The Other Olmsted: How Boston's Park System Is the Engineering Central Park Could Not Be

The thing to know about the Emerald Necklace is that it was, originally, drainage infrastructure.

When the Boston Park Commission hired Frederick Law Olmsted in 1878, they did not ask him to design a park. They asked him to fix a smell. The new Back Bay neighborhood, then under construction on filled-in tidal flats, had a problem at its western boundary. The Stony Brook and the Muddy River, draining the watershed south of the Charles, emptied into a tidal flat at the foot of the new district. Sewage and storm runoff pooled. The flat smelled. The wealthiest neighborhood Boston had built in fifty years was about to be uninhabitable because of a sanitary failure at its back door.

Olmsted's solution, drafted between 1878 and 1881, was a tidal saltwater marsh that would flush twice daily with the tides of the Charles. The brackish water would carry sewage and storm runoff out to the harbor. Salt-tolerant reeds would absorb the nutrients. Bridges and footpaths would let the public read the marsh as urban park land. The hydraulic function and the landscape function would be the same design.

This is what people miss about the Back Bay Fens. It is not, and was never, a beautiful natural marsh that Olmsted enhanced. It is an engineered sanitary system that Olmsted made beautiful enough to be readable as a park. The reeds are doing work. The meander of the channel is hydraulic geometry. The bridges are placed where the tidal flush patterns allowed pedestrian crossing.

The Fens was the first link of what would become the Emerald Necklace. The others followed: Olmsted Park, Jamaica Pond, the Arnold Arboretum, Franklin Park, all designed across the 1880s and 1890s, all connected by parkways Olmsted laid out as continuous green corridors. Add the three older parks the system absorbed at its eastern end (Boston Common from 1634, the Public Garden from the 1820s-1860s, the Commonwealth Avenue Mall from 1856), and the Conservancy's canonical count is nine. The parks Olmsted personally designed are roughly the western five. Eleven hundred acres. About seven miles end to end on foot.

That park system is the work most people do not associate with him.

Why Central Park is what gets remembered

Central Park was first. Olmsted and Calvert Vaux won the design competition in April 1858; construction in Manhattan ran through roughly 1873. By 1878, when the Boston Park Commission came calling, Central Park had been operating for fifteen years and was the most famous urban park in the world. The 1858 Greensward Plan became the template for the field.

Structurally, Central Park is one very large park inside a rectangle in the middle of Manhattan. Olmsted and Vaux drained the swamps, removed the squatter settlements (including Seneca Village, the largely African-American community whose erasure the modern park has only recently begun to acknowledge), graded the topography, dug the lakes, planted the trees, and built the four transverse roads. It was a single composition.

It worked. It is still working. Central Park is what most Americans picture when they think of urban park design.

But it is one park. It does not connect to other parks. It does not flush sewage. It does not anchor a neighborhood. It is a designed gem in a rectangle bordered on all four sides by the Manhattan grid. The rectangle could not be extended. Olmsted, looking back later, was clear about the limitation. He had wanted to do more.

In Boston, the rectangle was the wrong question. The site was not a single bounded piece of land. It was a watershed.

What Boston let him do that Manhattan did not

Olmsted accepted the Fens commission with the recognition that the problem was at watershed scale. The Stony Brook drainage, the Muddy River drainage, the tidal flat at their confluence, and the connection back to the Charles were one system. He proposed a chain. The Park Commission approved it piece by piece across the 1880s.

The result is the Emerald Necklace. The Riverway, named 1887 and substantially complete by 1895, takes the Muddy River south through an engineered corridor. Olmsted Park north of Jamaica Pond. Jamaica Pond integrated as a centerpiece. The Arnold Arboretum, brought into the system in 1882 under a thousand-year lease between Harvard and the city. Franklin Park, almost five hundred acres, the largest piece.

What unifies the chain is not aesthetic continuity. The parks look different. What unifies them is that they are connected by parkways Olmsted designed as continuous corridors, and that they are a single hydrological, ecological, and recreational system at watershed scale.

This is the move Central Park did not get to make. Central Park is the most famous example of a designed urban park. The Emerald Necklace is the most sophisticated example of a designed urban park system. The American urban park movement that followed, and the parkway concept that would shape American suburban planning through the 1950s, came out of the Necklace.

The honest claim is not that the Necklace is better. It is that the design problem was harder and Olmsted's solution is the work less often credited to him.

What the ground itself was doing

The site Olmsted was working on did not yet exist.

The Back Bay was a tidal flat in 1857. The Massachusetts state government had authorized its filling in 1856 under a compact between the state, the Boston Water Power Company, and the Boston and Providence Railroad. The fill operation ran continuously for twenty-five years, finishing in 1882. Gravel and earth were quarried from a pit in Needham, nine miles southwest. According to John Newman and Steven Holton's 2006 study Boston's Back Bay, a thirty-five-car gravel train arrived every forty-five minutes around the clock. By the time the operation finished, roughly five hundred and eighty acres of new land had been added to Boston.

When Olmsted accepted the Fens commission in 1878, the fill was four years from completion. He was designing on ground that was still being made underneath him. The tidal marsh he proposed would absorb the runoff from a neighborhood that had not yet been fully populated, on land that had not yet been fully solidified.

The labor that built the fill is the part of the story least often told. The crews were largely Irish immigrant labor, working in the wake of the Famine migration that had brought roughly a hundred thousand Irish into Boston in the 1840s and 1850s. They worked the gravel trains and the leveling crews. The Back Bay rose under their hands.

Most of them, because of the deed restrictions written into the land titles, would never live in the houses they made possible. The deed restrictions were not explicit racial covenants of the early twentieth century. They were architectural, use-based, and price-based: residential only, four stories or less, brick or stone construction, no commercial first-floor uses along Commonwealth or Marlborough. The aesthetic uniformity that makes Back Bay one of the most photographed neighborhoods in Boston was produced by a regulatory system designed to filter out anyone who could not afford to build to the specification. The fill workers were filtered out. They built the ground. They did not get the houses.

This is the second thing Olmsted's park system was doing alongside the drainage. It was anchoring an exclusive neighborhood. The mansions on Commonwealth and Marlborough needed a western boundary that was not a smell. Olmsted gave them one. The Fens stops the smell. It also stops the neighborhood.

Cynthia Zaitzevsky's 1982 Frederick Law Olmsted and the Boston Park System is the source most rigorous about both the engineering achievement and the social context. The park system is one of the great works of American landscape design. It is also embedded in a real-estate operation that produced one of the most economically exclusive neighborhoods in nineteenth-century Boston. Both are true.

Forty-five hundred wooden piles

The other thing the ground was doing was sinking.

Back Bay fill is, geologically, gravel and earth roughly thirty feet thick on top of marine clay on top of glacial till on top of bedrock. The marine clay compresses under load. A stone building placed directly on fill would settle and crack. The only way to put a substantial masonry building on Back Bay fill was to drive wooden piles down through the fill and the clay into the bearing layer below, cap them, and build the building on the platform.

Trinity Church on Copley Square is the textbook example. Henry Hobson Richardson designed it; construction ran 1872 to 1877. The church rests on approximately four thousand five hundred wooden piles, each driven through thirty feet of fill into the water table. The structural condition the church has carried for a hundred and fifty years is that the piles must stay constantly wet. If the water table drops and they dry out, they will rot. The church's foundation is a forest of submerged Yellow pine, and its continued existence depends on the foundation staying underwater.

Every major Back Bay building does some version of this. The BPL McKim Building, opened February 1895, is on piles. Most of the brownstone row houses on Commonwealth, Marlborough, and Beacon are on piles. The neighborhood's stability depends on the water table, which has been dropping slowly over the past century as the city's sewer infrastructure has been updated. There are documented cases of Back Bay buildings settling in the late twentieth century because their piles had been exposed to air.

This is the third thing Olmsted's system was doing, unintentionally. The Fens and the connected park corridor along the Muddy River are part of the water-management system that keeps the Back Bay water table stable. The system was designed for tidal flushing, was converted in 1910 to a freshwater lagoon by the Charles River Dam, and has been incidentally serving as part of Back Bay's pile-protection infrastructure ever since. The park is doing the work. It is also pretty enough to be photographed.

The layered Fens

One more piece. The Fens you walk through today is not, in fact, Olmsted's design.

His 1881 design was a tidal saltwater marsh. The Charles River Dam, completed in 1910, stopped the tides. The Fens became a freshwater lagoon. The salt-tolerant reeds no longer worked. The hydraulic flushing no longer happened. The marsh was now a stagnant freshwater body that needed a different vocabulary.

In 1930 Mayor James Michael Curley commissioned the landscape architect Arthur Asahel Shurcliff, who had trained at the Olmsted Brothers firm before going independent, to design a formal rose garden inside the now-freshwater Fens. The Kelleher Rose Garden opened in 1932. Geometric beds. Hedge borders. A vocabulary entirely unlike Olmsted's naturalistic-marsh original. Most visitors assume it is Olmsted Senior's. It is not. It is a post-dam overlay designed twenty-seven years after his death, by a designer his firm had trained.

The Olmsted Brothers firm, formed in 1898 by Olmsted's son Frederick Law Olmsted Junior and his nephew and adopted son John Charles Olmsted, ran from Fairsted in Brookline for eighty-one years before closing in 1979. Their projects are not Olmsted Senior's. He died in 1903. The work continued in his absence for most of the twentieth century.

The Fens is layered. Olmsted Senior's 1879 tidal-marsh design underneath. The 1910 dam conversion to freshwater on top. Shurcliff's 1930 rose garden as the most visible layer. To read it as a single Olmsted composition is to miss most of what is going on.

What to walk knowing

The Emerald Necklace is not a pretty park. It is one of the most sophisticated pieces of late-nineteenth-century landscape engineering in the United States. The Fens flushed sewage. The Necklace anchors a neighborhood on engineered ground. The connected-park-system concept was the prototype for the American parkway. The aesthetic experience of walking it is real. It was not the primary design intent.

Olmsted moved his home and office to Brookline in 1883, five years after taking the Fens commission. He bought an 1810 farmhouse two miles south of the Riverway and named it Fairsted. According to the National Park Service, Fairsted became the first full-scale professional office for landscape architecture in the United States. The Boston commission, the Brookline move, the firm the move created, and the connected-park-system you can still walk are the same story.

He died in 1903. The work he had started in Boston in 1878 continued without him.

Walk the Necklace as engineering. The houses on Commonwealth Avenue rest on piles that rest on marine clay under the fill. The Trinity spire stands on a forest of Yellow pine submerged for a century and a half. The Fens flushes drainage the bridges allow you to walk over. The Rose Garden is the post-dam overlay on the post-tidal park on the tidal flat. Everything is built on something else, and the something else is mostly invisible at street level.

That visibility is what makes Boston walkable as text. The seams show. The fill shows. The park shows, layer by layer, what it has been across a hundred and fifty years.

The Emerald Necklace is the Olmsted project that gets remembered second. The one to remember first.