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

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

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

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.