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January 7, 2020 Environment

How Philadelphia’s Water Pollution Problems Shaped the City

The way the city tackled its water pollution problems has made it an unexpected pioneer.  

Lithograph of a view of the Fairmount Water Works with the Schuylkill River in the distance, 1838.

Philadelphia just had its wettest decade on record, and all that precipitation has wreaked havoc on the city’s waterways. Like most old cities, Philadelphia has a combined sewer system—that is, one pipe is used to carry both sewage and stormwater. When it rains a lot, the system gets overwhelmed, forcing the water department to send raw sewage into rivers and creeks. City officials and engineers knew this was going to be a problem when they built the sewer system in the 1800s. The reason they used a combined system anyway can be best explained by two forces: knowledge ceilings and path dependency. In this episode, we explore how the city got to this point and how, in an interesting twist, it led to Philadelphia having one of the most innovative water systems in the country.

Philadelphia is home to the Distillations podcast. For this episode, we break down three centuries of water-pollution history in our backyard. It is a special collaboration with the Philadelphia Inquirer as part of its From the Source: Stories of the Delaware River series.


Host: Elisabeth Berry Drago
Reporter: Rigoberto Hernandez, Sebastian Echeverri
Senior Producer: Mariel Carr
Producer: Rigoberto Hernandez
Audio Engineer: James Morrison
Additional production: Dan Drago

Special thanks to the Science History Institute’s Center for Oral History and the museum team for doing some of the research that went into this episode.

Resource List

Grabar, Henry. “Tunnel Vision.” Slate, January 2, 2019.

Handy, Jam. “Waters of the Commonwealth.” Pennsylvania Sanitary Water Board, 1951.

Henninger, Danya. “The Incredible Fairmount Water Works: Explosions, Mark Twain and the Long-Lost Philadelphia Aquarium.” Billy Penn, October 10, 2015.

Kummer, Frank. “The Secret Scourge of Climate Change? More Raw Sewage in Philadelphia’s Waterways.” Philadelphia Inquirer, September 13, 2019.

Levine, Adam. “Fairmount Water Works.” Philadelphia Water Department Water and Drainage History Course, 2015.

Nemiroff, Sydney P., dir. “Road Ahead: Milestone 3.” Philadelphia Department of Records, ca. 1960.

Schulman, Alexis. “Sustainable Cities and Institutional Change: The Transformation of Urban Stormwater Management.” PhD diss., Massachusetts Institute of Technology, 2018.

Stutz, Bruce. “Philadelphia Is Tackling Its Stormwater Problem.” Yale Environment 360 (March 29, 2018).


History of Water Pollution in Philadelphia

Lisa: Hello and welcome to Distillations, a podcast that explores the hilarious, strange, and serious stories at the intersection of science, culture, and history, all powered by the Science History Institute. I’m one of your hosts, Lisa Berry Drago.

Philadelphia is the home of the Distillations podcast. And today our episode is all about the history of water pollution here in Philadelphia. This story is in our backyard, but it also has lessons other cities can learn from—specifically, how to manage your sewers with the threat of climate change looming.

It’s a collaboration with the Philadelphia Inquirer for their “From the Source: Stories of the Delaware River” series.

For this episode we worked with reporter Sebastian Echeverri. Over the summer, he was a AAAS [American Association for the Advancement of Science] fellow at the Philadelphia Inquirer, and he’s going to help us tell the story.

Sebastian: If you’re from Philadelphia, we hope this story will resonate with you because the city was shaped by water, figuratively and literally. So sit tight as we break down three centuries of water pollution history.

So the neighborhood we’re in is Juniata Park. We are sort of above, we’re in the Northeast.

Lisa: In a neighborhood just above Kensington, there’s a creek called Frankford Creek. It runs through a park and golf course. And just at the edge of it there is a giant gate that looks like the entrance to a castle. But it’s more of an exit, and it’s operated by the water department.

Julie: There’s a gate that opens when it overflows. And you know, you can drive a truck through that.

Rigo: You can drive a train through it.

Julie: Yeah. It is really, it is really big.

Sebastian: Julie Slavet is the executive director for the nonprofit Tookany/Tacony-Frankford Watershed Partnership. She works on ways to manage storm overflows in the city. She is worried about what comes out of that gate: raw sewage. There are 164 of those sewage overflows in the city, and this one is one of the biggest.

Julie: What basically goes into this little creek system is like the volume of the Schuylkill River. It’s enormous. I mean, you can see how eroded it is. I wouldn’t want to be standing here. If we were standing here when the combined sewage overflow gate opened, there’s no doubt in my mind that it’s not coming up this high. 

Lisa: The Schuylkill River is a 2,000-square-mile river on the west side of the city. It’s pretty big. So when it rains a lot, this area fills with 43 million gallons of foul-smelling sewage, plastic bags, and other debris.

Sebastian: This creek is one of the only recreational spaces for a part of the city that’s very poor. And it might surprise people, even the residents nearby, that this is totally legal and normal.

Julie: It is very likely that when it rains in Philadelphia, there’s combined sewage going into the creek. On average, there’s one combined sewage overflow into this creek once a week. So that’s a lot.

Lisa: What makes it more alarming is that during the last decade, Philadelphia has had the most rain ever on record.

Julie: It’s a really tragic human use of a natural asset. I mean, this is a creek that people should be able to enjoy. And because of the way we’ve developed the city, it is, you know, it’s polluted.

Sebastian: Philadelphia, like most old cities, has what’s known as a combined sewer system. It means that just one pipe carries both stormwater and sewage. So when it rains a lot, that rain can overwhelm the system, and this forces the city to send all that untreated sewage straight to the two rivers that surround it—the Schuylkill on the west and the Delaware on the east.

Lisa: This is somewhat unusual. Many cities get their drinking water from distant places—away from their sewage. New York, for example, gets most of its water from the Catskill Mountains.

Sebastian: The combined sewer was built around the 1860s as a response to typhoid fever. And the interesting thing is that the city knew back then this was going to be a problem, but they did it anyways. They simply didn’t have a better solution.

Alexis Schulman: They truly believed that the diluting powers of the rivers would be adequate to clean, basically still have clean water, be able to use it for the city’s drainage and sewage but not overwhelm their cleansing capacities.

Lisa: That’s Alexis Schulman, she is a fellow at the Academy of Natural Sciences in Philadelphia, and she wrote her dissertation on the history of stormwater management.

Alexis Schulman: You hear about these decisions that were made in the past, like creating a combined sewer, like dumping your sewage into the river, and you think, “God, how stupid.” But in having to go through this full history and understanding what was kind of structuring these decisions made me have a lot more empathy for the decisions. I can see, you know, I could see how that seems totally reasonable.

Sebastian: Why was the city built this way? It’s explained by two hidden forces we are going to talk about in this episode. One is that when anyone, including a city like Philadelphia, is responding to crisis, they have knowledge ceilings. You can only act with the information you have at that moment. And number two is this thing called path dependency. The most eloquent definition we’ve heard of this is, “History matters; what has occurred in the past persists because of resistance to change.”

Alexis Schulman: That’s the idea that preceding steps that we take in a certain direction, well, they incite more movement in that same direction. And it becomes more difficult to change course. So why does that happen? There are lots of different reasons, but one is you have sunk costs. And there’s a lot of uncertainty around that because people have now organized their expectations and their learning and their technologies around that original decision that they made.

Lisa: Probably the most familiar example of this phenomenon is your keyboard. The way it’s laid out,  Q-W-E-R-T-Y. It’s because typewriter makers put distance between the most-used keys so you wouldn’t press them all at once and jam it. There is no reason why we need it on a smartphone, but we still have it. This configuration became the standard. And once it’s locked in, it is extremely difficult, if not impossible, to get out of that path dependency.

Sebastian: We know that having a combined sewer system is a bad idea. And basically the city stuck with it because in time it became almost impossible to break away from it. But in an interesting twist, path dependency is also the reason why Philadelphia was able to build one of the most innovative water systems in the country.

Lisa: Those are not words we are used to hearing: Philadelphia as an innovator in infrastructure. Over the course of this episode we are going to find out just how Philadelphia got to where it is now.

Sebastian: And to see how we started on this path, we need to go back to a time before there even were any sewers. And like most Philadelphia stories from colonial times, it begins with the city’s favorite son, Benjamin Franklin.

Chapter One: The Benjamins

Lisa: My face is the coldest face in the world, just kidding. I have a scarf and you don’t, Rigo, so I’m sorry.

The Distillations team recently took a walk with our colleague Rebecca Ortenberg, who’s been doing some research into the histories of our local waterways. The Science History Institute is in Old City Philadelphia. Actually, we are right next to what was once Benjamin Franklin’s house. And the waterways we are talking about are literally underneath our feet.

Rebecca: In particular, where Lisa and I are standing right now, on what is now a very nice brick and cobblestone path, was a creek. It was called Dock Creek because it flowed to the Delaware River where there were docks. It has a very wonderfully descriptive name.

Lisa: Dock Creek ran for a few city blocks, and European settlers established their houses and businesses around it. This became the epicenter of life in Philadelphia.

Rebecca: It’s so weird to think about Philadelphia right now. You know, it’s a modern city. We’re all bricked over and everything, but there were all of these creeks that literally were flowing through one of the most significant urban centers of the late 18th century that were just like part of the landscape and part of like normal life.

Sebastian: By 1763 it also became the city’s open sewer and trash can. This is Adam Levine, the Water Department’s historian.

Levine: There were slaughterhouses along Dock Creek that would slaughter animals. They would then wash all the little bits that didn’t make it into the people’s dinners and into the butcher shops. They would wash that blood and the little bits into the creek.

They would take the hides of the animals and bring them to the tanneries. The tanners would soak those hides in baths of lye, sometimes for months depending on the quality of leather they were making. Then they would scrape all the hair and little bits of flesh that were left on the hide, and all of that lye and all that waste would then be dumped into the creek.

Lisa: This wouldn’t be such a big problem, except Dock Creek flowed right into the Delaware River, one of the two rivers that surround the city and the source of drinking water. The Delaware River is tidal, which means its mouth is at the ocean and those tides push the water back up. Remember this because, like the tide, this will come up again later.

Sebastian: During this time, the city is experiencing outbreaks of yellow fever. It is a nasty disease that gets its name from one of the symptoms: the yellowing of the skin. But it also causes internal bleeding and black vomit, and it killed about 5,000 people in 1793. That was about 10 percent of the city’s entire population.

Fried: No one had the slightest idea of what caused yellow fever, how to treat yellow fever. And regardless of how history remembers all this, nothing anybody did had anything to do with who lived and died of yellow fever.

Lisa: That’s Stephen Fried. He wrote a book called Rush, about Benjamin Rush, a so-called founding father and the main doctor who responded to the yellow fever epidemic.

Sebastian: This is before people understood that some diseases are caused by bacteria and viruses. We know now that yellow fever was transmitted by mosquitoes. But at the time they thought it was transmitted by bad odors, or miasmas. That theory was the norm. For example, the word for malaria is Italian for bad air.

Lisa: Back in Old City, remember all the lye and flesh and chemicals that have ended up in the creek? Dock Creek was widely considered the biggest source of bad air.

And so somebody has to see this as a problem, right? At some point, somebody sees this as a problem? Yes.

Rebecca: And one of those people is Benjamin Franklin.

Which is like Benjamin Franklin to have his nose in every single bit of business ever. But, and this is my personal speculation, but Ben Franklin’s house was right next to where the Science History Institute is now. So if you remember, we just walked across the street. So he was very close to this, like, terribleness that was Dock Creek, and he probably didn’t like that very much.

And he also liked to get people to do things that he wanted and knew a lot of people and was good at it. So he and other people were basically, as a way, honestly, of trying to get rid of the tanneries and the manufacturing happening around here, were like, “So Dock Creek is disgusting, we should cover it over.”

Sebastian:  They thought that if they covered the smell, then that would stop the miasmas from infecting them with yellow fever. This is Stephen Fried again.

Fried: It’s not surprising that after the yellow fever epidemic, one of the first things they focus on is literally filling in Dock Creek, which many have suggested is the first overt act of public health in America. It’s a big undertaking. It changes the economy of the city to some degree. People have to throw out their stuff somewhere else, and it physically changes Philadelphia. There’s actually, nobody would know Dock Creek exists anymore, where it is. But the idea was, if we do this, then there won’t be another yellow fever epidemic.

Lisa: We know now that covering Dock Creek didn’t work, and it wouldn’t work. The outbreaks continued. You might be wondering why would they do it? Fried says they had a knowledge ceiling. They didn’t have germ theory, they only had the evidence of their senses. And their senses were telling them that the smell was the problem.

Fried: One of the things you have to be careful of, especially when you’re dealing with science and medicine, is what the extent of knowledge was during the time.

Because I’ve read people writing about the yellow fever epidemic, and they almost are saying like, you know, to Rush, “It’s right in front of you. The mosquitoes are right there. How can you be so stupid? If you were only doing more of this, if you were only doing more of that.” The information simply wasn’t coming to them because of what they didn’t know.

Lisa: Covering Dock Creek was not the only action taken by the city to stop yellow fever. In his will Benjamin Franklin recommended that some of the money from his estate be used to bring water from other places.

Sebastian: A group of “respectable citizens” also petitioned the city to create a new water supply, somewhere away from the Delaware River, which was polluted and emitting those miasmas.

Alexis Schulman: So they acted on this pretty quickly once these respectable members of society petition the government. But they had to decide is this going to be a public or private program? Where are we going to source the water from? What is the design going to look like? So that of course took a few years. And then, you know, how are we going to raise the money for this? And what they ended up doing in that case was what essentially are revenue bonds. So that’s how they were able to raise the money. And then the design itself, there were lots of different ideas put forth. But Benjamin Latrobe happened to be in town. He was a young engineer.

Sebastian: Latrobe is a British guy, and the third Benjamin in our story. He is most famous for basically designing Washington, DC, from the ground up. He suggested that Philly get their water from the Schuylkill River, which is a smaller river on the west side of the city. This part of the city was mostly uninhabited, and therefore the quality of the water was more pristine—for now.

Alexis Schulman: And his plan was to use steam power, which was relatively new at that time, to power a pump that would draw water from the Schuylkill, send it to a reservoir at what now is Broad and Market, and then distribute it across the city by gravity. And so that project was actually accepted relatively quickly, and they found funding for it. It was also less expensive when compared to the private companies’ canal project.

Lisa: The plan included a structure along the Schuylkill River, near what is now the Philadelphia Museum of Art. The building housed a steam engine designed to draw from the river. But that technology was new and risky, and it didn’t work.

Sebastian: There were two boiler explosions in 1818 and 1821, and that killed several people.

Lisa: The city was at a critical juncture. Should they get their water elsewhere, away from the rivers? Remember, most cities don’t get their water from their own rivers; they get it from the mountains if they can.

Sebastian: The city decided to double down on getting their water from the river. Their fate was now going to be tied to those two rivers. So they partnered with a company that built a system of canals and a dam on the Schuylkill. Part of the dam construction included a canal that redirected water into a building which housed massive water wheels. The wheels turned thanks to the weight of the water and pumped the drinking water into Philadelphia proper.

Lisa: The operation came online in 1824, and they called it the Fairmount Water Works. The failed steam engine house was converted to a saloon with gardens. The Fairmount Water Works became the city’s most popular tourist attraction; it was the place to be in Philadelphia.

Sebastian: Philadelphia loves to claim we are the first at everything. However, the Fairmount Water Works was not the first water system in the country. But it was the first public water system. So how exactly did it work for regular people?

Levine: For five dollars a year they could tap into the water pipes, which were made of wood early on, with their own pipe, usually an iron pipe, and bring water into their own house or more likely into a faucet or a hydrant, they called it, in their yard.

The people who couldn’t afford that or didn’t have their own house, they could access any number of public hydrants, which were basically pumps where the water would flow into a well underneath the street, and then they would pump it out into a bucket. And these were all over the city. As the system expanded, as the city grew, hydrants were provided at regular intervals.

Lisa: So the city has its first water system that’s drawing water from the Schuylkill River. They quickly realized that they needed to avoid the problems they’d run into on the Delaware River and Dock Creek. Remember all those butcher shops and tanneries? So they bought up a lot of the land above the Fairmount Water Works. This land later became a park known as Fairmount Park.

Alexis Schulman: It was for the public, but it was also to protect the purity of the water and the drinking water. And that park expanded; they kept buying more tracts of land. And after the city consolidated, they were able to buy even more and the hope was that they could protect the purity of the water.

They were thinking about the connections between what’s happening on the land and happening on the water. I mean, it was all, it was very obvious to them. It’s just unfortunate that it was definitely never going to be enough.

Sebastian: There is one fatal flaw with this plan. The Schuylkill River is 135 miles long, and Philadelphia is at the furthest point of that downstream. Even if Philadelphia was the cleanest it could be, they were still getting all the stuff that people and industry upstream were throwing into the river.

Lisa: And this gets us to the next challenge of Philadelphia water: typhoid fever. But first we are going to take a bit of a sewer detour, because you can’t talk about water without talking about sewers.

Chapter Two: Typhoid and Filtration

Lisa: From the time the water system is finished in 1824 and until the 1850s, disease-related mortalities dropped thanks to the pristine waters of the Schuylkill River. But those pristine waters were about to become muddier in part because of a new invention known as the water closet, the precursor to modern-day flush toilets.

Sebastian: Up until this point people pooped and peed into a privy, which is a hole in the ground. It’s kind of like a porta-potty in that no flushing was required—or possible.

Levine: Starting in the 1830s more and more houses were being built with flush toilets. There you’re adding 5 gallons of water with the small amount of urine and the small amount of feces that you’re putting into the privy. And so very quickly the privy started overflowing, getting overwhelmed. They have to be cleaned far more often, and an overflowing privy is not just a nuisance, as the Board of Health called these things, but it’s a threat to the health of the vicinity because they thought that the odors were causing disease.

Lisa: The miasma theory of disease, that is the idea that disease spreads by odor, was commonly accepted until germ theory was introduced in the 1880s. These new water closets were now a threat. Instead of the waste percolating into the soil, the privies and cesspools were overwhelmed and that excess poop made its way into the streams and sewers. It also seeped into nearby wells.

Levine: By the 1860s this had come to a head. By that time the surveyors and regulators who were laying out the city had sort of evolved into city engineers. And they wanted to, you know, make the city bigger and better, and one of the ways was to take the underground storm sewers and to start connecting houses directly with those sewers, creating combined sewers that carried waste and stormwater and getting rid of privies. They thought it was better to get those odors into those storm sewers and flush them out into the rivers. They thought that it would become diluted and neutralized.

Lisa: There was a was a saying at the time, “The solution to pollution is dilution.” So the Department of Surveys—as the city department in charge of the sewers was called—built a combined sewer system that took stormwater and sewage and dumped them into the rivers on both sides of the city.

Alexis Schulman: At the same time, there were dissenters. A major dissenter was the Department of Public Health, who said exactly, pretty much predicted what happened.

They said, we’re pretty sure, because we’re talking about a tidal river, in the case of the Delaware, that the wastes are just going to be borne back up the river. And all of these things that they predicted are exactly what happened, and as the population also grew and industries grew, the problem was only made worse

Sebastian: But it’s not like the health department had a better alternative. They were stuck under a knowledge ceiling.

Alexis Schulman: Even the health department that said don’t build these combined sewers, don’t put the sewage in the river, they in the same letter said, we don’t know what the other alternative is, but can you wait a little bit more? But it’s like, you know, can you wait a little bit more?

Lisa: The tide of pollution, pun intended, had actually turned. Remember, we are downstream, so industrial pollution is building up too. The rivers are filled with sludge and waste.

Levine: By the end of the 1880s everybody in the city knew that the Schuylkill River was grossly polluted, that it was the cause of a lot of disease and death. Just like the climate deniers today, there were, there were …

Sebastian: Schuylkill deniers.

Levine: Schuylkill deniers, or even, say, miasma adherence.

Sebastian: The thing that was killing Philadelphians now was typhoid fever. It’s a bacterial infection that comes from water and food that’s been contaminated with sewage. The symptoms go beyond the fever; it can tear holes in your intestines and other organs in your body.

This is Gary Burlingame, he’s an environmental scientist with Philadelphia Water Department Laboratories. He’s in charge of the taste of the drinking water for the city.

Gary Burlingame: Imagine that over 100 years ago we were determining or demonstrating the safety of the drinking water based on how many people died of typhoid every year.

Lisa: Sixteen thousand people died of typhoid fever between 1860 and 1890, and for every death 10 to 15 other people became ill. Here Philadelphia is at another critical juncture. Should they get their water from another place?

Alexis Schulman: So you’ve already spent a lot of money, for example, on a water distribution system that’s drawing from your rivers. To change course and say, okay, now we’re going to draw from the Pine Barrens, which at one point was a possibility, is very costly. And there’s a lot of uncertainty around that because people have now organized their expectations and their learning and their technologies around that original decision that they made.

Lisa: The Pine Barrens are a forested area in New Jersey. Of course, we know now this did not happen.

Sebastian: Instead they doubled down on their historic decision to get their water from the rivers.

Lisa: There’s a chart behind Gary Burlingame’s desk that offers a clue to what happened next. The chart tracks the number of deaths due to typhoid fever in Philadelphia.

Sebastian: He keeps it there because it reminds him of why he does his job.

Gary Burlingame: And what it shows is in Philadelphia, Pennsylvania, it tracks the number of typhoid deaths recorded per 100,000 people in the city.

It starts out at about 60 or 80, and then it goes up and down in this bar graph until it really starts to dip around 1910.

Sebastian: So what changed in 1910? I mean, there’s really like a quick dropoff around that time period.

Lisa: What changed was that after a lot of public pressure and 10 years of delays, the city finally opted to filter their water with slow sand. It was something that they were already doing in Europe.

Levine: You’re the science museum; you can figure this out, but I don’t know how it works, but it does.

Lisa: Basically, imagine a giant room with sand pits that are all filled with water. After a few days, a gelatinous layer of bacteria will form on top of the sand, and it will start absorbing other organic matter too. The water that eventually percolates through the sand to the bottom is clean of bacteria.

Sebastian: By 1911 the city had built five of these sand filtration plants. The water was declared good enough to drink, but typhoid still continued to spread, and people weren’t totally convinced. The city had to do more.

Burlingame: So they removed a lot of the germs, but not all of them. And then in around 1913 we started adding chlorine at our treatment plans. And chlorine was a big thing. A lot of people didn’t want it. They, you know, they were claiming it’s a poison, and why are you putting it in the water? But we got it through here in Philadelphia.

Lisa: And the chlorine killed the germs. Since the water was so polluted, they had to use a lot of it, and it gave off a distinctive smell. Locals nicknamed it, among other things, “Schuylkill punch.”

Levine: Once we finished the filter plants and started chlorinating the water supply in 1914, typhoid fever and other waterborne diseases basically disappeared. There was just background levels of those diseases, which begs the question, what happened to the sewage that was being dumped in the rivers?

Chapter Three: Sweep Out the Rascals

Sebastian: We’re now into the 20th century, and there are no laws regulating sewage. Even though we weren’t drinking it, that didn’t mean people weren’t exposed. It was still a huge problem.

Levine: Most of it’s just still running directly into the rivers. And when I say running into the river, it’s just, you flush your toilet; it goes into the sewer; it runs out into the rivers, day and night, to the tune of hundreds of millions of gallons a day because the city’s population also peaked about this time. They were about two million people in the city then.

Lisa: We increasingly had the technology to fix this problem, now we needed the regulations.

Waters of Our Commonwealth: Here at our state capitol, Pennsylvania’s fight to check water pollution started in 1905 with a law requiring the treatment of sewage.

Sebastian: The 1905 clean streams law [Purity of Water Act] basically made it illegal to pollute the rivers and streams with sewage. Even though everyone agreed sewage was the problem, the city dragged its feet. The war and the Great Depression also caused delays. But one of the main reasons was because of politics: even though they dealt with the same deeply connected system, one city agency was in charge of the sewers, and another was in charge of drinking water. You can imagine the kinds of problems this caused. The state was patient for a few years until they weren’t.

Alexis Schulman: So in 1914, the state says to Philadelphia, enough, you can’t just be dumping all of your sewage into these rivers. You need to do something. You need to at least have a plan.

Waters of our commonwealth: Let’s see just how the treatment process keeps sewage from polluting our waters. When the flow of sewage first enters the plant, it is screened to remove coarse materials and rags and then passes through the grit chamber to remove fine grit and sand.

Lisa: So if the benefits are obvious, why did the city drag its feet for so long to build these plants?

Sebastian: Remember when we said earlier that one department was in charge of sewers and another was in charge of water? This wasn’t always a happy marriage. There was competition, politics, and money.

Lisa: Around the 1940s it became obvious that the situation had to change. The water department had to be consolidated. And Philadelphia had just the guy to do it.

Narrator: Mayor Richardson Dilworth reports on progress.

Dilworth: We can portray only a few results of combined planning and action here. These are measured in terms of brick and stone and steel. Also very much present is the heart and soul of a city reborn, the spirit of its dedicated people.

Lisa:  Dilworth is best known for being the mayor of Philadelphia in the 1950s. In fact, Dilworth Park, right outside City Hall, bears his name.

Sebastian: But before Dilworth was mayor, he was the city treasurer, and more than most, he wanted to root out the corruption at City Hall.

Alexis Schulman: Everything is extremely corrupt, and that is not like an overstatement or generalization. And he says, you know, we’re going to sweep these “rascals” out.

Lisa: One of the biggest issues was missing money. Among the departments that were investigated was the Philadelphia water department, which was in charge of collecting rate fees.

Alexis Schulman: I mean, you weren’t getting water for free. You were paying for it, and that’s a big money maker; so there are a lot of people who are going to be very interested in this system.

Sebastian: So the Dilworth investigation finds that $40 million went down the drain—though not just from the water department. It leads to a grand jury investigation, and the national press arrives in Philadelphia.

Alexis Schulman: Philadelphia sort of became like a horrifying laughingstock at the time because things were just so terrible.

Yeah, multiple people in government killed themselves, including someone at the water department, because it just was revealed that a lot of money was going missing.

Lisa: The Dilworth investigation had even more wide-ranging consequences. In the next election, reform-minded Democrats were elected, and they voted for a new city charter—a sort of new constitution for the city. And this new charter changed the way municipal services were organized. The Department of Surveys in charge of sewers was merged with the Department of Water in charge of the drinking water.

Alexis Schulman: And it gives this organization a lot of political independence. Now we have an organization that’s very insulated. It’s governed by civil service requirements. The only political position is the commissioner’s position. Its fees are set by itself. And it is able to decide—and it’s supposed to decide based on sound science and engineering—where to make appropriate Investments. So this is a very modern reorganization, and it’s what we’re working with today.

Sebastian: By the early 20th century, the water department is modern in terms of technology and governance, and this brings it in line with other cities. The quality of the drinking water is good too.

Alexis Schulman: But then cities are hit with this other pressure, which is the Clean Water Act, which says, you know, you need to upgrade your treatment so less pollution is going into the rivers. You can’t be dumping raw sewage into rivers anymore. I mean, it’s a sweeping, remarkable act.

Chapter Four: Big Sewage

Sebastian: Filtration made the water drinkable and the sewage was getting treated, but there was still a lot of industrial pollution; both the Schuylkill and the Delaware Rivers were lined with heavy offenders.

Waters of Our Commonwealth: Pollution comes from the rotting and decaying matter floating on or suspended in the waters, from liquid wastes discharged by factories and mills, from the black silt washed away when coal is cleaned before shipping, and from the discharge of vast quantities of raw, untreated sewage from our cities and towns.

Lisa: In 1972 Congress passed the Clean Water Act, and it had big implications for Philadelphia. The act basically demanded that cities make the nation’s waterways fishable and swimmable by 1984 and to eliminate sewage release by 1985.

Sebastian: The act also made it illegal for companies to dump waste into the river without a permit, and it gave cities more money to create secondary sewage treatment.

Waters of Our Commonwealth: Pennsylvania has well over 300 sewage treatment plants now in operation.

Sebastian: By the 1980s people actually began to see a difference. The rivers seemed cleaner. But these improvements actually illuminated a problem that was there all along.

Lisa: We’ve been talking about drinking water and sewer water, but there is a third type that we haven’t really talked about yet, and that’s stormwater.

Sebastian: Philadelphia, like most old cities, has a combined sewage system. The pipe for stormwater is the same one as sewage, and when it rains a lot, the mix of sewage and stormwater gets dumped right back into the rivers.

Lisa: There is an old joke: What do you get when you combine one gallon of stormwater and one gallon of sewage? Two gallons of sewage. So now cities have to pay more attention to their stormwater.

Stormwater picks up all kinds of stuff along the way, including animal waste and dangerous heavy metals. This creates problems like algae blooms that suck up the oxygen, kill fish.

Alexis Schulman: Turned out this was a pretty big problem. This is so much water. It’s not going into the ground anymore because there’s so little green space. It’s just going right into the gutters and the sewers. So how can we ask a municipality to treat this? And what they came up with was a requirement that cities had to have a stormwater management plan.

This is like adding insult to injury to cities; you know, they’ve just spent all this money upgrading the secondary, and now there are these new rules and requirements that seem almost like unattainable.

Sebastian: There’s basically one established way to address this problem, and it involves a lot of underground concrete, which is why it is known as a gray system.

Lisa: The gray system creates two sets of pipes, one for sewage and one for stormwater.

Sullivan: So all along your rivers and creeks, they would build these underground tunnels. So rather than that water flowing into the creek and river, it flows into this tunnel that really just holds the water and then slowly releases it after the storm to the treatment plant.

Sebastian: Chicago was one of the cities that opted for the huge pipes. For them, the pollution was in the Chicago River, which was reaching Lake Michigan.

Lisa: Chicago started building their giant tunnels in the 1970s. So far it’s cost them more than $3 billion.

Sebastian: Philadelphia did cost estimates on a similar system, and their giant tunnels would cost between $8 and $10 billion.

Alexis Schulman: These things are insanely expensive. They’re looking around saying, well, we can’t afford the option that seems most acceptable engineering wise. We don’t actually know what to do, and that period of instability at the water department in the 90s allowed this at the time middle manager named Howard Neukrug to emerge with an idea he had, which was, “Let’s start exploring what else we could do other than a huge tunnel.”

Lisa: Here is Howard Neukrug himself.

Howard Neukrug: We wanted to capture the rainwater before it becomes sewage. By capturing it we were able to reuse it, recycle it, infiltrate it into the ground, plant trees, and water trees with this water.

Lisa: This is a big deal. Remember in the beginning we told you that Philadelphia was going to come out of this story as an innovator? This is the idea.

Howard Neukrug: This was a new concept to EPA, and they did not, they fought us on it for about a decade. But they understood green infrastructure in and of itself, but there was nothing like gray infrastructure building a pipe. Because everyone knows what a pipe can do and how much water it can hold.

Sebastian: What he is suggesting here is nothing short of  the city breaking free of its past choices, of breaking path dependency. Up until now, it’s just been more pipes, more treatment, more chemicals, more plants, more gray.

Alexis Schulman: And he pitched this to the commissioner. And you know, no water commissioner wants to be the one responsible for saying to counsel and saying to rate payers, “Hey, I’m about to implement an $8 billion tunnel infrastructure initiative. Aren’t you excited about how much money everyone’s going to have to pay to make this happen?” So the commissioner at the time said, “Okay, like I’m going to give you a little bit of time to explore this.”

And what Howard did is he created this Office of Watersheds, and that language at the time is really weird, highly unusual for a water department to be using.

Lisa: A watershed is an area that separates water flowing from different rivers, basins, or bodies of water. He chose this definition because it encompassed the totality of the bodies of water in Philadelphia.

Howard Neukrug: And the whole concept of the Office of Watersheds, the whole concept of what we were doing is to create a value for that stormwater and manage that water in a way that perhaps gives additional benefits back to the citizens of Philadelphia.

Sebastian: So what his new office did was create what they call green water infrastructure: handing out free rain barrels and downspout planters, and installing rain gardens, green roofs, tree trenches, and wetlands all throughout the city. All of this green is designed to absorb water and slow it down so it doesn’t hit the drains all at once. Part of the additional benefit Howard is talking about is it provides additional green space for residents, kind of like Fairmount Park did back in the day.

Lisa: To use Chicago as a comparison again, a metaphor that Slate reporter Henry Grabar uses, is that if Chicago is building a bathtub, then Philadelphia is trying to build a sponge.

Sebastian: And we are going to need that sponge because there is a looming threat on the horizon—one that’s even bigger than yellow fever or typhoid fever. 

NBC News: According to a study by Climate Central, an independent group that analyzes climate data, extreme rain events won’t be stopping. In fact, they’re getting worse.

Chapter Five: Climate Change, the Next Threat

Lisa: Philadelphia just had the wettest decade ever. And this only makes the combined sewer problems worse.

Sullivan: If you have a drizzle that happens over eight hours, that’s very different than getting that same volume that happens in half an hour. So it’s really about the intensity of these storms.

Sebastian: That’s Abby Sullivan, with the city’s climate change office.

Sullivan: Climate change is changing the extremes. We already get these intense thunderstorms here in Philadelphia, and it’s making those storms more intense. That has implications for our wastewater treatment plants; it has implications for our entire drainage system; it has implications for flooding, surface flooding.

Lisa: So is the green infrastructure, our sponge, going to be enough to keep up?

Sebastian: The city is currently on year eight of a 25-year agreement with the EPA to reduce these combined sewer overflows. To get there, they are partnering with developers and nonprofits to create rain gardens and other greenery. The nonprofit where Julie, who we talked to at the beginning of this episode, works at is in charge of building some of them.

Julie: We’ve installed, as I said, planted, you know, a couple of thousand trees and shrubs; installed something like seven rain gardens; restored wetlands.

Lisa: Distillations toured a couple of the rain gardens next to Juniata Park. On the surface the rain gardens are basically the size of two parking spots. Our producer Rigo Hernandez actually missed it the first time he visited the park. Each green acre, as they call them, is able to absorb about one million gallons of rainwater a year.

The program also takes existing park amenities and gives them a facelift, like a baseball field in Juniata Park.

Rain Garden Tour: Basically, they took this entire baseball field and dug it up. And now underneath that baseball field is the equivalent of about 11 SEPTA buses’ worth of stormwater storage. That rainwater that’s coming from the neighborhood, it now has a place to go before it ever has a chance to go into the stormwater sewer.

Sebastian: Homeowners in Philadelphia can work with the city to build some of this green infrastructure on their property. The city finished more than 150 publicly funded projects, with another 300 in the works. But it can be hard to believe that a few rain gardens here and there are really going to have an impact on this climate change threat.

Alexis Schulman: There’s going to be probably a period of reckoning where they’re going to have to look—and that might be around year 15 just based on saturation level—whether they can look and say, “Okay, our model says this should be working, but are we seeing the on-the-ground reality of that.” And that is coming.

Lisa: What we have learned while doing this story is that the green infrastructure projects will eventually cost more than their original $2.4 billion price tag. And that’s because those rain gardens and green projects have to be maintained in perpetuity. Here’s Julie Slavet again.

Julie: So that’s a challenge for us.

We have not yet, I think, gotten to the point where we have felt like the owners have taken a hundred percent responsibility for maintenance. And I don’t think we expected that to happen really quickly. So we visit all our sites; we continue to provide support for them. We make sure that they’re working, and we do as much as we can to get the owners involved in maintenance.

Sebastian: Green infrastructure projects are also controversial within the department. Some engineers want to go back to creating a gray system, basically building those eight-billion-dollar tunnels we were talking about. But that is not a guarantee either.

Lisa: Remember how Chicago was one of the cities that opted to go for the gray system? Their Deep Tunnel, as the project is known, is mostly done. Well, it’s not going according to plan.

Sebastian: Chicago is also dealing with intense storms, and, as it turns out, these storms are way too much to handle by the city’s Deep Tunnel. Once again, officials had to discharge storm runoff and sewage into Lake Michigan.

Lisa: The tunnel isn’t as big as they wanted it to be because they ran out of money. And the city planners didn’t account for these intensifying storms.

Sebastian: What Philadelphia is doing right now is very much an experiment. The city could pivot away from the green infrastructure. Or it could keep going down this new path because of sunk costs; being stuck on paths is kind of what the story is all about.

Julie: I’m from Boston and I’m 61. So I remember a time when the federal government invested in things like this. And I think this is at that level. This is big enough that it deserves federal investment. It’s crazy to me. How else can you do stuff like this?

Lisa: The federal government is not helping Philadelphia pay for these green infrastructure projects. So our city relies on incentivizing developers to build green infrastructure into their projects or to partner with nonprofits like Julie’s.

Sebastian: More than likely the solution for Philadelphia might be to do something that Milwaukee is doing. They built the giant tunnels, but they also built the green infrastructure.

Lisa: Milwaukee now has on average 2.4 sewer overflows a year—compared to Philadelphia’s current once-a-week problem. 

Julie: It took a couple a hundred years to make the mess that we made. This is what makes me feel better. So, I think it’s going to take a while to really solve this problem.

Lisa: When it comes to our combined sewer, which is one of the biggest sources of our water pollution now, it’s funny to think that this problem was actually predicted by Benjamin Franklin. He described the situation. He said, when you cover a ground plot with buildings and pavements, it actually will carry off most of the rain and prevent it from soaking into the earth and renewing and purifying the springs.

Well, purifying the springs is exactly what Philadelphia is trying to do with those rain gardens.


Sebastian: One of the things that I thought was really interesting is that all the problems that we look back and are like, how did they make that choice? That was ridiculous. We want to think that that’s because we, you know, now are so much smarter than people who were dealing with those problems at the time, but in many of the cases, they kind of knew that there was still a problem. I mean, think of the sewer overflows and the fact that there was a tidal river, the idea of connecting the sewer system to the river, people were talking about at the time saying, “Hey, this doesn’t work. We just don’t have the technology to come up with a better solution.”

So people knew that things were going wrong. It’s just like it is today. We can easily point out how many systems in our lives are broken, but designing something that works is a lot harder than complaining

Lisa: I think we forget that one of the places that innovation can come from is practicality and desperation. Necessity really is the mother of invention in Philadelphia’s case. A lot of the times our problems are, you know, sometimes they’re made worse by the same thing. That eventually helps us find a solution to them.

And in this case, it’s that Philadelphia was such a poor city that we didn’t have the money to throw into a giant infrastructure project. We had to try something like a rain garden, and if that ends up being the best solution that helps us, you know, survive and thrive in climate change. Wow. That’s, we can take the chip on our shoulder and turn it into a crown.

Distillations is more than a podcast. We’re also a multimedia magazine. You can find our podcasts, videos, and stories at distillations.org, and you can follow the Science History Institute on Facebook, Twitter, and Instagram.

This story was reported by Rigoberto Hernandez and produced by Mariel Carr, Rigoberto Hernandez and myself. The episode was mixed by James Morrison. We want to give a special shout out to the Science History Institute’s Oral History department and the museum team for doing a lot of the research that went into this episode. This includes Rebecca Ortenberg, Christy Schneider, Samantha Blatt, Zack Biro, and Grey Pierce.

For Distillations, I’m Lisa Berry-Drago. Thanks for listening.

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