A Portland development firm that has amassed eight acres of property south of downtown near the city’s waterfront plans a tower district with a striking public plaza designed by a star Japanese architect.

The details are included in NPB Capital’s recently released master plan for the area, offering the first public look at the site’s design after a City Council debate earlier this year on height limits.

The council voted to allow towers up to 325 feet on parts of the site — the same height as some of the tallest buildings in the nearby South Waterfront district.

RiverPlace lies along the Willamette River between Tom McCall Waterfront Park and the South Waterfront, separated from downtown by busy stretches of Harbor Drive and Naito Parkway.

The master plan as proposed could bring up to 2,500 new apartments in several buildings to the spot, along with an office tower. They would share a large underground parking garage.

Because any housing project would be subject to a 2017 city mandate that developers include rent-restricted units in any new housing, it would also add hundreds of affordable apartments.

Architects for NPB Capital presented the master plan last week to the Portland Design Commission. The briefing didn’t address the towers and focused on public space, as well as how to make the site more accessible from downtown, which is separated from the site by a steep elevation change.

“I think right now the perception is that that district and the neighborhood is relatively difficult to get to, and that you drive by it, you don’t drive to it,” said Agustin Enriquez of GBD Architects. “A lot of this project is actually making it literally just accessible to the average Portlander or, say, visitor from out of town, or a student at Portland State University.”

A diagram that shows the proposed redevelopment of an eight-acre parcel in Portland's RiverPlace district, including the potential location for new skyscrapers.GBD Architects via City of Portland

The architects proposed connecting the new development to downtown with a new pedestrian bridge over Southwest Harbor Drive, a divided four-lane road that provides access between downtown and Interstate 5.

But that plan also calls for building a five-story base that some of the tallest towers in the development would share, resulting in an unbroken 725-foot-long block face. City planners deemed that plan architecturally concerning, saying it’s “critical” to break up the block for mobility and aesthetic reasons.

They also showed plans for a plaza concept called the Portland Steps, a stair-stepped plaza leading down toward the Willamette River banks.

The design draws the eye, but city planners raised concerns. The steps don’t provide for accessibility for people with disabilities and they could present safety concerns, they wrote. The terraces also could create “dead space” not easily reached by visitors, the planners wrote.

Neighborhood groups objected to the scale of development proposed, saying the area isn’t accessible enough by road to accommodate more traffic from all the new homes.

“The stunning mass and scale have impacts on and consequences for the transportation system, the public parks, essential services, schools and congested streets,” said Thomas Ray, who lives nearby and said he was speaking on behalf of the Downtown Neighborhood Association. “Pressure from this high density is likely to have unintended consequences for the entire neighborhood and the South Waterfront.”

Speakers also raised concerns about the removal of nearly 300 existing apartments on the site, which they said would be more affordable than the tower apartments that would replace them.

While GBD Architects of Portland presented the plan, Tokyo architecture firm Kengo Kuma & Associates is also attached to the project. Kuma designed an addition to the Portland Japanese Garden that opened in 2017.

Representatives of Kuma’s firm are expected to present at future hearings.

NBP Capital -- an investment firm led by siblings Lauren Noeker Robert and Spencer Noecker and backed by billionaire investor Nicolas Berggruen -- has been amassing property in RiverPlace over the last several years.

It acquired the RiverPlace Athletic Club in 2014, then evicted the operator of the gym in 2015 for failing to pay rent. It bought neighboring low- and mid-rise apartment complexes later that year, bringing its holdings to nearly 10 acres included in the redevelopment concept.

-- Elliot Njus

enjus@oregonian.com; 503-294-5034; @enjus

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