Undercity: The Infrastructural Explorations of Steve Duncan

For the past fifteen years, Steve Duncan has been exploring the rivers, tunnels, sewers and utility networks running beneath city streets around the world. Through his photography, historical research, public talks and tours, he seeks to communicate his profound (and infectious) enthusiasm for these underground marvels, focussing on how hydrological and wastewater technologies conform to their natural environments and relate to broader histories of design, ecology, public health and public works.

In so doing, he illuminates infrastructures that we take for granted — until, of course, we find our basements flooded — and reminds us that contemporary challenges of wastewater are much more than a technical policy issue. They connect us to our past, and just might motivate us to demand comprehensive, long-term infrastructure planning in the future. Plus, they are beautiful places to vist. Below, Duncan shares some of his photographs and his thoughts on why sewers matter, on the mutual influence of urban and natural systems, and on the importance of the visibility and public awareness of infrastructure. –C.S.

Croton Aqueduct Self-Portrait, New York, 2006
Cassim Shepard (CS):

What do you do?

Steve Duncan (SD):

I explore cities. I try to figure out how cities work, how the urban environment is created over time.

I started out by sneaking into underground tunnels, just for the fun of it, when I first moved to New York for college in 1996. My first explorations were the old utility and access tunnels running underneath Columbia University. Most people grow out of that kind of thing. I didn’t. I’ve kept on exploring layers of cities that we don’t normally visit.

So I define myself as an explorer, but I’m also an historian, a photographer, sometimes a tour guide. Recently, I’ve been trying to take my underground explorations into the public realm. I try to communicate what I find so interesting about these unseen places and systems to the public, because I think greater understanding and appreciation of infrastructural systems has the potential to change cities, and the world, for the better.

River Fleet Tunnel Intersection, London, 2007

At what point in your explorations underground did you discover that waterways were of particular interest to you?


To be honest, at first I didn’t really care about urban hydrological systems at all. But the more time I spent exploring beautiful, sci-fi-looking tunnels, the more I became increasingly interested in how these underground places are among the least seen and least understood components of a city, and yet among the most important in creating the places where we live and enabling the way we live everyday.

The water system is an easy example of this relationship between infrastructure and daily experience. You turn on the tap or flush the toilet and water appears. Our experience of the city would be very different if you couldn’t rely on water. But how the water gets to your tap or where it goes after you flush isn’t something we see. Water’s connected to these awesome infrastructure projects that are amazing places to visit.

It was probably around 2005 when my interest in these places evolved into a fascination with the history of their underlying systems. At the time I was exploring with a group of, basically, juvenile delinquents from Queens. And I remember thinking that I have to hang out with these guys because they’re the only people I can find who will go into a sewer with me! It’s hard to find anyone who even knows very much about sewers outside of the Department of Environmental Protection (DEP), and the amount DEP employees will share is limited. This invisibility really intrigued me. Especially as I began to understand how this underground layer of wastewater infrastructure is a carryover from the original topography of the land: cities are engaged in processes of natural flow and natural resource utilization. And you never cross the same river twice, right? It’s not the same water as it was five minutes ago much less one hundred years before. Sometimes the stream channel is changed a bit, but there is still continuity in the flow.

Antwerp, Belgium, 2012

So your work as a historian investigates these continuities between the natural and the built. And I know that John Muir is an important figure to you. Do you consider yourself a preservationist as well as an historian?


I do consider myself a historic preservationist of sorts, but I don’t think the term is adequate. When we think of preserving we think of keeping it the same. Preserving artifacts behind glass in a museum is fine for things that are no longer a part of our contemporary lives. But preserving natural environments or preserving cities has to acknowledge that they are constantly evolving. What I am most interested in doing is broadening our understanding of how cities work, and history is an inherent part of that. The whole point of historic preservation is that the site itself becomes a communication tool: by communicating history you preserve it. The more people understand, the more you have maintained it over time. 


Within that history and communication, what lessons for urban dwellers are contained within the systems you explore?


I think one of the important lessons has to do with how cities are networked and interconnected, how infrastructure connects different components as well as different geographic areas of a city. When I lived in Los Angeles and began looking into the development of storm drainage systems, some pretty basic question emerged: why did they have to keep on building new tunnels every ten years? Why did such huge local, county and federal investments in drainage fail to prevent flooding in downtown LA?

The answer is in the interconnections between different places. Somebody builds a new home in the Hollywood Hills or washes their car in the San Fernando Valley, and all that water flows downhill to another part of town. And building the infrastructure in one part of town actually channels water even faster without giving it a chance to sink into the ground. Development one hundred miles away can affect what’s happening in downtown LA. So, it’s not a drainage design failure, it is a failure of understanding the connections between different parts of the city and the ways that one kind of development impacts other areas.

Plaza Drain, Los Angeles, 2011

Beijing experienced something similar this summer with the tragic flooding that killed 70 people. I learned of this when a couple of Chinese magazines contacted me to ask how New York City, with its much older system, does relatively well with flooding. I realized from the questions they were asking that they didn’t have much of an understanding of how the development of some parts of Beijing – it’s doubled in size since the 1990s – affects the capacity of infrastructure in a different part of the city.


We have a similar challenge in Staten Island, where residential development has outpaced infrastructure investment, leading to a lot of stormwater runoff from rooftops and pavement…


And the ways the City has gone about addressing that with the Staten Island Bluebelt is a really interesting example of how far our urban planning and engineering knowledge has come since the postwar planning of LA. A lot of big cities are so built up that it’s hard to apply these lessons, But Staten Island still had enough open space to try some innovative approaches to retaining stormwater before it overwhelms the sewage system.

Wallabout outfall, CSO NC B5, Brooklyn, New York, 2011

Issues of stormwater runoff, combined sewer overflows (CSO), green infrastructure – especially in changing climate of stronger storms and rising water levels – are a very hot topic in New York these days. And one of the ways the CSO challenge is characterized is as an outdated 19th century system built with 19th century assumptions about plumbing, sanitation and waterways. Can you explain some of the intentional design choices that those systems were trying to address?


You’re right, when I talk about this stuff, it’s easy for it to come across as critical, because of contemporary ideas about sustainable water use and hydrology. But I think the design and construction of these engineering projects is pretty incredible. My historical research has convinced me that a lot of major urban infrastructural projects have come about in response to repeated catastrophes that have resulted from rapid growth. Basically, when enough people have died, we become willing to pay for expensive infrastructural systems.

For example, when the CSOs began to be constructed in the mid-19th century, New York was facing the huge public health crisis of water-borne communicable diseases. Combined sewer systems like the one in New York addressed that challenge, and were rightly recognized as a triumph of engineering.

See, our sewers depend on gravity to drain, but the topography of Manhattan Island is relatively flat, which led to a lot of build-up of silt and excrement during dry weather. One of the advantages of CSO is that rainfall will wash all that away. Rainfall was intentionally designed into the operation of the system to clean it. That cut down on smells and saved countless lives from disease.

In the second half of the 19th century, there was a huge amount of professional dialogue about how to make good sewers. And a lot of this was in the public sphere: great sewer engineers wrote books for the public and there was huge awareness and public appreciation for these systems.

If you go into sewers, you can tell the time period they were built from the shape and the materials used. The earliest sewers built in New York had round, brick tunnels with a small amount of flow. After a decade or so, the City realized that the dry weather flow in round sewers is very slow and easily clogged up, so it switched to an egg-shaped profile that sped the flow during dry weather. And in the 20th century, we see bigger, concrete and rectangular sewers. You can see an entire history of design choices that, for their time periods, each served the city’s needs incredibly well. And you can see how much our urban systems reflect pre-urban, natural systems.

Wallabout outfall, CSO NC B5, Brooklyn, New York, 2011

Explain what you mean by that. How do natural systems influence the design of urban systems?


The more you look at different layers of the city, the more you realize that we haven’t escaped nature in our modern city. Cities exist within natural environments, are shaped by natural resources, and function everyday through processes of interlinked natural and urban systems.

Since the glaciers retreated, rain has been falling on Manhattan Island in much the same way that it does now. Any drop of rain meanders across the topography of Manhattan Island today pretty close to the way it would have a thousand years ago. Because we’ve paved over most of the land, that water won’t sink in as quickly as it used to and its flow will be altered a bit, but the shape and contours of the land are similar to how they’ve always been. That’s what I mean when I say that there is no distinction between urban and natural. Our current sewer shed almost exactly matches the pre-urban watershed.

Take Minetta Brook for example. Minetta Brook was a medium-sized stream that ran through what is now Greenwich Village. It provided both water supply and a drainage route. Starting in the early 1800s, bits of it were covered over, and some of the marsh areas where underground springs fed into it were filled in. By the 1850s, it was almost entirely covered over. And since then, contractors working on building foundations along 5th or 6th Avenues keep “rediscovering” Minetta Brook. Underneath the NYU Law Library, brook water repeatedly bubbles up into the basement. And vestiges of it are still visible above ground if you know what to look for: lobby fountains memorializing it in a few 5th Avenue buildings, patterns of potholes where there is more underground water, particular kinds of manhole covers. Manhole covers in cities are like animal tracks in the forest: it’s not the thing itself, but if you’ve learned to read it, you can understand what’s going on.

While Manhattan’s street grid and various waves of property development in the area have diverted the underground waterway so that its route is impossible to discern, I worked with a friend to map out the historic watershed and the contemporary elevation and contours of that watershed. So then I could say with confidence, this is where Minetta Brook flowed. And the locations and design for the past two centuries of sewer building have depended on it.

Above: 2009 satellite image of Manhattan overlaid with Ebert Viele’s “Sanitary & Topographical Map of 1865,” showing route of Minetta Brook. Below: GIS model of Minetta Brook’s contemporary watershed flowing through combined sewer pipes. | Images by Steve Duncan and Liz Barry

Besides your photography, in terms of making some of these hidden natural and urban systems visible, what modeling and visualization strategies do you use?


I like maps a lot. Maps never tell you the whole story about anything, but maps are among the best tools I know of to communicate data about place (other than taking pictures and talking to everyone I meet at parties about sewers). Good mapping, in my opinion, is capable of connecting data to specific places and communicating it in an instant.

But my ideal way of raising awareness isn’t just to bring evidence of what’s underground – photographs, maps, historical records – aboveground. I also want to bring people underground to see for themselves. Some of the places I’ve seen – like the beautiful set of tunnels near Van Cortlandt Park pond in the Bronx – would be landmarked in no time if they were above ground. They’re just gorgeous: the craftsmanship of the construction, three or four layers of hand-laid brick in arches and sweeping curves.

One of my dreams is to help create a “sewer viewer,” a periscope on the sidewalk the size of a water fountain, kind of like those viewing platform binoculars you put a quarter into and are able to see some part of the environment that you might not focus on otherwise. The periscope would let you see into a tunnel and its flowing mass of water. I think opening that stuff to visibility would be very beneficial.

Knickerbocker Avenue Sewer, Brooklyn, NY, 2007

Why? How would that level of visibility enrich public understanding and make us more responsive to our infrastructure and environment?


By seeing, people would be better equipped to understand how stuff works as well as how previous generations dealt with these issues.

In the 1860s, everybody could see that the ferry boats between Manhattan and Brooklyn were full, the long lines waiting to get on the boat, the amount of time to get to work in the morning. So when the Brooklyn Bridge was proposed, citizens could see how that would apply to their lives.

We don’t see the processes going on underground, so we aren’t aware of them until there’s a problem. If the problems of CSOs were more visible, maybe people would be more conservative with their water usage when it’s raining. Or if people could see how awesome some of these old tunnels are, then the next time there’s a bond for infrastructure investment on the ballot, maybe people would remember that incredible tunnel from 1880 and vote for long-term infrastructure planning. I do think we have the power to make the city what we want it to be, and a lot of the time people don’t realize that. They think that issues in our environment come from the outside, but we have the power to shape it in the future just as we shaped it in the past.

History and the present are inseparable. When I was in high school I thought history was boring because it didn’t seem relevant to me. What’s made me into a historian is the realization that the past didn’t go anywhere. It’s been integrated into the present and filled the present. So we can’t always understand the present world around us unless we look closer. And looking closer means looking not just at the surface layer, but also at what lies beneath it.

Bangkok, 2011

Unless otherwise noted, all images by Steve Duncan. All Rights Reserved. 

Steve Duncan is an urban historian, explorer and photographer of the urban underground. He has photographed sewers and underground rivers in cities from Antwerp to Yangon, with particular focus on the underground hydrological and wastewater infrastructure of New York City, Los Angeles, Paris, and London. He has hosted a Discovery Channel show on urban archeology and has appeared on the History Channel and others as an expert on New York’s underground spaces. He received his MA in urban history and is currently working on his PhD in urban geography. For more information, visit undercity.org.

The views expressed here are those of the authors only and do not reflect the position of The Architectural League of New York.


Leni Schwendinger August 22, 2012

Great feature – excited to follow Steve’s progress!

Lou K August 27, 2012

An excellent read with delightful photographs. Many thanks!

Corey Hall March 2, 2013

What a well written article and what a great read. Been a fan of Steve’s work on undercity for a while now. I have a interest in Storm Drains myself and have explored a few and it is always interesting to see the maze of large subterranean pipes that are interconnected with the world we live in.

Michael DeMeo September 13, 2014

Fascinating stuff! Thanks for sharing. I worked building the Passenger Ship Terminal at 50th St in 1972,. I always wondered about the old brick lined out falls that ran right into the river at the pier. Hopefully these are no longer dumping raw into the Hudson as they were back then.