Assessment of the Vulnerability of Riverine Cities and Their Coping Capacity against Floods (Case Study: Ahvaz Metropolis)

Based on global statistics, floods rank the first among natural disasters that severely disrupt human life, property, and the environment. Iran, as one of the flood-prone countries, is located in southwestern Asia. The geographical elevation, maritime influences, seasonal winds, and proximity to mountain ranges or deserts play a significant role in its daily and seasonal temperature fluctuations, as well as its precipitation patterns and types. According to official statistics in Iran, among climate-related hazards, some 70% of the annual funds of the Plan for Reducing the Effects of Natural Disasters have been spent on compensation for damages from floods. Yet, what augments the importance of floods and their damages is the fact that human and urban centers have been located in flood-prone areas. Therefore, considering the dense populations and financial capitals in such areas, it is necessary to assess the vulnerability of urban floods, especially in big cities like Ahvaz. This metropolis, as the capital of Khuzestan province, is located in the marshy plains with a population of over one million people. It is traversed by the country’s most water-rich river, the Karun. The aim of this study is to assess the vulnerability of Ahvaz from flood as a natural hazard and its coping capacity. The methodology of the study is descriptive-analytical and is based on its practical purpose. Fuzzy Hierarchy Model (Fuzzy Analytic Hierarchy Process) has been used for the spatial analysis of vulnerability and the capacity to deal with floods. In summary, the findings are as follows: (a) Considering the floods that have occurred in the past six decades and comparing the affected areas with the results of this research in terms of highly vulnerable areas in the central part of the city, the model used has shown high efficiency in determining the vulnerability caused by urban flooding. (b) As far as vulnerability is concerned, location and physical–environmental conditions stimulate and reinforce other factors which are influential in determining the level of vulnerability. (c) Encroachment on river boundaries, especially limiting the river width, leads to a reduction in flood capacity and an increase in vulnerability in those areas. (d) The vulnerability level of Ahvaz to flooding, based on area, falls within five categories of vulnerability spectrum as follows: Very High 4.6%, High 8.7%, Moderate 13.4%, Low 15.2%, and Very Low 58%.