...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.
Planting Seeds
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.”
