University of Twente Student Theses


Flood Risk assessment in Barcelonnette, France

Bhattacharya, Namrata (2010) Flood Risk assessment in Barcelonnette, France.

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Abstract:Flood risk is the result of natural processes and anthropogenic activities. It calls for a close assessment of all issues related to extreme events with a view to correctly evaluate their impact and the risk associated with them. An integrated hydrological modelling approach for risk assessment and its effect on the study area in Ubaye River valley (France) has been adopted in this research. The steps entailed in the research can be broadly divided into four major parts. Firstly, detailed investigations of the available historical data were made to understand the probabilistic occurrence of the events. These were done by analysing the hydro-meteorological and cartographic data with statistical evaluation of the events. The second step involved modelling of events with selected return periods using SOBEK1D2D hydrodynamic model using a DSM that was generated by combining the natural terrain and manmade topography. The selected return periods used were 75, 100, 200, and 500 years. The model was calibrated based on varying Manning’s friction coefficient within the channel to obtain the best results using observed data for water depth for a recent event. In the third step, a vulnerability assessment was carried out by comparing depth and the duration of the selected flood eventswith the physical elements at risks. Finally, integrated risk assessment maps were prepared by combining the elements at risk with, the data on flood characteristics and stage damage functions. Risk maps were generated based on types and functions of the elements at risks for a better understanding of the flood situation in the area. The results from this research provided useful information on risk prone areas and the elements at risk especially near the vicinity of the river. The methodological approach of reconstruction of the events using SOBEK had achieved a result up to an accuracy level ranging between 0.29 m to 0.9 m after calibration of the model. The vulnerability assessment of the physical elements at risk had been achieved using stage damage functions used in Germany, United Kingdom and France. Risk assessment was analysed in terms of economic damage caused by differential effects of flood hazard. The incorporation of land use, economic data and flood characteristics information resulted in the level of risk delineation in different zones. The result from this study were further investigated in a comparative analysis of the changes that had occurred due to changes in protection plans like Prévention des Risques naturels prévisibles (PPR) and Plan d'Exposition aux Risques (PER) for the past 25 years . The final outputs from the study have a potential for flood risk communication among people and an impact on the strategic management decisions taken by the authorities and policy makers. Key words: DSM, SOBEK-1D2D, Hydrodynamic model, Friction, Hazard, Vulnerability, Risk.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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