Reston Land Corp. is planning to start construction on the first phase of the 70-acre so-called "downtown" of its highly touted 400-acre Town Center complex late next year.

But plans for height, density and use of buildings that will be proposed for construction in the Town Center are a tightly held secret. Reston Land has not yet submitted any proposals for the downtown core to Fairfax County for approval. Currently, it takes about nine months to get a major project involving a lot of acres approved in Fairfax.

Michael Was, executive vice president of Reston Land Corp., said Thursday that filings for rezonings for the Town Center are on the horizon. "We expect to get it in shortly," Was said.

Reston officials aren't saying what is planned for the Town Center, which is master planned for a PRC, planned residential community, on the Fairfax comprehensive land-use plan. The Town Center project has long been planned as a major goal for Reston. It is to be built at the intersection of Baron Cameron and Reston avenues.

Most of the Reston community has been developed in the PRC category, which was hailed as innovative when it was created in the 1960s to facilitate development of Reston as a planned community mixing open spaces with commercial buildings and a variety of residential style housing units.

Rezonings in Reston generally have sailed past Fairfax officials because of the PRC designation.

But that PRC land plan designation is beginning to spell some problems for Reston Land because county officials cannot impose height or FARs, floor area ratios, that determine density if a development is in a PRC category.

That is a luxury other major commercial developers in Fairfax covet. While most officials praise what the PRC category has produced in Reston, others are saying the time may have come for the system to look at the process. Because the county cannot limit height and density in the Town Center category, plans for the long-awaited Town Center may run into problems and are certain to generate strong debate between members of the Fairfax County Planning Commission and the Board of Supervisors.

In the past, Reston Land has been able to avoid facing up to the many changes in land-use planning and zoning that other developers have had to face in the past five to six years.

The first sign of trouble may have come last week when the Fairfax County Planning Commission deferred action on a major proposal for a 32-acre rezoning in the Town Center area to be known as the Baron Cameron Pond area. Although a preliminary plan for the site was submitted along with the rezoning application seeking to change the site from a residential to a PRC category, the conceptual sketch carried a notation saying: "This is not a preliminary or final site plan and as such it may be modified or revised at the discretion of the developer prior to site plan approval." The conceptual plan shows eight buildings clustered around a pond along Baron Cameron Avenue between the proposed Springfield bypass and Bennington Woods Road.

Richard M. Reid, staff coordinator for the county's zoning evaluation division, told the planning board "the commercial centers in Reston including the Town Center have no restriction on height and FAR." "The commercial centers in Reston including the Town Center have no restriction on height and FAR." -- Richard M. Reid, Fairfax zoning official

"There is nothing in the zoning ordinance that restricts a development to a number of commercial buildings," Reid said in response to questions from a planning commission member.

If the PRC status is approved for the entire 400-acre site now planned for the Town Center, some county officials said they fear they may be giving Reston Land Corp. a blank check to build whatever it wants without any height restrictions.

Hunter Richardson, vice president of commercial marketing for Reston Land Corp., said his corporation is "not coming at this with the intent of duplicating traffic problems" that plague other commercial centers in Fairfax.

He said the proposal now before the planning commission is on the periphery of the total Town Center area. "This is a very modest proposal," he said. However, the county planning staff is recommending that the proposal be denied or deferred until transportation issues can be resolved. The Baron Cameron Pond plan supports an above-grade interchange for the Baron Cameron Avenue intersection at the proposed Springfield bypass. As proposed by Reston Land, a ramp from the interchange would land in Herndon rather than Reston. But Herndon residents and officials apparently want only an at-grade interchange and want that to stay in Reston if possible, according to planning commission Chairman George Lilly.

Several county planning commissioners were disturbed by Reston Land Corp.'s reluctance to give details of what is proposed for construction on the 32-acre site.

"I think the applicant should give us some details. There should be something done by the applicant about the intensity of the use of the site," said commission member Suzanne Harsel. "If you are putting in 12-story buildings rather than four-story buildings, the traffic impacts are going to be different," she said.

Several county officials said they feared plans that might be filed for the entire Town Center area would also lack detail. But Reston Land officials said they hoped applications filed would answer any questions county officials may have.