NH024-06
Comp-Flood: Compound Flooding In Coastal Vietnam
Friday, 11 December 2020: 11:00
Virtual
Melissa Wood1, Nguyen N Hung2, Le Q Quan2, Stephen E Darby3, Joel Hirschi4, Robert Marsh5, Nikolaos Skliris5 and Ivan David Haigh5, (1)University of Southampton, Ocean and Earth Science, Southampton, SO14, United Kingdom, (2)Southern Institute of Water Resources Research, Ho Chi Minh City, Vietnam, (3)University of Southampton, Geography and Environmental Science, Southampton, SO14, United Kingdom, (4)National Oceanography Centre, Southampton, United Kingdom, (5)University of Southampton, Ocean and Earth Science, Southampton, United Kingdom
Abstract:
Compound flooding occurs when events combine concurrently or in close succession to exacerbate the severity of flooding. Even so, compound events are not ordinarily considered when characterising flood vulnerabilities in coastal areas, and as a result assessments habitually underestimate the potential severity of flood risk during extreme events. This omission has serious implications for disaster management and strategic flood planning for coastal communities. In Vietnam, 70% of the population inhabit highly exposed low lying coastal areas. Our Comp-Flood project is therefore examining the potential for combined coastal, fluvial and surface water flooding in the Mekong Delta, Vietnam, with a particular focus on the consequences of tropical storm activity. Early results are presented here.
Changes in monsoon precipitation and tropical cyclone activity, now and in the future (in RCP 21st century climate simulations), are attributed to modes of regional climate variability. Anomalous atmosphere-ocean interaction across the wider Indo-Pacific determines the variability, extent and scale of intense rainfall and sea surges in this region. We further utilise the statistically-generated STORM global synthetic tropical cyclone dataset[i], to obtain 10,000 seasons of past, present and (predicted) future large-scale tropical storm activity. Together, these meteorological data will drive coupled hydrological (SWAT), fluvial and coastal (MIKE 11 and 21) models to estimate the likelihood of compound flood events in the Mekong delta, to assess which weather patterns might lead to compound events here and to indicate the potential flood severity. The project’s results will be used to provide information to key stakeholders on flood exposure for regional emergency plans and to provide guidance for future flood preparedness and resilience planning.
[i] Bloemendaal, N., Haigh, I.D., de Moel, H., Muis, S., Haarsma, R.J. and Aerts, J.C., 2020. Generation of a global synthetic tropical cyclone hazard dataset using STORM. Scientific Data, 7(1), pp.1-12.
