront redevelopment master plan, in which the ballpark is a key.

Allowing private development to happen without the city's influence and controls would not achieve these goals, he said.

"We want to create a real destination," Altman said, "and that can't happen if this coordinated strategy does not take place."

Staff writer Dana Hedgpeth contributed to this report.

Ballpark architect Joseph Spear near First and N streets SE. The city wants to buy land to create an area with stores and residential units.