Net-Zero Park Design


John “Bill” Taylor, ASLA, of Carol R. Johnson Associates, and Mark Walsh-Cooke and Tom Kennedy of Arup, gave a talk on “The Next Generation of Net-Zero Park Design” at the 2011 ASLA annual meeting.

Problem: the earth’s resources are finite. The amount of usable freshwater, air, and, of course, oil, make up a very small amount of the planet. And, with the population growing, scarcity is bound to increase. Complicating matters, climate change is real. We will continue to see more flood events as the amount of rain is concentrated in fewer, stronger storms. More and more, our lives will be interrupted by unpredictable weather patterns. Tom Kennedy with Arup asked, “Where do we draw the line?”

“Net-zero” parks may be part of a global effort to deal with these changes. Bill Taylor, a landscape architect with Carol R. Johnson Associates, said that “the next generation of parks will be part of a massive urban and regional retrofitting.” Net-zero is a term used to quantify sustainability by paying close attention to a project’s impacts and resource consumption – usually in terms of water, carbon, and energy. When it comes to designing net-zero parks, however, there are more questions than answers. How is net-zero defined? According to Kennedy, net-zero is a lot like the term “sustainability” in that there are almost as many definitions for it as there are references to it. For landscape purposes, should net-zero refer to operational or lifetime costs? Does it involve offsetting carbon or energy expenditures? Does it consider the carbon impact of deliveries made to the site, or of importing water? “Net-zero is not really well defined yet,” said Kennedy. He proposes that while the definition is flexible, one should decide on their own definition of net-zero early on in a project’s lifespan. 

Taylor indicated there has been growing momentum around net-zero concepts in parks. Some precedents for net-zero park parameters may be found in New York City Mayor Bloomberg’s PlaNYC and his Parks department’s “A Plan for Sustainable Practices within New York Parks.” In addition, the National Park Service has recently declared their intention to focus on energy efficiency in future projects, avoiding the use of any fossil fuels where possible. Taylor also pointed to environmental concerns abroad. A recent article published by Harvard Business School asserts that over $500 billion dollars are projected to be spent on building “environmentally-sound” cities from scratch over the next decade. 

Several examples from practice were used to describe components of net-zero park design. Shams, in Dubai, which is to be located on a man-made island, is an example of “net-zero passive cooling of the public realm.” The design promises to use passive cooling to lower ambient temperatures by 4 to 7 degrees C. This is accomplished by creating 75 percent tree canopy, lowering the park level by 8 meters below surrounding streets, using cold deep sea water to flush canals that run along pedestrian corridors, and by surrounding the park with air-conditioned retail shops that exhaust cool air into low-lying areas.  The temperature difference between the air and the cold water canals will also enable heat exchangers to be used to cool surrounding buildings. Taylor acknowledged that irrigating trees in the public realm with water from desalination comes at a high energy cost. 

Another Central Park, this one in New Songdo City, South Korea, demonstrated rainwater harvesting strategies that would result in no civic water being needed for irrigation. A Jack Nicklaus Golf Park was used to demonstrate a low-tech solution to maintaining water level in the site’s ponds. The ponds were retrofitted with large diameter sub-surface pipes that connect them to each other so that water is distributed evenly without the use of pumps.   

Mark Walsh-Cook with Arup then outlined a landscape modeling strategy dubbed Integrated Resource Management (IRM), which optimizes strategies for development. This came out of the need for a more rigorous planning tool to maximize resource efficiency.  As Walsh-Cook says, “We need to achieve more with less.” IRM compares different design scenarios, which includes land use percentages, and measures the results through the lens of key performance indicators such as carbon, energy, and water use. 

Ultimately, said Kennedy, we need to reduce our per-capita demand for finite resources. Unfortunately, there’s very little in the way of governance in this matter, forcing us to change our behavior. As far as landscape architects, “We are the governance.  We need to self-police, and push each other.” Perhaps this means pushing forward with defining and implementing net-zero design. As Taylor said, “our future will be determined by our involvement in setting parameters.”  

This guest post is by Dakotah Bertsch, Associate ASLA, Design Associate, Design Ecology

Image credit: Shams Park / Construction Week

Cleveland Gets Serious About Fixing Its Problems


Facing continued economic decline and an ever-shrinking population, Cleveland, which has some of the highest foreclosure rates in the country, has come up with an aggressive plan to bring the city back. The new Reimagining Cleveland sustainability vision aims to reinvest in dense urban neighborhoods, build “catalytic infrastructure,” and turn vacant, abandoned lots into green open space, commercial and residential farms, even vineyards.

At the 2011 AICP Symposium held at the National Building Museum, Robert Brown, Director of Cleveland’s City Planning Commission, says Cleveland was once the 5th most populous city in the country, but is now in 44th place, with a population of less than 400,000. Over the past few decades, 86 percent of manufacturing jobs have been lost, cutting down the 223,000 jobs the city had in the 1940s. In the past five years, there have been 40,000 foreclosures, a trend, which, unfortunately, put Cleveland on the cover of The New York Times Magazine. During the same period, the city has demolished some 5,000 abandoned homes. Still, there are approximately 20,000 vacant lots, of which 8,000 are now in the city’s “land bank.” For the city, the primary challenge is how to retain an urban form while losing half of its population. The city sees mixed-use development; “catalytic infrastructure;” green open space, urban agriculture, and greenways, as key to dealing with these immense challenges. 

Development is to now be “concentrated in stronger areas.” To decide what these areas are, the planning commission undertook a lengthy mapping process and identified “walkable urban areas,” town centers like downtown, with its comedy clubs, cafes, restaurants, and shops. There are also efforts to revitalize the city center with a new “medical mart,” a one-stop medical facility, which will be linked to rebuilding the city’s older convention center. Nearby, Ohio’s first casino will open in an abandoned department store, all in an effort to increase people density, and bring in more restaurants and stores. “We want to get people on the streets.” Neighborhood arts districts, which Brown said “work much bettter in older urban cores,” are also key areas for investment, along with “live-work” districts in these communities. One former printing press now provides housing for artists. Other areas targeted for investment: Cleveland’s lakefront, which has been cut off by freeways and railroad. On the lakefront, there’s a new mixed-use development.

Cleveland sees bus rapid transit (BRT) as catalytic infrastructure and has invested $200 million in bring fast bus service and infrastructure to the central Euclid Avenue. There’s 4.5 miles of dedicated BRT lanes, 36 stations, 4 miles of parallel bike lanes, and new streetscapes and public art. Like many cities that have put in BRT (see earlier post), the results have been dramatic: Brown said the new system and streetscapes have led to $4.3 billion in new development, with 11.4 million square feet of new building space. Along this corridor, there’s mixed-use and mixed-income developments, including “supportive housing” for homeless, along with a new Museum of Contemporary Art. 

One new infrastructure project, the “Cleveland Opportunity Corridor,” will create Complete Streets through vacant, underutilized neighborhoods. Brown made a point of saying these “weren’t freeways” but will include bike paths, sidewalks, and green infrastructure. Another will create a new path under the freeways so there will be easier access to the beaches from neighboring communities. Also included in those plans are new multi-use trails and a lakefront development.

For the land that has “no market for development,” Cleveland is starting to think more creatively. Brown said the land will be used for green infrastructure, soil remediation, urban agriculture, or renewable energy. Much like Detroit, another large-yet-shrinking city (see earlier post), Cleveland is putting its natural resources to work in an effort to improve health equity throughout the city. As Brown noted, the average life expectancy within parts of the city is 64 years, while 88.5 is the average lifespan for residents in wealthier suburbs. Brown said about half of the difference is due to “diet and exercise.”

To “water our food deserts” and provide healthier food alternatives, Cleveland has totally revamped its codes on urban agriculture. Vineyards, orchards, and bee hives are now acceptable, along with small-scale and large, commercial urban farms. One 6-acre site is farmed by refugees, while a 26-acre “urban agriculture innovation zone” is in the works with USDA and local universities acting as key partners. One 5-acre indoor, worker-owned cooperative greenhouse will be put up in a low-income neighboorhood in an effort to create green jobs. Farmer’s markets are sprouting up everywhere.

In some areas, new rules enable urban gardens and also prohibit other uses, meaning that some land can only be used for urban gardening. Chickens, ducks, and rabbits (up to 6) are now permitted. For spots with further set-backs, gees, roosters, turkeys, and even pigs, sheep, and goats are now allowed. New ordinances mean that the “principle” use of some residential areas can be farms, with farm stands for selling produce and composting. There are also smart incentives: Like Detroit, Cleveland now offers to lease vacant land from its land bank for $1 if the tenant agrees to create and maintain a commercial urban farm (see earlier post). These farmers can get $3,000 to buy seeds, fertilizers, and equipment. Other pilot projects focus on applying phytoremediation to brownfields (see an animation) and introducing native landscapes. The goal is to ensure every Cleveland resident lives walking distance from a community garden. The city is also going to start using “health impact assessments” to measure the impacts, if any, of all their re-zoning efforts.

Explore Reimagining Cleveland’s growing list of innovative projects.

Image credit: Chateau Hough, Cleveland / Reimagining Cleveland

Green Infrastructure Means Jobs


At a packed briefing on Capitol Hill, an official from a regional wastewater management authority, a New York-based landscape designer, and the head of a niche-yet-growing green infrastructure engineering firm made the case that green infrastructure means more jobs for skilled designers and engineers as well as less-skilled maintenance crews. The meeting, which was organized by American Rivers, the American Society of Landscape Architects, the National Association of Clean Water Agencies, and the Water Environment Federation, was set up to show how green infrastructure can create more “permanent” local jobs while improving water quality and the environment.

Jeff Egar, Executive Director, Water Environment Federation, said the E.P.A.’s latest report to Congress on the country’s water quality clearly states that stormwater runoff is a “major source of water pollution.” As an example, the Chesapeake Bay is “still impaired because of runoff.” Also, the “dead zones” in the Gulf of Mexico continue to grow due to unabated runoff and overflow problems coming from delta communities upstream. Within cities, the issue is runoff that taxes systems and leads to overflow: older, combined sewage and stormwater infrastructure can be easily overcome by storms, which leads to flooding, with raw sewage pouring into rivers. This is one reason Washington, D.C. is investing billions in a new “large water storage tunnel.” Unfortunately, D.C.’s solution is “not holistic,” and doesn’t take into consideration the capacity of green infrastructure, which includes green roofs, rain gardens, bioswales, and bioretention systems, to catch rainwater where it falls.

Still, there are signs some local governments and wastewater utility authorities get it: “the enforcement community is slowly showing signs of acceptance.” He also pointed to his own projects when he was at a wastewater authority, which involved rebuilding a stream and creating “constructed wetlands” to deal with excess runoff, which ended up saving his district huge amounts of money.

Regulations Can Be Opportunities If You Are Creative

Ted Scott, Executive Vice President and Founder, Stormwater Maintenance, said there’s been a paradigm shift towards green infrastructure. Oils, greases, chemicals, and actual bits of old bottles and trash transform street stormwater runoff into a toxic stew. “Urbanization really equals pollution.” In the past, engineers have used “efficiency engineering,” which creates grey infrastructure that is “out of sight, out of mind.” That approach will no longer work considering a “plastic bottle you throw on the street in New York City now ends up in a huge garbage patch in the middle of the ocean,” said Scott (see an earlier post on the massive garbage patches.) Not only does runoff and trash spoil the maritime environment, they’re also now a public health issue for those in these urban communities.

Thirty years of research on green infrastructure systems has led to new knowledge. “Retention basins aren’t effective; they just push pollution downstream,” argued Scott. Permeable pavements, green roofs, bioswales — “distributed small-scale practices” — are far more effective than large ponds. To embed green infrastructure, then, there also needs to be a shift in land-use, with denser areas for development and lots of open space and dedicated areas for natural stormwater mitigation systems. These can now be “amenities, instead of hidden out of sight.”

Scott says while these systems have been in use since the early 90s, but it was really just in 2000 that he started to see green infrastructure projects take root. And even then, “many developers have resisted the changes.” In Maryland, when the state simply recommended these practices, few were doing it. Now, with the 2009 requirements mandating green infrastructure use on every site, we are seeing “urban micro-habitats” taking shape.

With the new rules, labor has shifted as well. In the face of more regulation, “cookie-cutter” solutions don’t work. “It takes creativity to get cost savings.” As a result, “landscape architects and more creative-minded engineers who don’t think linearly” are becoming more prominent. Maintenance has also changed. With more landscape design work, there’s more people and less equipment. “There’s been a move to landscape-based contractors, which provides more opportunities for unskilled labor.” Overall, Scott says his business has boomed as a result of new green infrastructure regulations. In an economic downturn, his employees are up 417 percent, revenue is up 540 percent, and profits have increased nearly 400 percent.

Demand Grows for Green Infrastructure

Tricia Martin, ASLA, WE Design, and president of the New York chapter of ASLA, sees growing demand for green infrastructure solutions. As a result, this has led to a shift within the landscape architecture community. Her small design business, which she owns with her husband, now integrates green infrastructure into most urban sites she works on. For Phoenix House, a program that educates youth in the city, rain barrels combined with comprehensive site system helped the non-profit save on water irrigation costs. The site itself was also built by the students in the program as part of a “green jobs training program.”

New York City is “plagued by polluted runoff” and overrun from combined sewer systems, which ends up in the local rivers. In fact, she said right now “80 percent of rain events result in sewage entering the rivers. This is totally unacceptable.” However, Martin likes that NYC is thinking big on stormwater management, with its new green infrastructure plan modeled on Philadelphia’s innovative program. The goal of NYC’s plan is to cut 12 billion gallons of stormwater runoff by 2030, a 40 percent reduction. Part of the plan involves converting 10 percent of the city’s impervious surfaces into permeable ones.

One project Martin is working on is the Brooklyn Greenway, a 14 mile bike and pedestrian path that is a “template for future green streets” in the city, and a “top priority” of the city government. Her firm is adding in “infiltration basins” around street trees. “These are basically bathtubs with plants.” The greenway is expected to the “spine of the system,” and provide a “methodology for the city” to follow for other green streets. Her work on the broader greenway neighborhood plan has involved “mapping steets and sidewalk widths,” figuring out where the opportunities are for green roofs on large institutional buildings, and identifying nearby schools, which can be used for educational green infrastructure. She wants to leverage capital improvement projects coming up and use those opportunities to retrofit existing streets. 


Martin argued that because of their interdisciplinary nature, green infrastructure projects are “challenging and fun.” These projects “mean more jobs for landscape architects, which means more jobs for engineers, horticulturalists, scientists, and maintenance crews.” She added that it’s not “about just doing good, but making good economic sense. We can’t afford big wastewater treatment plants anymore.”

Cleveland Creates a Green Infrastructure Index

While Philadelphia and New York City have gotten all the press on their big green infrastructure plans, Cleveland has been quietly moving forward with its own innovative program. Kyle Dreyfuss-Wells, Manager of Watershed Programs, Northeast Ohio Regional Sewer District and Chair, NACWA Stormwater Management Committee, said Cleveland’s approach represents “regionalism in action” because they’ve taken a broader view of the watershed. She pointed to examples of flooding and erosion, and how some homeowners have even tried to solve the problems on their own by devising railings to hold back collapsing soils. She said those homeowners were facing a losing battle because the source of flooding and erosion is “upstream, it’s from all those impervious surfaces” across the region.

For Dreyfuss-Wells, grey and green have to go together. With $3 billion in investments planned over 25 years and an annual stormwater management budget of just $38 million, every piece of green infrastructure “must add value.” So, the city mapped out and targeted all the overflow zones, creating a “green infrastructure index.” Some of these green zones are vacant lots, which have been “repurposed” through the addition of bioretention basins. Other more urban sites still in use get new bioswales and rain gardens. In one example, the Collonwood Recreation area, which was a vacant big-box store lot, was redeveloped as a community center, with “bioretention islands” that reduce off-site runoff to zero. She joked that “when you visit Cleveland, you’ll want to camp on some of these beautiful sites.” 

Dreyfuss-Wells concluded that these types of projects are responsible and “solve the problem, instead of moving it to another community.” Green infrastructure “supports local experts,” who can “ensure correct design and construction practices.” She urged water authorities to “partner with developers on redevelopment opportunities” from the get-go, integrate green infrastructure into current parks and large common areas, and find site-specific solutions.

Image credit: (1) 2011 Green Infrastructure Grant Project, NYC / WE Design (2) Brooklyn Greenway Map / WE Design

Developer Financed, Community Designed


A 4.2-acre park is slowly taking shape where a huge parking lot now exists on the southwest waterfront in Washington, D.C. Interestingly, the park, which is just a tiny piece of the $1.5 billion, 51-acre redevelopment project moving forward along the Washington Channel, is developer financed but community designed. Developers PN Hoffman and MadisonMarquette responded to community demands for their park to be moved up in the queue. Now part of the first phase of development, the park is getting expedited treatment, with designs completed by the beginning of 2013 and the official opening expected a few years later.

The new redevelopment along the waterfront will use a denser development strategy for the buildings and wharfs, with some 50 percent open space, said Elinor Bacon, a representative of the developers. “We will use five different landscape architecture firms. The firms all have different talents so will address different zones.” The waterfront community park, which is still unnamed, is just one of four “distinctive” public parks in the works.

Nelson Byrd Woltz and Jeff Lee & Associates are turning community input into actual park concepts and designs. Warren Byrd, FASLA, award-winning designer of CityGarden in St. Louis, said he started to understand what the community wanted during his first community meeting last December. The second community meeting then resulted in a set of very early concepts. Then, 5-6 concepts were boiled down to two through a design charrette with some 40 southwest community leaders. Listening to the group, which was separated into two teams in order to generate even more ideas, Byrd found that the community wanted to preserve the great views across the Channel, keep the 50-year old Willow Oak trees, create quiet spaces with sitting areas and gardens, and use sustainable best practices. Byrd also advised the community to extend the park up to the National Park Service waterfront promenade in order to “gain as much land as possible” and leverage the site’s natural 10-feet grade for stormwater management.

The eventual concept agreed upon by the community members (above) features an oval lawn surrounded by a pergola, with multiple paths. The lawn itself will be an “open formal green,” set amid diverse trees that will help create seasonal effects. An interactive water element will be added along one of the lawn’s curves. Shrubs will be set at a lower height for security reasons. Byrd said there may be a distinct “horticultural area” among the bioswales, rain gardens, and porous pavements (see image below). To be even more sustainable, the pergola may function as a sort of green wall or be solar-powered.

Parts of the park’s grade will be increased to 19-feet to enhance the power of the views. In addition, there will be a new pavilion closer to the access road, which, unfortunately, needs to be there for the police and fire departments and nearby condo residents. To preserve the sight lines, the pavilion may be covered in a green roof, effectively hiding it from those sitting above it. A separate children’s play area will also be added.

Carolyn Mitchell, former president of the Southwest Neighborhood Assembly and charrette participant, said “Nelson Byrd Woltz is first class. These are people of integrity.” She said community input yielded results: there are separate zones for kids and adults, and the pavilion is closer to the water. This design provides “something for everyone.” She added that Nelson Byrd Woltz was willing to go farther than the requirements of their contract in order to create something the community really wanted: a park all the way up to the waterfront. The landscape architects will now work the National Park Service to find ways to repair their broken sidewalks lining the edges of the park.

K Williams, President, Harbour Square, added that a “beautiful landscape is art, our living art,” in this case even more valuable because the community designed it. Also a plus: to ensure they sell condos, the developers are going to maintain the park, keeping it at a “very high standard,” and have agreed to do this over the long-term.

Image credits: Nelson Byrd Woltz

Review: NACTO’s New Urban Bikeway Design Guide


In an effort to create Complete Streets that are also safer for bicyclists, the National Association of City Transportation Officials (NACTO) announced the release of a new Urban Design Bikeway Guide last week. At the report launch, Janette Sadik-Khan, NACTO president and NYC Transportation Commissioner, Ray LaHood, U.S. Transportation Secretary, and Congressman Earl Blumenauer all emphasized that smart bicycle infrastructure design can not only make roadways safer for all, but can also boost economic growth, reports EMBARQ’s The City Fix

According to NACTO, the guide is designed for both urban transportation policymakers and planners and the actual designers of this infrastructure, including landscape architects and engineers. “First and foremost, the NACTO Urban Bikeway Design Guide is intended to help practitioners make good decisions about urban bikeway design.” The best practices included are based in the experience of the “best cycling cities in the world.” The authors of the report, which include landscape architects, planners, transportation engineers, and consultants in the U.S. and Europe, also conducted a comprehensive review of international design guidelines. 

The actual recommendations are broken into segments:

Bike Lanes, including conventional, buffered, contra-flow, and left-side variations;
Cycle Tracks, with a focus on one-way, raised, two-way versions;
Intersections, including “bike boxes,” crossing markings, two-stage turn queue boxes, median refuge islands, through bike lanes, combined turn lanes, and cycle-track intersection approaches; 
Bicycle Signals, including signal heads, detection and actuation, “active warning beacons for bike routes at unsignalized intersections,” and hybrid signals for crossing major streets;
Signs & Markings, with sections on colored bike facilities, shared line markings, and wayfinding signage and marking systems.

The recommendations are well-considered and most seem to be common sense. If widely implemented, they could help futher improve safety for bicyclists. This is an increasingly critical issue given more and more bicyclists, including older, and less experienced riders, are starting to commute on their bikes (see earlier post). According to some data, women may also be biking in fewer numbers due to perceived safety issues.

The real added value of this initiative may be the great Web site. Each recommendation features slideshows of images and 3D renderings, lists of benefits, typical applications, and detailed design guidance. Also useful: recommendations in the report are broken into levels: required, recommended, and optional, with different design details for each level of compliance. Lastly, there are maintenance recommendations, and lists of cities that have adopted these measures so transportation officials and designers can easily call their pals in other cities to talk about the nitty-gritty design and implementation problems.

As with any standardized design guidelines, they can be tweaked depending on location. “In all cases, we encourage engineering judgment to ensure that the application makes sense for the context of each treatment, given the many complexities of urban streets.”

Explore NACTO’s Urban Bikeway Design Guide.  

Image credit: NYC one-way bike lane / NACTO

Crowdsourcing Feedback on Public Spaces in San Diego


As the smart phone market continues to grow, more and more people are using these devices to access social networks such as Twitter and Facebook. The amount of location-based data (i.e. text, photos, video) being created everyday has created an unprecedented opportunity for landscape architects to learn more about how their projects, particularly major public spaces, are being used. In fact, the two-way communication of social networks coupled with GPS technology makes it possible for landscape architects to engage with users in real time. Social networks can also help facilitate a “community inventory” process as well as enable easier post-occupancy survey and analysis of built projects.

Throughout this year’s ASLA Annual Meeting and Expo in San Diego (October 30-November 2nd), a crowdsourcing event titled #LandarchSD will be held to demonstrate social media’s potential. However, in this case, we will use the Twitter hashtag, #LandarchSD, to harness the talent and expertise of the more than 6,000 landscape architecture professionals from across the United States and the world descending on San Diego. #LandarchSD will provide an opportunity for landscape architects themselves to collectively share their observations and discoveries about major public spaces in San Diego. In addition to creating a unique collection of information about the city’s public spaces and urban environment, sharing these insights from our perspective can raise the public’s awareness about how our profession enriches their use of public spaces and their lives.

Information will be captured through the use of mobile devices and shared by location-based posts on Twitter and the event’s Facebook page. Posts can contain text, photos, video, and more. Examples of content include statements, photos, or videos highlighting interesting design solutions or illustrating principles of good public space design in action, or comments on why users are using or not using a space and identifying opportunities for improvements.

If you are going to the ASLA Meeting or live in San Diego, we invite you to participate by using a social media application from your smartphone (whether it’s on a Android, Blackberry, or iOS browser) or your desktop computer. To participate or even just follow the event on Twitter, the hashtag #landarchSD will be used to compile the information. (For those unfamiliar with hashtags and their use, a hashtag is a word or string of words without spaces or symbols proceeded by the “#” symbol created by any Twitter user as a way to categorize messages. Hashtags facilitate finding related information or following conversation strings on Twitter. Learn more about what hashtags are. You can also just follow the hashtag.)

The event is being organized in conjunction with our education session “Social Media Strategies for Landscape Architects” held on Wednesday November 2, 1:30-3:00pm. At the education session, the panel will touch upon using social media for inventory and post-occupancy surveys and discuss the information collected through this initiative.

This guest post is by Brian Phelps, ASLA, Hawkins Partners, Inc.

Image credit: #LandarchSD

Three Years Later: California Academy of Sciences’ Living Roof Also Educates the Design Community


Three years ago the California Academy of Sciences museum re-opened in San Francisco. The original projections of annual visitors were for 1.6 million, a head count that has been far exceeded in the past three years. Some of the building’s popularity is undoubtedly due to its iconic 2.5 acre-“living roof”, celebrated in the early reviews for its innovative energy saving properties. The roof was, however, criticized for the high price tag it came with, and the unknown cost of its future maintenance. The technology used in this design is a part of the museum’s educational curriculum and it’s been the model for other green roofs since its completion. If green roofs are going to be a viable part of the infrastructure systems of our cities in the future, we need to openly evaluate what is working and what isn’t.

The California Academy roof contains enough solar panels to prevent the release of 405,000 pounds of greenhouse gases per year. The large glass canopy that surrounds the living roof contains 60,000 photovoltaic cells. The arrangement of the panels on the canopy shades pedestrians below and generates some 213,000 kilowatt-hours of energy per year.

In addition to energy savings, the roof helps cool the interiors beneath it. Those eye-catching mounts send cool air down into the open-air plaza while warm air from inside the building vents through the skylights. Sensors in the skylights gauge the interior temperatures and automatically open at a given threshold. The roof keeps the interior temperature an average of 10 degrees cooler than a standard roof would.

The 106,500 square foot green roof absorbs 3.5 million gallons of rainwater each year, a stormwater runoff reduction of 93%.

But does it mitigate the urban “heat island,” as green roof proponents promise? While studies show that expansive use of green roofs in a city can help cool air, this particular roof is in the middle of Golden Gate Park and not in an urban area where green roofs offer the most potential for heat island mitigation. Anecdotally, the fact that this living roof is irrigated year-round does contribute to lowering temperatures, both inside and around the building. And since the new building’s footprint is 1.5 acres less than the original building was, the acres returned to the site as green space help cool the area.

Even with all the advantages of the living roof, there are a few controversial items related to the project that are still subject to debate. While year-round watering contributes to cooling the building and its surroundings, the original intent was less resource intensive. Significant effort and testing went into creating a native California landscape on the roof, using plants that are indigenous to the area and that would survive its particular micro-climate. The design proposed that the plants would go dormant during the warmest months. But as long as the allure of the green roof is in its “greenness” it will be difficult to pull the plug on irrigation and the Academy misses the opportunity to educate the public that the green roof’s native plants have a dormant season.

Something for the Academy to consider: integrate semi-native, adaptive species that are evergreen and / or flower during the time when the native grasses go dormant. It goes against the “all native” approach, but perhaps this is true aesthetic of sustainability.

Also under debate is how the roof will hold up over time. Most buildings require periodic weathering and re-waterproofing. And since this is such an innovative project, it’s hard to predict the procedures that will be needed in 40 or 60 years to update and maintain the roof and building itself.

Dubbed a “high maintenance superstar” by Landscape Architecture Magazine, the living roof at the Academy of Sciences cost almost twice as much as a traditional green roof does. Typically, such roofs cost $15 – $20 per square foot versus the $28 – $35 per square foot for this living roof. With the unknown maintenance and upkeep costs in the future, the roof could continue to be expensive.

My suspicion is that much of the Academy’s green roof maintenance budget is spent pulling weeds and replacing plants. Perhaps the Academy could structure a funding program aligned with local universities (e.g. the funding grants come through the universities) offering students a chance to learn about green roof technology via a set of stewardship initiatives that could, among many things, include pulling invasive plants. This approach could free the Academy of out-of-pocket expenses and further its commitment to education.

Even with these drawbacks, the roof effectively teaches millions of people, communicating that design and sustainability matter. Its form and construction have inspired dozens of new green designs. These positive outcomes cannot be quantified by the price per square foot method. After all, the roof’s role in promoting public awareness of living roofs was part of the reason the California Academy of Sciences project was awarded LEED Platinum certification.

Gerdo Aquino, ASLA, is president of SWA, an adjunct associate professor of the Master of Landscape Architecture program at the University of Southern California and the co-author of Landscape Infrastructure (Birkhauser 2011). John Loomis, ASLA, SWA’s Sausalito office, was the landscape architect for the new California Academy of Sciences building.

Image credits: ASLA 2009 Professional General Design Honor Award. California Academy of Sciences. SWA Group / Tom Fox

Designing for Human Health


In a session at the 2011 GreenBuild in Toronto, architects and engineers discussed how cities can employ novel approaches to improve public health. Efforts to restore rivers, and also create earthquake and wind-proof buildings, can help communities become healthier, and also more resilient to population growth and catastrophic weather events.

The Value of Cleaning up Mexico City’s Rivers

Elias Cattan, Taller13 Arquitectura Regenerativa, proposed unearthing and restoring Mexico City’s network of rivers. Cattan said this project, while ambitious and somewhat costly, is crucial to “meshing our way of being with our ecosystems.” He pointed to other major cities like Los Angeles and Seoul that are planning or have already implemented major river restoration projects as models.

In Mannahatta: A Natural History of New York City, Eric Anderson shows how Manhattan looked before Europeans arrived. While it’s nearly impossible now to see the rich ecosystem that once existed on the island, in Mexico City, Cattan believes, it’s still apparent, just sullied. As a result, restoring that ecosystem “wouldn’t be a hard task.” Mexico City is a big sponge, with soil types that absorb water runoff from buildings. There are also some 45 rivers and more than 200 tributaries throughout the city. 

With this megalopolis’ “catastrophic” population growth, there’s effectively been an “ecocide.” It didn’t need to be like this. Cattan asked what the ultimate purpose of Mexico City is in nature? “What is the vocation of Mexico City?” Relaying the ideas of Richard Lovelock, with his conception of Gaia and Earth as one large living organism, Cattan said “everything in nature has some purpose.” While the “process or purpose” of Mexico City may now be in a “state of constant oscillation,” the soils and river system of the city can still offer a range of valuable ecosystem services. For example, the rivers, once revitalized, could provide clean water again. He said “the rivers here, when they are born, are clean. They only become toxic as they make their way through the urban fabric.”

Mexico City’s rivers are 80 percent clean water, 20 percent human sewage. “Rivers here are lubricants for sewage flow.” While Cheongyecheon in Seoul and the L.A. River revitalization projects aim to accomplish a lot, Cattan’s plan would combine restored rivers with different “mobility systems.” Rivers would be lined with restored wetlands filled with “native flora and fauna,” and provide an “axis for public transport.” On either side of the river, there would be Bus Rapid Transit (BRT), which Cattan sees as central to alleviating Mexico City’s major traffic problems. Also, these wetland and river systems would function as parks – something that is vitally important in a city with only 3.7 square meters of green space per person (a level far lower than the U.N.-recommended 14-16 square meters per person). However, it’s not clear whether Cattan’s plan, which he estimates would cost some $350 million, also includes a low-cost waste management system that doesn’t take rely on the rivers.

Getting Serious About Earthquake and Wind Proof Buildings

If restoring rivers are crucial to human health in urban environments so is making sure buildings don’t kill during catastrophic weather events. Moving towards the realm of buildings, Ronald Mayes and Leonard Morse-Fortier, engineers with Simpson Gumpertz & Heger, argued that no matter what level of green certification a building achieves, it shouldn’t be considered green if it isn’t earthquake and wind-proof.  Right now, most buildings, even green ones, are simply designed to protect people and don’t survive structurally, meaning all that material is wasted. Using “performance-based design” approaches, buildings can be designed to survive major earthquakes and storms.

Mayes said there’s a 60 percent chance an earthquake stronger than 6.7 will strike San Francisco in the next few years. A quake the strength of the one in 1906 would result in $111 billion in damages today. He wondered what the cost-benefit analysis is, what the threshhold is for paying extra for earthquake-proof structures. Right now, the extra cost “pay back is 3-7 years” on average.

A variety of new technologies, including “viscuous dampers, base isolation, rubber platforms” help make a 8.0 earthquake behave like a 5.5 one. Japan, with its high risk of major earthquakes, has taken these technologies seriously, building some 2,000 buildings using these approaches. In the U.S., there are just 200.

Mayes proposed a rating system or “report card” that could be posted on every building as a “communications tool for the general public.” He also called for “seismic resilience” to be adopted by LEED, perhaps as regional credits in earthquake-prone zones.

Morse-Fortier made an equally-sound case for wind-proof buildings. Right now, building codes “equal minimum standards.” In reality, trying to follow code is a “confusing process.” Still, he thinks buildings “shouldn’t fly apart in a hurricane,” meaning many developers and architects will need to go way beyond code to achieve true safety.

Making buildings wind-proof can be a costly undertaking. As a result, businesses and people need to do a cost-benefit analysis, and weigh the cost of creating a building that can survive high category hurricanes. Some buildings, like nuclear reactors and hospitals, “meet the criteria” for higher investment.

Wind can damage buildings through vibrations, “induced pressures and flows,” “windborne debris,” and “aero-elastic phenomena.” He thinks we should be able to “avoid cladding blow-out due to wind pressure.” Roofs gone missing are another avoidable problem. Furthermore, there are some types of roofs that are actually really dangerous. For example, he said “ballasted roofs” actually attack other roofs in a storm.

Morse-Fortier called on large-scale developments in windy areas to invest in wind tunnel studies. Even though these studies are an up-front cost, they help building owners figure out where they need strong structures and where they don’t. He said LEED should incentivize the use of wind-proof approaches and materials. It would have been interesting had he also discussed how green roofs perform in high-wind scenarios.

Image credit: ASLA 2011 Student Awards General Design Honor. Co-Modification Joseph Kubik, Student ASLA, Graduate, University of Pennsylvania
Faculty Advisor: Mark Thomann

Becoming Greenest: Recommendations for a More Sustainable Washington, D.C.

Washington, D.C. leadership has requested input from a range of organizations as it develops a new “unified vision” and “comprehensive framework” for a more sustainable Washington, D.C. The end goal: to connect sustainability with economic development and become the number-one, most sustainable city in North America. Washington, D.C. is currently ranked eighth in a recent Economist Intelligence Unit report sponsored by Siemens.

As part of this process, the American Society of Landscape Architects (ASLA) polled members from its Potomac, Northern Virginia, and Southern Maryland chapters and incorporated their input into a set of bold recommendations in the priority areas identified by the city government. Because the categories of recommendations will be evaluated by different D.C. agencies, recommendations are repeated when appropriate and relevant. Among them:

Energy: Reuse brownfields as solar energy farms. Through revised building codes and local tax incentives, expand use of smart tree placement and green roofs and walls. Reduce building energy use through green infrastructure. Incentivize the use of rooftop solar panels. Read research and recommendations >

Climate Change / Mitigation: Reduce total greenhouse gas (GHG) emissions by expanding urban park land, further improving bike and pedestrian infrastructure, incentivizing the growth in the number of bicycle and pedestrian commuters, creating highly walkable pedestrian-only areas, and introducing new innovative forms of public space such as parklets and underpass parks. Read research and recommendations >

Climate Change / Adaptation: Increase coverage of street trees for shade and expand use of green and cool (white) roofs in order to adapt to higher average temperatures along with more varied temperature fluctuations within the District. Improve building and landscape water efficiency measures. Develop resiliency plans for Washington, D.C.’s plant and animal life within parks and green spaces, including the introduction of wildlife migration corridors and heat and drought-tolerant plants. Read research and recommendations >

Water: Develop a comprehensive green infrastructure plan that leverages existing grey infrastructure. Use Sustainable Site Initiative™ (SITES™) guidelines to improve water efficiency measures, require the use of appropriate plant species in public and residential landscapes, and enable rainwater capture and filtered or treated greywater (and even blackwater) reuse for landscape irrigation. For stormwater management, require the use of green roofs for new buildings exceeding a minimum size. In addition, approve the use of rainwater cisterns for irrigation of green roofs and other green infrastructure. Improve the permeability of the District’s park surfaces and their ability to capture and store water. Create multi-use infrastructure, or rain gardens or bio-retention systems in District parks, turning them into green infrastructure and water treatment systems. Increase the use of bioswales near transportation systems, and add in permanent green street corridors and green alleys. Continue to expand urban tree canopy and preserve larger trees to manage stormwater runoff. Spread use of tree boxes and permeable pavements for stormwater capture. As part of a public education campaign, parks and public green space should follow the highest water efficiency standards. Read research and recommendations >

Transportation: Expand bike and pedestrian infrastructure. Create safe bicycle infrastructure. Connect the Metro system with bike infrastructure and bikeshare stations. Require secure bike parking within office and residential buildings. Incentivize the growth in the number of bicycle and pedestrian commuters. Create highly walkable pedestrian-only areas, and introduce new innovative forms of public space such as parklets and underpass parks. Read research and recommendations >

Waste: Set clear, ambitious targets and deadlines for achieving zero waste in the District and measure progress against targets. Ensure all building materials are reused in new buildings (if the materials are non-hazardous). Use Sustainable Sites Initiative™ (SITES®) guidelines for park maintenance and eliminate grounds waste generated from Washington, D.C., parks through composting. Read research and recommendations >

Built Environment: Invest in turning more brownfields into parks. Apply bio-remediation and other safe environmental remediation technologies during park development. Develop an Internet-accessible inventory of all brownfields in the city to enable easier remediation and redevelopment of derelict sites by local developers. Create a certification program for remediated brownfields to facilitate faster reuse. Invest in retrofitting older school buildings to make them LEED Platinum and also integrate green school redesign activities into school curricula. Ensure all schools apply Safe Routes to Schools design guidelines. Read research and recommendations >

Nature: Develop a biodiversity and environmental education action plan based on the concept of biophilia. Recreate wetlands along riverfront edges and reintroduce native wildlife. Reduce the mortality rate of trees and extend their lifespan by enabling them to grow in larger tree pits with structural soils and under permeable pavements. Use appropriate trees grown locally for urban forestry campaigns. Experiment with growing trees in park nurseries. Read research and recommendations >

Food: Develop a comprehensive urban agriculture plan. Evaluate all available empty lots (including brownfield sites) as potential opportunities for commercial and community urban agriculture. Develop new codes enabling local food production. As a priority, target food desert communities with high numbers of brownfields. Allow local residential food production. Develop new soil testing and clean-up requirements for growing food in former brownfield sites. Allow and also increase tax incentives for rooftop food production. Read research and recommendations >

Green Economy: Invest in bicycle and pedestrian infrastructure improvement projects to boost job growth. Use green infrastructure systems, including green roofs, to increase number of local, non-exportable green jobs. Launch a comprehensive green jobs program, training chronically unemployed and former convicts in brownfield remediation, green roof installation, and other tasks. Launch a national campaign in an effort to lure the best green talent to the District. Read research and recommendations >

Governance: Organize watershed councils at the local level and appoint ward-level sustainability advocates to help implement and align SustainableDC initiatives. Use Sustainable Sites Initiative (SITES) guidelines as a management tool for achieving high-performing landscapes across the district. Read research and recommendations >

Go to the report Web site and explore the recommendations in detail, or download the PDF version of the report.

Also, be sure to add your comments below on how D.C. can become greenest.

Image credit: ASLA 2011 Professional Design Honor Award. Monumental Core Framework Plan, Washington, D.C. AECOM, the National Capital Planning Commission, and the U. S. Commission of Fine Arts, Washington, D.C.

Neri Oxman’s Materials Revolution


At the 2011 GreenBuild, Neri Oxman, director of Mediated Matter at MIT Media Lab and one of the few who made Fast Company’s top 100 creative people list, wants to “introduce a new dimension or sensibility” into materials production. Proposing to turn the design and engineering worlds on their heads, she said we should no longer “design against an objective function, but instead design for multiple functions in one system. It’s about continuity, not repetitive, modular approaches.”

Oxman is focused on how to use design processes to “mediate between matter and the environment.” She said the natural world uses a range of principles, which is why we easily recognize so many forms. Natural objects are the result of some internal logic that generated the form. She thinks this logic can be harnessed to create building, medical, and even furniture innovations, but is still trying to figure out whether this would lead to a more sustainable future.

She used a few examples that demonstrate how nature creates forms that serve multiple functions. A chicken egg, for instance, is nearly impossible to break if squeezed at the vertical ends. This is because it needs to be strong while it’s being warmed. The horizontal edges are soft, though, and easy to crack: This is because the chick will eventually need to break through. This is a smart “material distribution strategy.”

People, in contrast, aren’t that smart when creating their own buildings and cities. “Nature has not designed buildings, habitable environments at mass scale.” (some sociobiologists may disagree with that statement). She said that biologists and architects have been discussing the ideas of architecture and ecology since Darwin released his theory of evolution. In recent years this dialogue has led to biomimetic design, a term she called “over or mis-used,” but is used to explain how to design and build using natural systems. For example, she showed images of a pine cone, and how the structure could be inverted to serve as a new can for Coca-Cola. It would hold more soda and be impossible to crush in transit. Shark skin, with its “micro-dermal teeth” served as a model for a new wall with patches that can respond to its environment. She also explored the idea of “form-finding, or discovering the form that a material wants to take.”

Within the architecture profession, she said there was a divide between the “formalists” and the sustainable designers. Formalists are primarily focused on, well, form, while sustainable designers are interested in following criteria, which usually leads to “new glass boxes that are more and more efficient.”

Also, since Mies Van Der Rohe first offered a design for a skyscraper in Chicago, the idea has been to create a form and then apply material. (However, some architects would disagree and say his skyscraper wasn’t possible without one material: steel). She said this skyscraper shows a process that hasn’t really changed for a hundred years: model, analyze, and then fabricate. In contrast, in nature, the modeler, analyzer, and fabricator are combined in one. A leg bone in a pregnant woman expands and grows denser as she puts on more weight, responding to signals from the body. Tree fibers change form depending on how much structural load is required to hold up a plant. “From trunk to leaf, it’s the same material.”

Some examples from her studio show her using natural logic to digitially fabricate forms that can serve multiple material functions. A chaise lounge is made up of just one silicon-like material broken into two types – soft and hard. Using the body to determine where the structural load would be greatest, she created a Zaha Hadid-like undulating form. “It varies its properties – it’s stiff and soft where it needs to be.” For the medical world, she said eastern medicine celebrates “continuity,” while western medicine separates everything into body zones. Using an eastern approach, she asked people suffering from carpal tunnel syndrome to create their own “pain map,” which she uses to generate a material, again, with hard and soft zones to provide both structural support and flexibility. In the realm of buildings, she wondered why concrete columns are solid all the way through, wasting materials, when they can be like bones or palm tree trunks, which are denser at the base and more hollow at the top. “We can relate to loading patterns instead of forms or ornamentation.”

Some future predictions: In 10 years, Oxman sees materials as “the new software,” and integrated into everything we do. The circuit board will be obsolete. The material itself will be smart. Materials will know how to change for its distributions. For example, buildings could have breathing skins that help modulate the interior temperature. By 2100, there will be “biofabrication and construction.” Then, one thousand years in the future, there will be “CAM-DNA.” In this example, a chair would be created out of DNA material and would grow with humans over their lifetime. Materials would think, respond, and compute things themselves. When hearing all of this, one professor at Harvard told her that the ideas were great, but the cost would be out-of control high.