Assessing catchment scale flood resilience of urban areas using a grid cell based metric

Fanlin Meng,Haixing Liu,Chi Zhang,Guangtao Fu,Yuntao Wang

doi:10.1016/j.watres.2019.114852

Fanlin Meng, Haixing Liu + Show 3 more

Open Access

https://doi.org/10.1016/j.watres.2019.114852

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Abstract

Urban flooding has become a global issue due to climate change, urbanization and limitation in the capacity of urban drainage infrastructures. To tackle the growing threats, it is crucial to understand urban surface flood resilience, i.e., how urban drainage catchments can resist against and recover from flooding. This study proposes a grid cell based resilience metric to assess urban surface flood resilience at the urban drainage catchment scale. The new metric is defined as the ratio of the number of unflooded grid cells to the total grid cell number in an urban drainage catchment. A two-dimensional Cellular Automata based model CADDIES is used to simulate urban surface flooding. This methodology is demonstrated using a case study in Dalian, China, which is divided into 31 urban drainage catchments for flood resilience analysis. Results show the high resolution resilience assessment identifies vulnerable catchments and helps develop effective adaptation strategies to enhance urban surface flood resilience. Comparison of the new metric with an existing metric reveals that new metric has the advantage of fully reflecting the changing process of system performance. Effectiveness of adaptation strategies for enhancing urban surface flood resilience is discussed for different catchments. This study provides a new way to characterize urban flood resilience and an in-depth understanding of flood resilience for urban drainage catchments of different characteristics, and thus help develop effective intervention strategies for sustainable sponge city development.

Highlights

Urban surface flooding, exacerbated by climate change and rapid urbanization, has caused grave negative consequences in many cities worldwide over the past decades (Hammond et al, 2015; Lo€we et al, 2017; Wang et al, 2018)
By incorporating resilience in urban flooding assessment and management, existing drainage capacity of an area can be better utilized and investment can be focused on places that are less resilient to flooding
The aim of this study is to propose a performance-based analytical framework for assessing flood resilience at urban drainage catchment scale

Summary

Introduction

Urban surface flooding, exacerbated by climate change and rapid urbanization, has caused grave negative consequences in many cities worldwide over the past decades (Hammond et al, 2015; Lo€we et al, 2017; Wang et al, 2018). Significant efforts have been made in developing flood assessment methods or frameworks (Hirabayashi et al, 2013; Jenkins et al, 2017; Morrison et al, 2017), which are essential to support decision-making for investment on flood management schemes such as the sponge city initiative in China (Jia et al, 2017). The current practice mainly focuses on the assessment of flood risk, i.e. the product of the likelihood of flooding and the related consequence. By incorporating resilience in urban flooding assessment and management, existing drainage capacity of an area can be better utilized and investment can be focused on places that are less resilient to flooding

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