مریم ملاشاهی

INTRODUCTION: Today, natural crises have become an inseparable reality of human life, and one of the key measures to prevent the destructive consequences of natural disasters in any region is the identification and zoning of natural hazards. Therefore, the purpose of this research is to identify the factors affecting the occurrence and zoning of natural hazards within Mehdishahr county, Semnan province. METHODS: This research was conducted using a mixed method (quantitative and qualitative) and the status of risk and crisis management in Mehdishahr was examined. Data were collected from existing documents, interviews with key stakeholders (local officials, experts, and representatives of local communities), and analysis of statistical data related to past incidents. Using the Analytic Hierarchy Process (AHP) method, the factors under study were compared in pairs and the weight of each was calculated. FINDINGS: According to the findings, floods have the greatest impact on the riverbed and distance from it, the river parameter with 0.335 plays more than one-third of the flood risk, and land use with 0.096 has the lowest sensitivity. Also, faults with 0.370 are considered the most important and land type with 0.087 is the least important factor in causing earthquakes. Based on the results obtained from the AHP model, human factors, especially roads and paths, have the greatest impact on the occurrence of landslides, and along rivers they account for one-third of the factors affecting the occurrence of landslides. CONCLUSION: Considering the factors affecting the occurrence of natural disasters in Mehdishahr county, some preventive measures are necessary to preserve natural resources and the environment, ensure sustainable economic and social development, and reduce vulnerability, including: changing land use and respecting the privacy of rivers, preventing construction on the banks of rivers, stabilizing and stabilizing slopes, observing building regulations, and strengthening local capacities through education, empowerment, and promoting public and specialized awareness.

Introduction: According to the flood records in Mazandaran province, this region is regarded as one of the flood-prone regions of the country, and due to the floods, it has suffered many casualties and financial losses. Therefore, this study aimed to investigate the settlements at risk of flooding as one of the main goals of this research. Methods: This descriptive-analytical study was conducted based on extensive and exploratory research approaches. The required data were collected from monthly discharge and the maximum instantaneous discharge in the stations of Mazandaran province along with the population statistics of the provincial cities, as well as the statistics of the Natural Resources and Watershed Management Organization concerning the floods. Accordingly, the statistics of hydrometric stations from 1971 to 2021 of Iran's water resources management main company, the population statistics of the province based on the census of 2015, and the statistics of floods that occurred from the beginning to 2021 have been used in this study. Flood return periods were obtained in the study stations in different statistical distributions using Hyfa software. Finally, Arc GIS software (version 10.3) was used to zone floods in Mazandaran province. Findings: Based on the results, about 1013 square kilometers of the province's surface accounting for 4.25% of its total area is located in the boundaries of large floods that have a return period of 50 to 100 years. Moreover, due to the high altitude, rainy-snowy events, and the significant amount of precipitation in Sarab (Dali Chai and Lar basins) and Payab, Haraz basin has a significant runoff rate discharge so that about 500 to 600 liters of water flow from this basin annually per square meter. Conclusion: According to the obtained results, strategies have been proposed to increase resilience against flood risk using different methods.