ارزیابی یک‌پارچه آسیب‌پذیری، تاب‌آوری و ریسک‌پذیری فضایی در برابر سیلاب در شهر ساری

تغییرات آب و هوایی با تاثیرگذاری در چرخه هیدرولوژیکی و افزایش شهرنشینی با افزایش سطوح نفوذناپذیر احتمال وقوع حوادث سیل را افزایش داده‏اند. در این تحقیق با رویکردی یک‏پارچه، آسیب‏پذیری، تاب‏آوری، و ریسک‏پذیری فضایی شهر ساری در مقیاس بلوک‏های شهری در برابر سیلاب  ارزیابی شده است. در این تحقیق برای نیل به هدف نخست شاخص‏های ارزیابی آسیب‏پذیری و تاب‏آوری تعیین و محاسبه شد. سپس، با استفاده از مدل‏سازی سیستم اطلاعات جغرافیایی (gis) و مدل‏های تصمیم‏گیری چندمعیاره (mcdm) توزیع فضایی آن‏ها به‏دست آمد. نتایج این تحقیق نشان داد که بیش از 600 هکتار از مناطق شهر ساری پتانسیل آسیب‏پذیری بالا و بسیار بالا را دارد. در مقابل، بیش از 800 هکتار از مساحت شهر ساری دارای تاب‏آوری بالا و بسیار بالاست. بااین‏حال، با ادغام نقشه‏های آسیب‏پذیری و تاب‏آوری، مشخص شد که حدود 600 هکتار از وسعت شهر ساری دارای ریسک‏پذیری بالا و بسیار بالا در برابر سیل ‏است. همچنین، نتایج نشان داد که بلوک‏های شهری در جنوب شهر ساری بیشترین ریسک‏پذیری نسبت به سیلاب را دارند.

Integrated Assessment of Vulnerability, Resiliency and Space Risk against Flood in Sari

Introduction Climate change and urbanization have put societies at the forefront of urban planning management challenges for a sustainable future (Bertilsson & Wiklund, 2015). 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 floods (Bates et al. 2008). Also, urbanization has increased the flood in recent decades with increasing levels of impenetrable and changing the flow paths (Chen et al, 2015). A flood itself is a natural phenomenon that is usually associated with positive consequences. But 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 (Becker, 2014). 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 (Cho & Chang, 2017). Vulnerability and Flood Resilience Assessment Methods, based on GIS Modeling and Multicriteria Decision Making (MCDM), have increasingly been used (Lee et al, 2013; Radmehr & Araghinejad, 2015; Sunarharum et al, 2015; Su et al, 2018; Birgani et al, 2018 ). Due to precipitation changes and increase of impenetrable levels in northern Iran, the probability of occurrence of flood in these areas has increased. Therefore, this research has been conducted with the aim of assessing the integrated vulnerability, resilience and risk taking of Sari city against potential occurrence of flood. Materials and methods This data includes the statistical blocks of the city of Sari along with the census data of 2017 from the Iranian Statistics Center, which includes demographic information, economic data and properties of residential units at the level of urban blocks. Digital Elevation Model (DEM) from the American Geological Survey. Indicators required after the study of existing research literature and existing data were determined. After determining the criteria and sub criteria, using the AHP questionnaire and according to expert opinion, the criteria and sub criteria are compared and ranked in a pair. Conclusion When natural hazards occur in a vacant area, it is only a risk, and the same danger if it occurs in the residential area and affects the human life of that area and causes the social and economic activities of the inhabitants to be troubled. Thus, the effects of natural disasters are determined by the degree of vulnerability of the community to a danger, or the opposite, its ability to deal with the disaster. This is not a natural vulnerability, but a result of changing natural, social, economic, cultural, political or even psychological factors that shape the lives of humans and create the environments in which humans live. In fact, natural disasters and disasters are the judgments of nature about human performance. Today, many habitable places are exposed to natural hazards. The spectacular point is that natural hazards can not be eliminated, but should be reduced to the management of this phenomenon or improve the survival of societies against such hazards. A study of the history of studies shows that the resilience of residents to natural disasters is promoted by social, economic, environmental and managerial factors. Vulnerability to natural disasters reflects the resilience to the positive aspects and strengths of societies. The research attempted to assess the vulnerability, resilience and spatial resolution of the Sari city to the flood with a comprehensive approach. The city blocks of Sari city were selected as the basis for measurements, so that the calculations needed to reach the target were made. The final output was the production of vulnerability maps, resilience and spatial risk aversion at the level of the city blocks of Sari. More than 600 hectares of the Saray area are highly vulnerable. Meanwhile, more than 800 hectares of Sari city area have high and very high resilience. According to these results, high and high risk taking in Sari is about 600 hectares. After weighing, the values of different indices in different dimensions were used by linear fuzzy method between 1 and 0. In this research, a linear method was used to fuzzy the indices. Then, the standard maps were combined with the help of gamma fuzzy operators. Keywords: Vulnerability, Resilience, Risk, Flood, Sari