Aliasghar Hodaei
Vahid Feizi - Assistant Professor, PhD in Climatology, University of Tehran, Tehran, Iran
Mehdi Najafi
Maryam Mollashahi

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 ۱۹۷۱ to ۲۰۲۱ of Iran's water resources management main company, the population statistics of the province based on the census of ۲۰۱۵, and the statistics of floods that occurred from the beginning to ۲۰۲۱ 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 ۱۰.۳) was used to zone floods in Mazandaran province. Findings: Based on the results, about ۱۰۱۳ square kilometers of the province's surface accounting for ۴.۲۵% of its total area is located in the boundaries of large floods that have a return period of ۵۰ to ۱۰۰ 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 ۵۰۰ to ۶۰۰ 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.

Flood, Return period, Crisis management, Mazandaran province, سیل خیزی, دوره بازگشت, مدیریت بحران, استان مازندران