Cities are sitting on a largely underused public resource: urban stormwater wetlands. If properly designed, these landscapes can reduce flooding, support urban wildlife, and serve as public space. A new report Design Guidelines for Urban Stormwater Wetlands — authored by an interdisciplinary group of researchers and students at the MIT Norman B. Leventhal Center for Advanced Urbanism led by Celina Balderas Guzmán, Heidi Nepf, and Alan Berger — advocates for the positive role wetlands can play in cities and outlines research that provides insights for landscape architects, engineers, and planners.
The authors make a case for the potential of urban wetlands, especially in a time of changing climate and deteriorating urban infrastructure. “Wetlands, the world’s most valuable terrestrial ecosystem, provide a multitude of ecosystem services: water treatment, flood protection, carbon storage, habitat, recreation, and aesthetic value,” they write.
And yet, in many cities, existing wetlands have been filled, paved, developed, or channelized, eliminating the benefits they provide. In this context, the authors see opportunity. “Just as urbanization has obliterated wetlands, urbanization can build them new,” they write. “While constructed wetlands are not in all aspects comparable to natural wetlands, they can partially restore some lost ecosystem services.”
However, urban wetlands present challenges for the prospective designer, not the least of which is understanding hydraulic dynamics well enough to create a design that is both beautiful and functional. This is where the team’s research steps in.
At MIT’s Nepf Environmental Fluid Mechanic Lab, the researchers tested dozens of different wetland landform configurations to better understand how “island size, shape, and placement affect hydraulic flow and provide ecological habitat.”
Researchers fabricated models of different topographies from high-density foam using a CNC milling machine. The models were then inserted into a flume (essentially a long, plexiglass tank that circulates water) for testing. The researchers used dye to track how different landform configurations impact the speed and direction of water flowing over the model.
In analyzing the results of these tests, the authors made some findings. First, topography matters. Topography describes the physical features of a landform. Results varied widely for the different landforms, meaning that certain design approaches are more or less appropriate depending on the goals of the design.
According to the authors, “wetland engineers and designers must make carefully considered design decisions based on hydraulic goals, balanced with ecological and urban goals as well.”
Second, in attempting to slow down water and filter pollutants, smaller interventions may be more effective. “Adding topography subtracts volume from a wetland’s potential water storage capacity,” they write, which means that “water will exit sooner simply because there is less water volume, leading to less pollution treatment.”
In their tests, the researchers found that models were most effective when the total volume of topography equaled approximately 10 percent of the total volume of the basin, although they caution this number may shift in real-world applications.
Of the thirty-four topographies tested, the team found two that provided the best balance of hydraulic performance and pollutant filtering capacity. They conclude the report by applying these topographies to two case study sites: Buffalo Bayou in Houston, Texas, and Taylor Yard, on the Los Angeles River in Los Angeles, California.
The case studies are intriguing, but may be frustrating to those hoping for a more detailed explanation of how to apply the team’s findings. However, the authors note that the studies are “urban design frameworks” and meant to be conceptual. Those seeking to transfer the team’s research to real world projects will likely find their topographic models to be helpful starting points, but will still need to develop unique design solutions that respond to site and program requirements.
Ultimately, Design Guidelines for Urban Stormwater Wetlands aims to “inform decision makers, planning agencies, consulting engineers, landscape architects, and urban designers about the efficacy of using ecologically-designed constructed wetlands and ponds to manage stormwater while creating new public realms.”
However, the authors do not present any hard and fast rules for designing urban wetlands. Instead, the report makes a compelling case for why constructed stormwater wetlands are an important and underused resource in urban areas, and provides information that may prove valuable to designers and public officials looking for ways to extract more public benefit from stormwater infrastructure.
“We hope this work gives practitioners and designers a new set of adaptable forms to work with and elaborate upon either in implementation or in future research,” says co-author Celina Balderas Guzmán, describing the study as “a crucial first step to explore forms and validate designs quickly and easily with scientifically rigorous metrics.”
In this respect, the report is a success, presenting imaginative possibilities for new urban spaces supported by hard research. As a resource for designers, Design Guidelines for Urban Stormwater Wetlands may not have all the answers, but it does have important ones.
Later this spring, the American Society of Landscape Architects (ASLA) will release a set of policy recommendations on climate change and resilience designed to better arm advocates pursuing changes in laws, regulations, and codes at the federal, state, and local levels. Introducing a panel at the group’s spring meeting in Washington, D.C., ASLA CEO Nancy Somerville, Hon. ASLA, explained that the recommendations will cover both natural systems and the built environment, and their goal will be to spur the use of financial incentives to encourage positive change.
Natural system recommendations will include measures designed to expand the use of green infrastructure; protect tree canopies, green bio-corridors, and open spaces; support biodiversity, especially among pollinators; and assist diverse plants and animal species migrate and adapt. Example recommendations include: create dedicated funding streams for green infrastructure; incentivize the planting of native and regionally-appropriate plants, protection of habitats, and the increase of biodiversity; and encourage the inclusion of climate change assessments in green space planning, including at the regional level.
Built environment recommendations focus on how to further encourage more resilient and sustainable growth patterns through the use of compact development, sustainable land development and zoning, and transit. Example recommendations include: restructure insurance to encourage resilient re-building; set up community investment trusts for green infrastructure and resilient design projects; and evaluate new transit projects through an equity lens.
A panel discussion then covered how allied organizations are maintaining a focus on climate change in today’s divisive political climate. ASLA President Greg Miller, FASLA, led Jeff Soule, director of outreach at the American Planning Association (APA); Mark Golden, CEO of the National Society of Professional Engineers (NSPE); Tom Smith, CEO of the American Society of Civil Engineers (ASCE); and Vaughn Rinner, FASLA, immediate past-president of ASLA, through a discussion.
To varying degrees, all organizations actively call for sustainable and resilient planning, design, and engineering that will help communities better protect themselves and adapt.
A key message, which was relevant for all organizations, came from Golden: “health, safety, and welfare (HSW) comes above all other considerations.” Following where the climate science leads, these organizations promote sustainable and resilient practices because they will help ensure health, safety, and welfare in an era of temperature and weather extremes.
According to Golden, more resilient buildings and landscapes are less costly to build if they are created in advance of a destructive natural event. A recent National Institute of Building Sciences (NIBS) report found that for every $1 spent on hazard mitigation saves $6 after a disaster. Sadly, though, most communities “continue to be reactive instead of pro-active” in preparing for climate change-driven natural disasters.
Rinner explained ASLA is now purposefully talking more directly about climate change. “The words we use matter. We take a strong position on climate change, sustainability, resilience, and adaptation.” She added that nearly a third of sessions at last year’s Annual Meeting & EXPO in Los Angeles were focused on climate change and resilience.
In the next year or two, Congress will be taking up a new transportation bill. The sentiment seemed to be advocating for a more sustainable transportation system at the federal level will be an uphill battle. According to APA director Soule, “we are actually regressing at the federal level and just trying to keep what we’ve accomplished.” Leadership on green and complete streets and other forward-thinking transportation systems now comes from states and cities. Most of the funds for transportation will be spent at those levels, too, so it makes sense to focus advocacy there.
ASCE CEO Smith said it’s increasingly important to leverage skills and resources from the local level. He sees the Rockefeller Foundation’s 100 Resilient Cities initiative, which is training chief resilience officers around the world, as a success story.
Rinner agreed, explaining that the bottom-up We’re Still In coalition — a group of American communities adhering to the U.S. commitments to the Paris climate accord — has signed up 2,700 cities and towns, and the numbers keep growing. “Local action can have a cumulative impact.”
States and cities can also experiment and create new models where the federal government cannot. For example, California has taken the lead in developing a new carbon trading system. “The rest of the world is watching to see if it works — and if it does, California’s model will become something more can follow.”
Smith brought up how the dearth of maintenance budgets hurts efforts to achieve greater sustainability and resilience. According to a report card ASCE releases every four years, the U.S.’s infrastructure now has a sad D+ rating. “Maintenance is the number-one issue.” To deal with this problem, ASCE is developing new guidelines to reduce infrastructure life cycle costs by 50 percent. “We’ve got to think differently in the future.” Smith sees some public-private partnerships as leading the way on the leaner, smarter infrastructure of the future.
In a reality check, APA director Soule cautioned there is still a major gap between high-level policy discussions on sustainability and resilience and the situation on the ground. For example: As New Orleans rebuilt after Hurricane Katrina, local officials and planners tried to stave off rebuilding in areas that had been deemed especially at risk of flooding, with the goal of saving those areas for permanent stormwater management. But the “political reality” demanded homeowners be allowed to build back where they had lived before.
The truth is no one wants to be told they can’t go back home and rebuild. As a changing climate impacts more communities, reconciling health, safety, and welfare considerations with people’s emotional attachment to a place will become an even greater challenge.
Today, a revamped master plan for the Smithsonian’s South Mall campus cleared one of the last remaining hurdles — approval by the Commission on Fine Arts. First released to the public four years ago, the original plan by Bjarke Ingels Group (BIG) and landscape architecture firm Surface Design, among other firms, was criticized for eliminating the beloved Enid A. Haupt Garden in favor of a more contemporary landscape. After years of refining the plan with significant public input, a revitalized garden, which is the legacy of the great philanthropist and horticulturalist Enid A. Haupt, is back at the centerpiece of the quadrangle framed by the Castle, Freer and Sackler Galleries, Ripley Educational Center, National Museum of African Art Museum (NMAAM), and the Arts & Industries building.
The updated master plan is smart: it proposes using a series of fully-accessible entrances to bring visitors down to a unified underground space that will seamlessly connect museums. This will also stop tourists and visitors from having to ascend and descend each time they want to visit a museum, going through security and checking bags over and over. The master plan will guide the 20-year-long $2 billion project.
Major updates made to the plan over the past four years:
The Castle acts a front door to the south mall campus, a portal into the more secluded quadrangle. According to Smithsonian Undersecretary Albert Horvath, more than 80 percent polled by the Smithsonian see the Castle as the central symbol of the museum and research system, so its enhancement as a hub is the first major project of the master plan.
BIG reduced the proposed excavation under the Castle by 50 percent, while still expanding the public space within the building and connecting it underground to the rest of the campus.
The 37-feet-tall Sackler and African Art Museum pavilions, which line Independence Avenue and hem in the south side of the quadrangle, will be removed in favor of smaller 26-foot glass pavilions at the north edge of the quadrangle. The pavilions were moved to the north end because “70 percent of the traffic” to the under-visited Sackler and NMAAM comes from the National Mall.
In a presentation to the CFA, BIG project manager Aran Coakley said: “the Sackler and National Museum of African Art lack a presence on the National Mall. Moving the pavilions, so they can be seen from the Mall, will elevate their visibility.” Despite the criticism about the contemporary peeled-up glass pavilions found in early proposals, they make a re-appearance here, but in a more subdued form.
The landscape is also poised for a major overhaul, but not for another decade. The Enid A. Haupt garden will be re-made because it rests on a green roof structure that needs to be rebuilt.
But perhaps more importantly, with the removal of the pavilions, the scale of the garden has changed and therefore the experience of the landscape needs to be re-considered.
As CFA Commissioner and landscape designer Liza Gilbert, ASLA, explained: “Everything has changed. The gardens are so much more open now with an expanded street presence.”
Furthermore, given new skylights will stream light deep into the museums from the edge of green roof that holds up the Haupt garden, there is a new design opportunity to “show how this all works. Visitors will be able to see the landscape layers, so it’s important to make them apparent.”
Gilbert called for a rigorous “landscape investigation” along the lines of what has occurred with the campuses’ structures, in order to turn the current plan’s “notional ideas” into a design that enhances the intimate scale of the gardens, improves resilience and sustainability, and illuminates how landscape architecture works.
Other elements of the plan: a new entrance for the Freer Gallery on the west side of the museum; an integrated underground circuit for trucks delivering and picking up art works; a revitalized Hirshhorn building and landscape and new design for a new sunken sculpture garden and subterranean exhibition spaces on the north side of Jefferson Avenue; clearer surface connections between all the buildings and museums and down to the new Eco-District that will line L’Enfant Plaza; redesigned connections between galleries underground and reconfigured spaces for artworks; a fully-restored Arts & Industries building; expanded events and educational spaces in the Arts & Industries building and Castle; and, lastly, an expanded Mary Livingston Ripley garden.
Next up for the Smithsonian: finalize the programmatic agreement, which concludes the Section 106 historic preservation consultation process, and discuss in one last public meeting. And in the early summer, take the final version of the master plan to the National Capital Planning Commission (NCPC) once more.
The Future of Honolulu Depends on Its Parks– Next City, 3/5/18
“Public parks have emerged as battlegrounds in the city’s response to a changing climate and a growing housing crisis. Could they also hold the solutions?”
Climate Readiness: Think Big, Act Fast– The Boston Globe, 3/8/18
“Until recently, Boston was ahead of other cities in planning for sea-level rise and the effects of climate change before a catastrophic storm like Sandy or Harvey hit.”
Louisville, Kentucky, has some of the worst air in the country. Given the city is a transit hub, tens of thousands of planes, trucks, and trains pass through the city each year, not to mention all the cars. Louisville is also an industrial center where chemicals are manufactured. Heart disease, strokes, asthma and other conditions caused by excessive pollution are found at very high levels. Last year, the city received a failing grade from the American Lung Association in its annual report.
In order to see if trees can help combat the negative health impacts of the city’s deadly air pollution, University of Louisville Medical Center, the Nature Conservancy, Hyphae Design Laboratory and other organizations are coming together in the Green Heart project, the first clinical trial where “nature is the pharmaceutical.”
According to the Nature Conservancy, “this ambitious effort will conduct a first-of-its-kind medical study by planting trees in strategic locations across a cluster of Louisville neighborhoods and observing precisely how they impact residents’ health.” The study is financed by the National Institutes of Health and Louisville-based philanthropies.
Dr. Aruni Bhatnagar at the University of Louisville Medical Center and his colleagues, who essentially created the field of “environmental cardiology,” are doing a controlled experiment to test the impact of nature, as if it was a drug, on a neighborhood scale.
The challenge is “a neighborhood is not a laboratory, where variables are easily controlled. And this project would be far beyond the scale of prior research that identified connections between neighborhood greenness and health.”
Bhatnagar said: “there has never been a rigorous scientific study that quantified the health effects of urban greening. This will be the first attempt to understand, is nature a viable, replicable therapy?”
This past October, the project has its official launch, with a community workshop and the start of baseline data collection. “Temperatures, particulate matter levels, volatile organic compounds in the air will all be tracked by a network of more than 50 passive air monitors as well as more elaborate monitoring arrays mounted on towers and even an electric car.”
Starting next fall, some 8,000 trees, shrubs, and other plants will be planted in South Louisville, according to a map devised by the Nature Conservancy, based in data on where likely impacts will the greatest benefit. As has been noted, trees catch small particulate matter in their leaves, reducing nearby air pollution by a third in some cases; and, if planted near highways, they can act as a buffer, reducing pollution by up to 60 percent.
The Green Heart project is now recruiting 700 neighborhood residents to “participate in several rounds of medical tests, tracking the residual evidence of air pollution in their blood and urine.”
The Nature Conservancy writes that “different chemical signals will be monitored, including the presence of cortisol and adrenaline that are produced when the body is under stress. Participants’ physiological reactions to air pollution will be studied over five years, because some compounds appear within hours of exposure while others take months or years to emerge.” Residents are essentially “human environmental monitors,” said Ray Yeager, PhD, a researcher with the University of Louisville Medical Center lab.
At the end of the five year study, the researchers will have a set of data on residents’ health — looking at both before and after the trees were planted, and, for comparison’s sake, data from people who live nearby but didn’t get new trees. It will be interesting to see if five years is enough to test the benefits of trees — newly-planted, young trees would appear to have less capacity to catch particulate matter and serve as buffers than mature, fully-grown trees with broad canopies.
Unhealthy air is estimated to claim 4 million lives a year. If Dr. Bhatnagar and his colleagues discover medical benefits from the strategic tree placements, the results of this study could result in a new public health model that can help reduce urban pollution-related deaths. Yeager is confident: “what we learn in Louisville is going to affect people all over the world.”
If benefits are proven, the study could also positively affect Louisville, reducing health inequities. The Nature Conservancy refers to data showing that life expectancy in the “leafy suburbs” of the city is 13 years longer than in South and West Louisville neighborhoods with lower incomes and less access to nature, proving once again that “zip code is a reliable indicator of health.”
If the results show positive benefits from trees, the city government should first address inequities and partner with local community groups to build robust tree canopies in the neighborhoods that lack them. With solid data, the city could also further invest in the existing urban forest, which loses about 55,000 trees every year.
Rarely have I worked on a project that I feel is quite as timely and potentially impactful as the Beach 41st Street Garden. With images of Texas, Florida, and the Caribbean fresh in our minds, this story of how nature has helped one Queens, New York, community heal following Hurricane Sandy is incredibly relevant.
When we finished shooting this past spring, it was months before the name Harvey had been uttered on a weather forecast. But by the time September had arrived, and with it a new wave of destructive storms, we at TKF felt a renewed sense of urgency to shine a light on what we had learned through our work in Queens post-Sandy.
When Sandy’s storm surge engulfed the Rockaways, the devastation was intense. You get a visceral sense of what the residents of Beach 41st Street, a New York City housing residence, lived through in the voice of Celeste Grimes, one of the resident gardeners we interviewed for the film. She described it in apocalyptic terms.
In 2014, TKF chose the Beach 41 Street garden as a site to receive one of only six grants awarded to clusters of cross-disciplinary research teams to study how healing green spaces help individuals and communities recover following various kinds of trauma.
The team that applied for funding on behalf of the Beach 41 Street project included social scientists Lindsay Campbell and Erika Svendsen of the US Forest Service; Keith Tidball, Director of the Cornell Cooperative Extension Disaster Education Network at Cornell University, Craig Desmond of Ecotone Building, and landscape architect Victoria Marshall, ASLA.
The team collaborated on a plan that would enable residents to revive the gardens and space; a healing exercise intended to meet what researchers understand is a desire innate in people to connect with nature, particularly in times of deep distress and trauma caused by nature.
For years now, social scientists, civic ecologists, horticultural therapists — among others — have been gathering evidence of the innate connection between people and nature, terming it biophilia. Expanding on that concept, Keith Tidball originated the term “urgent biophilia” to describe the intense need that arises post-disaster to connect with nature.
What the research team saw happening at the Beach 41st Street garden — between the gardeners and community and green space — was a living enactment of urgent biophilia. As they worked to restore the gardens, they were at the same time restoring themselves.
What we often miss in the media is the full scope of the damage that remains in the aftermath of the immediate aftermath of a storm. We know that recovery extends far beyond reconstruction and restoration.
But if our communities are to heal fully following natural disasters like Sandy, Harvey, Irma, Maria — and the countless future storms that are sure to arise in the coming weeks, months and years, we can’t ignore our green infrastructures. They are, without a doubt, essential to our well-being.
This guest post is by film maker Alden E. Stoner, who is also a board member of the nonprofit TKF Foundation.
This year, the Pacific Northwest saw an extraordinary fire season, with approximately 35 fires raging in Washington, Oregon, and Northern California by mid-September. While there is an immediate knee-jerk reaction to fires as entirely negative, wildfires are in fact a very natural part of the life cycle of forests. In addition to removing undergrowth so sunlight can reach the forest floor and new plants can grow, some plants, such as the lodgepole pine, even require fire to germinate and sprout.
What is so unusual about this year’s season is how long it has lasted: a full seven months. An unusually dry summer in a region known for rain, combined with a strong ridge high pressure that settled over the Pacific Northwest heating air and blocking storms from entering, resulted in dried-out plants and created the perfect environment for fires. In 2017, we have already spent more in national funds to combat the fires than in any other year on record, and the year isn’t yet over.
Similar to the hurricanes battering the East Coast this season, these events would be considered normal individually, if it were not for the acceleration of their natural cycles, creating increased numbers that are larger in scope. Looking at the total picture, the acceleration of these cycles is where we can see the inevitable consequences of climate change at work.
Living in Seattle, I have seen the effects of these fires firsthand. Getting up one morning this summer after having left the window open overnight, I went into my dining room and discovered that the wind had covered it entirely with ashes. Despite not being exposed to an active fire, the visible effects continued to blanket our city. And it’s not just the visible effects. Ash and smoke particulates in the air can cause breathing problems, especially for sensitive populations including those with heart and lung diseases such as asthma. Though fires may not be blazing downtown, they are have impacted the lives of everyone living in the Pacific Northwest and beyond.
Even if you don’t live in the Pacific Northwest, the fires are affecting you too, though you may not know it. The ash and smoke from the fires are not just settling on our cities, but also being lofted into the atmosphere and spreading around the globe. In this map created by NASA, you can see the ash and smoke from the Pacific Northwest fires drifting across the earth, reaching as far as Europe and Northern Africa. And due to their carbon gas emissions, the wildfires themselves contribute to accelerated climate change worldwide. While climate incidents like these can be “out of sight, out of mind” for those not actively experiencing them, the earth is a closed system: climate incidents that impact some of us, impact all of us.
So with climate change here to stay, how can we mitigate its impact to make our cities and dwellings safer? Landscape architecture can provide solutions to some of the problems posed by climate change. For example, better urban design can help reduce the sprawl at the intersection of urban and natural space, which is now in the most in danger of devastation from wildfires. For those already living at these intersections, landscape management of individual properties can help mitigate those hazards.
One such solution is to create a “defensible space” around homes at these intersections. These spaces create a barrier to impede wildfires from reaching homes, room for firefighters to maneuver if needed, and prevent fires in the home from spreading into the wild. Defensible space tactics can include reducing plant fuels around the home, incorporating fuel breaks such as gravel, and ensuring that all trees are cleared to 6-10 feet off the ground.
Careful selection of plants, too, can have an impact at these intersections. Plants that shed minimal amounts of leaves and needles provide less fuel for fires. Trees with low resin and sap content are also considered less likely to burn. Finally, native plants may be more fire-resistant or fire-adapted than non-native species. Over the last 30-40 years, we have gained an increased understanding of the environmental importance of using native plants in landscapes. But with climate change, we must also plan for a “different kind of native,” selecting plants with an eye towards the future, as current native species may not thrive in the environment as it changes.
This is where research and forward-thinking are most critical. Greater focus and funds towards researching the anticipated effects of climate change on an area allows us to plan for “new native” species that will thrive in their changing environment.
We must call on national agencies managing resources to do so with an eye towards the future, conducting research and careful planning to ensure that our natural resources and our built environments are protected. While the effects of climate change are inevitable, what matters now is finding ways to adapt to these new circumstances. You can see great work being done by the National Park Service in this area, preparing our natural treasures to survive and thrive in a world of accelerated natural cycles.
Tackling the problems posed by climate change can be overwhelming, but humans are highly adaptable species, and there are measures we can and should take to protect our future. That’s why the American Society of Landscape Architects (ASLA) has convened a blue ribbon panel of multidisciplinary experts to create innovative solutions that will make our cities and inhabited spaces climate resilient. The report will provide comprehensive public-policy recommendations for using resilient design to combat climate change. Learn more about how we’re developing policy recommendations to safeguard our cities and natural resources for the future.
This post is by Vaughn Rinner, FASLA, immediate past president of the American Society of Landscape Architects (ASLA) and a landscape architect with 40 years of experience.
In 2015, Los Angeles Mayor Eric Garcetti launched the city’s ambitious 20-year sustainability plan, which calls for increasing water conservation, generating renewable energy, achieving zero waste, investing in mass transit, and revitalizing the Los Angeles River watershed. Two years later, the city has already made great progress, but some of the big goals seem perhaps out of reach. For example, one is to reduce the urban heat island effect more than any other city in the U.S. — three degrees just within two decades. Currently, Los Angeles is about 40 percent rooftops and 20 percent roads. A new cool roof ordinance requires reflective roofs on new development and there are also tests underway to create cool pavement. The city also has goals to increase the tree canopy, and 18,000 trees were planted in 2016. Do you think these strategies are enough?
Our mayor is pretty incredible with his ability to articulate a road map towards being more sustainable. For a long time, landscape architects have been the voice for being thoughtful about water, drainage, and stormwater runoff. We’re happy to hear our political system is now actually enforcing, documenting, and requiring measures to manage water and fight the urban heat island effect. We can be strong advocates, but it’s sometimes hard to convince our clients of something that is more expensive. Now developers are being asked to step up to the table through enforceable obligations. As a community, landscape architects are happy about these efforts and really support the Mayor’s road map.
Los Angeles has already reduced per capita water use by 20 percent, meeting the 2017 goals. Eventual goal is 25 percent by 2035. In the city’s green building code, there are now water budgets for landscape irrigation, new incentives to remove turf in favor of residential gardens, and free recycled water deliveries for landscape use, along with millions for green street projects. Do these water goals go far enough? What else could be done?
This is a tough question for Los Angeles, because we always talk about the physical landscape, but the cultural landscape is also important. The whole dream of the backyard and the lawn is part of our culture. It’s really a culture that was described in the ‘50s and ‘60s through movies. In Hollywood, everybody had a front yard and backyard. The lawn was the default landscape.
We’ve made great progress to collectively redefine what the aspirational landscape is — it may no longer be a lawn and palm tree. It may be the beauty of the Santa Monica Mountains. Our native landscape has this inherent appropriateness and generates an emotional connection. We have been working really hard to replace the lawn. And if we can achieve that, it will be a huge step towards achieving these ambitious water goals. We’ve been irrigating grass for the last 50 years. We really need to change cultural expectations.
By 2035, L.A. seeks to add more transit infrastructure than any other city. The city seeks to pair this infrastructure with transit-oriented development. The plan calls for expanding zoning capacity and key transit nodes. How do you see progress going on that front?
Everybody in L.A. is really excited about this plan. We just moved our office to the Expo line. We’re right at the Crenshaw Station stop, and the Crenshaw Station is going to be the line that links LAX, our airport, with LACMA and Hollywood.
L.A. has been really behind in public transportation. Everyone is excited about the multiple new lines being built. We don’t have enough mass transit. Transit oriented developments are certainly going to change the face of the city, because they include higher-density floor area ratios (FARs), which help support new village neighborhoods. These developments will make the city more walkable and livable, because people will have these mini-centers around each station.
Looking ahead to 2035, the potential change created by autonomous or driverless vehicles is just wild. I went to a event sponsored by the Mayor’s office, where I was so proud to hear them conducting research on how our city form could change if we maximize transportation systems with driverless cars. Some of the predictions and studies on how L.A. could change are really astounding. We’re talking about maybe taking one freeway lane offline or creating green spaces by potentially eliminating a road lane. Can we transform them into greenways? Can we decommission parking lots because we don’t have much need for cars to be parked for eight hours while somebody is at work? Autonomous vehicles will change the character of Los Angeles.
By 2035, Los Angeles also wants all trips made by walking, biking, or transit to be 50 percent, up from 26 percent today. Measure M, a ballot measure that passed with 70 percent of the vote, will use a half-penny tax to raise $120 billion over the next 40 years for mass transit and bikeway projects. Los Angeles also launched a regional integrated bike share system plan and has set up more than 65 stations and a thousand bikes. Do you think this vision will come together? Will Angelenos bike share to the subway? Will the complete street infrastructure be there? I’ve heard there are neighborhoods that still don’t have sidewalks, let alone bike lanes.
There is great potential to achieve these goals. The basic urban form of Los Angeles are these village centers. We have a very disperse urban pattern. If you look at Boston and other cities, there’s a symmetrical layout, a center city with suburbs. We have a dozen or two dozen village communities between downtown and the West Side. As people are encouraged to use bikes and walk more, the village form of land use will help realize that.
The city also wants to ensure that 75 percent of Angelenos live within half a mile of a park by 2035. The past seven years the city has added more than 35 parks covering 16,000 acres, including your firm’s Grand Park downtown, which brought much-needed green space. Is the city on track for this ambitious goal? Does the 50 Parks L.A. Initiative, which assists underserved communities, have enough funds? How can the city ensure everyone benefits equally?
Los Angeles has a disparity in terms of where parks are located. There are some well-served communities and some underserved ones.
East L.A. and South Central do not have the kind of park density that they do in the Valley or other locations. It’s really hard for the city to acquire new land and buy space for parks. The problem is if you have a park desert, how do you find space there?
There have been examples of decommissioning public space and having communities take over ownership, at least as far as park development. For example, weird pieces of land next to freeways and other kinds of public spaces can be decommissioned and given to community groups. It’s a way of creating parks in neighborhoods without empty spaces.
There are also ambitious efforts underway with the L.A. River, and the plan Mayor Garcetti calls restoring 11 miles of the river, making accessible all 32 miles in the city by 2035. What do you want to see happen? How can the city ensure the revitalization doesn’t create a new High Line and become an agent of gentrification?
The L.A. River is on everybody’s mind. People have been working passionately on it for a long time. The first goal is to make it a great circulation system for biking and moving through these different regions. Any new projects along the river have to build in bike lanes and pedestrian walkways along the river. What’s important right now is zoning that allows for greater density along the river. If we can create more dense villages along the L.A. River, then we’ll see a built-in park system for these villages and good connective tissue besides the roadway network.
There’s a whole contigency who wants to return the L.A. River to a natural form, a landscaped waterway. In some places, it may be possible and still maintain the flood capacity, but I don’t think it needs to be done everywhere. I look at the land art movement. They had very architectural spaces that were really beautiful to experience. We need a whole series of solutions over the course of the river that also address the hydrological issue of maintaining the flood protection system. It doesn’t need to be all the same.
Gentrification is a big problem. Think of all the residential communities around the L.A. River that are going to suffer, because it has historically been viewed as an industrial landscape. Now, it’s going to transform into this positive, landscape-driven set of places. All the communities currently around it may be pushed out, so how we mandate keeping existing people in place through affordable options is going to be essential.
With your firm’s work at the Pete V. Domenici U.S. Courthouse in Albuquerque, New Mexico, your firm has demonstrated its commitment to sustainable design. The project was an early Sustainable SITES™ Initiative (SITES®) pilot project. So looking big picture, how can a sustainable, ecological landscape approach like you demonstrated in that project be applied to Los Angeles? What would an ecological Los Angeles in 2035 look like?
The most important thing that we learned with the Domenici project and the SITES® program is the critical need for documentation and ongoing monitoring, so you can really understand how a landscape is performing seasonally and over time. If we remove lawns and instead use native plants across the city, it’s going to cut down on irrigation.
Landscape architects need to become more proficient at quantifying every drop of water and being able to predict how new landscapes will perform. It’s our responsibility to go back and monitor landscapes, so that we have a database and can understand how water is being used.
While high-profile urban tree planting campaigns like New York City’s get a lot of attention, most U.S. cities have experienced a decline in their urban forests, with a loss of about 4 million trees each year, or about “1.3 percent of the total tree stock.” The Nature Conservancy builds the case for recommitting to expanding our urban canopies for health reasons, instead of just letting them slowly diminish.
The many benefits of trees are well-documented: they clean and cool the air, combat the urban heat island effect, capture stormwater, mitigate the risk of floods, boost water quality, and, importantly, improve our mental and physical health and well-being.
According to the report, the U.S. Forest Service and University of California, Davis found that “for every $1 spent in Californian cities on tree planting and maintenance, there were $5.82 in benefits.” Another study found that for every $1, benefits ranged from $1.37 to $3.09.
In particular, urban forests can help catch harmful particulate matter in their leaves and reduce “ground-level ozone concentrations by directly absorbing ozone and decreasing ozone formation.” High levels of particulate matter and ozone can trigger asthma and cause other respiratory problems. Planting trees to deal with these issues in New York City alone could result in $60 million in health benefits annually.
Researchers are more closely examining how trees fight air pollution. In Louisville, Kentucky, Green for Good is now testing a “vegetative buffer” at the St. Margaret Mary Elementary School designed to filter the particulate air pollution coming off a nearby heavily-trafficked roadway. Initial results show that “under certain conditions, level of particulate matter were 60 percent lower behind the buffer than in the open side of the front yard. Among the health study participants, immune system function increased and inflammation levels decreased after planting.”
A Harvard Nurses Study found a 12 percent reduction in all-cause mortality for those who lived within 250 meters of a high level of greenness. And an exciting study now underway will look at 4 million Kaiser Permanente members in Northern California with the goal of determining if there is a relationship between healthcare use and the proximity and amount of nearby tree canopy.
Despite all the great research, the news still hasn’t reached the general public or even arborists. This is reflected in the fact that average U.S. municipal spending on urban forestry has fallen by more than 25 percent since 1980, to around $5.83 per urbanite today.
If the 27 largest American cities instead reinvested in their urban forests, “planting in the sites with the greatest health benefits (the top 20 percent of all potentially plantable sites in a city)” the cost would be around $200 million a year. Maintenance funds would also need to increase. The total gap between current realities and this needed reinvestment in our communities’ health is only $8 per person — so in a city of one million residents, $8 million.
Trees just get a tiny share of municipal budgets. But with these arguments backed by numbers, the hope is a relatively cheap investment in trees for public health — which would also result in so many gains in livability and property values — can win greater support.
Gray infrastructures made of steel and concrete, which we built to connect our physical world, are shallow or even fake constructs that are destroying the real and deep connections between human beings and nature and among various natural processes and flows. The alternative is green infrastructure, or ecological infrastructure, the construction of which can be inspired by the ancient wisdoms of peasantry.
For the past twenty years, I have tried to revive some of these peasantry wisdoms and combine them with modern sciences and technologies to solve some of the most annoying problems in today’s urban environment, particularly around water. The solutions are simple, inexpensive, and beautiful and have been applied on a massive and extensive scale in over two hundred cities in China and beyond.
Gray Infrastructure and Broken Connections
Some people may think that our world, through our built infrastructure, is more connected digitally and physically than ever before: we have Facebook and WeChat on the one hand, and ubiquitous highways and pipelines on the other. But actually the opposite is true. More than ever we are disconnected from the communities we belong to, and we have alienated ourselves from our neighbors and from those we love.
Physically, the landscapes that we inhabit are visibly interconnected: motorways connect urban and rural settlements; power lines that transport energy connect power stations to individual families; pipelines that drain waste water connect our toilets to sewage treatment plants; aqueducts that transport drinking water connect reservoirs to our kitchens; airlines that transport food connect the farm in the southern hemisphere to the refrigerators in the north; trucks that carry fertilizers and herbicides on the highways connect city factories in the east with the peasants who farm in the rice paddies in the mountainous west.
We have created a connected world, but these connections are false: the landscape matrix and its invisible processes are fragmented and disconnected. The movement and cycles of water, nutrients, food, energy, species, and people are broken. The interconnected relationship between air, water, soil, nutrient, species, and people is being interrupted, and in a harmful way, more than ever before.
Let me offer an example concerning water. Over 75 percent of the surface water in China is polluted; 50 percent of China’s more than 660 cities are facing floods and urban inundation; and over 60 percent of China’s cities do not have enough water for drinking and for other uses. The groundwater table in the North China Plain drops over one meter each year; and over 50 percent of the wetland habitats have been lost in the past fifty years.
All these water-cycle related issues that impact our cities and our landscapes are actually interconnected, but the conventional infrastructural solutions designed to solve these problems are fragmented, isolated, and single-minded: We build water treatment plants to remove the nutrients that could be used in fertilizers for farming; billions of dollars are spent yearly on the construction of concrete dikes, dams, and pipes to control floods and stormwaters, but these structures eventually produce fiercer droughts, declines in groundwater levels, and habitat loss; a thousand-mile-long aqueduct built to divert water from Southern to Northern China caused serious damage to the ecosystem in the lower and middle reaches of the Yangtze River; ornamental gardens and landscapes as well as agricultural fields are over-fertilized and all those nutrients flush into the water system, polluting the rivers and the lakes. And again, the conventional solution is single-minded – build expensive water treatment plants that need huge amounts of energy (mainly from coal burning) to operate, which in turn create more air pollution.
An alternative solution might be the construction of green infrastructure, or ecological infrastructure, which creates a deep and true connection between man and nature and among various natural processes and flows.
The Ancient Wisdom of Peasantry
The connections between peasants and their farmlands illustrate the timeless interdependence of human culture and nature. One alternative to rebuilding the deep connections between human beings and nature and among various natural processes comes from the wisdom of peasantry, of field-making, irrigating, fertilizing, growing, and harvesting, which have transformed landscapes on a large scale and sustained humanity for thousands of years.
One category of peasantry wisdom is the making of fields through a cut-and-fill action. The peasant’s approach to cut and fill is one integrated action, meaning the earthworks created for farming happen on-site, with minimum costs for labor and minimum transportation of material to or from the site. It has, therefore, a minimum impact on the natural processes and patterns in the region. This tactic has been implemented by peasants in almost all parts of the world as a way to transform their otherwise unsuitable environments into productive and livable landscapes.
The second category of ancient peasantry wisdom lies in managing water and irrigating the fields. Modern methods of irrigation used in both farming and landscaping are represented by a system of pipes and pumps that is nearly invisible. It doesn’t relate to surrounding terrain and available water resources. The peasant’s approach to irrigation is deeply rooted in natural processes and patterns. Thousands of years of farming experience have made irrigation one of the most sophisticated techniques in agricultural societies. The use of gravity to irrigate the field requires precise knowledge, and the harmony between nature and subtle human intervention can turn such a serious science into an art form, an interactive medium of community building, and even a spiritual force.
The third category of peasantry wisdom is fertilizing. It is a magical component of traditional farming and a critical link, closing the circle by reusing the materials of human living. All wastes from humans and domestic animals as well as vegetative materials are recycled into fertilizers. Such a nutrient cycle is broken in our urbanized and industrialized settings. What peasants call fertilizers are today defined as “pollutants” in our lakes and rivers.
The fourth category of peasantry wisdom is growing and harvesting. Unlike planting and pruning in gardening to create a pleasant ornamental form, the peasant’s approach to planting is focused on productivity. Planting begins with the sowing of seeds, and the management process follows nature’s rhythm as a strategy of adaptation to the surrounding climate and conditions. Again, the self-sufficient nature of ancient agricultural economies requires each household to grow diverse crops, including grains, vegetables, fibers, medicines, fruits, timber, fuel, and even fertilizer proportionately to the seasonal needs of the family, and within the limits of nature and human capabilities. The meaning of harvest goes far beyond the production of foods and products. Harvests are productive in terms of their capacity to enrich the soil, purify the water, and make the land healthy. In other words, the peasant’s fields are net producers instead of net consumers of energy and resources.
This is not to say that one should give up the comfort of urbanization and go back to a peasant’s primitive life. These essential features of peasantry illuminate the underlying basis for rebuilding the connections between nature and human desires, balancing natural processes and cultural intervention, and help us to reclaim the harmonious relationships between human beings and nature.
Revival of the Ancient Wisdom to Create an Alternative Infrastructure
Imagine what our cities would look like if we did not drain the rainwater away through pipes and pumps, but instead used the ancient wisdom of peasantry in field-making to create a green sponge in the city that retains the rain water, creating diverse habitats and recharging the aquifer. In this way, the green spaces in the city become an ecological infrastructure that provides multiple ecosystem services that regulate the urban environment to be resilient to flood or drought, allowing clean water and food to be produced right in the middle of the city. Biodiversity would be enhanced dramatically; urban residents would have a green network for jogging, commuting, and relaxing; and real estate values would increase because of the beauty of, and access to, nature! That is what we have tried to do in many cities in the past twenty years: to transform the city into a sponge city.
Imagine what our cities would look like if we abandon the high and rigid concrete flood walls and instead revive the ancient wisdom of peasantry and create vegetated terraces at the river banks that adapt to the up and down of the water flow. Ecofriendly solutions like ponds and low weirs are designed to slow down the flow of water and let nature take time to nourish itself, so that diverse habitats can be created that enrich vegetation and wild life, allowing nutrients to be absorbed by the biological processes! That is what we have done to transform the mother rivers in many Chinese cities.
Imagine what our cities would look like if the nutrient-rich (eutrophic) river and lake water could be cleansed through the landscape as a living system, in the way that peasants have recycled organic waste, instead of using expensive sewage plants to remove the nutrients. We could produce clean water and nourish the lush vegetation. Native biodiversity could be improved. We could turn recreational spaces into urban parks and, in this way, urban parks could become producers instead of consumers of energy and water. That is what we have done to transform the landscape into a living system that mediates polluted water.
Imagine what our cities would look like if the brown fields of industrial sites are recovered by the processes of nature, where the ancient wisdom of the pond-and-dyke system is adapted to create a terrain that collects rainwater (instead of draining it away through pipes) and initiates the evolution of a plant community, remediating the contaminated soil during this process. At the same time, the industrial structures are preserved as sites of cultural heritage in the city. A unique landscape is created, featuring dynamic native vegetation and a touchable memory of the past, which attract urban residents because of its beauty as well as the diverse wild life that it maintains in the middle of the city. This is what we have done in several industrial cities.
Imagine what our cities would look like if we turn some of the urban land back into productive landscapes instead of into expensive lawns or ornamental gardens, so that the long-distance transportation of food can be reduced. Let the rice, sunflowers, beans, and vegetables be grown in the city, let the sun and moon tell the time for sowing and harvesting, let the seasonal change be noticed by the urban residents, let the process of food growing be known to the young, and let the beauty of crops be appreciated! This will not only make our city more productive and sustainable, but nourish a new aesthetic and a new ethics of land and food. This is what we have done in some Chinese cites.
By reviving the ancient wisdom of field making, irrigating, fertilizing, growing, and harvesting, and integrating this wisdom with the contemporary sciences and arts, we are able to build alternative infrastructures – nature-based green infrastructures replacing the conventional gray infrastructures – that are able to solve some of the problems in today’s urban environment, particularly around water, which are difficult or very expensive to solve through conventional means. Living with nature is inexpensive and easy, comfortable and beautiful, and an art of survival.
This guest post is by Kongjian Yu, FASLA, founder and dean of the College of Architecture and Landscape and Cheung Kong Scholar Chair Professor at Peking University, and founder and president of Turenscape. He was elected a member of the American Academy of Arts and Sciences in 2016.
This article was first published in Bulletin of the American Academy of Arts and Sciences (Summer 2017, volume LXX, number 4).