September 10, 2006
Landscape architects and the Wildflower Center are working on creating national standards.
By Heather Venhaus
Water resources are becoming scarce and expensive. Energy rates are rising.
Intensive maintenance costs money and generates waste and pollution. Meanwhile, resource-efficient design is increasingly becoming more economical.
As land itself becomes ever more precious, outdoor spaces can be designed to deliver value in as many ways as possible, increasing land values, rewarding the senses, promoting environmental quality, and enhancing mobility. Sustainable landscapes incorporate - and balance - our desire for beautiful and functional landscapes with our need to preserve valuable resources.
Green building standards, developed by organizations such the U.S. Green Building Council (USGBC), are driving environmentally superior building design and construction in the public and private sectors. The widespread adoption of these LEED® (Leadership in Energy and Environmental Design) standards has shown that measurable benefits - environmental, economic, and quality of life - result when people have the necessary information and tools to guide their building decisions and are recognized for their commitment to excellence. By extending this approach beyond structures to the planned landscape, we can realize even greater gains.
No comparable standards exist for sustainable landscapes at this
time, yet landscapes are one of the larger expense items and a major consumer of
scarce resources. A significant part of the built environment is landscape, not
structures. The planned landscape includes large campuses, public parks and
conservation areas, private resort and recreation areas, as well as
transportation and utility corridors.
Too often, we assume that because a space is green, it is also sustainable. Unfortunately, this is not necessarily the case.
Most urban and suburban landscapes in America are green, but far from sustainable. As invasive species, water quality and quantity, and resource consumption become critical issues across America, we must rethink our approach to our landscapes.
The American Society of Landscape Architects (ASLA) and the Lady Bird Johnson Wildflower Center are leading an effort to fill the gap that now exists in our ability to evaluate the performance of these landscapes.
After discussing the need for a sustainable landscape metric independently with the ASLA and the Wildflower Center, the USGBC encouraged the two organizations to jointly undertake the initiative now called Sustainable Sites. ASLA and the Wildflower Center have finalized a formal agreement to co-lead the Sustainable Sites initiative and are currently expanding the partner base and beginning fundraising efforts.
Sustainable Sites will provide a way to measure and recognize sustainability in landscape design, construction, and maintenance. Sustainable Sites will create incentives for project leaders to utilize stormwater management, biodiversity protection, pollution reduction, and other types of resource stewardship. Ultimately, the metrics and targets identified through Sustainable Sites could be integrated with existing building rating credit systems such as LEED®. The USGBC has expressed interest in the Sustainable Sites effort and is providing valuable guidance.
Defining A Sustainable Site
A sustainable landscape requires informed and thoughtful decision making about every aspect of the site – site layout and topography, hardscape and lighting, plants and irrigation systems.
Sustainable Sites will address issues on two fronts: efficiency for the private landowner and improved quality of the surrounding environment. For each issue, there is a design solution that can maximize conservation potential and sustainability such as:
Water waste – Design plantings and irrigation for efficient water use.
Water pollution – Design slopes and surfaces to minimize stormwater runoff, replenish groundwater and use plants to capture water-borne pollutants.
Biodiversity and Invasive Species – Establish and protect areas of biological richness through the use of native plants.
Resource waste – Select healthy, long-lived plant specimens.
Energy consumption– Minimize travel distances for materials. Design sites that do not require energy intensive maintenance to remain healthy and attractive.
Soil– Design so that site work minimizes soil compaction and avoids unnecessary soil compaction during the construction process.
Air – Use plants to capture airborne pollutants, shade summer sun and temper summer heat.
ASLA and the Wildflower Center are beginning this process by creating a Product Development Committee comprised of national experts with diverse backgrounds and expertise who will identify the primary issues related to landscape sustainability. Over a five to six year period, three Sustainable Sites products will be developed with each product building on the previous work.
1. Sustainable Sites Practice Guidelines and Metrics – A compilation of current research and technology meant to solicit feedback. This “best management practices” draft document is a precursor to the Sustainable Sites rating system and will be developed in years one and two of the project.
2. Sustainable Sites Rating System – A sustainable landscape metric associated with weighted credits and a recognition system will be developed in years three and four of the project.
3. Sustainable Sites Reference Guide – A user guide with information from pilot studies that further explains credit requirements and provides guidance for creative problem solving. The Reference Guide will be developed in years four and five of the project.
These metrics are planned to integrate with existing building rating systems. The USGBC is supporting the Sustainable Sites initiative with a letter recognizing the demand for additional tools suitable to a wider array of site and project type The Council is aware of the possibility that Sustainable Sites can enhance future generations of LEED.
ASLA and the Wildflower Center anticipate that the final rating system and reference guide will be in place in five to six years allowing ample time for feedback and improvement. As is the case with LEED products, the Sustainable Sites rating system will be tested through a series of pilot projects.
"We are acutely aware that the best standards in the world will not be used if they are not cost effective for the businesses and homeowners who use them," said Steve Windhager, director of landscape restoration at the Lady Bird Johnson Wildflower Center. “Like LEED buildings, it may cost a little more initially to create a sustainable landscape, but over the life of the project it should save a considerable amount of money."
The Sustainable Sites goal is an ambitious one – nothing short of creating measurable environmental change through an increased number of sustainably designed and managed large-scale landscapes.
Throughout time and place, human activity has affected the larger landscape.
Now more than ever, our interaction with the land must respect and accommodate natural systems together with human needs, present and future.
Informed design is the key to a healthy environment and cost effective projects. LDT
About the author:Heather Venhaus, ASLA, environmental designer in the Landscape Restoration Program at the Lady Bird Johnson Wildflower Center, is project manager for a broad range of environmental consulting projects and leads specialize outreach and educational projects involving conservation development and sustainable landscape initiatives. Ms. Venhaus is a member of the Central Texas Balcones Chapter Board of Directors, Chair of the South Central Regional Council and member of the national Chapter Steering Committee for the U.S. Green Building Council.