It’s an opportunity to build a neighborhood from scratch at a gateway to downtown Boston. To write an architectural exclamation point on barren parcels left in the wake of a massive public works project. And a chance to expand housing options in one of the city’s fastest-gentrifying neighborhoods.

But MassDOT’s housing affordability guidelines and goals for parks and public amenities on 9 acres in South Bay fall short of earlier recommendations, some activists say, and could squander a historic opportunity.

“It’s astonishing they’ve never been candid enough to share the analysis they’ve been doing,” said Lawrence Rosenblum, an architect and longtime resident of the nearby Leather District. “The feeling is they’re just looking to check off a box that says ‘community process’ – that’s how it felt to us.”

One of the final chapters in the transformation of the post-Big Dig parcels will play out amid a tangle of highway ramps and surface roads on the edge of Chinatown. MassDOT is offering four parcels including highway air rights to developers, as a showpiece of Gov. Charlie Baker’s 9-month-old program to dispose of surplus state properties.

A MassDOT district office and the Veolia North America steam plant occupy a 5.5-acre parcel on Kneeland Street. The offices would relocate and the steam plant would be rebuilt with much of the equipment relocated underground to make way for approximately 2 million square feet of mixed-use private development.

Urban planners have long viewed the area near the entrance to the O’Neill Tunnel as a potential cornerstone site on the southern edge of downtown. Land-use studies have recommended iconic public art, a signature public park in a neighborhood starved of green space, and a generous allotment of affordable housing to stem the tide of displacement.

MassDOT said it will issue an invitation to bid this month. Developers would have four months to put together plans for a “dense, mixed-use, multi-block redevelopment.” Building heights would range from 125 feet along Kneeland Street to up to 300 feet, or 30 stories, at the southern end of the site.

Rail yards covered much of the area until the 1950s, when they were replaced by highways including the Fitzgerald Expressway and the Massachusetts Turnpike Extension. The Big Dig reshaped the highway network, adding entrance and exit ramps for the O’Neill Tunnel, and leaving behind a grid of vacant parcels.

The area has a strategic location near the junction of I-93 and the Massachusetts Turnpike. Perhaps more important in the transit-oriented development climate, it’s a 5-minute walk from MBTA Red and Silver lines, commuter rail and Amtrak service at South Station.

A 2004 Boston Redevelopment Authority study contemplated development of a 20-acre cluster of 13 parcels in the neighborhood. But further study, including a 2012 Urban Land Institute report, concluded that none of the eight parcels south of the South Station Connector were suitable for development given a variety of site constraints.

Plans for a large mixed-income housing project on MassDOT parcel 24 at 75 Kneeland St. stalled during the recession before reviving in a partnership between the New Boston Fund and the Asian Community Development Corp. The first phase of One Greenway included 217 market-rate apartments and 95 affordable rentals. Another 51 affordable condos will be built in a second phase.

Affordability Limits Stir Debate

One Greenway highlighted the overwhelming demand for affordable housing in Chinatown. More than 4,400 residents submitted applications for the 95 income-restricted apartments.

When Baker announced plans to develop the Kneeland Street parcels this winter, Chinatown housing advocates hoped that the project could ease housing pressures in the neighborhood. Developers continue to target Chinatown parcels for boutique hotels while new luxury towers, such the 398-unit Ava in the nearby Theater District, are renting for an average of $4,000-plus per month.

Angie Liou, acting executive director of the Boston-based Asian Community Development Corp., said housing advocates originally requested that 30 percent of the residential units be income-restricted. MassDOT, in a draft invitation to bid released June 30, set the number at 20 percent. And it called for income limits ranging from 50 percent to 120 percent of the area median income (AMI), with a maximum average of 90 percent AMI.

That works out to an annual income of $70,650 for a two-person household, according to the Boston Redevelopment Authority’s 2016 affordability guidelines, more than three times the average household income in Chinatown. Units at the top end of the income scale could be occupied by two-person households earning as much as $94,200.

“Those units will be out of reach for our Chinatown families who will feel disproportionate impact from the development of these parcels,” Liou said.

Upset at what they regarded as MassDOT’s disregard for neighborhood opinion, dozens of Chinatown residents walked out of a June community meeting.

Baker said the income limits aren’t set in stone.

“It’s part of an ongoing conversation, and our goal here is to make sure we do a project that A) can get financed and B) will work for the community and the city,” Baker told Banker & Tradesman this month. “But in the end I’m sure we’ll come up with something that will work for everybody. There’s lot of work to do but I’m not worried. I think we’re dealing with parameters.”

Demand For Public Spaces and Parks

Echoing critiques of the Seaport District’s design, some housing advocates and community activists warn of another missed opportunity to build signature public spaces and parks in a land-constricted city.

The BRA’s 2004 South Bay Planning Study focused on the entire 20-acre South Bay district. The study, which didn’t factor in financial feasibility, envisioned a 2-acre park for sports and passive recreation that would extend the Greenway into the district, and elevated gardens and terraces offering views of Fort Point Channel.

By contrast, the June 30 invitation to bid only requires the developer to retain or relocate the Reggie Wong Memorial Park on Kneeland Street, which contains two basketball courts and a tennis court. It also requires the developer to cover the I-93 ramp on parcel 25, while considering materials that may encourage “creative open space opportunities.”

“I recognize what the goals of the governor are: trying to cash out on underutilized and unused state properties,” said Rosenblum, the Leather District resident. “But there’s no question that from MassDOT’s point of view, they just want to get rid of the property for the greatest amount of money.”

Options For An Island Of Land

In addition to the 5.5-acre Kneeland Street site, MassDOT is giving developers the option of bidding on parcel 27A, an oval of green space just south of the South Station Connector road. The 3.3-acre property is an asbestos landfill created during the Big Dig.

The property also has been mentioned as a potential helipad site for General Electric executives as the company moves its global headquarters to the Seaport.

In a May public presentation, MassDOT planners laid out the limitations of the site as a development parcel. A portion is reserved for a maintenance facility for the Greenway Conservancy, and the only entrance into the property is a 27-foot-wide driveway that runs beneath the South Station Connector from the MassDOT offices parking lot.

The lack of a “front door” to the property makes it unattractive to developers, MassDOT officials said. The agency concluded that the parcel was better suited for a public art installation or infrastructure upgrades.

But MassDOT did an about-face in early July, announcing that it would make the parcel available as an option to developers.

The agency declined requests for an interview with a project manager involved with the South Bay project.

In a memorandum responding to public comments, however, MassDOT hinted at its financial goals for the redevelopment. The delays and deep public subsidies needed to help build One Greenway illustrate the financial difficulties of developing expensive air rights parcels, the memo stated. And it rejected the arguments of residents who argued that the land, since it’s currently publicly owned, should be used for public benefit.

“The costs of replacing the Veolia plant, relocating the District 6 headquarters and covering the highway ramp on parcel 25 are very significant costs that must be covered by funds from the sale of the properties,” the March 24 memo states. “If all MassDOT received at the end of the process was replacement facilities, why go to the enormous effort involved? MassDOT would not be a very good steward of land and resources.”