Cities’ Wetter, Wilder Future

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Henry Grabar: It is jaw dropping when you see a lot of the destruction. And yet here we go again. More storms on the way.

Mary Harris: For the last month, being a meteorologist in California has been constantly coming up with new ways to register surprise.

Speaker 3: These storms have millions of people under alerts right now. There is just no relief. It’s been one thing after another.

Mary Harris: And as soon as one storm ended, another started up.

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Speaker 3: And this is the one on one freeway. You can see it is completely caked over in mud. There is water that is completely washed over this freeway.

Mary Harris: And the reason why over a three week period, San Francisco was wetter than any had been since 1861. Los Angeles set records to.

Speaker 3: Blow the freeway is the Ventura River in just 12 hours. Yesterday, that river rose 17 feet. So that is just.

Mary Harris: Throughout this deluge. There was one term. Reporters kept coming back to by way of explanation.

Speaker 3: It’s not a hurricane or a tornado. It’s called an atmospheric river.

Henry Grabar: We’ll say it’s because of something called an atmospheric river, which is effectively a river.

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Mary Harris: Atmospheric river.

Speaker 3: Technically, they’re the largest rivers of freshwater on Earth.

Mary Harris: An atmospheric river sounds dramatic. But when I called up Slade’s Henry Grabar, he thought about this term a little differently.

Henry Grabar: These sorts of atmospheric rivers are supposed to be a regular feature of the rainy season in California, and they’re accountable for, you know, 30 to 50% of the state’s rain and snow. So to some extent, this is just how California works. Like, you know, they get these extreme events that bring a lot of moisture at one time.

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Mary Harris: The question for Henry is what to do now because dramatic rain events like this one, they’re only getting more common. And not just in California.

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Henry Grabar: The National Climate Assessment has some good data on this. And they say that the the amount of rain falling in the top 1% of events is up by 37% in the Midwest, 10% in the Southeast and 71% in the Northeast. So, yes, the trend line is pointing towards more extreme events. And that’s happening because the more global warming there is, the warmer the air is, the more water vapor there is in the atmosphere.

Mary Harris: And I found myself wondering if the language around California’s rainstorms was a bit misleading. And the reason I say that is because focusing on how outstanding this rain event has been has a way of making you think the dangers over once it’s done. You know what I mean? Like back in 2017, you wrote about Hurricane Harvey in Houston, Texas. And the way you put it was we don’t put airbags in cars to prepare them to be hit by trains. Like, if you’re not expecting something, you don’t prepare for it. And so I wonder if you think we all need to be looking at storms like what just rolled through California and thinking, yeah, we’re going to be seeing more of that. It’s not getting hit by a train. It’s like just driving down the street. It’s normal.

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Henry Grabar: Yeah. We have surveys that show that storms like this are becoming more and more common, and yet in many cases, we’re still building to the historical pattern We’re building. Like we’re preparing for 20th century storms when that’s not what we’re getting anymore.

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Mary Harris: Today on the show, the global forecast calls for rain. Are we ready for it? I’m Mary Harris. You’re listening to what next? Stick around.

Mary Harris: When Henry Grabar thinks about how to manage rainfall, flooding, he thinks a lot about cities. First of all, because a lot of people live in cities. So fixing the way water is managed in an urban environment would help a lot of people all at once. But also, he thinks of cities because cities are places where humans are already aggressively shaping the landscape. Unfortunately, concrete and asphalt is often making these places more prone to flooding, not less. And you can see how in pictures from California earlier this month, all those roads covered in water and mud. Henry says he first started thinking about this connection between flooding and the urban environment. On a trip he took to Brazil.

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Henry Grabar: One of my first exposures to this topic was when I was in Sao Paulo, Brazil, which is one of the largest cities in the world. And it was a normal day walking around, taking photos, and it started to rain and sort of ducked into a cafe. And the rain got more and more intense. And I was watching these guys across the street at this garage, and they were working on these cars on the street. And they suddenly started moving them one by one, moving them away from the front door of the garage. And then the streets just filled with water, just a torrential flash flood flowing downhill. Cars bobbing up and down like boogies. Big bags of trash. Logs, all kinds of things.

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Mary Harris: And clearly, they’d been to this movie before.

Henry Grabar: Yeah, it was. It was wild. And I had this realization that, you know, when you’re in a giant metropolis like that, you are in a hydrological zone that’s totally manmade. It’s made of concrete and storm drains for sewers and all these sort of manmade infrastructure decisions that control where the water flows.

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Mary Harris: It’s interesting because in California, with the flooding there, it seemed in some ways like the state was caught unaware because there’s a drought there. So the idea that all of a sudden there could be flooding, it seemed surprising to a lot of people. But you’ve visited places where the flooding isn’t a surprise just to sort of see how will different municipalities deal with this threat that’s going to be getting worse across the country? Yeah. A few years back, I know you went to Chicago. So why did you want to go there in particular?

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Henry Grabar: Well, 50 years ago, Chicago was known in America to have the worst urban flooding problem of any city because it’s very flat and it rains a lot. And it had it’s pretty sprawling. Right.

Mary Harris: It’s funny. I don’t think of it as like being vulnerable to rain.

Henry Grabar: Yeah, Chicago has a ton of rainfall, flooding. And 50 years ago, they came up with a plan that has since been imitated by loads and loads of cities. And the plan was called the deep tunnel, tunnel and reservoir system. And they built 100 plus miles of gigantic subway size tunnel underneath Chicago, leading to three enormous suburban reservoirs. And all of this is supposed to hold billions of gallons of wastewater during the city’s big storm events. And it does.

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Mary Harris: These tunnels underneath Chicago. It seems like a very American like typical massive infrastructure project. Like, we can fix it. We’ll just build big tunnels and we’ll get it done. Is that what it ended up being? Like, did these tunnels fix the problem?

Henry Grabar: No. In a word, they did not fix the problem. But the Metropolitan Water District in Chicago would say that they worked because they do fill up, you know, these tunnels and the gigantic sort of infernal sewage filled reservoirs, which are really like these gigantic suburban quarries that they fill. They do fill. And so their argument is, you know, the Chicago River’s a lot cleaner than it used to be. Lake Michigan is a lot cleaner than it used to be.

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Henry Grabar: But the flip side of that is that actually there is still quite a bit of sewer overflow into the lake. The tunnels are barely completed and they’re already filling up entirely. And so, you know, part of what’s happened is, yes, Chicago would be in a much worse place if they hadn’t built this thing. But also they built this thing to correspond again to outdated expectations of how much it’s going to rain and what it’s going to look like when it rains. And the city still sees a lot of property damage from flooding as well. So I think the best way to assess it may be would be to say that it worked, but it was an incomplete solution.

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Mary Harris: So you’re not giving me a lot of optimism, like when I think about the fact that it’s supposed to be getting wetter all across the United States. And look at Chicago, which you say has been seen as a. Model of excellence. You’re making me a little worried about how we’re choosing to address the coming rainfall problem.

Henry Grabar: So there’s two schools of thought about how to respond to rainfall, flooding and maybe just flooding in general. And the first is gray infrastructure. And that has been the way that we have traditionally dealt with flooding risks. And that mostly that means building things out of concrete, sometimes out of steel, too. And the newer school of thought is green infrastructure, which is that we can actually use nature to our advantage here by trying to turn, especially in urban areas where everything is so paved and there’s so many impervious surfaces, we can try to plant more trees, more grasses. Roof gardens. Rain barrels create space for rain to collect where it falls instead of putting more pressure on the city’s infrastructure and instead of compelling ourselves to expand the sewers, dig deeper tunnels, bigger basins, install stronger pumps, all that stuff.

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Henry Grabar: So these two things are obviously symbiotic, right? You’re never going to get by with exclusively rain barrels and roof gardens and you’re never going to get by just with bigger and bigger sewers that you dig deeper every year as you adjust to the changing climate. But but they’re supposed to work together, right? And I think the advantage of green infrastructure is that it’s also very pleasant. It’s just nice to be around a greener city. And that carries benefits for air pollution and public health that go beyond just just catching rain when it falls.

Mary Harris: One city that’s recently invested in green infrastructure is Houston. And the reason why is simple. Hurricane Harvey in 2017.

Speaker 4: Hurricane Harvey barreling into the Texas coastline as a Category four storm with a 130 mile an hour winds. It’s the first Category four storm to hit the US in over a decade, threatening record rain totals.

Mary Harris: Harvey drenched Harris County for three days straight and in the aftermath, people in Houston had to take a hard look at the way their city had been designed.

Henry Grabar: Houston has been one of the fastest growing cities in the country over the last few decades, and a lot of that growth has happened in the west of the city on the Katy Prairie. And the Katy Perry has been turned from, well, a prairie into just a massive, massive subdivision. So that just shows that the amount of development that’s taking place in Houston has created a flooding problem. And so when Harvey happened, I think there was this kind of awakening that they absolutely had to do something to deal with flooding.

Mary Harris: So what have they done in the years since? Like, how have they rethought how the city operates and and what it requires of people building buildings, of people where they live?

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Henry Grabar: After Hurricane Harvey, obviously, they’ve been very, very focused on what they can do. They’re sort of throwing everything at the wall to see what sticks. They passed new building regulations. I mean, this is a big part of it, too, right? It’s not all about public infrastructure. It’s also about the types of structures you’re building. And in Houston, they have these new rules that any water that you displace from your property by building something on, you know, what had formerly been, you know, prairie or grassland, you have to find a way to keep that on your property.

Henry Grabar: So my friend Nick, who’s a developer in Houston, invited me out to his strip mall that he just built. And we go out there and in front of it there’s this huge parking lot. Then there’s the building, and then in back there’s this kind of like, huge hockey rink sized subterranean grassy pit. It looks like a Native American earthwork. And that’s the detention pond. And that is the result of these new Harris County regulations that say that you need to try and hold water on your property instead of sending it into the, you know, the city system of the county system.

Mary Harris: So is the idea that when it rains, all the water in that parking lot will just flow to this pit and create a little lake?

Henry Grabar: Yep. Yeah, that’s right. Yeah. And then it gets held in that held in that detention pond until the county and city systems are ready to to handle more water coming downstream. Some people say it hasn’t gone far enough. I’ve talked to some people in Houston who say that there’s you know, there’s 100,000 structures that are in the 100 year flood plain still existing structures and that those people should not be there. But yeah, what are you gonna do about that? Like relocate 100,000 people?

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Mary Harris: Hmm.

Mary Harris: Well, I mean, you have raised this kind of interesting issue, which you’ve talked about how the growth of cities like historically flooding natural disasters have been kind of a check on urban growth. And it just raises this question of with a city like Houston or a lot of cities. Like, when do you say we have to stop growing? Like that’s the solution here?

Henry Grabar: It’s certainly a concern in Houston when you have all these people living in a place that we know is dangerous, that we know is likely to flood. The advantage that cities have in this context with rainfall flooding is that they have a lot of people in them. And the more people you have, the more money you have to pay for this infrastructure to protect yourself. And so a place like New York City should be able to spend enough money to protect its critical infrastructure, like the New York City subway. And a place like Chicago did spend enough money to build 110 miles of tunnel underground to bottle up rainstorms.

Mary Harris: Even if that’s maybe not the best solution.

Henry Grabar: It’s not the best solution, but it just goes to show that these places where lots of people live, they may be super vulnerable, but they also have resources to deploy.

Mary Harris: We’ll be right back after a break.

Mary Harris: Following the California rains, I was struck by something one researcher told a newspaper. He said people might not even want to know about the damage rain can do because then they’d have to deal with the problem. Henry says there’s something to that because every solution, even a good one, comes with tradeoffs. But the thing is, we’ve made these tradeoffs before, just not for rain.

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Henry Grabar: For example, in Louisiana, the Mississippi River has has a big dam on it called the Old River control structure. And the idea here basically is that if there ever comes a point where and this has happened before, I mean, the various floodways along the Mississippi River here, where they can open it up and basically decide that they’re going to flood a bunch of of low lying land to protect New Orleans. And that’s an example of the kinds of tradeoffs that we are willing to make when it comes to river flooding and how we’re going to adapt when the river rises. And I think lots of big rivers have that type of infrastructure built into them. But when it comes to urban rainfall, flooding, we’re kind of unprepared, you know, in part because it’s a phenomenon that just seems to have become so much more serious, even just in recent memory, in terms of the damage to infrastructure, in terms of lives lost in New York where, you know, 11 people died in their basement.

Mary Harris: That was in Hurricane Ida a couple of years back.

Henry Grabar: Yeah. So, yeah, I guess when it comes to rainfall, flooding, we don’t really have those kinds. We haven’t really made those kinds of difficult choices. Right. But the status quo, right, is is not great. Right. Lots of properties, flooding repeatedly, lots of pollution flowing into rivers.

Mary Harris: There’s another reason some leaders might be avoiding difficult choices. They don’t have the data they need to understand the way rainfall is going to impact them. Government flood maps are simply out of date. One report looked at rainfall flooding in addition to coastal and river flooding and found 14 and a half million properties in the U.S. were at substantial risk. That’s double the latest analysis from the Federal Emergency Management Agency.

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Henry Grabar: And in the United States, this is a big issue because FEMA publishes these flood maps that are supposed to tell you how at risk you are, how at risk your property is. And in these FEMA flood maps, they mostly focus on storm surge risk along the coasts and flooding risk along rivers and in low lying areas. But that’s not necessarily how rainfall flooding happens. And so you see this massive divergence between the properties that FEMA predicts will be damaged in a storm and the properties that actually are.

Henry Grabar: You know, there’s a few different things happening. You have neighborhoods that might have insufficient sewer capacity to carry away a super intense spot or, you know, rain that falls there for a few hours. You might have neighborhoods that have been built with like lots of impervious surface so that the rain has nowhere to go when it falls. And obviously all this metropolitan development often engineered at least where it was engineered to accommodate storm figures that are now totally obsolete, is colliding with a period of more intense rainfall events.

Mary Harris: That being said, in December, President Biden signed a bill requiring the National Oceanic and Atmospheric Administration to update its rainfall records.

Henry Grabar: But it’s not going to happen for a few years. And even once it happens, it’s going to be contested. New York City, for example, recently got dealt a new set of FEMA maps showing a much broader range of properties falling in the 100 year flood plan. And the city basically went to Washington and said, no, these aren’t these aren’t. Right. Huh. You didn’t get it right. You need to adjust these because it’s a huge financial hardship for anybody who ends up in the hundred year flood plain. And suddenly, if they have a federally insured mortgage, they’re required to buy flood insurance, which could cost thousands of dollars a year.

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Henry Grabar: And you could say, yes, well, they should have flood insurance. Okay. But they weren’t aware of those risks, perhaps when they moved to the neighborhood. And some of these neighborhoods might be low income places where people just can’t afford that. And so even making people aware of the risks of the places they live can have all sorts of social consequences. So I can understand why some politicians might prefer, let’s call it, you know, perhaps a head in the sand approach. But you know, sometimes also that the possibility of a once in a 500 year storm coming might not be the neighborhood’s number one priority. And maybe that’s fair.

Mary Harris: Hmm.

Mary Harris: Looking forward, are there places that make you especially nervous when it comes to rainfall flooding?

Henry Grabar: I think the thing that makes me the most nervous about rainfall, flooding is the critical infrastructure that’s at risk because and we’ve talked a lot about the various ways you can approach this problem, whether it’s changing building codes, whether it’s asking people to get insurance, whether it’s green infrastructure, whether it’s gray infrastructure, big tunnels underground, all these things are possible. But at this rate, it’s just not happening fast enough. And there’s all this critical infrastructure.

Henry Grabar: I’m thinking in particular of something like the New York City subway that’s just left there waiting for the next disaster to come. I mean, it’s been 11 years since Hurricane Sandy. And still when it rains a lot in New York, you see all this water flowing into the subways like a lot of the damage from rainfall, flooding. It’s not actually like a house flooding, but it’s like infrastructure that gets taken down society like, you know, like critical institutions that become unavailable, like it’s that sort of stuff.

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Mary Harris: Well, it’s funny, too. You mentioned the subways. And I feel like in New York City, whenever there’s a big rain, you’ll see some video floating around Twitter of a subway station that’s flooded. Someone kind of casually walking through it like, oh, well, I’ve got to get the train. It’s like people expected and are also kind of like it’s kind of funny and surprising. But at the same time, like those New Yorkers, they get through it. And that attitude, I don’t know if it’s fixing the problem.

Henry Grabar: Well, first of all, the subway is naturally below ground by definition. So there will be some water.

Mary Harris: Literally. I have water pumped out of it every day.

Henry Grabar: Yeah, that’s normal. That’s normal to some extent. But we do know is that there’s an urban flooding event happening in the U.S. about once every 2 to 3 days, according to a study of National Weather Service data. So it’s clear that it’s it’s real and especially compared to the way that, you know, the U.S. Army Corps of Engineers has, for example, channelized and dammed and gated the nation’s rivers in preparation for river flooding. It seems like cities are way, way behind.

Mary Harris: Henry Grabar, Thank you so much for joining me. I’m super grateful.

Henry Grabar: My pleasure.

Mary Harris: Henry Grabar is a staff writer at Slate. He covers housing, transportation and urban policy. And that’s our show. What next is produced by Elena Schwartz, Carmel Delshad and Madeline Ducharme. We’re getting a ton of support right now from Anna Phillips, Jared Downing, Victoria Dominguez and Laura Spencer. We are led by Alicia montgomery with an assist from Susan MATTHEWS. Ben Richmond is the senior director of podcast Operations at Slate. And I’m Mary Harris. And go track me down on Twitter, Say hello and not Mary’s desk. Thanks for listening. Catch you tomorrow.