Comprehensive Assessment of Flood Susceptibility in the Gorganroud Watershed Based on Influential Factors

Najafi Vafa, Azam; Hosseini, Seiyed Mossa; Jafarbeglou, Mansour; Hosseinzadeh, Mohammad Mehdi

doi:10.22111/jneh.2025.48905.2049

Comprehensive Assessment of Flood Susceptibility in the Gorganroud Watershed Based on Influential Factors

Document Type : Research Article

Authors

¹ PhD Student in Geomorphology, Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran

² Associate Professor, Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran

³ Associate Professor, Department of Physical Geography, Faculty of Geography, University of Shahid Beheshti, Iran

10.22111/jneh.2025.48905.2049

Abstract

Floods, as integral components of the natural hydrological cycle, can lead to significant social disruptions and morphological alterations in riverine and floodplain environments. Understanding the contributing factors and their relative impacts on basin flood susceptibility is vital for sustainable water resource management and flood risk mitigation. This study presents a streamlined approach to assessing flood susceptibility in the Gorganrud River Basin by integrating a comprehensive set of influencing factors. These factors encompass climatic variables (mean daily and hourly precipitation, snow depth, and snowmelt water equivalent), topographic features (digital elevation model, slope, and aspect), geomorphological characteristics (distance to main rivers, soil texture, geology, proximity to faults, drainage density), land use/land cover, vegetation status, and anthropogenic interventions. Each of the 13 factors was standardized and equally weighted, followed by a weighted linear combination to generate the flood susceptibility map. Validation was conducted using the mean time series of peak discharge data from 26 hydrometric stations, employing Spearman's rank correlation and receiver operating characteristic (ROC) curve analyses. Sensitivity analysis involved sequentially omitting each factor to evaluate its influence on flood susceptibility outcomes. Findings indicate heightened flood potential in the southeastern, western, and northeastern sectors of the basin. The Spearman correlation coefficient and area under the ROC curve (AUC) for the 100-year return period across 15 hydrometric stations were 0.66 and 0.68, respectively. Sensitivity analysis identified hourly precipitation, snowmelt water equivalent, and elevation as the most influential factors. The proposed methodology offers a practical framework for identifying flood-prone areas within the Gorganroud Basin, facilitating prioritized management and watershed planning interventions.

Keywords

Main Subjects

Hydrology & Hydrogeology

References

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