Flood risk map from hydrological and mobility data: a case study in S\~ao Paulo (Brazil)

TL;DR

This paper develops a flood risk map for São Paulo using hydrological and mobility data, highlighting flood susceptibility and impact, to aid urban planning and disaster management.

Contribution

It introduces a novel method combining hydrological and mobility data to classify flood risk levels in an urban setting.

Findings

Flood susceptibility is strongly influenced by proximity to watercourses.

Most flood impact components have few cells in the Very High risk class.

The method effectively identifies high-risk flood zones in São Paulo.

Abstract

Cities increasingly face flood risk primarily due to extensive changes of the natural land cover to built-up areas with impervious surfaces. In urban areas, flood impacts come mainly from road interruption. This paper proposes an urban flood risk map from hydrological and mobility data, considering the megacity of S\~ao Paulo, Brazil, as a case study. We estimate the flood susceptibility through the Height Above the Nearest Drainage algorithm; and the potential impact through the exposure and vulnerability components. We aggregate all variables into a regular grid and then classify the cells of each component into three classes: Moderate, High, and Very High. All components, except the flood susceptibility, have few cells in the Very High class. The flood susceptibility component reflects the presence of watercourses, and it has a strong influence on the location of those cells classified as Very High.