Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam
Flood risks resulting from tropical cyclone (TC) activities are one of the most severe natural hazards in Northern Vietnam. Conventionally, the TC intensity has been the primary measure used to assess the severity of the flood hazard, often overlooking other possible critical factors. There have bee...
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| Other Authors: | |
| Format: | Conference Paper |
| Language: | English |
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2024
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| Online Access: | https://hdl.handle.net/10356/179714 https://aprumh2024.wcdr.ntu.edu.tw/ |
| _version_ | 1826113239492067328 |
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| author | Angkanasirikul, Warinthorn Jian, Wei Lo, Edmond Yat-Man |
| author2 | Interdisciplinary Graduate School (IGS) |
| author_facet | Interdisciplinary Graduate School (IGS) Angkanasirikul, Warinthorn Jian, Wei Lo, Edmond Yat-Man |
| author_sort | Angkanasirikul, Warinthorn |
| collection | NTU |
| description | Flood risks resulting from tropical cyclone (TC) activities are one of the most severe natural hazards in Northern Vietnam. Conventionally, the TC intensity has been the primary measure used to assess the severity of the flood hazard, often overlooking other possible critical factors. There have been some studies on simulating event-based coastal flooding using numerical models at the city level for certain parts of Northern Vietnam. However, since TCs often impact large areas along their trajectories, evaluation of regional-scale hazards would require extensive data and computational effort.
Our study examines the characteristics of the selected 72 landfall TCs in Northern Vietnam from 1979 to 2023 for their linkages to TC-induced floods experienced in the region. We evaluate the flood severity (FS) using three metrics: area, duration, and magnitude, determined by grid-level river discharge thresholds over a 3-year return period during the TC events. Based on literature review, we consider a total of 18 potential factors related to TC characteristics, catchment characteristics, event-specific antecedent catchment state and responses. We assess their correlations with the event-specific FS metric using Spearman’s correlation, conditional probability, and variable interplay. Results suggest that average daily precipitation exhibits the strongest correlation with FS area, while runoff coefficient correlates highest with FS duration. FS magnitude is most strongly linked to the event time series – defined as the ratio between direct runoff volume and direct peak flow of TC-induced floods, followed by runoff coefficient. These findings underscore the complex interplay of multiple factors in characterize the severity of TC-induced flooding severity in Northern Vietnam.
We further carefully chose seven factors, based on their Spearman’s correlation coefficients with the FS measures, to generate the regional flood susceptibility map. The result shows that 51% of the region is considered as relatively low for TC-induced flood hazard, with 39%, 7% and 3%, as moderate, low, and relatively high, respectively. Although the area exposed to relatively high likelihood of TC-induced flooding is small in percentage, it covers approximately 4,200 km², impacting key economic activities such as rice farming, plantation, and fisheries. This map emphasises the significant potential for TC-induced flood risks to affect livelihoods and economic activities in Northern Vietnam. |
| first_indexed | 2025-03-09T10:48:15Z |
| format | Conference Paper |
| id | ntu-10356/179714 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-03-09T10:48:15Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | ntu-10356/1797142024-10-13T15:36:07Z Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam Angkanasirikul, Warinthorn Jian, Wei Lo, Edmond Yat-Man Interdisciplinary Graduate School (IGS) School of Civil and Environmental Engineering 19th APRU Multi-Hazards Symposium 2024 Institute of Catastrophe Risk Management (ICRM) Engineering Flood severity Flood susceptibility Tropical cyclone Flood risks resulting from tropical cyclone (TC) activities are one of the most severe natural hazards in Northern Vietnam. Conventionally, the TC intensity has been the primary measure used to assess the severity of the flood hazard, often overlooking other possible critical factors. There have been some studies on simulating event-based coastal flooding using numerical models at the city level for certain parts of Northern Vietnam. However, since TCs often impact large areas along their trajectories, evaluation of regional-scale hazards would require extensive data and computational effort. Our study examines the characteristics of the selected 72 landfall TCs in Northern Vietnam from 1979 to 2023 for their linkages to TC-induced floods experienced in the region. We evaluate the flood severity (FS) using three metrics: area, duration, and magnitude, determined by grid-level river discharge thresholds over a 3-year return period during the TC events. Based on literature review, we consider a total of 18 potential factors related to TC characteristics, catchment characteristics, event-specific antecedent catchment state and responses. We assess their correlations with the event-specific FS metric using Spearman’s correlation, conditional probability, and variable interplay. Results suggest that average daily precipitation exhibits the strongest correlation with FS area, while runoff coefficient correlates highest with FS duration. FS magnitude is most strongly linked to the event time series – defined as the ratio between direct runoff volume and direct peak flow of TC-induced floods, followed by runoff coefficient. These findings underscore the complex interplay of multiple factors in characterize the severity of TC-induced flooding severity in Northern Vietnam. We further carefully chose seven factors, based on their Spearman’s correlation coefficients with the FS measures, to generate the regional flood susceptibility map. The result shows that 51% of the region is considered as relatively low for TC-induced flood hazard, with 39%, 7% and 3%, as moderate, low, and relatively high, respectively. Although the area exposed to relatively high likelihood of TC-induced flooding is small in percentage, it covers approximately 4,200 km², impacting key economic activities such as rice farming, plantation, and fisheries. This map emphasises the significant potential for TC-induced flood risks to affect livelihoods and economic activities in Northern Vietnam. 2024-10-11T03:40:53Z 2024-10-11T03:40:53Z 2024 Conference Paper Angkanasirikul, W., Jian, W. & Lo, E. Y. (2024). Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam. 19th APRU Multi-Hazards Symposium 2024. https://hdl.handle.net/10356/179714 https://aprumh2024.wcdr.ntu.edu.tw/ en © 2024 National Taiwan University. All rights reserved. application/pdf |
| spellingShingle | Engineering Flood severity Flood susceptibility Tropical cyclone Angkanasirikul, Warinthorn Jian, Wei Lo, Edmond Yat-Man Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title | Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title_full | Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title_fullStr | Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title_full_unstemmed | Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title_short | Key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in Northern Vietnam |
| title_sort | key factors influencing the flood severity and susceptibility from landfalling tropical cyclones in northern vietnam |
| topic | Engineering Flood severity Flood susceptibility Tropical cyclone |
| url | https://hdl.handle.net/10356/179714 https://aprumh2024.wcdr.ntu.edu.tw/ |
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