عنوان مقاله [English]
Climate change and urbanization have put societies at the forefront of urban planning management challenges for a sustainable future. Recent studies show that climate change is likely to increase the hydrological cycle and increase the probability of severe weather events such as droughts and flood. Urbanization has increased the flood in recent decades with increasing levels of impenetrable and changing the flow paths. A flood itself is a natural phenomenon that is usually associated with positive consequences. However, when the flood occurs in the urban environment, it has devastating consequences for residents, in terms of property destruction as well as a threat to human health. The sensitivity of the elements depends on the readiness of the flood and the ability to deal with the event. The vulnerability of urban elements depends on the characteristics of building structures, services, equipment and fittings, the mobility of equipment and materials available. Vulnerability and Flood Resilience Assessment Methods, based on GIS Modeling and Multi-criteria Decision Making (MCDM), have increasingly been used to evaluate the hazard risks in settlements.
Due to precipitation changes and increase in impenetrable surfaces in northern Iran, the probability of occurrence of flood has increased in these areas. Therefore, this research has been conducted with the purpose to assess the integrated vulnerability, resilience and risk taking of Sari City against potential occurrence of flood.
Materials and methods
The data used in this research are including the statistical blocks of the city of Sari and the census data for 2017 from the Iranian Statistics Center, as demographic information, economic data and properties of residential units at the level of urban blocks. Digital Elevation Model (DEM) has also been derived from the American Geological Survey and used in the analysis. Exploring in the research literature and existing data helped us determine indicators for analysis. After determining the criteria and sub criteria, we have used the AHP questionnaire according to expert opinion, the criteria and sub criteria are compared and ranked in a pair.
Results and discussion
The weight of vulnerability and resilience indicators in different dimensions was obtained using expert opinion and AHP method mentioned in the methodology. According to the results, the spatial vulnerability of the later environmental flood has a higher weight and has a higher value in resilience to the flood of socioeconomic dimension. The central parts of the city have a higher resilience than the periphery of the city and the southern part of the city has a very low resilience. In many traditional approaches to flood risk assessment, vulnerability is considered equivalent to risk level. This is despite the fact that risk-taking today is measured by vulnerability and resilience.
The research had assessed the vulnerability, resilience, and spatial resolution of the Sari city in flooding conditions with an integrated approach. Urban blocks of Sari have been selected as the basis for measurements in order to make the necessary calculations to achieve the goal. Therefore, in this research, the flood has not been simulated and only vulnerability and resilience of urban structures have been evaluated in the urban blocks. The final output was the production of maps for vulnerability, resilience and spatial risk-taking for the urban blocks of Sari. According to the results, more than 600 hectares of the urban areas of Sari have high and very high vulnerability. Meanwhile, more than 800 hectares of the area has a high and very high resilience. According to these results, high and very high levels of risk taking in Sari are about 600 hectares. Compared with other studies, there has not yet been an article on the assessment of vulnerability and spatial resilience in flood conditions in the city of Sari. In 's research using f including: distance from the river, runoff coefficient, CN coefficient, population density, residential density, slope, land use, age of the building and open space of Sari in terms of risk Flood zoned. The results Mahmoud Zadeh and Bakui based on fuzzy analysis showed that the highest flood risk of Sari were located in the center and south parts of the city. Their flood zoning map showed that 24% of Sari was in a very high risk area and 37% of that was very low in flood risk. However, the basic principles of flood risk taking require a vulnerability assessment, resilience and then risk-taking. The occurrence of natural disasters today is a repetitive phenomenon that in some cases is accompanied by severe material-spiritual damage. Therefore, academic experts and planners are trying to assess different approaches and patterns by developing appropriate plans in line with damage reduction of natural disasters.