PMC Property Group plans a pair of mostly glass-and-metal towers at a long-languishing development site on the Schuylkill's eastern bank, the company's latest bet on sustained demand for apartment living in Center City.

PMC, already thought to be Philadelphia's biggest residential landlord, is proposing the two towers at a parking-lot site at 23rd and Arch Streets where a previous iteration of the project, known as "River Walk," had been planned by a different developer.

The PMC proposal calls for 32- and 28-story towers with 321 and 291 units, project architect Anthony Kim, of Gensler in New York, told members of the Logan Square Neighborhood Association last week. The towers also would feature spaces for retail, including a large supermarket.

The project would be a short jog up the Schuylkill River Trail from developer Carl Dranoff's One Riverside condos and even closer to the former industrial building PMC is converting into a new headquarters for the food- and facilities-services giant Aramark.

It's also right across the river from University City, where central Philadelphia's most ambitious master-planned development proposals - Schuylkill Yards and uCity Square - are in the works.

Some headwinds exist for PMC, however, with emerging signs that multifamily rental demand may be flagging because of an abundance of new inventory due to hit the market over the next few years.

Average rents for Class A high-rise apartments decreased 1 percent in the year ended Sept. 30, compared with a 3.6 percent rise during the year-ago period, according to the Washington-based real estate tracker Delta Associates.

But PMC executive vice president Jonathan Stavin said the growing population of Center City residents drawn by increasing job opportunities there would sustain the project, which could cost as much as $300 million.

"We're confident that the project will be successful, and that the apartments will lease," he said.

PMC paid $28.5 million in July 2015 for about seven acres along John F. Kennedy Boulevard that includes the project site, eyed for development for at least a decade.

The most recent plans, by the Wayzata, Minn.-based developer NP International, involved a soaring tower on the sliver of land between JFK Boulevard and SEPTA's Regional Rail tracks, with smaller buildings to the north.

PMC's proposal leaves the land along JFK undeveloped for now, with both towers rising in phases north of the SEPTA tracks.

The project is permitted under a zoning change secured by a previous developer that expires at year's end. PMC plans to ask city officials to extend that zoning for five more years.

The company is eyeing a June groundbreaking for the northernmost tower, with construction expected to take about a year.

PMC is negotiating with a supermarket to occupy about 60,000 square feet on the building's second floor, between levels of parking for customers and apartment residents on the first and third floors.

The south tower's first three floors would be mostly for resident parking.

Stavin said PMC isn't burying parking because it would be risky to use the building's lower levels for other purposes on the flood-prone riverfront.

"What drives us here is the neighborhood very much wanted retail," he said. "I wouldn't be able to find a tenant that would sign a lease in a floodplain."

215-854-2615 @jacobadelman