Assessment of urban flood vulnerability using the social-ecological-technological systems framework in six US cities

Heejun Chang,Arun Pallathadka,Jason Sauer,Nancy B Grimm,Rae Zimmerman,Chingwen Cheng,David M Iwaniec,Yeowon Kim,Robert Lloyd,Timon Mcphearson,Bernice Rosenzweig,Tiffany Troxler,Claire Welty,Ryan Brenner,Pablo Herreros-Cantis

doi:10.1016/j.scs.2021.102786

Abstract

As urban populations continue to grow through the 21st century, more people are projected to be at risk of exposure to climate change-induced extreme events. To investigate the complexity of urban floods, this study applied an interlinked social-ecological-technological systems (SETS) vulnerability framework by developing an urban flood vulnerability index for six US cities. Indicators were selected to reflect and illustrate exposure, sensitivity, and adaptive capacity to flooding for each of the three domains of SETS. We quantified 18 indicators and normalized them by the cities’ 500-yr floodplain area at the census block group level. Clusters of flood vulnerable areas were identified differently by each SETS domain, and some areas were vulnerable to floods in more than one domain. Results are provided to support decision-making for reducing risks to flooding, by considering social, ecological, and technological vulnerability as well as hotspots where multiple sources of vulnerability coexist. The spatially explicit urban SETS flood vulnerability framework can be transferred to other regions facing challenging urban floods and other types of environmental hazards. Mapping SETS flood vulnerability helps to reveal intersections of complex SETS interactions and inform policy-making for building more resilient cities in the face of extreme events and climate change impacts.

Highlights

Flooding is a major form of hazard that affects millions of people worldwide
Because many cities are located in river floodplains or along the coast, urban areas are frequently exposed to floods; approximately 1/8 of urban land in the United States is located in high-risk flood zones, affecting nearly a quarter-million people living in those zones (Qiang, Lam, Cai, & Zou, 2017)
One additional census block group in northeast Phoenix has high social vulnerability. This area is among the larger, newer census block groups in the north, and has a high percentage of renters and low median household income, but is dominated by young English-speakers, in contrast to the two southern/ western areas of high vulnerability

Summary

Introduction

Flooding is a major form of hazard that affects millions of people worldwide. According to the OECD (2016), global flood damage exceeds $40 billion annually. Drainage patterns and flood-mitigation infrastructure in most cities are not designed to adapt to the anticipated climate change-induced urban flooding hazards, posing potential technological risk to cities (Gimenez-Maranges, Pappalardo, La Rosa, Breuste, & Hof, 2020; Moh tar, Abdullah, Maulud, & Muhammad, 2020; Rosenzweig et al, 2018). It is this city level that emerges as a critical geographic level for under standing and mitigating flood hazards. Integrating the mul tiple domains of social, ecological and technological concerns is critical at the urban scale

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Conclusion