Two development scenarios included in the Austin Street request for proposals/Image courtesy of BPDA and Mayor's Office of Housing

Boston officials have begun the formal process of selecting a developer for an 5-acre Charlestown site that’s the showpiece of Mayor Michelle Wu’s plan to stimulate housing production through public property dispositions.

Proposals are due July 10 to develop the Austin Street parking lots, which are being offered through a 99-year ground lease.

An appraisal determined the fair market value of the site at $3 per square foot of development, but price is only one of the factors that the BPDA will use to pick a developer.

Affordability, generous swaths of open space, ground-floor community uses and designs that limit air pollution from nearby Interstate 93 also will play into the selection process, which is being overseen by the Boston Planning & Development Agency and Mayor’s Office of Housing.

Proposals are required to set aside at least 60 percent of units as income-restricted. The restricted units will be offered at a maximum 80 percent of area median income for apartments and 100 percent of AMI for condominiums.

Preference will be given to proposals that include deeper affordability and a higher percentage of family-sized units and home ownership units.

Development scenarios include building heights up to 150 feet at the northern end of the site near Community College station on the MBTA’s Orange Line. The BPDA-owned lots are currently used as paid parking, primarily by Bunker Hill Community College students.

The city is offering $30 million in federal ARPA funding for five priority sites identified in a 2022 city-wide land audit, including the Austin Street lots.

The Mayor’s Office of Housing also will consider requests for funding above its standard $1.5 million cap. Eligible proposals are required to include deeper affordability components than the minimal requirements, including more units reserved for households earning a maximum 30 percent of area median income.

Four development scenarios presented in the RFP allow densities ranging from a floor area ratio of 3 to 4, and retaining 1.9 to 2.3 acres of open space.

The site is one of the first being offered through Wu’s surplus property disposition program, following the land audit of nearly 3,000 parcels owned by the city and quasi-municipal agencies.

Other priority sites expected to begin the disposition process this year include a two-thirds-acre parking lot at 290 Tremont St. in Chinatown and a 4-acre Boston Water and Sewer Commission parking lot on Harrison Avenue in Roxbury.

The BPDA will select a project review committee from the Charlestown community to review proposals and recommend a developer to the agency’s board.