Although most public comment about the PortAmerica project in Prince George's County has focused upon the height of the World Trade Center tower, another aspect of the plan -- the residential-commercial community proposed for the Smoot Bay waterfront -- is a good bit more challenging from an architectural point of view.

The tower issue was primarily symbolic. The developer and a legion of supporters in the county understandably were enthusiastic over the idea of an attention-getting skyscraper rising from a gentle hill alongside the Potomac. Opponents disliked the notion with equal vehemence because a 52-story building in this location would irremediably alter the century-old visual balance of the national capital region, with the Capitol and Washington Monument as centerpieces.

But with the height controversy apparently resolved -- the tower as reconfigured will be less than half as tall, with the leftover square footage distributed among six lower, flanking buildings -- one can take a closer look at plans for the waterfront complex.

For its famous architects, Philip Johnson and John Burgee, who together have designed a host of skyscrapers, this must have seemed a heaven-sent opportunity (the deity, in this case, being a determined Virginia developer named James T. Lewis). Rarely nowadays do architects get commissions to plan and design an entire place -- houses, public buildings, stores, restaurants, hotels, marinas, parks, sidewalks ... the works.

Johnson, the 81-year-old former architectural historian who turned architect at age 40, insisted that Lewis and colleagues visit sites in Europe -- Mediterranean harbor towns, Regent's Park in London, the Royal Crescent at Bath, England -- in order to better comprehend his aims for PortAmerica. An enclave conceived as an 18th- or 19th-century city, it's not exactly a great leap forward in late-20th-century American design, but it'll be quite a break from the conventional suburban mold.

The site plan, with residential units clustered in rows around parks, resembles nothing quite so much as James Oglethorpe's 1734 plan for Savannah (Oglethorpe, of course, came from London). The Johnson-Burgee plan, however, introduces elegant curves (such as those at Bath or the Quadrant along Regent Street) into the urban grid and, rather than plotting public activities and buildings at the borders of each neighborhood park, places them entirely at water's edge.

This decision to maximize waterfront exposure is the plan's best touch. Smoot Bay will be given a hard, urban edge in the form of a curving, mile-long esplanade, lighted and lined with trees. Conceived as a regional tourist attraction -- connections by boat to and from Washington and Alexandria have been talked about -- it will also serve the needs of its two local communities, office workers at the trade center and occupants of the nearby residential units (1,150 are planned).

Appropriately, each end of the esplanade is to be given special treatment. At the sheltered northern harbor, close to the Woodrow Wilson Bridge, there will be a 500-slip marina and two public buildings -- a visitors' center and a museum of an as yet undetermined type. (The marina is fine, but the museum will take careful, creative planning if it is not to become just another specious shell.) At the southern tip, where the bay and river join, there's to be a low-rise hotel and, jutting into the water, an octagonal, shed-like structure designed to house a restaurant.

In between, there'll be a lot of variety -- a community center with a church-like steeple and two flanking, arcaded buildings for local retail (presumably food markets, drugstores, dry-cleaning establishments and the like); another low-rise hotel; a few fortunate rows of houses and low apartment buildings; and an urbane row of five-story buildings with stores (presumably of a more upscale, touristy mix) occupying the lower levels and residences above. Care has been taken to integrate these buildings with the waterfront (unlike, say, the rude, backs-to-water arrangement of buildings in Washington's 1960s Southwest). As a whole the esplanade promises to be a regional asset, a trendy but civilized place, a splendid meeting between "city" and water.

PortAmerica is not quite a city, of course. The conception is urban, as is the primary grouping of houses -- they'll be set close to the streets in rows, with alleys for garages (as in much of Washington) instead of the customary suburban curb cuts for autos. And, within the limits of an upper-income market, there's a welcome mix of housing types -- condominium apartment buildings, apartments above stores, row houses and, eventually, where the hill becomes steeper at the back of the site, a development of detached, single-family homes.

As in so many suburban residential clusters, however, there is scant provision here for economic diversity -- most of the workers in PortAmerica's stores and offices will by necessity live elsewhere and travel to and from work by car. Indeed, the reliance upon the automobile is almost total, with the significant exception that at PortAmerica (unlike, say, Tysons Corner), once the car is lodged in a parking structure, visitors will be encouraged to explore the place, and especially the waterfront, on foot.

The controversy over the trade center tower has tended to obscure the fact that this center and the residential-shopping-eating complex are two discrete developments -- the tower and its surrounding buildings are set upon the crest of a hill about a mile from the waterfront and separated from it by a massive roadway connection to the Interstate highways (95 and 295) that meet at the site's northern border. Although the architects must be credited for establishing a visual connection between the two -- a long, straight boulevard, on axis with the tower and the center of its "campus," will extend up the hill from the water's edge -- in order to get to the action along the waterfront, office workers at the trade center will have to drive (or, possibly, get on a bus).

It is too early to comment in detail on PortAmerica's architecture -- the buildings are no more than sketches at this point. But among the sketches are buildings that give one pause. With their awkward, truncated pyramid tops, dormers and high windows, the mirror-image pavilions housing the visitors' center and museum suggest the same sort of arbitrary historicism that afflicts the vaguely Gothic Johnson-Burgee design for the trade center tower. They're high-image buildings, to be sure, but they're also functionally neutral -- anything could go inside -- and their stylistic relationship to their immediate neighbors, a set of rather sedate, classic revival city buildings, is uneasy.

Still, even if this is an authoritarian, all-at-once approach to city planning, there's something to be said for the overall consistency of the design philosophy. The idea of creating a set of variations upon 18th-century themes in the housing units seems especially promising, and the variety of building types in the project represents a tremendous opportunity to create a lively and rhythmically varied townscape. Because plans for it have such strong urban design underpinnings, one can at this point be reasonably optimistic about end results at PortAmerica.