Site Specific

The building industry’s best-known sustainable rating system has always acknowledged that the design and construction of a man-made structure must consider the surroundings. The earliest versions of the U.S. Green Building Council’s (USGBC) Leadership in Energy & Environmental Design (LEED) rating system included categories for sustainable sites and water efficiency at the level of an individual project–and its more recent and less narrowly focused rating system for neighborhood development has greatly expanded LEED’s purview in the selection of building sites and enhanced its role in protecting local ecology. Still, the rating system’s detailed requirements and recommendations for landscape strategies barely scratch the surface of what should be done to reverse the devastation that decades of poor design, construction, and maintenance practices have wrought on vital natural ecosystems, say many landscape architects.

While LEED has successfully increased the efficiency of buildings, observes Hunter Beckham, principal of SWT Design, a planning and landscape architecture firm in St. Louis, the rating system leaves out “many opportunities to address and improve the site.”

Recognizing this omission, the Lady Bird Johnson Wildflower Center at the University of Texas in Austin hosted the Sustainable Sites Summit in fall 2005. Approximately 50 professionals, including landscape architects, civil engineers, government employees, scientists, and academics, attended the meeting, from which grew the Sustainable Sites Initiative. Referred to as SITES for short, the initiative is a highly ambitious effort to create voluntary national guidelines and performance benchmarks for the design, construction, and maintenance of landscapes with or without buildings.

Novus International, an animal health and nutrition company headquartered in St. Charles, Missouri, earned a three-star rating from the SITES pilot program for its 9.7-acre campus renovation, completed in 2011. As part of the project, an interdisciplinary team led by SWT Design turned a barren retention pond (below) into an amenity that encourages staff interaction on terraced stairs (above) while supporting wildlife habitats.

Photos © SWT Design

Market Transformation

SITES is spearheaded by the American Society of Landscape Architects and the United States Botanic Garden, both based in Washington, D.C., in addition to the Lady Bird Johnson Wildflower Center, which was established in 1982 by the former First Lady and actress Helen Hayes to protect and preserve North America’s native plants and natural landscapes. Many other agencies and organizations, including the U.S. Environmental Protection Agency, the Nature Conservancy, and the USGBC, are supporting the effort. The initiative’s overarching goal is to establish a LEED-like rating system that will set in motion a market transformation toward sustainable landscape practices across industry sectors in much the same way that LEED did for buildings. More than 150 teams, representing projects in 34 states and the District of Columbia plus three other countries, have just completed a two-year pilot study of the SITES preliminary rating system.

“It’s about accelerating change in the market,” says landscape architect Debra Guenther, a partner at Mithun in Seattle, who contributed to the initial development of SITES and has worked on several of its pilot projects. She believes that even though the technical know-how had already existed in certain circles, the rating system integrates the information so that more people can access it and apply it to projects. “It becomes a touchstone, a resource that you can point to and say that these are the best practices agreed upon by a range of experts in the industry.”

A few of these best practices will sound familiar to those accustomed to LEED, although some of the nitty-gritty details will vary. For example, according to the SITES preliminary version, which was released in 2009, at least 95 percent of all prime farmland, unique farmland, and farmland of statewide importance with healthy soils–in addition to areas within 100 feet of a wetland–must be designated as vegetation and soil protection zones (VSPZ). In contrast, the current LEED for Neighborhood Development (ND) allows a similar farmland requirement to be met by purchasing easements on other land with comparable soils and limits new development to within 50 feet of wetlands. And LEED for New Construction (NC) does not require but will give credit to projects that do not develop buildings, hardscape, roads, or parking areas on such prime soils or within 100 feet of a wetland.

Other best practices break new ground, figuratively if not literally. While both LEED NC and LEED ND encourage an integrated design approach by offering a credit for teams with a LEED-accredited professional, SITES requires the establishment at pre-design of an integrated design team that, in addition to the client, includes site design, construction, and maintenance professionals with expertise in vegetation, water/hydrology, soil, landscape ecology, materials, and human health and well-being. The preliminary guidelines also call for a detailed assessment during pre-design of what is already on or near the site to capitalize on existing conditions and resources (and they provide an extremely thorough seven-page worksheet for guidance).

Natural Processes

Some professionals will ask why a rating system specifically tailored to landscapes is needed. SITES developers astutely nipped that question in the bud by preparing the document “The Case for Sustainable Landscapes” (available at sustainablesites.org). In addition to presenting a general discussion of sustainability and the principles upon which SITES is based, the authors introduce the critical but not well-known concept of “ecosystem services.”

The term refers to all the benefits that an outdoor environment in its natural, undeveloped state provides to humans and other forms of life–from producing food and decomposing wastes to cleansing air and water and providing recreation and respite. One of SITES’ basic premises is that any parcel of developed land, no matter its size or function, can contribute to these life-sustaining processes if designed, constructed, and maintained properly. For example, with the right soils, a backyard or commercial property can better store rainwater, thereby minimizing stormwater runoff that scours impervious surfaces along its route of pollutants, dumping them into streams. And with proper vegetation, the same land could support pollinators necessary for local agriculture.

Hunts Point Landing, a part of the South Bronx Greenway, will be open later this year. Spearheaded by the New York City Economic Development Corporation, the greenway was designed by Mathews Nielsen Landscape Architects to provide waterfront access, improve air and water quality, reestablish habitat for native plants and wildlife, and introduce alternative modes of transportation to this industrialized area along the East River.

Renderings © New York City Economic Development Corporation

Unfortunately, such ecosystem services have been taken for granted for so long that most developers typically do not put a dollar amount on them. Increasingly, however, efforts are being made to rectify this serious accounting gaffe. An article posted last April on the website of Scientific American, for example, reports that the World Bank has been encouraging countries registered for this year’s U.N. Conference on Sustainable Development in Rio de Janeiro, which took place in June, “to commit to implementing natural accounting systems alongside their gross domestic product measurements.”

Of course, protecting our environment requires not only an appreciation of the true benefits we receive from it and the actual dollar value associated with these benefits, but also an understanding of the complex, overlapping natural processes that allow these benefits to accrue. “The Case for Sustainable Landscapes” briefly outlines the “natural biogeochemical cycles” by which “water, carbon, and nitrogen move through the biosphere, atmosphere, and geosphere in a complex dance that preserves and sustains all life on the planet.” Best landscape practices require detailed knowledge of these cycles so that man-made sites can support, rather than stifle, these vital flows.

Preliminary Guidelines

To support this complex biogeochemical dance, more than 50 experts divided among five technical subcommittees (hydrology, vegetation, soil, materials, and human health and well-being) undertook the daunting task of developing an organized set of specific and verifiable strategies that could be applied to any type of site in any bioregion.

A report was released in 2007 calling for public feedback, and the development team received hundreds of comments in response. These were reviewed and incorporated as appropriate to create a document that followed the format of LEED. “We didn’t want to reinvent the wheel, nor did we want to create any market confusion, so we used LEED as a model,” explains SITES director Danielle Pieranunzi. This undoubtedly will make it easier for USGBC to incorporate elements of SITES into LEED v4, the version of the rating system slated to launch in 2013.

The SITES preliminary guidelines and performance benchmarks are divided into nine categories that address an array of issues relating to the development of a landscape project: site selection; pre-design assessment and planning; water; soil and vegetation; materials selection; human health and well-being; construction; operations and maintenance; and monitoring and innovation. In its current form, the rating system consists of 15 prerequisites and 51 credits spread out across the nine categories.

Designed by James Corner Field Operations, the 4.25-acre Woodland Discovery Playground at Shelby Farms Park in Memphis, was completed last year and earned a one-star rating in the SITES pilot program. An arbor of native woody trees and vines organizes the playground into six outdoor rooms, providing children with varied spatial and sensory experiences.
Photos © James Corner Field Operations

Prerequisites, which are considered entry-level requirements, do not generate any points toward certification. They range from “protect floodplain functions” and “preserve threatened or endangered species and their habitats” under site selection to “restore soils disturbed during construction” under the construction category and “provide for sustainable site maintenance” within operations and maintenance.

Point-generating credits are elective strategies. A project, for example, can garner 5 points if the team selects a grayfield for redevelopment, or 10 for a brownfield. And the project can accumulate 2 to 8 points if the team restores soils disturbed by previous development–in addition to fulfilling the prerequisite of restoring soils disturbed during the current construction.

To receive points, the project team must submit documentation demonstrating that all 15 prerequisites plus the selected credits have been implemented. As currently structured in the 2009 version, a maximum of 250 points are available. Projects are awarded one star if they earn at least 100 points from any combination of categories, two stars for 125 points, three stars for 150 points, and four stars for 200 points or more.

Pilot Phase

In June, SITES wrapped up its two-year pilot phase, which was designed to test the preliminary guidelines, benchmarks, and certification process across all types and sizes of projects before the rating system is finalized. To make sure the requirements of the rating system at each step in a project’s evolution could be adequately assessed within a two-year period, SITES also selected projects with different time frames and at different stages of development. (To learn about one that is almost complete–the Center for Sustainable Landscapes in Pittsburgh–see the opposite page.)

Although pilot participants were asked to submit as much documentation as possible by June of this year, the first three projects were already certified this past January. A three-star rating was awarded to the campus of Novus International’s headquarters in St. Charles, Missouri, and one-star ratings were awarded to Woodland Discovery Playground at Shelby Farms Park in Memphis, and to the Green at College Park of the University of Texas at Arlington. SITES will continue to accept subsequent documentation from yet-unfinished pilot projects as they are completed, at which point they will be assessed according to the 2009 rating system.

Feedback from the pilot phase will inform the next iteration of the rating system, which is expected to be released in 2013. Once this is available, the SITES program will officially be launched and open to any project team. Those interested in pursuing SITES certification will be required to pay a fee, although the specific amount has yet to be determined.

Word on the Ground

Comments from landscape architects working on pilot projects reveal both strengths and weaknesses in the 2009 preliminary guidelines, which are still “in a state of evolution,” stresses David Yocca–a member of SITES technical core committee and a principal at Conservation Design Forum, an ecological design services company with offices in Elmhurst, Illinois, and Ann Arbor, Michigan.

“The guidelines are excellent,” says Sarah Weidner Astheimer, senior associate at James Corner Field Operations in New York, the landscape architect on the Woodland Discovery Playground. Astheimer reports that, although her office has long maintained sustainability as an important goal, the firm’s internal approach had never been as rigorous as the process developed by SITES. She and her colleagues now use the 2009 guidelines as a tool to assess the sustainability of other projects–even those that are not part of the pilot program.

As would be expected, some of the difficulties faced by designers reflect the marketplace barriers that SITES is trying to remove. For Woodland, Astheimer was unable to identify a nursery that committed to recycled water and recycled material to satisfy a credit within the materials selection category. And Yocca reports that finding companies familiar with some of the maintenance and stewardship practices recommended by SITES–such as the use of controlled burning for native landscapes–can still be difficult in many regions.

Meanwhile, designers on several different pilot projects expressed concern that meeting the preliminary guidelines’ soil testing requirements on very large sites could cost thousands of dollars because so many tests are requested per acre. At least in this case, says SWT’s Beckham, “the scientific requirements are a little too stringent for the reality of the market.”

And more than one landscape architect felt that particular credits in the preliminary rating system were written in such a way that some projects would be denied potential points even though their strategies were environmentally sensitive. Astheimer, was surprised that, for example, while a project can earn points for replanting a stream edge, a project that purposefully and thoughtfully avoids any impact on a stream receives nothing. Similarly, Signe Nielsen, principal of New York–based Mathews Nielsen Landscape Architects, felt that Hunts Point Landing–a 1.5-acre park created along the East River in the Bronx, on a site that was once paved over and home to a coal gasification plant–was penalized on several counts. For one, the project used no wood, so it was ineligible for points associated with using sustainable wood. For another, the project’s only structure is an uninhabitable kayak storage facility, so it was ineligible for points associated with using vegetation to help reduce heating and cooling loads in habitable buildings.

Furthermore, Hunts Point Landing–which Nielsen believes is the most sustainable project on which she has ever worked–was not eligible for a significant portion of the total possible points because they call for the “maintenance, preservation, protection, or reuse of water features, plant communities, soils, and on-site materials.” According to Nielsen, at Hunts Point these elements either did not exist or were so contaminated that they had to be capped. She concludes that “ultra-urban brownfield sites are effectively penalized [by SITES] because they are wastelands to start with.”

Top diagram: A three-block section of the former Washington, D.C., canal system that more recently served as a school bus parking lot will be remade into Washington Canal Park, another SITES pilot project. The design by OLIN calls for diverse outdoor programming. Bottom rendering: A linear rain garden doubles as a stormwater collection basin. Diagram & Rendering © Olin

Civil engineer Steve Benz, who is a partner in the Philadelphia office of OLIN, a landscape architecture firm, also struggled with this issue on another urban brownfield in the pilot program–the Washington Canal Park in Washington, D.C. A member of SITES’ technical core committee, he acknowledges that the initiative to date has primarily focused on the preservation of a site’s ecological capacity, which is typically of greater significance on less developed land, rather than on the sustainable challenges and realities of urban density.

“It’s more difficult to resolve how the current SITES system works in urban settings,” says Benz, who adds that the technical committee is learning about this and other “procedural disconnects” from the pilot program and is working on addressing these concerns.

A former chair of USGBC’s sustainable sites technical advisory group (TAG) who now serves on the organization’s water efficiency TAG, Benz hopes that the pilot program will shed light on the usability and practicality of SITES. He believes that LEED has been successful in terms of market penetration because the older rating system is well understood and achievable. However, he worries that the preliminary version of SITES may attract only a small number of projects because it asks for such high performance. To appeal to the broadest possible audience and generate the greatest positive impact, he says, “this currently highly rigorous rating system may have to lower its sights a bit.”

Performance Based A Pittsburgh Botanical Garden Targets a Trio of Certifications By Joann Gonchar, AIA

The 2.65-acre site surrounding the Center for Sustainable Landscapes (CLS) at the the Phipps Conservatory and Botanical Gardens in Pittsburgh is still being installed. However, once complete, the landscape will help the 24,000-square-foot building satisfy its water needs without relying on external sources other than rainwater. Photo © Alexander Denmarsh Among the more than 150 projects participating in the SITES pilot is the Center for Sustainable Landscapes (CSL) at the Phipps Conservatory and Botanical Gardens in Pittsburgh. The recently completed building, which houses the 119-year-old public garden’s educational and research programs and administrative offices, is seeking the highest level of SITES certification—four stars. In addition, the $14.5 million project is targeting a LEED Platinum rating as well as “Living Building” status. The latter designation is widely regarded as one of the toughest green building certifications to achieve. In order to satisfy the requirements of this rating system trifecta, the design team developed a “synthetic solution” in which the 24,000-square-foot CSL and the surrounding 2.65-acre site work as one, explains Chris Minnerly, principal of Pittsburgh-based The Design Alliance, the project’s architect. The building steps down with its steeply sloping site, has its long axis oriented east-west to minimize solar gain and a thermally robust exterior envelope with a skin of wood reclaimed from dismantled Pennsylvania barns. It will generate all of its own energy with photovoltaic panels, a vertical axis wind turbine, and geothermal wells. The landscape is still in the process of being installed, but once complete later this summer, it will include water features, native plant materials, and rain gardens. The scheme will do more than merely look good, says José Almiñana, a principal at Philadelphia-based Andropogon, the project’s landscape architect. “It will perform.” SANITARY WATER SYSTEM STORMWATER SYSTEM Diagrams © The Design Alliance One of the roles the landscape will play is helping the CSL satisfy all of its water needs (except for drinking water and a few other uses) without relying on external sources other than rainwater. The building and its environs will manage stormwater and treat wastewater. It will put these sources to use for toilet flushing and to offset the significant irrigation demands of the conservatory’s greenhouses. Phipps’s collection of orchids, for example, will be watered with graywater (water generated by the CSL’s lavatories) and blackwater (water from toilet flushing), but only after the effluent is cleansed in a number of on-site treatment steps that include a traditional septic system and a constructed wetland containing plants such as cattails and rushes chosen for their ability to strip the water of nutrients. A solar distillation system will provide the final purification step. A separate set of systems will collect rainwater from the CSL’s green roof and the roofs of neighboring buildings, directing it to a lagoon where hydrophytes (plants that thrive when submerged in water) will help remove the small amount of impurities found in roof runoff. After UV treatment, the water will be allowed to infiltrate into the ground or will be stored in cisterns for various non-potable uses on site. When completed, the lagoon will support full aquatic environments, providing a habitat for fish and insects. The lagoon, along with the constructed wetland, will transform the normally hidden, workaday processes of stormwater and wastewater management into landscape amenities that are completely independent of freshwater sources.

Learn At Your Own Pace:

You can take this course and follow along at your own pace. Speed up, slow down, or stop now and finish later. Click "Take the Course Test" to go straight to the test and earn your credits. You'll know immediately if you have earned credits and you will be able to print out your certificate of completion instantly.

Learning Objectives

At the end of this course you will be able to:

Explain the goals of the Sustainable Sites Initiative (SITES) and discuss why a rating system specifically tailored to landscapes is needed. Outline the structure and requirements of the current version of SITES. Explain the concept of ecosystem services and describe how a landscape can provide such services. Discuss the strengths and weaknesses of the current version of SITES.

This course was approved by the GBCI for 1 GBCI credit hour(s) for LEED Credential Maintenance.

Course Outline:

This course is a presentation designed to earn you 1.00 AIA/CES Learning Unit. Use the onscreen controls to pace the presentation to your liking, and then click "Take the Course Test" to take the exam for this course and earn your credit.

Take the test