Evaluation and analysis of resilience of 29 neighborhoods in Tehran's district 5 against environmental crises based on ecosystem approach

Introduction
The metropolitan city of Tehran, as the political capital of Iran, has a population exceeding 8 million and a population density of 12,200 individuals per square kilometer. Spanning an area of approximately 751 square kilometers, Tehran is situated at an elevation ranging from 900 to 1800 meters in the southern foothills of the Alborz Mountains. This high population density, coupled with exposure to various environmental hazards, has rendered crisis management in this city a complex and multifaceted challenge. Environmental crises such as earthquakes, floods, fires, water and air pollution, and land subsidence have exacerbated Tehran’s environmental vulnerability, posing substantial risks to urban security and public welfare, particularly in highly susceptible areas such as District 5. A comprehensive understanding of the dimensions of vulnerability in District 5 against environmental crises is imperative for devising effective management strategies aimed at mitigating vulnerability and risk while enhancing urban resilience. Accordingly, the primary objective of this study is to assess the level of urban resilience in District 5 of Tehran concerning environmental crises. Additionally, this research seeks to identify structurally and functionally deficient neighborhoods in order to propose evidence-based and practical strategies for addressing these weaknesses and enhancing resilience. The findings of this study contribute to a deeper understanding of the challenges ahead and facilitate targeted planning and optimal resource allocation.
 
Materials and Methods
The study area comprises District 5 of Tehran Municipality, selected as a representative case due to its distinct characteristics, including its exposure to multiple environmental hazards. A mixed-method approach was employed to assess urban resilience against environmental crises, encompassing earthquakes, floods, subsidence, and fires. Data were obtained through expert interviews with urban planners and environmental specialists, literature reviews, examination of relevant documents and records, and field observations. In this study, urban resilience indicators were employed to evaluate the resilience of neighborhoods in District 5 of Tehran against environmental crises. The assessment was conducted based on four main criteria: socio-economic, physical-structural, accessibility, and environmental, incorporating 37 sub-criteria. Each sub-criterion was mapped as a distinct data layer using ArcGIS software. Subsequently, fuzzy logic operators were applied to standardize (fuzzify) the data by converting values into a range between zero and one. The Analytical Network Process (ANP) was employed to determine the relative weight and significance of each criterion and sub-criterion, enabling the consideration of interdependencies among them.
The spatial layers corresponding to each criterion were integrated and analyzed using fuzzy logic operators. 
Finally, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was utilized to rank the neighborhoods of District 5, and a classical clustering approach was applied to classify them based on their resilience levels.
 
Results and Discussion
The results indicate that the socio-economic criterion, with a fuzzy membership degree of 0.45, is the most influential determinant of urban resilience in District 5 of Tehran. Factors such as the structural integrity of residential buildings, the presence or absence of informal settlements, accessibility to essential services (e.g., healthcare, educational institutions), exposure to flood-prone areas, and land-use classification significantly influence the resilience levels of this district. From a spatial perspective, neighborhoods such as Shahin, Northern Jannat Abad, and Al-Mahdi, located in the northern part of the district, demonstrate the highest levels of resilience. This resilience is attributed to factors such as robust building structures, the absence of informal settlements, sufficient distance from flood pathways and pollution sources, availability of open spaces, and optimal access to service centers. Conversely, neighborhoods such as Ekbatan, Bimeh, and Kan exhibit the lowest resilience levels, highlighting critical areas for intervention. The least squares regression indicated that the fuzzy algebraic sum operator (SUM) demonstrated the best performance in detecting neighborhood resilience against environmental crises.
 
Conclusion
The southern neighborhoods of District 5, including Ekbatan, Bimeh, Kan, Apadana, and Eram, exhibit lower resilience due to high population and building densities, the presence of aging infrastructure and informal settlements, environmental pollution, and socio-economic and infrastructural deficiencies, along with limited access to essential services. These findings underscore the heightened vulnerability of these neighborhoods to environmental crises, indicating their potential to sustain substantial damage and loss in the event of a disaster. This study provides critical insights by systematically identifying weaknesses and vulnerabilities within District 5, thereby equipping urban policymakers and decision-makers with essential data for informed decision-making. The adoption of targeted interventions, such as infrastructure enhancement, urban renewal, public awareness campaigns, and the reinforcement of crisis management systems, can significantly bolster resilience levels. Future strategies should prioritize investment in upgrading infrastructure, retrofitting vulnerable urban fabrics, increasing public preparedness, and strengthening disaster management frameworks to enhance overall urban resilience.