Abstract
Flood risk maps are important references for disaster prevention and emergency response. The accuracy of risk maps is greatly affected by the resolutions of hazard and vulnerability maps. To determine the impact of map resolutions on flood risk analysis, a total of 12 risk maps were generated for Shanhua District, Taiwan, via the integration of hazard and vulnerability maps under two resolutions and three return periods. The hazard, vulnerability, and risk maps were classified into five levels according to flood depth, socio-economic indicators, and their products, respectively. The results show that the downscaling of hazard maps greatly increases the hit rate by 28% and decreases the false alarm rate by 53% in the flood risk analyses of households. In contrast, the downscaling of vulnerability maps only slightly increases the hit rate without an obvious decrease in the false alarm rate. To improve flood risk analysis under time and budget limitations, numerical downscaling of hazard maps should be given higher priority because it reduces the structural errors in hydraulic simulations that cannot be compensated for by the statistical downscaling of vulnerability maps.
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Acknowledgments
This research was partially funded by the Ministry of Science and Technology (grant no. MOST 109-2625-M-006-012). The authors would like to thank the Central Weather Bureau, the Water Resources Agency, and the National Science and Technology Center for Disaster Reduction for providing research data.
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The data that support the findings of this study are available from the corresponding author JHJ upon reasonable request.
Funding
This research was partially funded by the Ministry of Science and Technology, Taiwan (grant no. MOST 109–2625-M-006-012).
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JHJ and PV initiate the research; PV analyzed the data; JHJ and YLK review the manuscript.
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Jang, JH., Vohnicky, P. & Kuo, YL. Improvement of Flood Risk Analysis Via Downscaling of Hazard and Vulnerability Maps. Water Resour Manage 35, 2215–2230 (2021). https://doi.org/10.1007/s11269-021-02836-0
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DOI: https://doi.org/10.1007/s11269-021-02836-0