Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 4Citation - Scopus: 3Assessment of Soil Erosion and Sediment Delivery Ratio in the Arghandab Catchment, Kandahar Province, Afghanistan by Using Gis-Based Rusle Method(Taylor & Francis Ltd, 2024) Ansari, Ahmad; Tayfur, Gokmen; Mohammadi, ShahinA significant proportion of Arghandab Catchment in Kandahar Province, Afghanistan has been under potential degradation threat due to soil erosion. This study assessed the extent of soil erosion and estimated the sediment delivery ratio (SDR) in the catchment by employing the Revised Universal Soil Loss Equation (RUSLE), utilizing the Geographic Information System (GIS) and the Remote Sensing (RS) techniques. Data, related to rainfall erosivity (R factor), soil erodibility (K factor), slope length and steepness (LS factor), cover management (C factor), and support practices (P factor), employed for the RUSLE model were processed using the GIS tools and R-Studio software. Average RUSLE factor values estimated in the studied area ranged from 51.8 to 124 MJ mm ha-1 h-1 year-1, 0.03725 t ha h ha-1 MJ-1 mm-1, 9.2, 0.445, and 0.75 for R, K, LS, C, and P factors, respectively. The results revealed that the average annual soil loss from the catchment was 6.81 t ha-1 yr-1, ranging from 0.002 t ha-1 yr-1 in the flat areas up to 94.7 t ha-1 yr-1 in the hilly and mountainous regions. Soil classes of slight, moderate, high, very high, severe, and very severe covered areas of 20.1% (263,542.3 ha), 12.2% (160,286.5 ha), 22.8% (298,740.6 ha), 20.3% (265,546.8 ha), 17.6% (231,224.4 ha) and 6.9% (90,879.9 ha), respectively. The computed SDR for Dahla Reservoir located in the catchment was found to be in between 24.2% and 36%. LS factor was identified as the most crucial variable associated with soil erosion. The findings from this study can be applied when designing effective conservation strategies in the management of erosion and water management.Article Citation - WoS: 16Citation - Scopus: 19Comparative Analysis of Estimation of Slope-Length Gradient (ls) Factor for Entire Afghanistan(Taylor & Francis, 2023) Ansari, Ahmad; Tayfur, GökmenSlope length gradient (LS) is one of the crucial factors in the Universal Soil Loss Equations (USLE, RUSLE). This study aimed at estimating the slope-length and slope-steepness (LS) factor for the entire watersheds of Afghanistan by using three different methods, namely; (1) LS-TOOLMFD (Method 1); (2) The Method of Equations (Method 2); and (3) The approach of Moore and Burch (Method 3). The first method uses the digital elevation model (DEM) in the ASCII format, and the other two methods use the DEM in the spatial domain. The results show that the LS-factor of the study area ranges from 0.01 to 44.31, with a mean of 5.24 and standard deviation of 6.95, according to Method 1; 0.03 to 163.49, with a mean of 9.6 and standard deviation of 13.58, according to Method 2; and 0 to 3985, with a mean of 7.16 and standard deviation of 29.7, according to Method 3. The study reveals that Methods 1 and 2 are more appropriate than Method 3 because Method 3 yields high LS-factor values close to or at streamlines located near mountainous regions. The highest LS values are found to be in the northeast, north, and central regions of Afghanistan, which is consistent with the high mountains and deep valley geomorphology, indicating that these regions are particularly vulnerable to soil erosion by rainfall-runoff processes. The sediment delivery ratio (SDR) for the Upper-Helmand River Basin (Upper-HRB) is also estimated by the RUSLE, employing the LS factors produced by the three methods. The results revealed that the average annual soil loss is found to be, respectively, 9.3, 18.2, and 11.1 (ton/ha/year) by using the three methods, corresponding to SDR of 23.5%, 12.1%, and 19.9%.