Investigating Tradeoffs of Green to Grey Stormwater Infrastructure Using a Planning-Level Decision Support Tool

Abstract

Integrated decision support tools are needed to investigate the tradeoffs of stormwater control measures (SCMs) and determine the optimal suite of SCMs based on the needs of watersheds. In this study, an urbanized watershed undergoing infill development (the Berkeley neighborhood located in Denver, CO, USA) was modeled using a modified version of the U.S. Environmental Protection Agency’s (EPA) System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN). The primary goal was to compare the relative performance between green and grey SCMs, use optimizations and a planning-level approach to assist in decision-making, and discuss how stakeholder and community preferences can shift which SCMs are optimal for the watershed. Green and grey SCMs have variable hydrologic performance based on design and function, and both offer benefits that may be important to decision makers. Our results showed that infiltration trenches and underground infiltration were optimal for reducing flow volumes while vegetated swales and underground detention were optimal for pollutant concentration reduction. Stakeholders value both of these benefits and so the optimal stormwater solution in the Berkeley neighborhood included a mix of green and grey SCMs. Determining the optimal SCMs while considering tradeoffs in costs and associated benefits was complex and multifaceted. Modeling results such as those presented here are critical for informing stakeholders’ decision-making process.

Comprehensive Assessment of Water Sensitive Urban Design Practices based on Multi-criteria Decision Analysis via a Case Study of the University of Melbourne, Australia

“…The results are consistent with the research of Alves et al [93], Gallo et al [50], Bakhshipour et al [94], and Damodram et al [95]. Alves et al [93] applied MCDA methods to assess the flooding management in three study areas (Marbella, Ayutthaya, and Sukhumvit) and concluded that the green and grey combination measures provided more advantages compared with previously developed methods.…”

“…Alves et al [93] applied MCDA methods to assess the flooding management in three study areas (Marbella, Ayutthaya, and Sukhumvit) and concluded that the green and grey combination measures provided more advantages compared with previously developed methods. Gallo et al [50] developed a modeling framework that encompasses green and grey stormwater facilities and was applied into the Berkeley neighborhood. They also reported that the optimal stormwater solution in the study area is a mix of green and grey combination.…”

Stormwater Management Modeling in “Sponge City” Construction: Current State and Future Directions

“…The environmental benefits of SCP include improved hydrological performance (Dagenais et al, 2017;Spahr et al, 2020) such as stormwater quality improvement, flood mitigation, runoff reduction and groundwater recharge, as well as indirect benefits related to ecosystem services (Andersson et al, 2015;Dietrich and Rahul Yarlagadda, 2016;Gallo et al, 2020). Improved ecosystem services include adjustment to the local microclimate, carbon sequestration and storage, biodiversity conservation and restoration, and air pollution (Gómez-Baggethun and Barton, 2013;Ando and Netusil, 2018;Kazak et al, 2018).…”

Quality Assessment of Small Urban Catchments Stormwater Models: A New Approach Using Old Metrics

“…Urban drainage models usually aim at supporting decisions on flooding mitigation, pollution control, sewer system management and, increasingly, city planning and regeneration [1][2][3]. Depending on the objectives of the work and the availability of hydrological and asset data, the models can be either distributed and physically based or more aggregated and conceptual [4][5][6][7].…”