(Unedited) Podcast Transcript 353: Depave Cities

September 30, 2021

This week on the podcast we’re joined by Mary Pat McGuire, Associate Professor of Landscape Architecture at the University of Illinois.  Mary Pat talks with us about what happens to water after it hits the pavement, the damaging environmental impacts of covering cities in pavement, and steps we can take to reduce runoff in green cities.

You can find the audio of this episode at Streetsblog USA and Libsyn.

Below is a full unedited transcript:

Jeff Wood (43s):
Mary Pat McGuire, welcome to the Talking Headways Podcast.

Mary Pat McGuire (1m 19s):
Thank you very much. Glad to be here.

Jeff Wood (1m 21s):
Well, thanks for being here before we get started. Can you tell us a little bit about yourself?

Mary Pat McGuire (1m 26s):
I am a landscape architect, licensed landscape architect in Illinois in Virginia, and previously in California. I was in practice for about a decade after graduate school in landscape architecture, but I’m now in academia. I do design research as a professor at the university of Illinois, and I have a pleasure of teaching landscape architects with undergrad and grad level. And I also have taken my experience and practice into research environment and so explore issues of design, but through research now

Jeff Wood (1m 58s):
That’s awesome. How did you get into landscape architecture? What, what was the defining moment that you decided, Hey, this is for me.

Mary Pat McGuire (2m 5s):
Well, yeah, it was a little bit of a Securitas path. People don’t mind landscape architecture, certainly not in high school or before that, even in college. I think a lot of people don’t find landscape architecture, they find architecture or planning or engineering or something like that. Many people find it as a second career, particularly coming, coming back into grad school. We have a lot of second career students for me personally. I was on a pathway toward environmental law. I was really interested in large planetary issues having to do with environmental degradation, overpopulation, you know, the divide between what we were calling then first and third world, but developed in less developed countries, the inequities about power over, you know, where are we putting our waste?

Mary Pat McGuire (2m 52s):
You know, I mean, it was just all kinds of issues that I was interested in deforestation and, you know, ocean acidification, all those issues. And I realized also that I was really interested in cities. I was living in Washington DC at the time and walking around a lot between my legal research job at this time, as I was thinking about environmental law and also just the experience of living in cities and also became really interested in film and other kinds of visual media and noticing that not everybody was looking at the environment around them. And so what I was interested in is, well, how is it that we start getting people to look at the world around themselves and different ways that we can live within it more, some biologically locally with nature and to stop polluting our waterways, et cetera.

Mary Pat McGuire (3m 37s):
And so I started looking at film studies and other kinds of more like arts and design fields that I hadn’t considered in the past. And I found architecture, but that wasn’t quite it either. I wasn’t really necessarily interested in building design. And I took a summer career discovery program at Harvard university. This was back in the late nineties. And one of the fields that students were studying in addition to architecture was landscape architecture. And I was really intrigued. I attended a couple of lectures by landscape architects and realized like, whoa, what are they studying? It wasn’t just plants. And it was really about the entire city itself as a kind of broader design realm that buildings do sit within, but it was the ground plane and all the spaces in between and the public realm and all of this that they were looking at and designing.

Mary Pat McGuire (4m 27s):
And I just, I got incredibly excited about that and realized that, well, there was a field that was designing cities and designing the experiences of cities and the way they worked and the way they interacted with natural systems. And so that, that was what set that off. And then I stopped by to graduate school in landscape architecture. And the field itself is very synthetic. It brings a lot of both like the art and science, you know, of what we do and our relationship with the planet together. And that, that was it. I mean, I attended graduate school at the university of Virginia, which is a fabulous fabulous school and then got into 10 years of practice. And then I’m already explained I’ve been coming out of practice. Now I’m more into research environment.

Mary Pat McGuire (5m 7s):
That’s how I found landscape architecture. Not many people find it, but many people who I, I hear later in life, they start to reflect upon things that they wished they had known about earlier. And so actually, if, if anything could come through this podcast today, it would be for them more people would find landscape architecture. We’re always trying to get the word out about what our field does.

Jeff Wood (5m 28s):
It’s funny because you know, I’ve had actually had a lot of students message about the podcast. One of the things I do ask and I ask it purposefully is, you know, how did you get here and why? I think people will find these circuitous routes to their final destination. That really fascinating because in order to be a planner or in order to be a landscape architect, you don’t necessarily start out as a planner, as a landscape architect. And so you can take many, any number of routes to get there, but you’ll get to the ultimate place in the end. And it’s really fascinating how people get there because people finding what they love is, is a really experience.

Mary Pat McGuire (5m 58s):
Yes, absolutely. And there’s so many dynamic ways to do what we do in each of our fields and the fields themselves are changing, you know, as we’re like facing such bigger issues, particularly having to do with climate and urbanization where our own fields are having to adapt themselves and start to expand their tool set, et cetera. And that was an all of us within it. It’s, you know, it’s a change or die moment. So, and so we’re all figuring out, okay, well, what does landscape architecture want to do today that, that she didn’t do, you know, 10 years ago

Jeff Wood (6m 30s):
You have any major influences like landscape architects that kind of made you think differently, maybe about the profession?

Mary Pat McGuire (6m 37s):
Well, many too people jump out to me, although I don’t want to neglect, mentioning other professors of mine at Virginia, but there were two landscape professors, landscape thinkers, one Beth Meyer, who was a leading theorists in the field who really taught me to develop what we call maybe site thinking. Was it thinking about what is the site for design? And this actually gets us a little bit into maybe the subject that we’ll talk about, which is the paving, but what is the site that designer wants to effect? And the way that that program taught me to think is to question the grounds for design or the assumptions that we have about what our field should be doing and where we should be acting.

Mary Pat McGuire (7m 22s):
And with whom that was a really big for me. The other was a professor named Julie Bargmann, a landscape architect, who she’s also quite well known in the field and internationally for studying toxic landscapes and the legacies of industry and how those have affected communities and of course, oils and water and plant systems. And to also come up with new ways of engaging those histories through design so that we are both regenerating systems on those sites, but not forgetting those histories and the process. And so they really launched me into my own career or my own pathway, but who I’ve really been interested in from a design similar to some of the French landscape architects that exist now to who in some ways are dealing with post-industrial conditions and also thinking about the futures of cities, but there’s more experimentation and more open-endedness with their design methods.

Mary Pat McGuire (8m 12s):
So they’re not. So I think the American American design idiom includes a lot of what we might think of as like sort of finished products of design. That’s something that we look at, or that’s very imageable. And this process orientation that I think that the French many, many Europeans are really much better at embrace more open-ended systems thinking as a forest, rather than thinking as like a singular Grove of trees or something in a park settings. That’s maybe not the best way to describe that, but there’s definitely a lot more looseness and embrace of difference and diversity and landscapes. And that’s not to say that Americans aren’t doing that, but they’re less interested in like the perfect coping detail, you know, on our training hall, then they are the underlying kind of beauty of something that maybe is simpler in its design, but more effective in its aesthetic outcomes.

Mary Pat McGuire (9m 5s):
So, yeah, I mean the list is long. There’s also an extraordinary woman right around my age too. I just admire her so deeply named Kate Orff. She and her incredible team is practicing out of New York city. And they’re also raising the bar, not just on the work and the scale at which they were, but also they are completely expanding the tool set for how landscape architects are, are operating and making change in the way that we think about the future of not just specifically like New York, but really the planet. So there’s many, many people doing incredible work,

Jeff Wood (9m 40s):
Speaking of the planet before we get to the subject, but I feel like I’ve been bummed out by all the news and everything lately. Obviously the UN general is happening right now and talking about climate change and we have some bills in the house and the Senate kind of trying to get done, but being not blocked yet, but perhaps will be by fossil fuel interests. I’m curious how you feel generally about where we’re going and how we’re getting there.

Mary Pat McGuire (10m 4s):
Yeah. It’s, I mean, it’s a great question. I’m probably on the same emotional rollercoaster maybe that you are, that many of us are, but I’m really motivated to kind of continue working too. So I think that’s what keeps me moving forward, but I think I’ve passed through that sort of the stages of grief. I can remember 10 years ago, I started studying climate change. And when I moved to Chicago, I was taking some courses with some climate scientists and was embracing them the reality of the path that we’re on. And that was just 10 years ago. And we still, the media still wasn’t really covering climate. It was interesting climate change or climate adaptation. And I went through some really heavy emotional periods realizing exactly the path that we are on, but I’ve since then also in my own work, tried to retool to think about, okay, where is it that we can actually adapt and mitigate against that?

Mary Pat McGuire (10m 59s):
And because we know so much about what has happened, and we know so much about how we could reverse some of these trends, maybe not slow some of the path that we’re already on, but definitely reversed some of our own actions that have led to that. That it’s a matter of political will as a matter of leadership, it’s a matter of decision-making and reallocation of effort. So that gives me hope. Some of the crises that have come up, particularly having to do with the pandemic and the economic crisis. I think these are actually like a part of a giant, what I’ve read has called like the kind of wrecking ball against some of our ways of working and living. And so in some ways, I think we’re just going to keep, like trying to tip this thing over. And at some point we will either act out of desperation or if we can get some of this legislation passed and start allocating effort toward rebuilding infrastructure, et cetera, and especially through natural systems, then that would be great.

Mary Pat McGuire (11m 49s):
Yeah. I’m not a barrier head in the sand kind of person, but I’ve moments of feeling a lot of despair, but I also feel like I’m in a field that can actually be part of creating change or at least giving the tools to others to do that at different scales. So that’s where I am right now, overwhelmed and really exhausted. It’s very depleting to do this kind of work. I know you confront these topics a lot in your work.

Jeff Wood (12m 19s):
Yeah, it’s, it can be a little bit overwhelming sometimes, especially when you go through the thousandth article about climate change in one form or fashion, and, you know, yesterday that UN released or actually who the world health organization released a numbers about how we need to reduce the amount of particulates in the air by 50% on PM 2.5 and that’s already hard to fathom. So, but let’s, let’s get some positive going on here. I wanted to chat with you because I really thought that you had an interesting piece in next city thinking about kind of the negative impacts of pavement and going to school in Austin and dealing with the aquifer things down there. Obviously there was a large discussion about impervious cover. I’ve been paying attention to this topic for quite a while, but I’m wondering when did you initially realize that pavement was a key part of many of these environmental ills that we’re seeing?

Jeff Wood (13m 5s):
Wow.

Mary Pat McGuire (13m 6s):
I had a growing sense that we needed to look at pavement, look at the ground plane in particular in cities for some time, but I had a kind of key moment, but it was also about 10 years ago, maybe fewer than 10 years ago, eight years ago or something. When I moved to Chicago, I started looking very carefully at water in that city and starting to devote my time and my research toward looking at designing water and surrounds water and storm water problems. And to make a long story short was confronted with the fact that if we don’t change the way we designed the ground plane, we’ll never be able to invite water in as a part of our urban environment.

Mary Pat McGuire (13m 47s):
But Chicago was the place where I, where I first confronted that because I mean, it’s, it’s highly paved. I mean, I think it has percentages of imperviousness that are, you know, could be among the highest in the country. And certainly it’s also an overly engineered city. It’s like a really has a huge underground stormwater collection infrastructure, but it took me a little while to start to put the pieces together where I started to actually see the surface of the city and see pavement as a kind of headwaters to a much larger territorial watershed. That the reason why we have so much underground infrastructure isn’t because we have more rain than anyone else it’s because we’ve actually paved over the ability of the soils to take, to infiltrate that water in some degree.

Mary Pat McGuire (14m 35s):
And so I started look kind of poking around at this issue, looking around at this issue, it just looking at the ground. Now I’m the landscape architect too. So, but I also was living in Chicago and I was surrounded by seas of pavement and huge roadways that no one was driving and huge parking lots that were abandoned. And I started moving around the city and looking at this more carefully and realizing how much we’ve like forgotten that we had an incredible coastal landscape there already and started realizing that nature and in the city and the city of Chicago is kind of, you can find it, you can drive to it, but it’s really hard to find it underneath your feet. And so what I realized is that we had this incredible, you know, the whole ground plane was engineered to get rid of water and we’ve completely denatured ground plane and ooze of continuous asphalt and how directly that was connected to this underground collection system.

Mary Pat McGuire (15m 31s):
And there’s more to the underground system that we may not have time for, but we live in a reversed watershed in Chicago and all the rainwater that falls there is collected and it’s actually exported outside of the watershed. And so there’s this whole crazy story that I started to research and learn about. I do think that in working in the green infrastructure environment in Chicago, I do not think that we’re going to move forward into a green infrastructure context where we, where we really are rebuilding our natural systems as a form of infrastructure in cities. If we don’t address the extensive gray infrastructure of pavements throughout cities, that to me has become like a, just a huge realization.

Mary Pat McGuire (16m 13s):
And there was a moment in which, and I want to say this was in 2013. I was still living in the core of Chicago and like a water main broke in our street. Something happened out there and there was flooding, it was winter and it was a very cold winter and it was flooding and everything started to freeze up. And so the crews were coming out to try to fix the water pipe, but they couldn’t get underneath the ground without actually like, you know, using a backhoe. And they had to pound through ice to get through to the streets. And then under to get through the street to get down to the, try to fix whatever was like leaking underground and like bubbling up. And I, and they were pounding on this pounding on us and they were scraping and scraping and scraping the ice and scraping through the pavement and scraping through the asphalt and all this stuff.

Mary Pat McGuire (16m 55s):
And I just, I was looking out my window at the situation, cause it was loud. It was like two in the morning. And I realized that this relationship between water and pavement was one that literally needed to be broken through that we literally needed to break through the pavement. There were these gash marks on the street, you know, for the next two years there. And I just kept reminding me. And I remember that night, I wrote the pay of Chicago, you know, on a piece of paper, really big and tape it to my bathroom mirror. So that, and I looked at that every morning, you know, while I was brushing my teeth and I just kept thinking like, there’s something here, there’s some relations, there’s a problem here.

Mary Pat McGuire (17m 35s):
There’s a problem here. You know? So that’s, that’s really where, where a lot of that started. And then I got more serious and started looking at pavement

Jeff Wood (17m 44s):
Through that process, a little bit of connection and or disconnection between the water and pavement. I’m wondering if you could kind of explain to listeners and myself, even, you know, once a drop a waterfalls from a cloud to the earth, what happens after it hits the pavement and what’s the process and where is it going? You know, cause I think that process kind of informs how we think about pavement and its interaction with the environment, as well as with our natural systems that surrounded.

Mary Pat McGuire (18m 11s):
I mean, that is the direct relationship. So we have all this naturally falling rainwater, which is a nourishing element and a joyful element. I mean, we all love the way the rain sounds, the way it feels. Well, maybe not all of us and in increasing storms in our topic, it’d be destructive. It could be a roast of, you know, but yeah, we have this beautiful rain falling and a majority of it hits hard surfaces in cities. If we have 50 to 80% of our cities are impervious either through roofs or through pavements, we have a lot of water. That’s basically running off, it’s being collected somewhere. It’s being diverted somewhere. We have a drainage system. That is what I think of as a series of points, lines and planes have talked about this a lot about how there’s a geometry across the surface of cities.

Mary Pat McGuire (18m 59s):
That’s designed to collect water rainwater and to get rid of it. So it travels along surfaces. It collects usually let’s say in a street environment, it runs off the street pavement or parking lot. It usually collects in curbs, which are the lines or collects and drain endless, which are the points, but there’s a geometry, a surface geometry that’s designed to get rid of that water to drain it away. And it goes into underground pipes and it will be conveyed and discharged in a water, says shutting downstream. But if you’re in a sewer shed system, which many older cities are, we have a combined sanitary sewer system and that rainwater is coupled with sanitary water and it goes to a treatment plant and then it gets treated and then also still discharged to those same waterways.

Mary Pat McGuire (19m 49s):
And so the problem there is that, and it depends on which city in which region you’re talking about in terms of its precipitation patterns. But the trend is just to collect a lot of rainwater needlessly into those systems or to discharge them needlessly downstream. And we’ve inherited, I should say, also that system from modern engineering, you know, it was for a time considered to be, you know, the way that we would design cities is to remove water from the city because it was seen as a problem to urbanization. Well, we since have learned that the problem of a, you know, sending your water downstream you’re de-watering cities, which we know we need that water. And we could use that water in many of our water resources or water supply systems could benefit from better storage of rainwater, but that pavement is it’s draining water away.

Mary Pat McGuire (20m 37s):
It’s also sealing soil. So it’s compacting soil, it’s sealing soil. It’s keeping air from moving back and forth between the atmosphere and the rhizosphere it’s cutting off roots. You. So we’ve got limited root area for our soil, for our plants is creating urban heat island also. So yes, we’re gathering needlessly, a lot of water, both in small storms and in large storms. And we’re sending it away rather than thinking about how to harness that water, how to nourish, you know, soils and plant fruits, et cetera, reuse that water in a small rain cycle. So if we were in a non urbanized environment, 80 90% of rainfall would be naturally taken up through that system at a local scale.

Mary Pat McGuire (21m 21s):
And you’d only see, you know, like 10%, maybe 20% of the larger storm actually running off. And so, and that’s because we have more intact soil systems and root systems that actually act like a sponge and hold that water and those near surface soils. And they also, you know, there’s a lot of uptake through plant roots and through trees and there’s a lot of transpiration cetera. So once we have an extensive pavement system and a drainage system, we’re basically like allowing that water to run off in basketball quantities. And it also takes a lot of, you know, surface oils in particular, it’s from roadways into those waters includes those waterways downstream. So they’re direct, highly hydrologic impacts.

Mary Pat McGuire (22m 2s):
There’s also, I should’ve mentioned the problem of localized flooding too, that if you have extensive pavements, it’s basically, and particularly in flatter cities, you’re going to have a lot of water just sitting on that surface and not able to absorb into the soils. So the consequences are local and they’re territorial regional, I should say. But then paving itself is creating, you know, a lot of problems in cities to having to do with urban eating heat island, as I mentioned. Yeah. I would say that’s the other, the other really, really big problem with that?

Jeff Wood (22m 34s):
Well, we spent so much money on this gray infrastructure pipes, concrete culverts, combined sewer systems, et cetera, and thinking about trying to keep the water instead of sending it away. Well, how would we do that? And what would the investment in the type of infrastructure that would allow us to keep it? What would that entail?

Mary Pat McGuire (22m 51s):
Yeah, that’s the huge debate now is infrastructure investment. As you mentioned, also, the infrastructure bills that are out there, extraordinary sums of money are spent on gray infrastructure systems. But to answer your question, there’s a couple of, couple of ways to think about it. One is that yes, if we move from a gray infrastructure investment to a green infrastructure investment, or we talk about as a green, blue infrastructure investment because of the presence of water that does mean reallocating budget toward building great and green infrastructure, there’ve been many studies that have shown that there are not just quantitative benefits to green infrastructure in terms of the stormwater capture potential of green infrastructure, but all of the other co-benefits that are both measurable quantifiable, that you can say that this is worth the investment, you know, but there are other intangible benefits too.

Mary Pat McGuire (23m 41s):
When you start to think about how the development of natural systems are natural spaces in communities would benefit, you know, children’s health, a sense of wellbeing, a sense of connectivity to land. So it does have such a range of different benefits from things that are measurable, air quality improvements, for example, food growing. You know, if you start thinking of that green infrastructure can also allow the development or allocation of green infrastructure can allow for other kinds of productivity in the landscape. And so there’s, there’s a number of ways of thinking about that. It depends on who you’re talking to about how you evaluate the potential for green infrastructure to be an, a sound or a good investment.

Jeff Wood (24m 19s):
I mean, I’m thinking of, I think you have processes like, like Philadelphia’s and how they’re working on not spending as much money on the gray infrastructure and allocating a certain amount to doing the green infrastructure where they can capture water where it is and how much money that actually saves them in the long run, but also how better for the environment and all of the other co-benefits that you mentioned before in terms of the heat island effect, the particulate matter, all of the water pollution reduction and things like that, as it, as it kind of filters through the soil. But it’s just, I’m thinking about how hard it is for us to kind of include this type of thinking into what we’re generally doing in terms of constructing roads and thinking about pavement generally, because when we kind of repair a road or we, we build a new road or we think about a new transit line or those types of things, a lot of times the engineers will look at that specific engineering process of building that line, but there’s all these other things that need to happen for it to be sustainable in one way or another.

Jeff Wood (25m 17s):
And so including green infrastructure and some people will, you know, they’ll add like a little thing here and a little thing there, but it’s actually the whole process that needs to be amended. And I’m curious like how that’s done, if we can actually do that in from an engineering context. I mean, not just from landscape architecture, but from thinking about transportation models and thinking about, you know, building roads and transit lines and those types of things, like how do we incorporate the systems thinking that allows us to be more sustainable.

Mary Pat McGuire (25m 45s):
Yeah. Thank you. That’s I mean, you said it so well, and I’m glad you brought up Philadelphia. They’re a great city for explaining that they did have a sort of fork in the road where they were evaluating the trade-offs between green and gray infrastructure investment. And they like Chicago, we’re under consent decree from the EPA to make a decision about how to improve the quality of their waterways and the problems of combined sewer overflow, et cetera. And so I think that at a core level, Philadelphia was also more advanced than a city like Chicago and already looking at the presence of vacant land. For example, I mean, they were trying to look at for a number of years, how they could take some of the changes across the city and make those opportunities.

Mary Pat McGuire (26m 30s):
So how to think about vacant land is more productive land. For example, I think at a gut level, they were also questioning the production of just more underground tunnels. And so they said, well, they’re thinking like, well, great green infrastructure, as many other benefits for the city. So they did a full study to evaluate how they could capture that runoff through the land instead throughout the city, rather than thinking about building an underground tunnel, that would really be multifunctional. It would do one thing and not benefit anything else. And so they undertook that study and then they made a commitment and they sign the consent decree with TPA to go green instead of gray. And that is complicated. And I know that these things are hard to roll out, but what that results in is a series of planning and policies around, as you said, it’s, it’s a systems way of thinking about the continued development and urbanization of the city of Philadelphia.

Mary Pat McGuire (27m 25s):
It means that in every way you look at every opportunity to capture storm water through, through the city, through the fabric of the city. So the street, right? So in a way, as you said, like if you’re going to be reconstructing a street, you should be thinking about how to retrofit the street to capture stormwater. We know how to do it. There are many, many design manuals out there to do complete and green streets. We understand how to re-engineer surface paving. We know how to collect water underground through, you know, stone reservoirs. We know how to create continuous soil volume, you know, for growing trees and other absorptive plants. We know how to, re-engineer the section of the street to absorb stormwater, et cetera.

Mary Pat McGuire (28m 7s):
So that’s a perfect example of where it’s about change management at a city level. It’s about all of the different agencies that are involved with advancing the cities through 21st century design to think about coordinating in reconstructing our cities for English, probably just say it’s about climate change out of rotation. So, yeah, I mean, I, I think it’s about all of our disciplines starting to work together to think about how we through building design, urban design, landscape architecture, and the planning of both reconstructing neighborhoods, but also any kind of see new developments aren’t going to, I’ll mention that new developments sometimes as better at these things, because you can kind of start at the beginning and you could integrate natural systems design into an urban development, but what we’re confronted with now and the things that I’m just fascinated with are how do we retrofit?

Mary Pat McGuire (29m 3s):
How do we come back in and do the thing you’re asking? How do we retrofit and reconstruct existing conditions or existing situations? And that’s a bit trickier one because it requires a different kind of coordination where we have to just, we have to kind of like find those spaces in the landscape, you know, in are, when I say landscape, I don’t mean the garden or the park over there. I mean, I think of everything as, as a landscape of constructed landscape, we have to find those opportunities and you’re right. It can’t just be a small little thing over there, a small bio swale, or just like take out a couple of parking spaces. You know, we really do have to think at bigger and bigger scales about how to retrofit the ground and at every new project opportunity to integrate more absorptive surfaces and to re-engineer the section of ground.

Mary Pat McGuire (29m 50s):
So can no longer be one solid impervious surface that is basically, you know, negating any potential infiltration. That’s just a kind of like heat bounce, and also quite unpleasant to interact with visually and through our bodies. And to start thinking about the ground as a more dynamic surface and that there is research, and I’ve done some research with some geologists and engineers here at the university of Illinois to evaluate, well, how much land do we need to retrofit? I mean, if it were me, I would say, well, all of, you know, all of it, but I’m also a realist. And I have worked with them to understand the role of soils subsoils that wants D paved, you know, once retrofitting a street or a parking lot, or some kind of other urbanized surface that, you know, how much do we need to retrofit and do we need to know about the soils, those native or sub soil conditions there, we need to understand how water would flow to those new openings in the ground, you know, and what should be the, not just the percentage of, let’s say surface disruption or surface redesign, but what would be the distribution of that?

Mary Pat McGuire (31m 1s):
You know, how much of a parking lot, or how much of a whole neighborhood, you know, should, should we be thinking about D paving and then resurfacing or bringing to life? So, yeah, it’s incredibly in tangled question. And also one that is only can only be answered specifically city by city and neighborhood by neighborhood. The kind of each condition is going to vary.

Jeff Wood (31m 27s):
I’m also curious how, you know, obviously cities are important flashpoints for this, but you’ve written that kind of many of our environmental programs and other items are focused on wilderness generally instead of cities. And I’m not saying that that wilderness is not important. We obviously need continuous ecosystems and wildlife corridors and those types of things, but, but why do you think we focus so much on wilderness? And then we forget this huge ecosystem that we, you know, a majority of us 80% or so live in metropolitan areas. We live in this space and we live in this ecosystem, but we tend to ignore it when it comes to like environmental issues. You know, cities are kind of the central focus of thinking about pavement, about impervious cover and et cetera.

Jeff Wood (32m 8s):
But a lot of our environmental programs, a lot of our environmental focus seems to be on wilderness areas. A lot of the money that we spend on environmental protection even goes to wilderness areas. And so I’m wondering why, you know, it’s important to think about cities as almost wilderness or environmental instead of just those kind of wilderness areas that have quote unquote been less touched

Mary Pat McGuire (32m 29s):
From a, from a conservation position in particular. Yeah. The sense that nature is out somewhere out there, right. Somewhere at the city. Yes. This is a huge problem and a huge mistake. And one that I think we’re obviously all trying to recover from, particularly since the kind of early considerations of where nature is. It has changed a lot since populations have grown in cities have expanded and we’ve woken up and realize how much has been lost. And yet we have intense concentrations of people living in these kind of denatured zones, and that has had a direct impact on their health and broader wellbeing. But we also, the impacts of cities as cities have had on a regional scale has also come to light.

Mary Pat McGuire (33m 14s):
When you have, again, I hate, I’m sorry to bring Chicago up again, but Chicago is this incredible case study of like continental scale consequence. When we know that are discharged out of our homes here in Chicago is ending up in the Gulf of Mexico. I mean, that’s a really big eyeopening connection that many people don’t understand. And so we have to work back. We have to work at this at both ends. We know that air and water and land are all affected by everything that we’re doing and this, you know, and you just have to look at the different scales of impact. You can, you can analyze those relationships between the urban and the wild at a range of different scales to understand the impacts to biodiversity, you know, in terms of migration patterns, in terms of certainly hydrologic impacts, et cetera, and to return a kind of natural systems thinking back to the way that we design cities, both for the kind of local scale of effect there, but also to understand that we have incredible opportunities to rebuild fragmented ecologies that cities have broken, you know, so we’re a piece of the puzzle, the sort of the gradients of wildness as it were, you know, we have a lot of work to do to recover there.

Jeff Wood (34m 29s):
If you were to do pave Chicago, what would the results be? I mean, would you see changes in the heat island effect? Would you see different species popping up? Would you see a different city than you would see today? Like what happens if your goal comes to fruition?

Mary Pat McGuire (34m 46s):
The answer would be yes. And yes, it’s such a good question because some of the imagination that I’ve had around D paving started with looking back in time to understand what was there before the city was there. And I created some maps with one of my research assistants that visualized a way of looking, looking at the land before all that pavement was there. We actually mapped all of the pavement that exists in the streets and the alleys and the parking lots. We also looked at compacted embarrass soil because it functions the same as paved land, although it’s not technically paid, but it’s compacted in the same degree.

Mary Pat McGuire (35m 30s):
And we created this map and visualization of like, what would these neighborhoods be like if we, if we actually and transform those paved spaces. And it was like this whole new system, this whole new network of land and a liveliness started to shine through. And, and I started to wonder, you know, when, when people say DP of Chicago, some people get really upset by that because they think there’s sort of a loss that’s going to happen or some kind of, oh no, we’re going to try to resist radicalizing the idea. But to me, these kinds of windows of these windows of natural systems are these like pockets of habitat start to emerge.

Mary Pat McGuire (36m 11s):
But it’s the aggregate of these not small acts of D paving, but systems of D pavings, small moves, small retrofits through city through your streets, pardon me through parking lots. And through alleyways starts to incrementally introduce nature in a way that it starts to get reconnected. I mean, animals need pathways to travel. Birds need connected canopy. Even those of us who walk through our cities, we know what it means to have shade to walk underneath. So it doesn’t take that much to actually start to trigger those responses, you know, unearthing soil, allowing water to penetrate through, to plant trees. You know, I think there’s an amazing way that we can think about this deep paving as a kind of subtractive process, the way that you might think about what’s a good way to describe it.

Mary Pat McGuire (37m 0s):
But I see it as a series of small moves with great impact. And what I mean by small is, you know, what would it look like to take out 10 foot wide of paving through every street? You know, what it, what would it mean to take out, you know, every third parking spot in a parking lot, because that ratio of two to one, it would mean something quantitatively from an engineering firm and from a hydrologist temporary. But what you put in that place incrementally can start to add up into a new kind of natural system throughout the city. So poking holes and pavement is a good idea. Removing some entirely would also be completely justified in certain parts of the city that were abandoned.

Mary Pat McGuire (37m 43s):
Lots are sitting. There’s no reason why we as a city, can’t see systemic D paving as a part of climate change adaptation. Let’s put it this way. We know that we cannot live with the situation as it is. We know we can’t live with concentrations of, to some, in some places 80% pavement, particularly in the industrial quarters is very much tied to land use. So residential areas might be a place of doing small interventions. When you get into commercial land juice and you get into industrial land use, you see opportunities to do more aggressive, deep paving. And when you D pay, then you have the opportunity to do urban forestry, for example, to start thinking about what is the transformation of those sites.

Mary Pat McGuire (38m 29s):
So if you subtract something, what do you want to add back in? And that too, at a community scale needs to be decided by people who live there, you know, what are the things that are missing in their environment and what are the experiences that they’re not having? And so those decisions would happen to be made kind of at a local scale.

Jeff Wood (38m 48s):
It’s interesting. We have, because of the pandemic, we have a lot of slow streets that have popped up around the country and here in San Francisco, there’s a one on Sanchez street, which is close to my house. And when I walk down it, and I know that it’s going to be a slow street from now, because a lot of the neighborhood has organized around that. I often wonder what it looked like if you decided to just take away the pavement, right? Cause if you’re going to make it a slow street, why not make it a grass street, kind of like those grass tracks for tramways and in Europe, you know, where they don’t pave under the tracks, they just let it, let it be grass. And then the tracks go through the center. I wonder what that would look like. And I feel like that would be a benefit to the city and maybe even more cities. And if you can think about it that way, instead of, you know, maybe the negative connotation of that might, some people might take in that de paving a whole place.

Jeff Wood (39m 32s):
You can actually take it and think about it from a positive perspective. You have these Greenways that are actually green, you know, have these connections throughout the city. They’re actually connected. I, I grew up in a place where it was a suburb of Houston, but every part of the neighborhood was connected by these trails and they were pavement trails, but then it was green and grass all around. And you had 80 miles where you didn’t have to cross a road to get to any part of the neighborhood of a hundred and a hundred thousand people, 60 to a hundred thousand people. And so that idea of getting to any place in the city without having to be on a road and with going through these greenbelts seems to be a really powerful idea that could catch on if people start to realize what that actually meant versus we’re not trying to take away your mobility, or we’re not trying to take away something.

Jeff Wood (40m 16s):
We’re trying to add something to the,

Mary Pat McGuire (40m 18s):
Yeah, I love what you’re getting at. I love your description of that too. And that is something that in my field of landscape architecture, I’m really interested in trying to find ways for a general audience to describe different ways of thinking about the role of the ground in not just in climate change adaptation, but also in just different ways of living. We have different ways of reconnecting ourselves with land in the cities. So I’m a big fan of what I call design operations, but let’s make it simpler just like ways of designing that involve hybridity. You know, that involve the hybrid between things that we might think of as structured ground for when we do need load bearing ground, you know, for, for some vehicles, et cetera, and natural systems that, that those things can be interwoven together at finer scale so that you don’t get monoliths of pavement just because a car might drive there.

Mary Pat McGuire (41m 13s):
It doesn’t mean that the cars drive there all the time. And what else, what other purpose is that ground for us, particularly as we’re not driving as much anymore. And car usage is, you know, predicted to drop, et cetera. I mean, I think that we don’t need as much pavement as we have. We pretty much have maxed out as much pavement as we actually could need up to a certain point. So hybridity is a really big one. Modularity is also an interesting way to think about the ground plane, that we more regularly alternate different kinds of materials in our environment. So your example of where people walk and where people drive, I mean, that can certainly, and we can certainly live with more vegetated ground. We can actually structure the ground with more open grid systems that allow plants to grow up between them, you know, in LL soils and gravels to be there and allow for more water infiltration through them.

Mary Pat McGuire (42m 3s):
So we know, we know that we can develop driving surfaces that are more infiltrative that actually have also, they’re having a lot of like vegetation growing through them. And that’s definitely the case in parking situations, parking surface situations where you really don’t need solid pavement in the parking areas themselves. So they can be imagined more like parking gardens, you know, where they’re more garden than parking surface and actually slows people down to, you know, I mean, could drivers start to slow down when they realize that they’re kind of the intruder in those spaces? You know, so yeah, there’s a lot of ways to imagine that. And for me, you know, when you talk about your experience and also you cited a European example, by the way, which I think they’re just, there’s a lot, a lot more examples coming out of there, that context than our own.

Mary Pat McGuire (42m 50s):
If we start to put people and animals and other species first, we can totally imagine our cities in very different ways, especially starting with the ground, getting rid of curves, for example, getting rid of the amount of paving, et cetera. So, and actually hearing you talk through that, I think too, about how wonderful it is to work with students. And I would love to work with even younger students and even with children to imagine what these streets should be like for us. I mean, if they’re truly the public realm, you know, how would we imagine them differently all the way down to the ground? If we were to imagine a process where we really just like and visualize everything between our houses, what would we put there instead? You know, why is it that the car would dominate that design?

Jeff Wood (43m 31s):
Well, it’s interesting. You say kids. We had one of my favorite guests that we’ve had as is Antonia milkshake, who wrote a couple of books about walking and her first book, she writes about how kids that grow up in cities. They don’t have the, quite the same neuro diversity in terms of their motor skills, because they end up walking on pavement, which is totally flat and there’s no adversity to it. Right? And so when you grow up in a suburb where you grew up in a place where there’s grass or other, in a way you actually develop better motor skills, because your need to change according to the situation, if you step on some grass and there’s like a little lump, you have to adjust your ankles and where they go. And so that’s an interesting point too, is thinking about how younger people need this kind of a environment to actually make themselves more responsive to the environment instead of just being in a one dimensional space.

Mary Pat McGuire (44m 17s):
I that’s so interesting and on their phones too, when they’re walking on the sidewalk, right? Yeah. Maybe a limit, but that is so interesting too. I’m going to have some students I’m working on urban forestry project right now in my studio, in my design class. And the students have been recalling what it felt like to climb trees, you know, that kind of thing. And so, and we, I mean, when you get into pavement areas, there’s also a lack of trees, you know? And so that those things are all always related to each other about what people are experiencing with nature and through their bodies, whether it’s trees or whether it’s the ground. But yes, there’s a completely different relationship that the body has with the ground when you’re actually interfacing with soils and roots.

Mary Pat McGuire (44m 57s):
And you start to become aware of an entire world around you, more mindful of even where you’re stepping, who’s living under there, you know, and understanding about this kind of connectivity between different species, that kind of imagination is something to, in your question about why the wild is out there and not inside of our cities, conceptually and practically speaking is that we need to invite, you know, we need to invite these different experiences back into our worlds. I mean, if, if our children and even in our generation, many people have lost, you know, that sense of connection and we don’t need to be traveling out. And actually we need to be leaving some wild areas without our intervention, you know, without our involvement, we don’t need to go and visit nature.

Mary Pat McGuire (45m 39s):
We need to rebuild nature right. In our backyard. I’m glad you’re bringing that up. That’s where much of my sense of the city was also leading me toward looking at this too, was because of my own, my own experience in walking the city. And I also have spent a lot of time on water on boats. And so I have this different sense that occupying different elements, like occupying water. Yeah. It gives you a different appreciation for how your kind of body can experience, you know, the world.

Jeff Wood (46m 8s):
I have another question about this. It’s a little bit of a climate question. I mean, we’ve seen these incredible rainfall amounts in places like Houston for Harvey, 50 inches. I think it was during Ida central park, got three inches in 10 minutes. I’m wondering if any systems, whether it’s green or gray without over-engineering could ever take these kinds of rainfall amounts without being swamped.

Mary Pat McGuire (46m 31s):
Well that’s yeah, that’s probably the toughest question you can fill out there for, for anyone. One of the problems that we’re experiencing with the impacts of those rain quantities is that we not just because we’ve paved so much, but because we have torn out some of our natural infrastructure that may have been able to buffer, you know, those are quantities of rain. So in the examples of, of Texas, you know, we’ve, we’ve removed so many of our natural marshes or natural wetlands, et cetera, that I can’t speak specifically to the amount of rain that was, you know, when we start to get up into 40 inches, I mean, that’s, that’s super in superintendents, but those spaces are we’re affordable, you know, but we paved them over now.

Mary Pat McGuire (47m 14s):
So this is a problem where water once was, we now are building cities and obviously our cities are not designed for that quantity of water nor are underground, underground, or above brown, gray, or green infrastructure designed for those kinds of quantities of water. But the problem is that we’ve built in places that were naturally designed to attenuate storms like that. The three inches though, is that is more manageable. I mean, I don’t use the three inches in 10, 10 minutes to, okay.

Jeff Wood (47m 43s):
I think it was, yeah, I read too. It was three inches in 10 minutes in central park and then there’s, that was measured. And then there’s other places that I heard from other folks that it was much more, I think in flushing and other places, there was, there was a really intense downfall that was even more than the three inches that was marked there.

Mary Pat McGuire (48m 0s):
It’s interesting because in some of the research that, that, that I’ve done with geologists and engineers, we’ve been testing in the model we tested how much rainfall could be captured in a two hour period. So it wasn’t 10 minutes. And at first, some of the reviewers of the work up witnesses, again, up in the Chicago Calumet region who were kind of like looking at us like we’re crazy and looking, you know, trying to think about storms have that capacity or that intensity, but more and more, even just in the last two years has been interested in trying to understand rainfall quantities and short, shorter, and shorter duration. So we’re no longer looking at having a rainfall in 24 hour periods.

Mary Pat McGuire (48m 41s):
And actually much of, many of our cities can handle, you know, certainly one inch, but sometimes two or three inches in a 24 hour period, again, with a mountain amount of green infrastructure, that’s designed to take that. But in these higher intensity storms, we are finding that if we do retrofit land, particularly if we’re the focus on deep paving, which is obviously the source of flooding and runoff. So basically you’re replacing part of the problem with the solution you’re job, just trying to fit a small amount of solution around. You’re actually addressing the root problem, which is paving and compacted soil. We’ve found that particularly in certain soil environments, natural soil environments, that we can, we can design for a few inches of rain.

Mary Pat McGuire (49m 25s):
So if, if cities want to move in that direction, that there is research to suggest that we could do it, but it means, yeah, it means D paving. It means looking back and reversing the patterns of urbanization through the last hundred plus years and thinking through March 21st century technology, which is our natural systems, the capacity is there. Those soil systems are remarkable sponges. So the more that we can integrate them back into our cities, by deep paving, the root of the problem, then yeah, we can, we can deal with rain in bigger storms. Are we still going to have flooding? Yes. And we know, particularly in coastal environments with not just rain precipitation, but the issues of coastal surge, the issues of salt, water, inundation, you know, so many of the other, particularly the winds, et cetera, that we’ll probably be dealing with managed retreat from a lot of those areas.

Mary Pat McGuire (50m 22s):
I mean, we’re kidding ourselves. We think we’re going to solve this by just designing places better. We’re going to be enough to live in different places because of some of the effects of climate.

Jeff Wood (50m 33s):
Well, I want to let folks know where they can find your work. Where can folks find you the on online? Where can folks find a DP pave Chicago? What’s the best place for folks to find out what you’re doing?

Mary Pat McGuire (50m 44s):
Yeah. I would love for people to reach out. I am at the university of Illinois in Urbana champagne. It’s where I teach and do a lot of my research. I’m also up in Chicago where I do a lot of my work. Find me, people can find me in two places at the university of Illinois website, if you Google department of landscape architecture at the university of Illinois, but I also am the lead coordinator for a small design lab called water lab. Well, we were kind of located in Chicago, but with Kobe, we’re sort of consolidated and not like doing much public programming still, but we’re [email protected]

Mary Pat McGuire (51m 25s):
And so people can read about some of the research that we’ve done. Some of the design projects that we’ve undertaken and this D of Chicago initiative is posted there. You don’t have a Twitter account, which is just my name, Mary pat McGuire. Welcome to people finding me. I’d like for our work, some of our research, which we didn’t talk about a lot today, but to get out there and to see if we might find other collaborators on doing design and research projects. I’m also really interested in developing a DP program in Chicago, much like the ones that have taken off in other places coming onto the Portland program. But also Puget sound is doing some remarkable things with D paving at a community level.

Mary Pat McGuire (52m 6s):
So de paving can be a kind of community education tool, as well as, you know, changing people’s, you know, environments right around them, but it can also be a larger watershed management tool. So I think we’re at the beginning of a movement where we start thinking about not just moving forward through new fancy technological fixes, but, but actually thinking about, you know, on making, let’s say unmaking an undoing some of the sources of the issues that we are actually trying to design design differently now. So I welcome anyone contacting me also on the water lab.org website too. There are some things there’s a list of publications that are on there, and there are some papers that have been written, some articles, et cetera.

Mary Pat McGuire (52m 52s):
And if the link doesn’t go through, I’m happy to send a copy of that material to anyone directly.

Jeff Wood (52m 59s):
Awesome. Well, Mary pat McGuire, thank you so much for joining us. We really appreciate it.


Listen to the Talking Headways Podcast

Testimonials

…the first thing I read every morning is the newsletter to see what’s been out there. It’s great to have an aggregator that pulls everything together so nicely.

Joe Cortright, City Observatory


I think that the email newsletter that you do every morning is the best one that I get, and I get a lot of them.

Mary Newsom, The UNC Charlotte Urban Institute


Really is the best daily urban newsletter out there.

Eric Jaffe, Editorial Director Sidewalk Labs

Subscribe

To Receive The Overhead Wire in Your Inbox Daily

Premium Daily Subscription

The Premium Daily Subscription is our most information packed offering, chock full of over 30 pieces of news every single day. Included are popular features such as the quote of the day and the most read article from the previous day. Also included is our weekly roundup for times when you are strapped for time but need to know what’s going on.

Premium Weekly Subscription

The Premium Weekly Subscription is for professionals constantly under a time crunch. We take the most read items from the week before and share them with subscribers along with more in depth analysis of a single popular topic.

Learn More and Subscribe

Top Links

of the past 48 hours

Video of the Day

Friends of The Overhead Wire

Back To Top

Welcome to The Overhead Wire

What Can We Help You Find?

Try Our Newsletter For Free