Developers recently submitted detailed plans to city and state officials for their proposed One Charlestown development that would gradually replace the 75-year-old Bunker Hill project with a 3,200-unit mixed-income development featuring buildings ranging from 6 to 21 stories, new park space, new stores and 13 new streets.

The city last year designated Corcoran Jennison Associates of Dorchester and Sun Cal of New York for the project, which will be built in several phases and which will include 1,100 subsidized units to replace the Bunker Hill ones that would be torn down. Current residents will have a right to one of the new apartments.

Some 600 of the new units the developers plan to pay for the project will be sold as condominiums, with 78 of those designated as "workforce" units sold to people making no more than the area median income.

In their filing, the developers explain why they'll be using several different architects to design the buildings:

Built in 1941, the apartments today are geographically isolated and physically degraded. The redevelopment will provide new buildings designed to respect history, incorporate contemporary style, and reflect Charlestown's character. New neighborhood-serving retail along Bunker Hill Street and two new parks will provide amenities for all of Charlestown. A new street grid will connect existing and new north-south streets across Bunker Hill Street to create walkable connections between the center of the new development and the rest of the neighborhood. Instead of acting as a barrier that divides, Bunker Hill Street will become a seam that unites the community. Charlestown has a rich history that will be layered into the landscape design and cultural programming of One Charlestown. The design will connect landmarks like the Bunker Hill Monument and the Charlestown Navy Yard, and the landscape will interpret many aspects of Charlestown's history. A new plaza will be introduced that reflects the history of the Site and a new common area will be created for gathering with neighbors from all over Charlestown. The Project will complement Charlestown's fine-grained urban fabric with architecture that blends style with sensitivity to history. Multiple architects will collaborate on each new block of buildings in order to create a range of styles that reflects Charlestown's unique character. One Charlestown will create friendly neighborhood streets lined by buildings with front doors, stoops, and porches that open directly to the street, connecting neighbors and bringing life to the sidewalk outside of homes. New streets will follow the best practices found in Boston's Complete Streets guide and strengthen connections to the Navy Yard and Bunker Hill Street. Taller buildings will be appropriately located toward taller features like the Tobin Bridge, or set back from main streets. All units in the redevelopment will meet the same high standard of design, regardless of their designation as market-rate or affordable. As envisioned by current residents of the Charlestown Public Housing development during visioning sessions, amenities such as common lobbies, lounges, mail rooms, outdoor terraces, and fitness rooms, will be available to all residents. Underground parking garages, capped with landscaped roofs that function as courtyards, will replace surface parking lots. There will be street parking along the new streets as well. The proposed open space network and pedestrian public realm will strengthen the connections to the existing street network of Charlestown, and create a series of publicly accessible amenities and destinations.

The project needs state approval because a small portion - 0.15 acre - sits on former shoreline land subject to state coastal regulations. The land was filled in sometime between 1852 and 1868.

One Charlestown project notification form (19.7M PDF).

More renderings from the One Charlestown filing: