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By Mary Nunn, RLA & Nandan Shetty, NYC Parks Green Infrastructure Unit
New York City is the densest city in America and as a result, largely impervious. The impacts of this are numerous, including combined sewer overflows, flooding, and damage of infrastructure and property. According to the Natural Resource Defense Council, the 100-year flood will occur as frequently as every 15 to 35 years in New York by the 2080s. Traditional wastewater infrastructure, such as overflow systems and treatment plants, comes at a high cost both financially and environmentally. In contrast, a green approach to addressing these problems — including green roofs, parkland bioretention systems, stormwater greenstreets, and right-of-way bioswales — supplies a myriad of social, economic, and environmental benefits in addition to managing runoff.
In New York City we are currently constructing hundreds of green infrastructure sites in the city’s most polluted “sewersheds”. The road to implementation remains perhaps one of the most challenging in the country, given the city’s degree of urbanization, physical and political complexity, and aging infrastructure. Given this, we have developed a university partnership model that aligns us with academics who are similarly motivated and interested in understanding these considerable challenges. Together, we undertand that green infrastructure is a new technology with many variables and unknowns. Our joint research challenge is to monitor performance, so that stormwater capture is quantified, cost effectiveness is known, and construction details and designs are constantly improved.
Our academic partners at Drexel University have used live tracking to monitor the performance of several constructed sites. At the stormwater greenstreet located on Nashville Boulevard between 116th Avenue and 209th Street in Queens (Nashville), 100% of stormwater runoff entered local catch basins and ultimately the combined sewer system prior to installation in 2011.
Over our 2012 monitoring season (April - November), we found that 21 out of 24 storm events were 100% retained within the site. During only three storm events, ponding inside the greenstreet caused brief overflows to the local catch basin. On an annual basis, the site’s performance suggests 74% - 86% retention of all rainfall over its catchment area, dependent upon annual precipitation variations. Furthermore, our data suggests that the Nashville site can retain 100% of the flow directed to it during all storms with less than 1.6 inches of rainfall.
In addition, Nashville was closely monitored during both Hurricane Irene and Superstorm Sandy, and it captured much more stormwater runoff than anticipated. Although the site was sized for a 5:1 ratio of catchment area to planting area, during Superstorm Sandy, inflow from the street was approximately 31 times direct precipitation on the site. Given the location of the site at a low point of the neighborhood, the increased ratio most likely occurred due to clogged drainage upslope. In total, approximately 40,000 gallons of water deposited by Superstorm Sandy either infiltrated into the site or evaporated.
We know that green infrastructure works, but there is much more to be gained by fostering a constant university partnership, especially given the scale of investment in these systems. A “design - build - research” feedback loop is requisite to monitor and learn how we can continue to improve performance-based green space.
Mary Nunn, RLA is a Landscape Architect with the NYC Parks Green Infrastructure Unit. At Parks, she has worked on a variety of projects citywide with an emphasis on sustainable design and stormwater management. Currently, she is responsible for the project management and design of green infrastructure systems in the Bronx River and Hutchinson River sewersheds.
Nandan Shetty is a PhD candidate at Columbia University, and has been working at NYC Parks Green Infrastructure Unit since 2008. Nandan received a MS from Columbia University in Civil Engineering in 2013 and a BE from Dartmouth College in Environmental Engineering in 2008.
By Pamela Blackmore, 2013 National Olmsted Scholar Finalist
Landscape architects in the Intermountain West face unique challenges when trying to implement low-impact development (LID) strategies. LID applications are rare in these semi-arid environments, and studies analyzing LID effectiveness in these environments are even fewer.
I have been part of an interdisciplinary research team at Utah State University, currently analyzing the effectiveness of LID in Daybreak, an award winning, master-planned community and the largest green infrastructure project in Utah. It is recognized as one of 500 U.S. new urban sites and has been featured as a Case Study Brief in the Landscape Architecture Foundation (LAF)’s Landscape Performance Series.
The landscape architecture firm Design Workshop, was responsible for the design of open spaces, including the 65-acre, man-made Oquirrh Lake, stormwater canals, and 25 acres of constructed wetlands, bioswales, and infiltration basins. This integrated stormwater management system was designed to infiltrate runoff up to the 100-year storm event, reducing infrastructure costs by an estimated $70 million.
Our study objective is to analyze the effectiveness of LID strategies on stormwater quality in Utah’s unique environment and climate. Two sub-watersheds within Daybreak were compared, each with different stormwater management strategies. One watershed focuses on LID designs, such as using a bioswale to detain and filter runoff. The other watershed largely follows traditional stormwater management methods. As the lead research assistant of this study, I am helping analyze key contaminants that are associated with urban development, including heavy metals, total suspended solids (TSS), nitrogen, and phosphorus.
Preliminary results show the effectiveness of the LID strategies in Utah, particularly when comparing first flush samples. It is evident that there are huge reductions in these pollutants as a result of the LID designs.
Daybreak’s integrated stormwater system has already provided salient enviromental and economic benefits. Our current study further demonstrates performance of the LID applications, and the data can inform future designs. The research team will present project findings at the 2013 American Water Resources Association conference to international, multidisciplinary audiences. Our communication of successful LID projects such as Daybreak is expected to further promote sustainable design and demonstrate the benefits of high performing landscapes.
Pamela graduated from Utah State University (USU) with a BLA in 2013 with Departmental Honors. She has worked as a LAF Case Study Investigation (CSI) Research Assistant for two summers on eight case studies, participated in Dr. Bo Yang’s Daybreak stormwater quality study, and continues to research and write articles with Dr. Yang. She received USU’s 2013 Honor’s Thesis Award, Faculty Medal and Laval Morris Travel Fellowship. She is currently working as an intern in Design Workshop’s Salt Lake City office.
The 2013 Case Study Investigation (CSI) program officially ended on August 9 with each of the faculty-student research teams presenting their work during a 1.5-hour, information-packed webinar. The researchers described a variety of exemplary projects, the research process, and some of the key environmental, economic, and social benefits that they were able to document.
This year’s teams demonstrated creativity and ingenuity with the methods they used to observe and quantify performance. Two of the teams went in to detail about the methods and processes they pioneered and tested through CSI.
The University of Oregon research team discussed their experience using Jan Gehl’s Public Life Public Space survey to assess the social benefits of three exemplary public spaces: Portland’s Director Park, Randall Children’s Hospital, and Dutch Kills Green in Queens.
The Utah State University research team presented two innovative methods they developed to assess landscape performance on three residential sites in Aspen, Colorado: (1) A visual analysis of landscape buffering and (2) A bioclimatic analysis of Human Comfort Zone.
Want to learn more? Look for the resulting 20+ LPS Case Study Briefs from the 2013 CSI program in Sept/Oct, as we publish several each week.
The Council of Educators in Landscape Architecture (CELA) has announced that it will offer a new “Landscape Performance” track at its annual conference, starting in 2014. The CELA conference focuses on recent research and scholarship in all aspects of landscape architecture.
“The decision to offer this track underscores the explosion in interest and number of proposals that CELA has seen in recent years on this topic,” said CELA President Sean Michael, PhD.
“Landscape performance should be fundamental knowledge in landscape architecture, though it is not highly developed yet,” said CELA Vice President of Research Ming-Han Li, PhD, PE, PLA. “The new track will help ensure that the latest research and thinking on landscape performance is a regular part of the dialogue at the CELA conference.”
Landscape Performance joins ten track categories used to organize the conference sessions and papers: Design Education & Pedagogy, Communication & Visualization, Design Implementation, Urban Design, Landscape Planning & Ecology, Research & Methods, Service Learning & Community Engagement, Sustainability, People-Environment Relationships, and History, Theory & Culture. Members of the academic community and others submit abstracts to each track for peer review which, when accepted, are presented at the annual conference and published in the proceedings.
LAF will co-chair the new Landscape Performance track along with a representative from CELA. The move is the latest step in an ongoing partnership between the two organizations. In 2011, the CELA Vice President of Research began serving on the LAF Research Committee, and last year, CELA and LAF leadership began serving on in an ex officio capacity on the other organization’s Board of Directors.
For more than 90 years, CELA has been concerned with the content and quality of professional education in landscape architecture and with generating high quality research.
Last week at the annual Council of Educators in Landscape Architecture (CELA) Conference in Austin, Texas, LAF presented new insights on landscape performance gleaned from the Landscape Performance Series (LPS) and the Case Studies Investigation (CSI) program.
Executive Director Barbara Deutsch and Programs Manager Linda Ashby participated in four sessions, presenting alongside past CSI Research Fellows, student Research Assistants, and other colleagues. LAF’s sessions at CELA included panels on evaluating landscape performance for environmental, social, and economic benefits, as well as a panel on applying science to design for and evaluate performance. These sessions offered participants an introduction to both the LPS and CSI research programs, and a critical look at the research methods employed.
The first session introduced CSI and the concept of quantifying performance benefits. The session offered the opportunity for audience members to discuss the program’s approach, as well as participants’ strategies for quantifying specific social, environmental and economic benefits. Participants introduced their own experiences: for example, Jessica Canfield (Kansas State University) presented her CSI research evaluating the Frontier Project, a demonstration project in California which seeks to encourage visitors to incorporate energy efficient and water-wise practices in their homes. Canfield’s team studied the site’s rainwater infiltration, irrigation water needs and projected carbon emissions and analyzed attendance records and surveys with on-site employees. Canfield and others, including Mark Storie (University of Maryland), also discussed their strategies for obtaining data and the varying levels of data availability at different types of sites.
Many of landscape performance sessions focused on research methods. At the panel on environmental performance, Barry Lehrman (Cal Poly Pomona) described his experience “measuring the (not so) unmeasurable,” introducing the tools used by his CSI research team, including affordable temperature gauges and water quality meters. In response to presentations by Lehrman and his fellow panelists, moderator Kristina Hill, PhD (UC Berkeley) described the recent context for measuring landscape performance, noting that until recently many metrics were discipline-specific, leading to “very little synthesis.” She challenged those attending the session to “be critical in our reflection on these metrics” so researchers could continue to advance their strategies and obtain a holistic understanding of the benefits of landscape design.
Participants in CELA sessions also discussed means of communicating the concept of landscape performance benefits to policy makers, other design professionals, and the general public. Presenting in a panel on economic benefits, Dennis Jerke (Texas A&M) noted that “we have to be good communicators… and explain what the metrics mean and how the value has been generated.” Similarly, Mary Myers, PhD (Temple University) noted that comparing a project’s performance to its initial goals can be a helpful strategy for engaging clients and others in the discussion. To Myers, “the metrics should measure the extent to which goals were met” whether in terms of stormwater mitigation, improved biodiversity, economic development or public access.
LAF looks forward to continuing the dialogue started at CELA Conference and bringing the new insights to the 2013 CSI program and its participants.