December 15, 2009 | General

Performance Guidelines For Sustainable Sites

High Point residential greyfield redevelopmentBioCycle December 2009, Vol. 50, No. 12, p. 32
The Sustainable Sites Initiative released its guidelines and performance benchmarks for site design, development and maintenance. Pilot projects are being sought to test the prerequisites and credits.
Nora Goldstein

IN early November, the Sustainable Sites Initiative released its Guidelines and Performance Benchmarks 2009, a point-based credit system that picks up where the U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED) credits effectively leave off: outside the building skin. The Initiative is a collaboration between the Lady Bird Johnson Wildflower Center, the American Society of Landscape Architects and the U.S. Botanic Garden. Since 2006, the 55 individuals who make up the Initiative’s volunteer Technical Subcommittees, Steering Committee and Executive Committee, and staff have been developing “clear and rigorous criteria for sustainable landscape design, construction, operations and maintenance,” according to the Benchmark report. “The Initiative’s central message is that any landscape, whether the site of a large subdivision, a shopping mall, a park, an abandoned rail yard or a single home, holds the potential both to improve and to regenerate the natural benefits and services provided by ecosystems in their undeveloped state.”
Kresge Foundation headquarters, Troy, Michigan
The seed for developing a credit system for sustainable landscapes was planted in 2002 when the USGBC held its First Annual International Green Building Conference and Expo in Austin, Texas. “The USGBC held its Board meeting at the Lady Bird Johnson Wildflower Center (LBJWC),” recalls Steve Windhager, Director of the Wildflower Center’s Landscape Restoration & Sustainable Sites Initiative. “My boss at the time was close friends with many on the Board and he jokingly told board members that USGBC didn’t do much outside of the building skin. The response was, ‘We are a bunch of architects. If you want something outside the building you need to do that.'”
Several years later, LBJWC had another opportunity to discuss the need for developing a comprehensive set of credits for site development and maintenance. This time, Windhager said the Wildflower Center was willing to tackle the challenge. “We were told that if we were serious, that we should contact the American Society of Landscape Architects (ASLA) because they were thinking about doing the same thing,” he says. “Heather Venhaus on our staff, who eventually became the Sustainable Site’s manager, joined ASLA’s Professional Practice Network (PPN) on sustainable design and development. It became clear that this largely volunteer effort needed a staff level commitment in order to make progress, so the Wildflower Center decided to put over half of Heather’s time into researching what it would take to develop a full-fledged credit system for sustainable sites.”
In 2005, LBJWC hosted a meeting to discuss the results of the research and an initial draft credit system that Venhaus and the PPN had developed. “This crystallized what needed to happen to move this forward,” says Windhager. “By early 2006, ASLA and the Wildflower Center were able to line up funding and were joined by the U.S. Botanic Garden in leading the Sustainable Sites Initiative. The Steering Committee was formed and by early 2007, the initial Technical Committees assigned to develop the prerequisites and credits were assembled.”

The Sustainable Sites Initiative defines ecosystem services as the “goods and services of direct or indirect benefit to humans that are produced by ecosystem processes involving the interaction of living elements, such as vegetation and soil organisms and nonliving elements, such as bedrock, water and air.” The ecosystem services that a sustainable site can “strive to protect or regenerate through sustainable land development and management practices” include global and local climate regulation, air and water cleansing, water supply and regulation, erosion and sediment control, pollination, habitat functions, waste decomposition and treatment, human health and well-being benefits, food and renewable nonfood products, hazard mitigation and cultural benefits.
“The services people enjoy from healthy ecosystems are the unobtrusive foundation of daily life,” says the introduction to the Guidelines and Benchmarks. “… Yet because these services occur largely in the background, governments and businesses don’t include them in their conventional cost accounting. In fact, people often underestimate or simply ignore these benefits and services when making land-use decisions – only to realize later how difficult, expensive, and sometimes impossible it is to replicate ecosystem services once they are lost. …. The Initiative is dedicated to fostering a transformation in land development and management practices that will bring the essential importance of ecosystem services to the forefront. For purposes of the Initiative, land practices are defined as sustainable if they enable natural and built systems to work together to ‘meet the needs of the present without compromising the ability of future generations to meet their own needs.'”
Guiding principles were developed first to provide a framework around which criteria and benchmarks could be established. These include: Do no harm; Design with nature and culture; Use a decision-making hierarchy of preservation, conservation and regeneration; Use a systems thinking approach; and Foster environmental stewardship.
Based on these guidelines and principles, Initiative staff and the committees and subcommittees worked to develop “clear and rigorous criteria for sustainable landscape design, construction, operations and maintenance.” Technical subcommittees assigned to develop the criteria and credits were divided into five elements of sustainable sites: Hydrology, Vegetation, Soils, Materials and Human Health and Well-Being. Two drafts of the guidelines and benchmarks (November 2007 and 2008) were circulated for review and public comment. Responses were reviewed and many incorporated into the final Guidelines and Performance Benchmarks 2009.
The Sustainable Sites committee members completed a series of weighting exercises to establish the ranking system for the 51 credits based on the guiding principles. This resulted in the development of a 250-point system. Levels of achievement, to be analyzed during the upcoming pilot phase, are assigned stars, i.e., One star equals 100 points (40% of total points) and four stars equals 200 points (80% percent of total).
Prerequisites and credits fall into nine categories based on the development process (possible points are included after each category): Site selection (21); Pre-Design Assessment and Planning (4); Site Design—Water (44); Site Design—Soil and Vegetation (51); Site Design—Materials Selection (36); Site Design—Human Health and Well-Being (32); Construction (21); Operations and Maintenance (23); and Monitoring and Innovation (18). To participate in the voluntary program, all of the benchmarks outlined under prerequisites for each category must be met. Benchmarks outlined under credits are optional, but a certain number of them must be attained for a project to achieve eventual certification as a Sustainable Site. The goal, according to the Initiative, was to have benchmarks that “are based on sustainable outcomes rather than on strict prescriptions and specific technology, thereby encouraging innovation, inspiring a change in thinking and providing flexibility.”
For example, the prerequisite under Site Design—Water is to “Reduce potable water use for landscape irrigation by 50 percent from established baseline.” A possible credit, worth 2 to 5 points, is “Reduce potable water use for landscape irrigation by 75 percent or more from established baseline.” Prerequisites for Soil and Vegetation are: Control and manage known invasive plants on site; Use appropriate, noninvasive plants; and Create a soil management plan. A site can earn 6 points if it minimizes soil disturbance in design and construction.
The benchmarks apply nationwide on a site-by-site basis, accommodating regional differences and the variations inherent in different site types, whether urban or rural, already developed or undeveloped. They are intended to apply to sites of new construction as well as to projects that include major renovations to an existing site. They can apply to sites both with and without buildings. The benchmarks encourage food production, community gardening and edible landscapes as potential components of a site. The Sustainable Sites Initiative created a library of case studies that illustrate sustainable landscape practices at various stages of development (see
The Archer-McNamara<br /> Blitz Build
The Sustainable Sites Initiative has instituted a two-year pilot program to help ensure that the Guidelines and Performance Benchmarks 2009 are both practical and effective as a tool for recognizing projects that incorporate sustainability at every stage of development. Specifically, the pilot program will evaluate the appropriateness of the point system and of credit weights in a variety of climate zones, geographic areas and project types – e.g., public, private, greenfield, brownfield, greyfield, urban, suburban, rural, commercial, residential, cultural/historical, small and large sizes.
The deadline for submitting applications to become a pilot project is February 15, 2010. (Applications are available at the Initiative website, Initiative staff expect to accept between 75 to 100 pilot projects, each testing a whole range of credits. For those projects accepted into the Pilot phase, there is a sliding participation fee based on the project’s landscape budget ranging from $500 for projects under $100,000 to $5,000 for projects with costs over $1 million. Projects that have achieved a level of certification (minimum of all prerequisites and 40 percent of the points) by the end of the program will be recognized as certified pilot projects.
“We are looking for projects that are in every phase of design and/or completion,” says Windhager. “Some may be a gleam in the eye and will test the early design credits because they won’t make it through construction in two years. Other projects may have been completed 10 years ago but were ahead of their time in terms of the practices they were using. These can test out the site maintenance and monitoring credits. However, every pilot needs to show how they meet all the prerequisites. We want every credit tested multiple times. Our goal is to make sure all the prerequisites and credits as they are laid out work. If they don’t we will tweak and refine them to make them workable. We also will refine the rating system as necessary.”

The interdisciplinary and consensus-based approach used to develop the guidelines and performance benchmarks resulted in necessary validation by the design, development and maintenance professions and reflected the important role they play in achieving sustainability. The dozens of scientists and technical experts that volunteered on the various committees were vetted and selected based on their expertise and professional credentials. As a result, the facilitated process was driven by science and practice from the bottom up. “This broad expertise and experience of the committee and subcommittee members contributed to making the end product very well balanced between continuing to push projects to excel and ensuring that the benchmarks actually could be attained, and together are reflective of the state of the knowledge and practice,” notes Windhager.
He emphasizes that gaining adoption of the guidelines and benchmarks has been made easier because many of the practices outlined in the credits are already in use, e.g., through low impact development concepts and existing green building credits. “We are standing on the shoulders of giants,” says Windhager. “We have compiled things that have been out there for a long time – many advocated by BioCycle, such as the ecosystem contributions of healthy soils and materials reuse and recycling. The difference is that we have developed performance criteria and a rating system around them. We have witnessed how the LEED credit system has accelerated adoption of green building practices. We anticipate the same with sustainable sites.”
All of the Sustainable Sites Initiative prerequisites and credits are being reviewed by LEED Technical Advisory Groups for potential incorporation into USGBC’S next LEED update, anticipated to occur in 2012. About 20 percent of the Initiative credits were initially derived from LEED, although many of those have been modified to better apply to landscapes. “When we started, we had hoped that the credits we developed would just get incorporated in LEED,” he adds. “At the time, we didn’t view the Initiative as a separate certification program. But as we have continued to develop the program, we have seen the need to maintain a separate rating system even after LEED incorporates some of our credits into their system. To that end, we are in discussions with the Green Building Certification Institute – the certifying arm of USGBC – to have them also handle a separate certification program for sustainable sites. For example, a park may not have building components to certify under LEED, so they can apply for Sustainable Sites Initiative certification. Some projects may want to do both programs.”

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