Sustainable Landscape Construction

Minimizing the effects of construction-related activities on the environment accounts for only 21 out of a possible 250 points under the proposed Sustainable Sites Initiative (SITES) rating system. But don’t let the figure deceive you, say landscape contractors and other professionals familiar with both the SITES Pilot Program and the sustainability movement.

There are many ways to have a positive environmental impact on a project during the construction phase. As Nancy Somerville, executive vice president and CEO of the American Society of Landscape Architects (ASLA) points out, significant elements of construction appear within other SITES rating categories, including how companies protect and restore soil and vegetation, and the choices they make when selecting materials.

“Achieving sustainability can be compared to a three-legged stool,” Somerville says. “Without all three key elements working together—design, construction, maintenance—sustainable goals will not be met.”

Reusing and Recycling Materials

In St. Louis, SWT Design is managing two SITES pilot projects, one at its headquarters and another at a nearby corporate campus. “From the beginning, we have applied every green initiative possible, from sorting out metal and recycling during the demolition phase to installing a green roof, rain garden and permeable parking lot,” relates SWT’s Hunter Beckham, a registered landscape architect.

On the corporate campus, SWT incorporated the re-use of materials in its design.

• On-site rock and aggregate will be used to help establish an aquatic habitat, in addition to being used as base material for an employee walking path.
• Dead or invasive trees along a fence row will be removed, sent to a recycling facility, and eventually reused as mulch on site.
• All soil will stay on site as part of a newly developed interpretive trail and meadow habitat—saving dump truck fuel and helping reduce the project’s carbon footprint.
• Additional solar panels will offset the energy required to power Wi-Fi at a newly constructed garden gazebo, as well as offset the energy consumption of the electric car chargers and security lighting that is going into the new design.

“Twenty-one points out of 250 may not like seem like much, but it can make or break the level of certification you want,” says Beckham. Among other SITES initiatives, SWT designed-in zero water runoff for the corporate campus, employing percolation pits and clean aggregate to facilitate the performance of permeable pavers.

Protecting Vegetation

“It seems that more of our customers want us to preserve existing vegetation,” explains Andrew Key, president of Heads Up Landscaping in Albuquerque, NM. “In a recent Santa Fe park project, for example, we employed significant tree protection with tree barriers, and completely avoided excavation around the canopy. When working at large housing sites, we establish appropriate parking areas ahead of time, and define those areas where heavy equipment will not be used.”

The preservation rules don’t exclusively apply to vegetation either, says Key, a LEED GA (Green Associate). At one recent project, a resident prairie dog was relocated to make way for new construction.

In Albuquerque and other parts of the Southwest, water conservation is a big issue. “We harvest rainwater on many sites,” Key points out. “Cisterns are not new. In fact, their use dates back more than 2,000 years. What is new and exciting is the technology that connects the saved water to an irrigation system.”

In addition to water, vegetation needs the right soil conditions to prosper. Although his company is primarily maintenance-oriented, Pacific Landscape Management president Bob Grover has plenty of opportunity to practice sustainability on large-scale renovation projects.

“We inherit many properties that are environmentally unfriendly,” Grover says. “Soil is often poor and compacted, to the extent that we have to free it of construction debris, add topsoil, and amend with organic material. Good soil allows plants to be more tolerant and forgiving in less than perfect growing conditions.