It’s easy to list the reasons why we are supposed to love urban agriculture: the food it yields is fresh and local; the farming it requires is fun and social; the effect on neighborhoods is revitalizing and healthy. Critics point to its inability to replace existing production and distribution channels for produce, but what if its impact extended beyond the small farm or immediate community? What if it could solve other problems? One of New York’s greatest environmental challenges is its combined sewage overflow (CSO) problem. Our outdated sewer system is designed to collect stormwater runoff, domestic sewage, and industrial wastewater in the same pipe on its way to a sewage treatment plant. When the rain is heavy, though, volume exceeds capacity and untreated wastewater flows right into our waterways. Green infrastructure is a term that refers to a wide range of technologies and systems to improve water quality through the capture and reuse of stormwater. But the policies that incentivize green infrastructure and those that govern urban agriculture are not coordinated. In some cases, urban agriculture is actively excluded from official definitions of green infrastructure. In an effort to support farming in the city and help scale it up, Tyler Caruso and Erik Facteau set out to prove scientifically the environmental benefits of rooftop and other urban farms, in particular their ability to manage stormwater, with their research project Seeing Green. In describing this project, Caruso and Facteau touch on issues that range from the effect of scientific research on public policy, the shift towards a definition of sustainability that includes performance alongside design, and the need to layer different registers of analysis in efforts to bring about a city that is more responsive to natural systems. – C.S.
What is Seeing Green and how did it come about?
Erik Facteau: Seeing Green is a research project that studies specific urban agricultural sites in the New York City area in order to demonstrate how urban agriculture should be considered as a viable and important component of a city’s green infrastructure. One of the sites we’re currently looking at is Brooklyn Grange, a rooftop farm in Long Island City; another that we will be looking at is Added Value, a raised bed farm in Red Hook. We’re also looking at the rooftop farm atop the Parks Department’s Five Borough Administrative Building on Randall’s Island.
By measuring evaporation and evapotranspiration rates, we are looking to create metrics to calculate how much water urban farms are managing, through both detention (meaning the temporary storage of excess stormwater) and retention (the indefinite storage of excess stormwater). This will tell us how much water urban farms keep from entering the sewer system, therefore reducing combined sewer overflows.
When you start to get these numbers, you can begin to extrapolate over larger areas of land – whether it’s exisiting farms or underutilized land with farming potential – to determine how much water can be managed and what the best practices are for doing so. Right now, we are looking at a couple different sites as a base line and moving forward from there.
Tyler Caruso: This project began as a graduate research project and as it has evolved to include a series of interesting collaborations; and the sponsorship of the Open Space Institute has helped us pursue these partnerships. In one project, called “Farming Up,”Alec Baxt and Lise Serrell look at nutrient quality of crops growing in urban environment compared to rural environments. “Don’t Flush Me” is a project that puts sensors in sewage outflow points and notifies individuals about how much wastewater they produce during and immediately after those weather events that cause sewage to overflow into the harbor. Another one is called “Farming Concrete,” for which Mara Gittleman has been calculating the area, weight and monetary value of food grown in community gardens in New York City.
Facteau: Another project we’ve been involved in has been to set up a demonstration project on the roof of the Association for Energy Affordability‘s headquarters in the Bronx. We emulated the green roof condition on part of the roof and installed a container underneath so we could measure the amount of water running through the green roof and then compare that to the amount of water rushing off the impervious surface of the regular rooftop.
Caruso: If you take all of these metrics and you collapse them – you look at the nutrient level of both the soil and the crop, you look at the stormwater management potential, the energy rate reduction, the food production potential — the combined analysis is much more powerful. The guiding idea is this: if you can first define the benefits and know what they are and research them, then you can quantify them, and then you can monetize the benefits — and that’s when it really becomes valuable to private property owners and cities. At that point, the research can begin informing policy. And it can begin informing the development of best management practices around the design of farms. For example, if we observe nutrient run-off, we can help design small wetlands around the drain. If we know how much water an urban farm can manage at a particular soil depth, and how much productivity and costs would be affected by increasing its depth, then we can inform building owners about the best investment to reach the desired productivity and the desired environmental outcomes. It’s a necessary step if we want to see urban agriculture grow in New York City.
How did you both get involved in this topic?
Facteau: My background is in microbiology and mycology, working mostly on plant restoration projects and the symbiotic relationship between fungi and plants. I studied environmental science and forestry in college. And I met Tyler while in the graduate program in environmental systems management at the Pratt Institute.
Caruso: Before this, I was working on landscape design and urban agriculture projects and designing and installing grey water systems in San Francisco. When Erik and I started the discussions that eventually led to Seeing Green, we were looking for a thesis project and decided to work together. At the time, there were lots of projects around that dealt with urban agriculture, and most of them were primarily concerned with the economic or social benefits. They might mention the environmental benefits of farming in the city, but not in great depth. The potential of urban agriculture as green infrastructure was a connection that hadn’t yet been made. In 2010, we started noticing how much City agencies were talking about green infrastructure, and realized that if we wanted our cities to support urban agriculture under the banner of green infrastructure, we would have to quantify the environmental benefits.
Facteau: The green infrastructure documents from the City that we were looking at all seemed to focus on traditional green roofs. So we started researching how much water these systems could actually handle while simultaneously looking at how rooftop agricultural projects are performing.
Caruso: The grants that Erik is referring to include a green roof tax credit incentive, issued through the Department of Buildings, that specifically prohibits urban farms because of plant selection and because of speculation that irrigation – traditional green roofs don’t require irrigation; agricultural green roofs do – would make rooftop farms less able to retain stormwater than a traditional green roof. That’s a clear example of the city implementing progressive green infrastructure policies that exclude urban agriculture. And in this case, the policy is based on hypotheses that are scientifically untested.
We also find the language of these policies to be more prescriptive than performative. Our methodology for the Seeing Green project looks closely at performativity: how well urban farms and green infrastructure perform over time.
A common criticism of LEED certification system for green buildings is its focus on the design of a building as opposed to looking at how it performs in the long-run, through energy audits or other measurements. With LEED, there is currently no follow up once a building is certified. The next wave in green design – whether it’s buildings, landscapes or infrastructure – is ways to measure performance. That’s what inspired us to develop our thesis project into a larger initiative: to support urban agriculture by defining and quantifying its environmental benefits and seeing how performative it can be.
What kinds of tools or precedents were out there to help you analyze, monetize, to quantify or identify proper metrics?
Caruso: I know everyone says this, but I think social media – Twitter, Facebook, etc. – has really helped empower people with a DIY attitude, has helped citizens’ groups to form, has helped individuals collaborate with a science lab.
Platforms like Kickstarter have created more of a sense of “we’re all in it together,” and that attitude has definitely benefited us.
Facteau: Kickstarter was a huge help in getting this off the ground. We had worked out our methodology as part of our thesis project at Pratt, and when we finished that we asked ourselves, “Where do we go from here?” We knew the equipment that we needed, and we knew that farmers and communities would really value the information we wanted to collect. So we used Kickstarter not only to raise money for equipment but also to raise awareness. Groups from England, from Australia, from the west coast contacted us because of their interest in the research.
Caruso: I just spoke to someone preparing a research report on the potential for urban agriculture in San Francisco. Another group in Minneapolis recently requested our collaboration on a large-scale urban agriculture initiative out there. Around the country, and the world, it’s a really supportive community. There are also some big research initiatives right here in New York….
Like “Five Borough Farm,” which Urban Omnibus featured last year. That effort is also trying to push the idea of metrics.
Caruso: Exactly. I think one of Five Borough Farm’s contributions to the field is its focus on the public health perspective. There’s also the work Kubi Ackerman is doing at Columbia’s Urban Design Lab to evaluate New York’s capacity for urban agriculture. We’ve used some of his preliminary numbers to help us make the case that if we have x amount of stormwater, and if we extrapolate from the knowledge of how many vacant lots or rooftops could be used to scale up urban agriculture, then we can start to talk about how to address the combined sewage overflow problem. If we know that we could manage this many gallons through urban farms, and how much money the city spends per gallon on treating stormwater and wastewater, then we can calculate how much money the city could save if urban agriculture were considered one of many pieces of the green infrastructure puzzle. When you compare that to the cost of retrofitting or constructing new sewage treatment plants, and factor in the amount of energy that goes into treating wastewater, the savings become astronomical. Plus, there are all the benefits that urban agriculture advocates have made well known: vacant land is being re-utilized by communities, increasing property values, supporting economic micro-enterprises, contributing to healthy living, decreasing public health costs. Once you start layering all those factors, the potential of these farms or community gardens is phenomenal.
Speaking of that kind of layering, and the multiple ways to discuss the benefits of farms and community gardens in the city, how did you decide to focus specifically on the intersection between stormwater management and urban agriculture?
Caruso: Our primary goal was to support urban agriculture in whatever way we could. We started by talking to farmers and asking them what would help their efforts. What we heard from people was the need to preserve existing urban farms and expand the agricultural capacity of the city. To do that, we wanted to make a quantitative case for the benefits. Our initial plan was to look at more metrics beyond stormwater.
Facteau: We also wanted to look at carbon capture as a way to show farms as potential carbon sinks and look at temperature differences in order to see urban agriculture’s role in mitigating urban heat island effect. Existing equipment for measuring carbon capture are suited for huge plots of land much more than an acre-size roof. There is definitely potential to look into that more in the future.
Stormwater emerged for us as a focus because of the rooftop tax credit issue we mentioned earlier – that it’s unfounded to exclude urban agriculture from green roof incentives without considering the numbers. We thought this was a good opportunity to initiate a policy change.
But of course we are very interested in some of the other environmental factors. For example, comparing different soil mediums — what is used on rooftops is not technically soil, because dirt would be too heavy for most building capacities, but an engineered alternative – in terms of drainage, nutrient leaching, nutrient run-off, the remediation quality of the engineered growing medium and of the plants themselves, temperature fluctuations, etc. Those are some of the things we want to look at down the road. I think the more metrics you can get together, the more powerful a statement you can make. The social benefits – from filling in gaps in the foodshed to bringing people together in a shared community project – are well known. The environmental issues, particularly related to roofs, require more research.
You have discussed the potential for this research to affect policy and to help building owners understand their options. What are some other lessons to be learned from this research? What else do you hope will be done with your findings?
Caruso: The green roof tax credit is being amended. And the hope is that other plans put out by city agencies or reports by national organizations will factor some of this into their thinking. The American Planning Association, for example, puts out a guide for agriculture; if city planning institutions start to consider urban agriculture as a viable step for cities to strengthen local economies, expand regional foodsheds and isolate and address environmental challenges, that would be great.
The US Green Building Council’s recent announcement that the retrofitting of existing buildings is eligible for an innovation credit is an interesting tactic and a change in the right direction. I think as LEED begins to move more towards performativity and long-term monitoring, we’d like to see services such as Seeing Green becoming inextricable parts of measuring performance.
Some city agencies have legitimate concerns about scaling up rooftop gardens. The Fire Department is worried about the height of plants allowed and how that affects fire safety. The Buildings Department is worried about buildings’ structural load capacity. But hopefully the Parks Department will be a leader in this effort; working with them has been a great partnership for us. Their experimental roof garden on Randall’s Island is intended specifically to inform what kind of green roof systems they should be implementing on their buildings. If other City agencies did the same thing and committed to doing pilot projects on City-owned property, it would have a huge impact.
Recently, some have voiced skepticism about the viability of urban agriculture, dismissing it as a phenomenon only relevant to small portions of the population. What’s your response to those voices?
Caruso: I think when people hear the term urban agriculture, they make the mistake of thinking that its advocates are postulating that a city the size of New York or San Francisco or Chicago could grow all its food within its borders. Most farmers would laugh at that, given the amount of effort it takes to productively and intensively grow on even an acre of land. But I think it’s incredibly important that urban agriculture is part of a regional foodshed, is part of supporting local, decentralized economies and healthy, active and safe communities.
Once again, I think layering the environmental benefits, the social benefits and the economic benefits is really important to counter skepticism about urban agriculture’s viability.