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The water's edge

Between the boundaries lies a complex, permeable domain

The physical dialogue between the public realm and the private realm forms our cities. In simple terms, the “public realm” consists of places where anyone can go; the “private realm” is available by invitation only. Designers respond to the evolving cultural boundary between these two realms by creating buildings, spaces, and connecting infrastructures that directly shape our urban experience. They make the public/private boundaries visible.

Polarized views fill the air within significant territorial struggles about which places should be public or private. The interplay pervades — and sometimes bedevils — the regulation, funding, and design of urban projects. Professionals and their clients devote substantial time and resources negotiating workable boundaries.

But complex urban communities do not always fit simple public/private distinctions. We experience layered and permeable edges between these realms. In fact, we can find a third and more foggy realm, comprising quasi-public places and spaces. Boston’s waterfront is an emerging case in point.


Shimmer, a public art installation at the corner of Dorchester Avenue and Congress Street in Boston, by Claudia Ravaschiere and Michael Moss. Fluorescent and jewel-toned Plexiglas changed the public perception of a familiar urban environment. Photo: Sylvia Stagg-Giuliano

Take a walk along the urban waterfront and look around. At first, the public/private boundary seems perfectly clear. You can plop down on a bench in the small park (public) where Central Wharf used to be, at the foot of an office building where tenants have spectacular views (private). You can look into an inviting street-level seafood restaurant — great if you have the appetite and the bucks — but is it a public place? You can watch families with gangs of excited kids parade into the New England Aquarium after paying a fee, which helps support this outstanding nonprofit institution. Is it public, or private?

Advocates frequently seek clear distinctions in these circumstances. Some might lay claim to waterfront views they enjoy. Public ambitions may extend to access and use of the land at no cost, without regard for private title. The private advocates typically cite the economic potential of sought after waterfronts, with buildings for living, working, shopping, eating, and entertainment. Private fishing, boating, and shipping companies also claim the water’s edge, arguing that working waterfronts are scarce and diminishing resources for water-dependent enterprise.

The contrast between public and private places is a touchstone of urban design, often portrayed with stark distinctions in a figure/ground relationship. The iconographic diagram of this duality is the Nolli Map, named for architect and surveyor Giambattista Nolli’s 1748 chart of Rome. Nolli’s elaborate engraving recorded footprints of all spaces behind closed doors as darkened shapes. This was the private realm and formed the “figure” parts of the map. He left uncolored all other exterior and publicly accessible street-level interior spaces. This revealed the public realm available for civic life, picturing the “ground” that contrasted the private city.

The plan hints at the volumes of the buildings and the spaces that they define. In the mind’s eye, Nolli provides a pedestrian’s perspective of a balanced composition that includes rich sequences of streets and plazas connecting the accessible interiors of churches and civic structures. But we can also invert this perspective and imagine being within the houses, palaces, and buildings that conceal the private life of the city. The seductive map conveys a compelling vision of clear, artfully shaped boundaries between public and private worlds.


​Public and private divisions of space along Boston’s waterfront. Illustration: Kyle Nelson

Maybe 18th-century Rome really was like that, but Boston is not. This city was derived from a colonial heritage and has evolved with intertwined gradations of rights, places, and spaces.

Key legal frameworks date from prerevolutionary times. The Massachusetts Bay Company launched the colony as a commercial venture, after all, and did not separate “public” and “private” as we might today. Open waterways were needed by everyone, so the Commonwealth held all rights below high tide for public benefit. But there was a quasi-public zone above low tide. Under the Colonial Ordinances of 1641–47, the intertidal zones could be privately owned, but the Commonwealth preserved limited public rights for access to the water for fishing, fowling, and navigation. Above high tide, land was available for private ownership and use.

This mix of public and private rights along the waterfront evolved over the centuries and is even more complex today. In 1866, Massachusetts defined public rights along waterfronts in Chapter 91, a state law. Further regulations and interpretations dramatically expanded the role of Chapter 91 over the past 40 years.

For example, limited public waterfront rights remain within the presumed location of many historic tide lines, even if those lines were obliterated by urban fill and the land is now private. When fill covered tidal flats at the Fan Pier of South Boston more than a century ago, quasi-public rights remained. But our right to fishing, fowling, and navigation has been radically reinterpreted as a right for the public to enjoy private waterfront land for less water-dependent uses — including effective rights for wining, dining, exercising, enjoying jazz concerts, or simply taking in the view. We may still hold the right to take a potshot at a passing seagull, but legal advice should be sought before trying that out.

Private rights also persist on some properties if approvals and licenses secure appropriate public access. So private sector funds create layers of both public and quasi-public spaces and activities as a condition of the private development.

We now have special regulations to implement quasi-public spaces and uses, leading to obscure technical language and convoluted standards that have provoked innovative solutions. For example, “Facilities of Public Accommodation” (FOPAs) allow people to enjoy the waterfront, even if they are private establishments — like that seafood restaurant near the Aquarium. “Special Public Destination Facility” (SPDFs) are private or public interior facilities that are particularly attractive to the public with civic programming — like the Aquarium and other museums. “Offsets” provide public benefits to balance the presumed detriment if a project exceeds certain dimensions: so shadows from a tall building like the one being constructed at Lovejoy Wharf could be offset with space provided on the ground level for a visitor’s center. These are just tips of the regulatory iceberg.

People may ask whether all of these really constitute public benefits. The answer is no. Some of these are quasi-public benefits recognizing quasi-public rights. A kind of shared ownership breeds hybrid places.

What does this all mean for the urban environment and its form? A single segment of Boston’s waterfront shows the results: Atlantic Wharf is a mixed-use development with offices and residences along Boston’s Fort Point Channel that includes both historic restoration and a 395-foot tower. The project has designed, packaged, and paid for both public and quasi-public amenities onsite and around the Harbor. The project provides for the Boston Society of Architects’ ground floor information center (a FOPA). There is a waterside restaurant with outdoor seating, a wide-open public plaza and publicly available restrooms (more FOPAs). A dock serves water taxis and private vessels (a water-dependent FOPA). The project helped fund a park next to the Children’s Museum (which is an SPDF). Atlantic Wharf supports programs organized by the nonprofit Friends of the Fort Point Channel, ranging from live music, temporary art in the water and on the shore, exercise programs, and other activities.

Boston’s harbor serves as a useful point of reference, but you will find the foggy third realm of shared public/private placemaking as a fundamental part of urban design in most communities, if you look for it. These are the office building and hotel lobbies where you can take shortcuts between streets when it rains. These are the public entertainment events filling Copley Square for a few hours on stages erected by corporate stewards of public relations budgets. These are the well-designed bus stops owned by a company that puts slick ads on the sides to pay for them, placed on public sidewalks serving public buses. These are the cafés spilling tables out onto the sidewalks of Boston (or Paris, or Rome), making money for their owners. It’s the thick spatial edge between public and private.

It’s not exactly the Nolli Map, but it seems like a good way to build a city. ■


Detail of the 1748 Nolli Map, a chart that shows the public (uncolored) and private (darkened) spaces of Rome.