A Block-Level Categorical Flood Risk Mapping to Aid Shelter Location

Abstract

Flood shelters are crucial for mitigating flood impacts, providing temporary refuge. However, their effectiveness hinges on strategic placement near flood-prone areas, guided by accurate risk maps. Traditional flood risk analysis fails to distinguish floods based on their extent and duration, even though they have varying impacts. This study introduces a novel approach to flood risk mapping by creating maps specific to varying flood severity levels, offering a more precise understanding of spatial risk distribution compared to conventional methods. By classifying floods and computing hazard for each severity category, it provides a detailed understanding of relative hazard dynamics and their spatial variations. We further compute risk by combining hazard, vulnerability, and exposure at block level for each flood category. These category-specific risk maps highlight how risk differs across flood types at a granular level, demonstrating the benefits of such classification for tailored risk assessments. Analysis of categorized risk maps alongside current shelter locations reveals disparities between hotspots and shelter placements, highlighting the importance of effective shelter location and evacuation planning based on localized risk assessment. Fine-scale risk information is vital for informed community-level flood mitigation. The developed method offers a generalizable approach for categorizing risk maps across various spatial scales and global locations.