Rouse Co. officials are expected to discuss broad outlines next month of their plan to develop the last large parcel of land in Columbia's Town Center as a commercial and retail site.

The 51 tree-shrouded acres next to Merriweather Post Pavilion has enough space for two big-box stores, other retail development and an office complex. The proposal, which is expected to be discussed during a Sept. 16 Howard County Planning Board meeting, could encompass 1.2 million square feet of commercial and retail space.

In January, the county Zoning Board rejected a Rouse proposal that would have increased the housing density throughout Columbia and would have resulted in about 1,600 new housing units behind Symphony Woods, on the same site, next to Merriweather Post. Rouse is appealing that decision in Howard County Circuit Court.

Dennis W. Miller, a Rouse vice president who is overseeing development of the site, said the latest plan clearing the way for large-scale retailers is not an effort to pressure county officials into allowing the housing units there instead.

The parcel, which is bounded by Broken Land Parkway and Little Patuxent Parkway, is already zoned for retail and commercial use. The proposal, which includes the county's planned extension of Hickory Ridge Road, must be approved by the Planning Board.

"Anything that is allowed under commercial could happen over there," Miller said. "We've had a lot of interest from all types of retailers."

The nearest big-box retailers -- Home Depot, Target and Wal-Mart -- are within a few miles of the Town Center site, on Columbia's eastern edge. The site is even closer to other retail; it is a few blocks from the Mall in Columbia.

Rouse has announced plans to sell Merriweather, which it opened in 1967. The documents filed with the county's Department of Planning and Zoning show that Rouse intends to keep the Merriweather parking lots and adjacent land, but they provide few other specifics about the plan for the site.

Rouse isn't certain what its final proposal might entail and at this point is not required to offer the Planning Board anything more detailed, Miller said.

The possibility of big-box stores on the site arose in a traffic study Rouse commissioned that examined the potential impact on roads of a new business development. The study mentioned large-scale retailers, along with office and retail space. Although few details have emerged, the prospect of big-box stores in Columbia's Town Center and the sale of Merriweather have begun to stir controversy among some residents and officials.

"My sense, and I think that of the public, is that we could do better," said County Council member Ken Ulman (D-West Columbia), who chairs the Zoning Board.

"I'm not saying I don't want to let them develop it," Ulman said. "But I will prevent big-box stores from going into that property. I hope we can work together to find a solution."

Last year, Rouse asked county officials for permission to develop Columbia to the maximum of 2.5 residential units an acre, instead of the 2.35 units now allowed under the special New Town zoning regulations. The county Zoning Board, which comprises the five-member County Council, rejected that plan in January, with some members saying they were frustrated by the lack of detail from Rouse.

Miller said the potential sale of Merriweather and development of adjacent land are unrelated. He said he thinks the sale could benefit the county if Merriweather were converted into a smaller, enclosed venue that would operate year-round and offer Howard residents a wider range of performances.

Miller said he envisions dance performances and smaller, and in some cases more traditional, musical concerts than Merriweather has been known for. Miller said that the return this year of I.M.P., the Bethesda-based rock promoters who had managed the site for several years, helped improve ticket sales.

"You can still see the decline," he said.

In recent years, Merriweather has been forced to compete with much larger entertainment venues, such as Nissan Pavilion in Prince William County.

Seth Hurwitz, I.M.P. chairman, said he and his partner, Rich Heinecke, were pleased with their profits and were eager to book acts into Merriweather for next year. Hurwitz wouldn't disclose this season's ticket sales.

It's not yet clear whether the amphitheater will reopen next year or in what format. A citizen advisory panel, appointed by County Executive James N. Robey (D), is examining the wisdom of having the county buy it.

Meanwhile, Ulman said even if the county buys Merriweather, the development of surrounding land and the loss of parking spaces there could ultimately spell its demise.

A centerpiece of Columbia, Merriweather has been a favorite stop on the summer concert tour for big-name rock groups and bands, including the Grateful Dead, Jimmy Buffett, Willie Nelson and, more recently, Dave Matthews Band and Mariah Carey.

A further hint of what might be on the horizon for the 51-acre site could come Sept. 13 and 23, when the County Council will examine possible changes in the New Town zoning regulations, which have given Rouse broad latitude in developing Columbia since the 1960s. The changes could tighten county oversight of development in the planned community.