دانشگاه شهید بهشتی پژوهشهای دانش زمین 2008-8299 16 Special Issue 2025 12 01 The relationship between morphometric parameters of alluvial fans’ upland catchment basin and soil resistance properties The relationship between morphometric parameters of alluvial fans’ upland catchment basin and soil resistance properties 31 51 106283 10.48308/esrj.2025.238347.1249 FA Amjad Maleki Department of Geography, Faculty of Literature and Humanities, Razi University, Kermanshah, Iran 0000-0003-0175-9038 Kazem Bahrami Department of Geography, Faculty of Literature and Humanities, Razi University, Kermanshah, Iran 0009-0005-3770-7514 Solmaz Moradi Department of Geography, Faculty of Literature and Humanities, Razi University, Kermanshah, Iran 0009-0009-4380-0482 Journal Article 2025 02 20 Morphometric properties of alluvial fans’ upland catchment basin e.g. the area, length of the main flow channel, and slope can affect particles’ features like roundedness, surface texture, and shear resistance i.e. grains’ angle of internal friction and cohesion. To carry out the current study, first 21 alluvial fans were selected through examining satellite images and conducting field observations. The selected alluvial fans were similar in terms of lithological features and different with regard to their morphology. Samples were obtained from the top, middle, and bottom of alluvial fans. The results showed that, through geomorphological processes, alluvial fans’ area and length of the main flow channel increases and their slopes declines from the top to the bottom. These features make grains at the bottom more rounded and less rough. The highest degree of roundedness and smoothness were observed in particles in the largest area, the longest main flow channel, and the lowest average slope of catchment basin. Depending on the morphometric parameters of the catchment basin, the angle of internal friction ranged from 44.3 ˚at the top to at the bottom of alluvial fans. Indeed, the highest angle of friction was detected in alluvial fans with the smallest catchment basin area, shortest main flow channel, and highest slope. Thus, the rise in catchment basins’ area and length of the main channel flow and the reduction in their slope will lead to smaller angle of internal friction. Morphometric properties of alluvial fans’ upland catchment basin e.g. the area, length of the main flow channel, and slope can affect particles’ features like roundedness, surface texture, and shear resistance i.e. grains’ angle of internal friction and cohesion. To carry out the current study, first 21 alluvial fans were selected through examining satellite images and conducting field observations. The selected alluvial fans were similar in terms of lithological features and different with regard to their morphology. Samples were obtained from the top, middle, and bottom of alluvial fans. The results showed that, through geomorphological processes, alluvial fans’ area and length of the main flow channel increases and their slopes declines from the top to the bottom. These features make grains at the bottom more rounded and less rough. The highest degree of roundedness and smoothness were observed in particles in the largest area, the longest main flow channel, and the lowest average slope of catchment basin. Depending on the morphometric parameters of the catchment basin, the angle of internal friction ranged from 44.3 ˚at the top to at the bottom of alluvial fans. Indeed, the highest angle of friction was detected in alluvial fans with the smallest catchment basin area, shortest main flow channel, and highest slope. Thus, the rise in catchment basins’ area and length of the main channel flow and the reduction in their slope will lead to smaller angle of internal friction. https://esrj.sbu.ac.ir/article_106283_65015786703160bf60e65208c44e28d8.pdf