Methodology for climate change assessment of flood dynamics using deterministic hydrological model - Application to the Vugia-Thubon catchment - Vietnam

In recent years, Climate Change is commonly known as global warming and associated with sea level rise. Such process is one of the most serious challenges facing the human beings in the 21st century. Under the impact of these phenomena, extreme climatic phenomena are expected to be more frequent and serious, leading to natural disasters especially related to water. Flood risk represents a major issue especially for developing countries where the economy as well as the adaptation capacity against disaster is still poor. As shown in World Bank studies, with more than 70% of the population working in agriculture, inhabitants essentially concentrate at the coastal plain, Vietnam is one of the countries most heavily affected by the consequences of climate change. To get more understanding on the impact of this natural phenomenon to Vietnamese people, a methodology has been elaborated in order to assess different climate scenarios over a large catchment and flood dynamics. The simulations are based on a validated deterministic hydrological model which is integrating geology, soil, topography, river systems and climate variables. The validation of this model is obtained through measurements and observations made at different stations within the catchment. The actual climate in the period of 1998-2004 is properly reproduced by the model which provides a clear view about the flood processes. Future climate is obtained from downscaled GCM data that provide a scenario for 2094-2100 of hydrological variables. The new simulation allows to analyze the changes in the flood dynamics and to perform the frequency and the return period analysis. The approach allows providing an operational model for integrating the climate change within the engineering design activities dedicated to flood protection measures and resilience strategies.