1 June 2015

Robust Cost-Benefit Analysis to Assess Urban Flood Risk Management: A Case Study on Ho Chi Minh City

Ho Chi Minh City (HCMC), a fast-growing city located in the lowlands of South Vietnam,experienced record high flood levels in recent years. As HCMC accounts for 23% of the national GDP, increasing HCMC’s level of protection against flooding is of vital importance. Many flood risk mitigation strategies have been proposed to protect HCMC. This paper describes a cost-benefit analysis of a selection of these strategies, including a probabilistic risk analysis and a robustness analysis. Probabilistic modelling has been applied in addition to regular hydraulic modelling to provide reliable flood maps of HCMC and to provide input for the flood risk estimation. In the cost-benefit analysis, flood risk reduction is considered as the main benefit of the strategy investment. To test the robustness of a flood risk mitigation strategy, a sensitivity analysis has been carried out to obtain insight into the impact of a number of uncertainties on the outcome of the CBA. With this HCMC case, we demonstrate a successful application of a framework for robust CBA in urban flood risk management taking into account future uncertainty ranging from climate change, sea level rise and land subsidence to investment costs, phasing of the investment and macroeconomic growth.

Ruben Dahm, Frits Dirks , Jarit van de Visch, Ferdinand Diermanse, Marjolein Mens, Long Phi Ho. 13th International Conference on Urban Drainage, Sarawak, Malaysia, 7–12 September 2014