Philadelphia, which defines green infrastructure as anything that captures the first inch of rainwater, has new street-greening standards. The goal is to remove 50% of impervious cover in 20 years. The inspiration for the program came in 2000 from a landscape architecture professor, Anne Spirn, now at MIT, who was at the University of Pennsylvania in West Philadelphia. Spirn had ideas for the area’s renewal. “We put her in a van with civil engineers, went to a site, and she gave us a vision,” says Neukrug.
Planners also support the landscape architects’ comeback. They bring “very valuable skills to the team,” says Joe MacDonald, a senior associate with the American Planning Association.
Even engineers are warming to the idea of the landscape architect. Neukrug says it is “fun” to watch the marriage of the professions. “They are both so creative in different ways,” he says, adding that it may be a forced marriage at first, but resentment decreases as parties work together. Engineers have “secretly” always wanted to handle things differently, says Neukrug, an engineer.
Landscape architects are getting assertive. A decade ago, “we would accept the engineer’s solution,” says Jeff Zimmermann, a principal in the Denver office of Design Workshop Inc., which designed the sustainable Glacier Club golf course, in Durango, Colo. “Today, we are more critical, knowing there are ways to step more lightly on the land,” he adds.
Kevin Shanley, CEO of landscape architect-planner SWA Group, wants the landscape architect to lead the team, not just be on it. Low-impact development involves living things that landscape architects, not engineers, are trained to consider, says Shanley, in SWA’s Houston office. Landscape architects need to get involved politically to push landscape infrastructure, he says.
One example is Houston’s Buffalo Bayou project, a public-private partnership downtown, planned and designed by SWA. The shores of the derelict stormwater channel are becoming 850 acres of public green space and trails. Fund-raising and initial planning for the second phase is starting. The first 3,000 lineal ft, called Sabine-to-Bagby, was completed in 2002 for $15 million. During last year’s flooding caused by Hurricane Ike, the area performed better than expected, says SWA. There was minimal damage, and the park was back in service in a couple of days. Properly built, storm channels can be parks most of the year, says SWA.
The firm also is involved with reforesting highway corridors to sequester carbon, improve runoff, build habitat and look good. “Infrastructure needs to provide multiple benefits,” says Shanley.
Depending on the project’s details, a sustainable landscape can cost anywhere from $25 to $50 per sq ft on ground to $200 per sq ft on structure. Landscape architects charge from $70 to $120 per hour, or 5% to 15% of the project’s cost.
How did society get into this fix of fractured infrastructure? Sources say the big culprits are development and very strict interpretation of Euclidian zoning, which rigidly segregates land uses. “We have been isolating land uses in favor of an auto-centric development model in the U.S. for almost 80 years,” says Curt Johansen, executive vice president of developer Triad Communities, Vallejo, Calif. “That must end immediately,” he says.
It has taken five years for Triad to get zoning approvals for its 350-unit Angwin Ecovillage, a sustainable farming community in Napa County, Calif., currently under environmental review.
Also over the past 50 years, high-impact building and roadway development have reduced the amount of permeable surface to accept stormwater, increasing flooding and pollution. Stream flow speeds in Houston, for example, have increased from under 5,000 cu ft per second in 1930 to about 27,500 cfs in 2000, says the U.S. Geological Survey. With stream-flow increases come a greater potential for flooding. The actual stream flow from 2001’s Tropical Storm Allison in Houston’s Brays Bayou peaked sharply at about 34,000 cfs, 20 hours from the start of runoff. This compares to a more gradual stream flow in 1915, before development (see graph, p. 87). Allison, which caused $5 billion of damage in Houston, would have been a nonevent even 50 years ago because the natural landscape would have absorbed the water, say sources.
Seeds for the landscape infrastructure movement were planted during the environmental movement of the late 1960s. The 1972 Clean Water Act mandated control of point-source water pollution. Stormwater is part of that equation because of combined sewer overflow (CSO) systems in many cities. Years into CWA, it became clear nonpoint-source pollution—stormwater runoff in general—had to be addressed to meet clean-water goals. In the 1990s, cities, under threat of fines as a result of regulations to limit stormwater runoff, started seeking economical ways to handle it.
Another impetus for sustainable landscape has come from the U.S. Green Building Council’s green building-rating system, called Leadership in Energy and Environmental Design (LEED). Introduced in 2000, the tool soon focused attention on sustainability, including site issues. “If it were not for LEED, this would not have happened as fast,” says ASLA CEO Nancy Somerville.
But LEED was too building-centric for landscape architects. So ASLA decided to develop its own rating system, called the Sustainable Sites Initiative (ENR 11/17/08 p. 16). SSI is an interdisciplinary effort of ASLA, the Lady Bird Johnson Wildflower Center and the United States Botanic Garden, with support from USGBC and others. The goal is to create voluntary national guidelines and performance benchmarks for sustainable land design, construction and maintenance practices. Guidelines are expected later this year. The SSI rating system is due out in 2011 and a reference guide in 2012. SSI is designed to be used by itself but will be incorporated into LEED. Information is available at www.sustainablesites.org/.
Zoning is not the only obstacle to sustainable landscape. Initially, there was no proof the systems work. There was concern about maintenance and general resistance to change. “Just trying something new has its obstacles,” says Kevin Perry, a stormwater specialist with Nevue Ngan Associates, Portland, Ore. Perry designed the first green street in 2003 for Portland, a pioneer in this area.
Consequently, most projects have redundancies. Thomas R. Tavella, president of the Hamden, Conn.-based landscape architect that bears his name, does not mind if there is still a catch basin in the corner. “It is OK to have redundancy. It is part of the education process,” he says.
Recent research, such as field work at the University of New Hampshire Stormwater Center, demonstrates green streets and roofs manage and clean stormwater. Consequently, municipalities are becoming strong proponents, say sources.
More significantly, green landscape architecture is causing a fundamental shift in how design occurs. Karen Janosky, a Mithun associate principal, sums it up: “It is an amazing era and an incredible time to go into landscape architecture.”
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