Urban flood hazard analysis in present and future climate after statistical downscaling: a case study in Ha Tinh city, Vietnam

ABSTRACT

Vietnamese cities are highly vulnerable to urban flooding as a consequence of climate change and rapid urbanisation. In this study, current and future pluvial urban flood hazard was assessed for Ha Tinh city. Climate scenarios were obtained after statistical downscaling by applying a quantile-perturbation approach on ensembles of 170 global and 20 regional climate models. Flood impact analysis was based on the 1D-2D dual drainage modelling approach. Extreme daily rainfall intensities are projected to increase by 5 to 20%, whereas wet day frequency will decrease with some uncertainty. Larger changes in rainfall intensities were obtained for the finer scale climate models. Under the 95% upper limit scenario for future rainfall intensities (2071–2100), a 20-year intensity in the current climate would become a 2-year storm in the future and the flood extent is projected to increase by 30–40%. This indicates a need for climate adaptation measures and sustainable future urban planning.

KEYWORDS:

• Urban flooding
• statistical downscaling
• climate change
• Ha Tinh city -Vietnam

Acknowledgements

DHI is acknowledged for providing the license of MIKE Software package. The existing 1D-2D urban model and urban drainage parameters data were provided by the Enabel (formerly called BTC) project, namely Integrated water resources management and urban development in relation to climate change in Ha Tinh province (IWMC). We also acknowledge the World Climate Research Programme’s Working Group for producing and making available their climate model outputs. Our colleagues at KU Leuven, who supported the climate change analysis, are acknowledged for their help in this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research was supported by a Ph.D. fellowship grant as part of the VLIR-UOS TEAM project, namely WAMADE (WAter MAnagement and urban DEvelopment in Ha Tinh in relation to climate change). The project is conducted in cooperation with VNU Institute of Vietnamese Studies and Development Science, Vietnam (VNU-IVIDES), and KU Leuven, Belgium.