Relationship between residential house damage and flood characteristics: A case study in the Teesta River Basin, Bangladesh

The flood damage function model is indispensable for flood damage assessment as it can provide useful information for establishing flood protection strategies. For the assessment of residential house damage in different areas, flood damage function models have been traditionally proposed considering only the depth-damage curve. However, flood duration and flood may also have an influence on flood damage. Conventionally, the damage rate was estimated based on information about monetary losses collected from local people or insurance payout databases. This research proposes a new methodology to establish a flood damage function model that considers flood depth, flood duration, and flood velocity. Field surveys were conducted in the Teesta River Basin of rural Bangladesh. For each house, a questionnaire survey was conducted to identify the flood information (flood depth, flood duration, and the qualitative representation of flood velocity), household structure information (area, plinth height, and ceiling height), structural damage mechanism, and the required amount of material and labor to repair the damage after each flood event. Finally, a flood damage function model including the impacts of house types and different flood parameters was established through multiple regression analysis. The consistency of the model was verified through the estimation of different statistical parameters. It can serve as a flood loss estimation model as it correlates flooding with various parameters, such as building materials and their damage mechanism.