A modified eco-efficiency framework and methodology for advancing the state of practice of sustainability analysis as applied to green infrastructure
Authors: Ghimire Santosh R , Johnston John M 
Published: March 2017

Abstract

We propose a modified eco-efficiency (EE) framework and novel sustainability analysis methodology for green infrastructure (GI) practices used in water resource management. Green infrastructure practices such as rainwater harvesting (RWH), rain gardens, porous pavements, and green roofs are emerging as viable strategies for climate change adaptation. The modified framework includes 4 economic, 11 environmental, and 3 social indicators. Using 6 indicators from the framework, at least 1 from each dimension of sustainability, we demonstrate the methodology to analyze RWH designs. We use life cycle assessment and life cycle cost assessment to calculate the sustainability indicators of 20 design configurations as Decision Management Objectives (DMOs). Five DMOs emerged as relatively more sustainable along the EE analysis Tradeoff Line, and we used Data Envelopment Analysis (DEA), a widely applied statistical approach, to quantify the modified EE measures as DMO sustainability scores. We also addressed the subjectivity and sensitivity analysis requirements of sustainability analysis, and we evaluated the performance of 10 weighting schemes that included classical DEA, equal weights, National Institute of Standards and Technology's stakeholder panel, Eco-Indicator 99, Sustainable Society Foundation's Sustainable Society Index, and 5 derived schemes. We improved upon classical DEA by applying the weighting schemes to identify sustainability scores that ranged from 0.18 to 1.0, avoiding the nonuniqueness problem and revealing the least to most sustainable DMOs. Our methodology provides a more comprehensive view of water resource management and is generally applicable to GI and industrial, environmental, and engineered systems to explore the sustainability space of alternative design configurations. Integr Environ Assess Manag 2017;13:821–831. Published 2017. This article is a US Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

Key Points
A modified, flexible and transparent eco-efficiency framework consisting of 4 economic, 11 environmental, and 3 social indicators was developed, and a sustainability analysis methodology was demonstrated using alternative rainwater harvesting design configurations. Life-cycle assessment and life-cycle cost assessment were utilized to calculate the indicators; and 1 economic, 4 environmental, and 1 social indicator integrated in a single sustainability score using Data Envelopment Analysis. Subjectivity and sensitivity were addressed by evaluating 10 weighting schemes including classical Data Envelopment Analysis, equal weights, National Institute of Standards and Technology, Eco-Indicator 99, Sustainable Society Foundation's Sustainable Society Index, and derived Thresholds. Threshold weighting schemes revealed unique sustainability scores identifying the least- to most-sustainable Decision Management Objectives, and threshold schemes were recommended over other schemes.