Numerical models are increasingly important for assessing urban flooding, yet reliable input data are oftentimes hard to obtain. Taking Ho Chi Minh City in southern Vietnam as an example, the first paper (https://doi.org/10.5194/nhess-23-2313-2023) explores the usability and reliability of open-access data to produce preliminary hazard maps that provide first insights into potential flooding hotspots. As a key novelty, a normalized flood severity index is presented which combines flood depth and duration to enhance the interpretation of hydro-numerical results. A comparison of locally reported inundations with flood severity hotspots finally validates the presented methodology and underlines the importance of open-access data for independent studies in data-scarce regions.
Like many other coastal megacities in low-elevation coastal zones, Ho Chi Minh City suffers from the convoluting impact of changing environmental stressors and rapid urbanization. The second paper (https://doi.org/10.5194/nhess-23-2333-2023), therefore, assesses the potential of different adaptation options against the background of the low-regret paradigm. Specifically, a large-scale flood protection scheme as currently constructed (1) and the widespread implementation of small-scale rainwater detention as envisioned in the Chinese Sponge City Program (2) as well as their combination (1+2) are scrutinized. Beyond the typical quantification of potential risk reductions in terms of decreased flood depths and extents, this study considers the previously defined flood severity index as well as the absolute number of affected small and medium enterprises which emphasizes the economic relevance of local stakeholders.
Paper 1:
Scheiber, L., Hoballah Jalloul, M., Jordan, C., Visscher, J. & Schlurmann, T. (2023): The potential of open-access data for flood estimations: uncovering inundation hotspots in Ho Chi Minh City, Vietnam, through a normalized flood severity index, Nat. Hazards Earth Syst. Sci., https://doi.org/10.5194/nhess-23-2313-2023.
Paper 2:
Scheiber, L., David, C.G., Hoballah Jalloul, M., Visscher, J., Nguyen, H.Q., Leitold, R., Díez, J. & Schlurmann, T. (2023): Low-regret climate change adaptation in coastal megacities – evaluating large-scale flood protection and small-scale rainwater detention measures for Ho Chi Minh City, Vietnam, Nat. Hazards Earth Syst. Sci., https://doi.org/10.5194/nhess-23-2333-2023.
