Landscape performance evaluation in socio-ecological practice: current status and prospects
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In the past decade, performance evaluation becomes a priority area in research and practice in the landscape architecture profession, with its influence originating from the USA and extending to other countries. The goal is to quantitatively demonstrate the environmental, social, and economic benefits of built landscape projects or, at the planning and design stage, to gauge the project’s level of fulfilment to intended goals. Structurally, the evaluation framework facilitates a healthy partnership of diverse stakeholders, including researchers, designers, clients, users, and policy makers. When adaptive design, design for resilience, and design under the uncertainty of climate change become the new norms in landscape architecture practice, performance metrics will gain interest in the communication of design merits. The author reports the current status of landscape performance evaluation by introducing the major players in this enterprise, including supporting professional organizations, accrediting and regulating agencies, research programs, and leading professional firms. In addition, 102 published landscape performance evaluation case studies are analyzed to demonstrate their contributions at the scholarly, practical, and policy levels. Last, the author suggests that the current scope of performance evaluation be expanded and offers recommendations for future development in this area.
KeywordsSustainability Ecological resilience Planning Policy Landscape architecture foundation Ecosystem services Green infrastructure Knowledge implementation and impact research
Landscape architects play an important role in socio-ecological practice through planning, design, and management of the built environment in responsible and artful ways. For more than a century, the landscape architecture profession has made significant contributions to societal sustainability agendas (Simo 1999). Examples include providing human health benefits by offering “nearby nature” (Ulrich 1984; Taylor et al. 2001; Jiang et al. 2014), enhancing flood resilience in metropolitan areas during the changing climate (Eisenman 2005; Fletcher et al. 2015), and increasing landscape aesthetics and ecological resilience (Gobster et al. 2007; Jorgensen 2011; Rottle and Yocom 2011). Frederick Law Olmsted, founder of the profession, for example, presided over several large-scale green infrastructure projects (many with partner Calvert Vaux) that are doing real and permanent good—Central Park in New York, Emerald Necklace in Boston, and park systems and parkways in Buffalo, Niagara Falls, Louisville, Milwaukee, and other cities in the USA.
The level at which landscape projects fulfil their intended purpose and contribute to sustainability can be defined as project performance (Landscape Architecture Foundation [LAF], n.d.). Documenting project performance benefits (environmental, social, and economic) becomes an increasingly important topic in socio-ecological practice and research (Xiang 2019a, p. 2; Felson et al. 2013, p. 882). Despite the acknowledged contributions from landscape projects, research in landscape architecture has drawn criticism on the basis that research findings are not always informing practice and, at times, are irrelevant to the needs in practice (Milburn and Brown 2016, p. 75).
There are three important reasons to advocate for “practice-based research” that focuses on landscape performance evaluation. The first is that socio-ecological problems are complex and wicked (Rittel and Webber 1973, p. 136; Xiang 2013, p. 1). Adaptive design solutions require the integration of new knowledge, such as that generated from empirical research, into the design process. This process should be participatory and transdisciplinary (Head and Xiang 2016, p. 4). In addition, the ability to assemble a transdisciplinary design and research team becomes increasingly important because landscape architects nowadays are tackling more complex, large-scale projects (Domlesky 2018, p. 125).
The second reason is that the process of performance evaluation can build a stronger connection between practice and academy to collectively examine issues emerging in practice. Because the evaluation process requires authentic involvement of all parties (researchers, designers, clients, and users), knowledge co-generated through this process can be readily applied in practice (Innes 1995). The third reason is the imperative to enhance an interdisciplinary culture in the landscape architecture profession. Compared with allied disciplines (e.g., planning, urban design, and architecture), the cultural inertia tends to make landscape architects look inward (Thompson and Steiner 1997, pp. 3–5). When the allied disciplines embrace interdisciplinary practices and contribute to the society at higher levels, landscape architecture becomes marginalized if its cultural deficiency is not addressed (Brown and Corry 2011, p. 329).
The objective of this paper is threefold: (1) to introduce the current major players (e.g., supporting, accrediting, and regulating agencies and programs) in landscape performance evaluation; (2) to analyze a comprehensive database of performance evaluation case studies and then synthesize their contributions at the scholarly, practical, and policy levels; and (3) to extend the current scope of performance evaluation and offer recommendations for future research.
2 Landscape performance evaluation: context and genesis
There is a widely recognized need for research among landscape architecture professionals. A survey of the American Society of Landscape Architects (ASLA) members showed that 95% of the professionals believe that research is an essential way to improve practice (Chen et al. 2017, p. 3669). At the same time, professionals are concerned with the possible disconnection between research produced in academia and research needs in practice (Chen et al. 2017; Milburn and Brown 2016). A key way to bridge this gap is to collaboratively identify research questions and co-generate findings that are useful and impactful.
In the same vein, leaders in the profession called for “practice-based research” and urged that research be conducted based on project context and be site specific (Murphy 2005; Culbertson 2011). Sometimes, sophisticated clients request that performance evaluation be conducted to uphold project credibility (Culbertson 2011). Dr. Kurt Culbertson, chairman and CEO of the landscape architecture and planning firm Design Workshop, suggested a framework for collaboration and called for a national research agenda (Culbertson 2011, p. 235). Meijering and colleagues’ Delphi study further recommended that “umbrella organizations, such as ECLAS [European Council of Landscape Architecture Schools] in Europe, CELA [Council of Educators in Landscape Architecture] in North America, and the world-region subgroups of IFLA [International Federation of Landscape Architects]” take leadership to determine research agendas in different regions of the world (Meijering et al. 2015, p. 86). “Measuring landscape architecture performance and impact (indicator construction, visual impact assessment, quantification of costs and benefits)” are listed as research priorities identified by international experts in academic and professional practice (Meijering et al. 2015, p. 94). In addition, Hensel at Vienna University of Technology (Austria) introduced the “integrative sustainability approaches to architecture, urban design, and landscape architecture from a performance-oriented design perspective,” and this emerging field is interdisciplinary in nature and research-by-design focused (Hensel 2019).
“Landscape performance” was proposed because of inherent needs in practice. The concept was first put forth as a research initiative by the Landscape Architecture Foundation’s (LAF) Board of Directors (representatives from firm principals, industry partners, and academics). The purpose was to fulfil LAF’s mission of research, through the generation of research funding and building team capacity. LAF thereafter initiated several research programs to support performance evaluation, whose collaboration framework evolves over time through dialogues among diverse stakeholders (Deming 2015; Ndubisi et al. 2015).
An important contribution of performance evaluation is to build a healthy partnership among stakeholders (e.g., designers, researchers, clients, users), whereas in conventional practice, this type of partnership is not fully explored, or the post-construction evaluation is conducted in a cursory way. Performance evaluation hence offers an innovative framework of co-learning and knowledge co-generation (Xiang 2019a, pp. 1–2). Another contribution of performance evaluation is the quantitative demonstration of a landscape project’s environmental, social, and economic benefits—the three pillar areas supported by sustainability science (Burton 1987; Singh et al. 2012). The past few years witnessed the successful implementation of several programs at the LAF and other agencies, which produced many studies that report project performance benefits and impacts (Myers 2013; Luo and Li 2014; Burke 2018; Yang 2018, pp. 250–255). A common thread is that landscape architects can effectively and confidently convey project merit, supported by tangible evidence (LAF 2016).
3 Current status: major players, requirements, and resources
Although the concept of performance evaluation of landscapes is not new, it was the LAF that first proposed the evaluation framework that forged the partnership of academia with the professional world. The LAF is a non-profit organization established by influential leaders in Washington, D.C., in 1966 (Yang 2018, p. 4). The aim of landscape performance is to “fill a critical gap in the marketplace and make the concept of landscape performance and its contribution to sustainability as well known as building performance is today” (Ndubisi et al. 2015, p. 48; LAF, n.d.). The Landscape Performance Series (LPS) is LAF’s flagship research program that demonstrates project post-construction performance, with its pilot version launched in 2010. Currently, LPS provides perhaps the largest database of performance evaluation case studies. In addition, LAF offers a repository of online tools for calculation of performance and other data and sources (http://landscapeperformance.org/).
LAF’s efforts received widespread support in academia. In 2012, the Council of Educators in Landscape Architecture (CELA) responded to this emerging area by opening a Landscape Performance Track in the annual CELA conference. CELA is the international organization whose objective is to “encourage, support and further education in the field of landscape architecture specifically related to teaching, research, scholarship, and public service.” From 2013 to 2017, the number of submissions to the landscape performance conference track almost trebled. In addition to this robust growth, many studies have been published in CELA’s peer-reviewed publication Landscape Research Record. CELA also embraces a multitude of dimensions in performance evaluation. Recent efforts include opening another new conference track, Landscape Architecture for Health, which aims at disseminating research on the health benefits of landscape designs.
Likewise, the Landscape Architectural Accreditation Board (LAAB) recognizes the importance of integrating landscape performance into higher education. LAAB is the official accrediting body for first professional programs in landscape architecture in the USA. There are seven standards that landscape architecture programs shall address in the Self-Evaluation Report submitted to LAAB prior to an accreditation visit. “Landscape performance” was added in LAAB’s latest Accreditation Standards for First-Professional Programs in Landscape Architecture (LAAB 2016). Effective in autumn 2017, programs including all bachelor’s- and master’s-level landscape architecture programs that are scheduled for accreditation reviews are subject to this new requirement (LAF 2016).
In professional licensure, the Council of Landscape Architecture Registration Board (CLARB) administers the Landscape Architect Registration Examination (L.A.R.E.) and has its licensure boards across the USA, Canada, and Puerto Rico. The L.A.R.E. examination assesses candidates’ ability to protect the public’s health, safety, and welfare. There are four sections in the current examination: Sect. 1 Project and Construction Management, Sect. 2 Inventory and Analysis, Sect. 3 Design, and Sect. 4 Grading, Drainage, and Construction Documentation. The ability of candidates to conduct performance evaluation is assessed; particularly in Sects. 1 and 4 (CLARB 2017, pp. 7–10). For example, in Sect. 4, Rational Method is one of the content areas in which candidates are expected to have working knowledge of calculating stormwater runoff peak discharges before and after project development.
The ASLA works in partnership with CELA and LAF to evaluate submissions to the Research Category of the annual Professional Awards. Several winning projects demonstrated outstanding performance benefits, although “landscape performance” is not required in the evaluation criteria. For instance, in 2017, three of the five awarded projects in the Research Category presented observed performance data (ASLA 2017). Another significant aspect is that design process has more credibility if it answers research questions on project performance—a comment made by the Awards Jury on Andropogon Associates’ 2016 winning project on the University of Pennsylvania campus (Andropogon Associates 2016).
Since 2012, the U.S. Environmental Protection Agency’s (EPA) Office of Water has been managing the annual Campus RainWorks Challenge design competition, which highlights the performance benefits and climate resilience of green stormwater infrastructure on university campuses. There are two submission categories: Demonstration Project and Master Plan. For both categories, project submissions are required to report the anticipated performance benefits. In addition, “performance” is a high-stakes evaluation criterion. In fact, in 2017, this criterion had the highest percentage of the total evaluation points (20 of a total of 100 points) (U.S. EPA 2017, p. 10).
Selected funding agencies and programs that support landscape performance research
CLASS Fund, USA
California Landscape Architectural Student Scholarship (CLASS)
Fund projects broadly on landscape sustainability topics in continental USA
Environmental Protection Agency, USA
Design, implementation, and performance evaluation of green infrastructure adoption on university campus
Landscape Architecture Foundation, USA
Case Study Investigation (CSI)
University researchers in partner with industry leaders to examine project performance post-construction
Landscape Architecture Foundation, USA
Pedagogical innovations in design process for performance evaluation
Landscape Architecture Foundation, USA
Fellowships for Innovation and Leadership
Support mid-career landscape architects to explore, research, and develop big ideas and initiatives.
Landscape Research Group, UK
International research fund and student awards
Multidisciplinary landscape approach. Enables landscape research that contributes toward greater justice and sustainability
National Natural Science Foundation, of China
Supports landscape performance data collection. Education and outreach activities are encouraged or required
National Science Foundation, USA
Support landscape performance data collection. Education and outreach activities are encouraged or required
In addition, four recent texts provide different perspectives and approaches to performance evaluation (Van den Brink et al. 2016; Canfield et al. 2018; McCoy et al. 2018; Yang 2018). Van den Brink and colleagues compiles a comprehensive and timely text, Research in landscape architecture: methods and methodology, that introduces various methods that evaluate the performance of designed landscapes (Van den Brink et al. 2016), including grand challenges that the society is facing (e.g., urban water, health, and thermal comfort) (Ibid). McCoy and colleagues’ book, A landscape performance + metrics primer for landscape architects: Measuring landscape performance on the ground (McCoy et al. 2018), is part of the ASLA Landscape Architecture Technical Information Series. It offers rich information on methods and equipment for data collection and analysis that are most pertinent to landscape field work (e.g., measuring soil infiltration rates). Canfield and colleagues’ book, Landscape performance guidebook: A guide for metric selection (Canfield et al. 2018), provides a comprehensive list of metrics and methods for evaluating benefits in the environmental, social, and economic categories. Illustrated with examples from LAF’s performance case portfolio, this book also suggests a procedure to conduct performance evaluation with a compilation of resources. Furthermore, Yang’s book Landscape performance: Ian McHarg’s ecological planning in The Woodlands, Texas (Yang 2018) reviews the current state of landscape performance scholarship and further demonstrates the long-term benefits of The Woodlands town development, using quantitative and qualitative methods. The book strongly supports McHarg’s ecological design theory and demonstrates the importance of performance evaluation to building urban resilience (Lieberknecht 2019; Xiang 2019b, c).
Selected scholarly outlets to disseminate landscape performance research findings
Landscape Architecture Frontiers
Higher Education Press, China
Landscape Architecture Journal
Beijing Forestry University, China
University of Wisconsin Press, USA
Taylor & Francis, UK
Landscape Research Record
Council of Educators in Landscape Architecture (CELA), USA
Socio-Ecological Practice Research
4 Current status: insights from LAF’s comprehensive database
4.1 Case study investigation program
SEPR’s knowledge I&I research framework (Xiang 2019a, p. 1) was used to review the contributions of LAF’s comprehensive database of performance evaluation—LPS case studies. Case Study Investigation (CSI) is a premier grant program that supports the LPS. Since 2011, the annual CSI program provides funding to 5 to 10 research teams from several countries to conduct evaluation of built project performance. With more than 110 peer-reviewed case studies published, LPS is perhaps the most comprehensive and rigorous database of landscape performance research freely available to international audiences (https://landscapeperformance.org/).
Two other aspects of the LPS database make it ideal for the evaluation of the current status of landscape performance. The first is the competitive selection process that ensures the competency of research teams. To receive CSI program funding, research teams including research fellows and research assistants from academic institutions and design firms submit proposals based on high-profile built projects. Forty-six research fellows from 33 different academic institutions and 79 landscape architecture firms have participated. The second aspect is the high-quality built projects selected for performance evaluation, toward the end research product of a published LPS case study. Many projects have achieved noteworthy recognitions prior to entering into the CSI program, such as receiving awards from national and state chapters of ASLA, Urban Land Institute, IFLA, and other agencies. LPS case studies undergo a double-blind peer-review process, with reviews provided by university faculty, practitioners, and LAF’s Research Committee members before acceptance for publication. Participation in the CSI program does not guarantee publication of one’s case study. Using the published LPS case studies as dataset, guiding research questions include: (1) How did research outcomes evolve in the past CSI programs? (2) Who were the major contributing firms? (3) To what extent did the LPS portfolio impact sustainability policy and practice?
Published LPS case studies followed LAF’s standard publication format, including 24 required sections (Yang et al. 2016, pp. 318–319). The most important section is the detailed Methodology document that provides descriptions of the ways project benefits were evaluated. The LAF defines project types and benefit subcategories (http://landscapeperformance.org/). There are 18 subcategories of the environmental benefits, including (1) land (land efficiency/preservation; soil creation, preservation/restoration; and shoreline protection); (2) water (stormwater management; water conservation; water quality; flood protection; water body/groundwater recharge; and other water); (3) habitat (habitat creation, preservation/restoration; habitat quality; and populations and species richness); (4) carbon, energy and air quality (energy use; air quality; temperature and urban heat island; and carbon sequestration and avoidance); and (5) materials and waste (reused/recycled materials; and waste reduction).
The social benefits category comprises a total of 11 subcategories. These include: recreational and social value; cultural preservation; health and well-being; safety; educational value; noise mitigation; food production; scenic quality and views; transportation; access and equity; and other social. The economic benefits category has a total of 8 subcategories: property values; operations and maintenance savings; construction cost savings; job creation; visitor spending; increased tax revenue; economic development; and other economic.
After these subcategories, performance benefits are evaluated quantitatively based on sustainable design features of the project. An example of environmental benefit would be, “Ten new trees (sustainable design feature) trapped 1500 lb of carbon annually in tree biomass (performance benefit).” An example of economic benefit would be, “A new public park (sustainable design feature) increased adjacent property values by 10% (performance benefit).” An example of social benefit would be, “Five new seating areas (sustainable design feature) increase the social value of space and result in an increase of café patronage by 30% on weekdays and 50% on weekends” (adapted from LAF 2012).
Two sets of analyses were performed. The first set of analysis answers research questions 1 and 2 (see Sect. 4.1), by reviewing published LPS case studies and synthesizing their scholarly and practical contributions. In total, 116 case studies had been published by 2017. Fourteen case studies were produced in LPS’s pilot program prior to 2011. For the purpose of this report, these studies were excluded from the analysis and 102 studies were finally analyzed. Performance benefits are presented by environmental, social, and economic categories on each LPS case study’s webpage (https://www.landscapeperformance.org/). Each performance benefit statement was reviewed, and the total number of performance benefits and the number of benefit items in each benefit category were calculated. Because the number of case studies produced each year differed, to standardize the comparison, the average numbers of performance benefits documented per case study and the percentages of each benefit category for each year were calculated. Other typologies and details such as project type, location, size, and climate zone were also retrieved from the LPS webpage. The published LPS database is compiled in an Excel file, which is retrievable from (https://www.landscapeperformance.org/case-study-briefs).
The second set of analysis examines LPS case studies’ impacts on sustainability policy and practice to answer research question 3 (see Sect. 4.1). This was done through review of the Overview, Methodology, Challenge and Solution, and Lessons Learned sections of the case studies. In particular, in one instance, an urban redesign project in Bagby Street, Houston (USA) influenced future streetscape project development policy and guidelines in the city. It is worth mentioning that the Bagby Street case study established a new section, Policy Impact. It should be noted that LPS case studies document the impacts on sustainability, which often occurred prior to projects entering the CSI program. However, in other cases, it was the strong evidence of performance benefits that triggered positive changes or initiatives moving toward institutional changes (Wang et al. 2016; Canfield et al. 2018).
4.3.1 Overview research outcomes
Research outcomes and performance benefit category breakdowns in the Landscape Architecture Foundation’s Case Study Investigation (CSI) program 2011–2017
Number of case study projects
Avg. benefit reported per case study
Environmental benefits (%)
Social benefits (%)
Economic benefits (%)
Regarding percentage breakdowns, environmental benefit was the most frequently documented category, with 50% of all named benefits over the survey period. Social benefit listings increased over time and were 30–40% of cases in most years. This was partly due to LAF’s stringent requirement starting in 2012, which mandated that all three benefit categories be documented for each case study. This requirement was developed to address the situation in the 2011 cohort of studies that focused mostly on environmental benefits. However, economic benefit remained a relatively weak category, whose percentages stayed at 20% or lower (except in 2015). In 2017, social benefit became the most documented category, consisting of 53% of the total benefits examined in that year. In addition, there was a steady growth in the number of subcategories of benefit in parallel to the growing research outcomes. The LAF’s subcategory of benefit is a dynamic system that evolves over time when new benefit types are identified. All the 37 subcategories of benefit defined by the LAF have been evaluated in published LPS case studies.
4.3.2 Major contributing firms
Leading landscape architecture firms in participating Landscape Architecture Foundation’s Case Study Investigation (CSI) program 2011–2017
Number of CSI case studies
Design Workshop (USA)
Conservation Design Forum (USA)
Michael Van Valkenburgh Associates (USA)
Beijing Tsinghua Tongheng Urban Planning and Design Institute (China)
Andropogon Associates (USA)
TBG Partners (USA)
For example, Design Workshop has been using Legacy Design®, the firm’s philosophy and methodological framework for performance evaluation, in the recent decades (Design Workshop 2007, p. 10; Jost 2012, pp. 97–99): year 2019 marks the 50th anniversary of Legacy Design. As a comprehensive approach toward sustainability, Legacy Design specifies performance metrics in the four categories of environment, community, economics, and art, to guide the design process and ultimately as a framework to evaluate project outcomes. This process strives to balance environmental sensitivity, community connections, artistic beauty, and economic viability (Culbertson 2011, p. 235; Leonard 2013, pp. 92–94; Mendenhall 2016).
Other selected firms on the forefront of performance evaluation are SmithGroup, Conservation Design Forum, TBG Partners, and SWA Group. (1) SmithGroup, as a leading multidisciplinary firm, provides generous resources and support for research. The firm established high benchmarks in striving for sustainability, featuring many high-profile, transdisciplinary projects. (2) Conservation Design Forum is renowned for its integrated ecological design focusing on water. The firm is on the forefront of land use planning, preservation, and restoration. Many of the firm’s projects feature green infrastructure and performance. (3) TBG Partners is a well-established firm based in metropolitan areas in Texas (USA). Excellent design outcomes rely on the five key roles (scientists, artists, designers, futurists, and composers) that design teams play simultaneously in every project. (4) SWA Group’s history of research initiatives can be traced back to 2008. The firm allocates sizable funds annually to support research. SWA’s XL Lab (Experiments in Landscape and Urbanism) is the engine for research and innovation.
Firms that published two LPS case studies include: Michael Vergason Landscape Architects, Mithun, Moriyama & Teshima Planners, Perkins + Will, PWP Landscape Architecture, Site Design Group, and Ten Eyck Landscape Architects. Finally, the remaining 63 firms each contributed one case study.
These leading firms exhibit several common traits (see Table 4)—they are well established in the field, known for their high-quality design and delivery and their competency at complex, interdisciplinary projects, and present a commitment to sustainability. In general, large firms have a stronger impetus for innovation than small and medium-sized ones and can afford staff time and other resources (Gnyawali and Park 2009).
Number of projects and project locations in the USA (by state), as reported in the Landscape Architecture Foundation’s Case Study Investigation (CSI) program 2011–2017
Number of case study projects
California (10 projects), Texas (9), Washington (7)
New York (6), Pennsylvania (6), Washington DC (6), Colorado (5), Illinois (5), Michigan (5), Virginia (5), Arizona (4), Florida (4)
Missouri (3), Alabama (2), Georgia (2), Indiana (2), Kentucky (2), Massachusetts (2), New Mexico (2), Oregon (2), Wisconsin (2), Connecticut (1), Iowa (1), New Jersey (1), North Carolina (1), Tennessee (1), and Utah (1)
4.3.3 Implications on sustainability policy and practice
Selected impactful projects from the Landscape Architecture Foundation’s Case Study Investigation (CSI) program 2011–2017
Charles City Permeable Streetscape Phase 1
Charles City, Iowa
Streetscape and transportation
Conservation design forum
Middle Blue River Basin Green Solutions Pilot Project
Kansas City, Missouri
Community and streetscape
URS corporation/Vireo (east of Troost Avenue) URS Corporation/Taliaferro & Browne (Troost Avenue and west of Troost Avenue)
Bagby Street Reconstruction
High Desert Community
Albuquerque, New Mexico
Performance benefits highlights and implications in policy or practice from selected projects from the Landscape Architecture Foundation’s Case Study Investigation (CSI) program 2011–2017
Performance benefits highlights
Implications in policy or practice
Transformed the old taxi dispatch center into a multifunctional light industrial community. Design highlights stormwater management and innovative creation of public spaces. Intercepts, infiltrates, and evaporates 80% of annual rainfall through detention gardens, surface swales, and pre-existing shallow ponds
Functions of Stormwater Controlled Landscapes recognized by Denver’s stormwater codes. The first in Metro-Denver to use porous landscape detention gardens to meet requirements for stormwater quality
Charles City Permeable Streetscape Phase 1
One of the largest permeable pavement projects in the US Stormwater peak flow reduced 75% for 10-year events and 40% for 100-year events. Most impassable streets regain their functions in normal storm events
Innovative design secured federal funding for Phase I. Due to Phase I’s success, an additional $731,000 federal funding granted for Phase II. Spurred additional phases in an adjacent neighborhood
Middle Blue River Basin Green Solutions Pilot Project
First large-scale green infrastructure project (GI) for Kansas City’s Overflow Control Program. Reduced stormwater runoff volume and peak runoff volume by 80% and 76%, respectively. Meet Environmental Protection Agency’s water quality standards in tackling Combined Sewer Overflows (CSOs)
The first “Kansas City Green Neighborhood.” Provided the city with confidence to use GI as an effective and economically viable alternative. Generated applications in other retrofits and new developments. Ameliorated CSOs issues in Kansas City, a good example for other US cities that face CSOs
Bagby Street Reconstruction
First Greenroads certified project in Texas. Increased safety compared to situations before reconstruction. Contributed to a $53 million (or 26%) increase in property values of surrounding buildings (2013–2015). Devoted 4% (compared with typical 1%) of construction budget to aesthetic improvements, gave Houston Midtown a unique look
Formed the basis of design for numerous active reconstruction projects in Midtown Houston. Became a catalyst for a policy-level change: city of Houston Mayor’s Complete Street Executive Order (2013) mandated the Planning and Public Works Departments work together on all new transportation developments, and required a Complete Streets analysis and an annual report. Promoted future intergovernmental collaborations on public projects
High Desert Community
Low-impact design practices (e.g., water conservation, wildlife habitat restoration, material recycling, and cultural endowment) to reduce ecological footprint. Conserved natural arroyos and placed development out of pre-existing hydraulic paths. Uses only 20% of city’s annual water allowance in landscape areas, saving as much as 28.7 million gallons or $300,000 each year
Prompted city of Albuquerque and state of New Mexico updated water conservation and landscape planting ordinances. Influenced Albuquerque’s Design and Construction Regulations by providing its drought tolerant plant list to the City Planning Department. Spurred regional nursery sales of native plants by requiring large orders of native stock for both open spaces and residential landscape construction
5 Discussions and prospects
5.1 Lessons learned
Reviewing published LPS case studies has identified trends and insights applicable to future work. The disparity of percentage breakdowns resonates with the challenges reported by the CSI research teams regarding data and tools availability and the lack of expertise to evaluate certain benefit items (see Table 3). Pedagogical improvements are needed to address these challenges to better incorporate social and economic theories and tools that overlap with landscape performance. Most curricula in landscape architecture programs focus on environmental benefits; few courses introduce methods and roadmaps for evaluating social or economic benefits (Wang et al. 2016, p. 10).
In this sense, the CSI program offers a possible model of pedagogical improvement. A unique aspect of the CSI program is the healthy partnership among researchers (university faculty and students), practitioners (landscape architecture firms), and the sponsor (LAF). The framework for collaboration ensures collective learning and knowledge co-generation. This process provides an excellent training opportunity for next-generation designers and professional leaders. During the CSI program, various means are provided to ensure meaningful communication and knowledge dissemination. LAF facilitates constant contact throughout the case study research, including the research report preparation and publication phases. In most cases, research teams visit design firms in collaboration and conduct field work to collect data. Follow-up phone calls and meetings are typical and frequent. LAF also hosts a final presentation webinar, which is open to all and especially of interest to current and past CSI program participating firms, university faculty and students, LAF Board of Directors, and other project stakeholders.
For the LAF to further increase its impact, it is expected that performance-centric research programs go beyond documenting performance benefits to proactively influence sustainable policies and practices, such as by taking advantage of the existing partnerships with the professional world and municipalities. In a nutshell, better landscape performance evaluation would enhance the rigor and validity of professional practice, and contribute to the theoretical framework of sustainability.
Landscape performance also complements the current applications of sustainability rating systems, such as Leadership in Energy and Environmental Design (LEED) (U.S. Green Building Council 2009) and its pathway toward performance evaluation, Sustainable Sites Initiative (SITES™) (Calkins 2011; Steiner et al. 2013), the WELL Building Standard (International WELL Building Institute 2019), and the Living Building Challenge (International Living Future Institute, n.d.). These rating systems generally evaluate the levels of “greenness” of project sustainability before construction. For the purpose of this report, it is suggested that landscape performance expands the scope of evaluation, as elaborated next.
5.2 Expanding the scope of performance evaluation
For performance evaluation of built projects, it is important to clarify research goals, incentives, and expected outcomes early in the process for all parties involved (see Fig. 3). There may be achieved intentions, failed intentions, and unexpected outcomes (positive or negative). Clarifying design intent, project goals, and expected outcomes will assist with performance evaluation. In fact, several aforementioned programs and endeavors at the LAF, CELA, and U.S. EPA are tackling forecasted performance benefits at the planning and design phase. Evaluating design performance at this phase has become a required component in landscape architecture curriculum and a common practice in design studio instruction (see Sect. 3 in LAAB).
5.3 Inspirational examples and prospects
Design for urban resilience facing climate change is an important consideration in future community developments or design retrofits (Calkins 2011; Zuniga-Teran et al. 2019). “Specifically, attention should be given to … how resilient landscapes can fulfil their intended goals” (Ndubisi 2016, p. 199). This statement is central to the question that landscape performance research aims to answer (Yang and Li 2019, pp. 211–212). Inspirational examples can be found in the works of forerunner Ian McHarg and his team members at the University of Pennsylvania in the early 1970s. Featured studies include Medford, New Jersey (spearheaded performance zoning) (Cohen 2019a), The Woodlands, Texas (performance of ecological planning) (Yang and Li 2016; Cohen 2019b, p. 343), and complex river basins of the Potomac and Delaware (Juneja 1974; McHarg 1996, pp. 273–285). In particular, The Woodlands project demonstrates “how well a design of plan has performed in reaching its targeted goals” (Ndubisi 2014, p. 433). It is also a fine example of how adaptive, participatory, and transdisciplinary approaches (Head and Xiang 2016, p. 4) were applicable in a major development in an evolving socio-ecological context (Steiner 2011, pp. 77–85; Yang 2018). Julius Fabos, Ervin Zube, and other colleagues at University of Massachusetts Amherst were also active and conducted similar works from 1970 to 2000 (Fabos 2004, p. 327).
Design Workshop is a contemporary example that actively pursues “research in design” through the firm’s research program that tackles emerging topics, including performance aspects of green infrastructure (designworkshop.com/research.html). In the same vein, CELA compiles research needs submitted by professionals and academic researchers to CELA’s Research Problem Statement, which is expected to become a central portal for knowledge exchange and capacity building for landscape architecture research.
Incremental changes that integrate education and practice are also occurring in other countries. One example is provided by LAF research fellow Jie Hu, a professor at Tsinghua University (China) and director of Beijing Tsinghua Tongheng Urban Planning and Design Institute (Beijing, China). Hu’s team, which includes university students and designers, have participated twice in the CSI program. Most team members believed that performance evaluation has resulted in a more credible and rewarding design process for them, and the evaluation process allows them to deliver stronger projects in the future (pers. comm. from Jie Hu, 21 October 2018).
There are other signs of progress. In particular, improving the policy impacts on sustainability would be one of the focus areas of performance evaluation research and outreach. In their recent article in Nature, Safford and Brown (2019) offer recommendations to gain traction with policy makers, with two suggestions of particular relevance. “Repackage your work” (Ibid, p. 682) is a suggestion to change the format of communication from peer-reviewed article (status quo in academia) to a synthesis of key findings and recommendations such as in the format of a two-page policy summary. Another suggestion, “sustain and amplify your engagement” (Ibid, p. 682), focuses on the collective action of researchers with similar interests and on sustaining a decent level of engagement with key players such as policy makers (Ibid, p. 682). As a case in point, the aforementioned Bagby Street LPS case study is a good example that strives to influence policy changes. The newly created section of Policy Impact will shed light on how future LPS case studies are prepared and inspire other performance-centric research and outreach efforts. In a similar vein, supported by efforts at LAF, CELA, IFLA, ASLA, U.S. EPA, and other organizations and agencies, researchers in this enterprise can take advantage of the existing partnerships in the industry and with municipalities. Collectively, performance evaluation research would seek further commitment by research funding agencies and private foundations, and increase the level of engagement with the process of decision making on sustainability policies.
This paper introduces the current status of performance evaluation through a review of the major players and associated programs and initiatives, as well as by reviewing a comprehensive database of performance evaluation case studies. In addition, the findings extend the current scope of performance evaluation that focuses on empirical examination post-project implementation, to encompass forecasted performance benefits at the planning and design phase. The process of performance evaluation, as exemplified in LAF’s CSI programs, demonstrates the benefits of an interdisciplinary collaborative approach that can produce innovative and original solutions to the management of multifunctional landscapes. Landscape performance evaluation, therefore, augments the compelling portfolio of the landscape architecture profession through the articulation of project values and their essential contributions to society.
In conclusion, performance evaluation offers an exciting opportunity for collaboration between academics and professionals and contributes to socio-ecological practice research. As a research and practice front, landscape performance evaluation enhances the rigor and validity of landscape architecture practice and contributes to theoretical sustainability framework and the practical application of that framework.
I thank anonymous reviewers for valuable comments which significantly improve this manuscript.
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