Flood Risk Assessment in Urban Areas Based on Spatial Analytics and Social Factors

Costas Armenakis,Ying Zhang,Ravi Persad,Erin Du,Sowmya Natesan

doi:10.3390/geosciences7040123

Abstract

Flood maps alone are not sufficient to determine and assess the risks to people, property, infrastructure, and services due to a flood event. Simply put, the risk is almost zero to minimum if the flooded region is “empty” (i.e., unpopulated, has not properties, no industry, no infrastructure, and no socio-economic activity). High spatial resolution Earth Observation (EO) data can contribute to the generation and updating of flood risk maps based on several aspects including population, economic development, and critical infrastructure, which can enhance a city’s flood mitigation and preparedness planning. In this case study for the Don River watershed, Toronto, the flood risk is determined and flood risk index maps are generated by implementing a methodology for estimating risk based on the geographic coverage of the flood hazard, vulnerability of people, and the exposure of large building structures to flood water. Specifically, the spatial flood risk index maps have been generated through analytical spatial modeling which takes into account the areas in which a flood hazard is expected to occur, the terrain’s morphological characteristics, socio-economic parameters based on demographic data, and the density of large building complexes. Generated flood risk maps are verified through visual inspection with 3D city flood maps. Findings illustrate that areas of higher flood risk coincide with areas of high flood hazard and social and building exposure vulnerability.

Highlights

In recent years, large Canadian cities have experienced significant flooding, resulting in the loss of lives, the endangerment of vulnerable populations, the disruption of services, and substantial damage to properties and critical infrastructure
The risk was determined by integrating the values for the flood hazard impact, the vulnerability of people, the exposure of the physical infrastructure, and the risk resiliency to cope with the flood event
Social vulnerability is associated with a lack of resources to mitigate, cope with, or recover from disaster

Summary

Introduction

Large Canadian cities have experienced significant flooding, resulting in the loss of lives, the endangerment of vulnerable populations, the disruption of services, and substantial damage to properties and critical infrastructure. While accurate flood forecasting contributes significantly to the reduction of fatalities and damages, a very important contribution is the generation of flood maps and the estimation of flood risk. Flood maps indicate the inundated areas based on the rising water levels. Earth observation (EO) datasets (spaceborne, aerial, and low-altitude) together with geographic information systems can be extensively used to determine the extent of flood areas based on terrain elevation, hydrology network, land cover, and land use. Geomatics technologies such as earth observation satellites, Geographical Information Systems (GIS), Global Navigation Satellite

Methods

Results

Conclusion