Evaluating Risk of Economic Loss due to River Flood in Urban areas (Study Area: Kan Watershed)

In this paper, direct loss to structures and their properties due to rivers’ floods in urban areas was investigated. Risk evaluation and flood management require an algorithm for evaluating economic loss due to flood. In this research, hydraulic properties such as depth and flow velocity were used to detect the destroyable areas during the flood event. Then the flow depth was used to estimate the economic loss due to floods with different return periods; 2, 5, 10, 25, 50, 100 and 500-year. The economic loss due to floods was calculated using the depth–loss functions of five different models. Furthermore, the costs of expected annual damage (EAD) for structures in the study area were determined for plan floods, of which the critical areas at the region were distinguished. The results showed that using depth-loss function of Arrighi et al. (2013) is more logic in the study area and it can be employed for risk management and flood insurance studies when the proper data are not exist. Finally, the depth-loss functions’ uncertainty were investigated using the First Order Variance Estimation (FOVE) method and the estimated loss confidence interval was determined. The procedure introduced in this paper provides a tool for rapid and acceptable approximation for risk assessment in urban flood-prone areas, especially where detailed information about structures and their pertinent properties cannot be provided.