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Analysis of the relationship between landslides and drainage network indices (Case study: six drainage basins in the folded Zagros)
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Forouzan Naseri1   , Shahram Bahrami *1 , Alireza Salehi pour milani1 , Mohsen Ehteshami-Moinabadi1 |
| 1- shahid beheshti university |
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Abstract: (188 Views) |
The drainage network is one of the factors affecting the occurrence of landslides and, by controlling the concentration of runoff and surface erosion, has a significant impact on the stability of slopes and the occurrence of landslides. This study aimed to analyze the spatial relationship between drainage network indices and morphometric characteristics of watersheds and the occurrence of landslides in basins from the Ilam-Kermanshah area in the folded-thrust belt in western Iran. For this purpose, using a digital elevation model with a resolution of 12.5 meters and 1:50,000 topographic maps, watersheds and drainage networks were extracted in Global Mapper, Google Earth, and Arc Hydro software. Also, in order to extract and locate 323 landslides, satellite images available in Google Earth, spatial analyses in ArcGIS, and field observations were used. Then, the relationship between the drainage network hierarchical anomaly index (∆a), drainage density (Dd), drainage density of first-degree stream (Dd1), drainage network frequency (Df), ratio of the number of first-degree stream's to the total number of stream's (N1/N), stream's bifurcation ratio (Rb) and bifurcation index (R), ratio of landslide area to basin area (LA), and landslide density (LD) of the basins were calculated and analyzed. The results showed that the distribution of landslides is a function of a complex interaction between the tectonic structure, the geometry of the drainage network, and the hydrological characteristics of the basins. The drainage network hierarchical anomaly (∆a), drainage density (Dd), and stream's bifurcation ratio (Rb) had the highest correlation with the density of landslides, while the drainage density of first-degree stream (Dd1) and drainage network frequency (Df) were also effective in increasing the instability of slopes. These findings indicate that the analysis of drainage network morphometric indices can be used as an effective approach to define and evaluate landslide-prone areas. |
Article number: 6 |
| Keywords: Landslide, Drainage Network Morphometric Indexes, Hierarchical Anomaly, Ilam, Zagros |
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Full-Text [PDF 2003 kb]
(85 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2025/11/10 | Accepted: 2026/06/16 | Published: 2026/06/17
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