Manizheh Razavi Hosain Abad; Alireza Amirian Chekan; Mohammad Faraji; Jamal Mosavian
Abstract
Soil aggregate stability and its spatial distribution can be considered as a good indicator for assessing the results of measures conducted for mitigation soil erosion. This study was conducted in two adjacent sites in Chahmari region, Kuzestan province. At one site afforestation and contour furrowing ...
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Soil aggregate stability and its spatial distribution can be considered as a good indicator for assessing the results of measures conducted for mitigation soil erosion. This study was conducted in two adjacent sites in Chahmari region, Kuzestan province. At one site afforestation and contour furrowing were conducted to control soil erosion and the adjacent site with no controlling measures was considered as control. A total of 150 soil samples were collected from the surface layer (0-5 cm) of two sites and mean weight diameter of aggregates (MWD) were measured using dry and wet sieving (MWDd and MWDw, respectively). Based on digital soil mapping (DSM) approach and to map MWD spatially, several environmental covariates were derived from a Landsat 8 image and a digital elevation model (DEM). Two machine learning algorithms including artificial neural networks (ANN) and regression trees (RT) were used to predict MWD with covariates as inputs. Results indicated a significant difference between MWDd in two sites, but no significant difference was found between MWDw. Correlation analysis revealed no correlation between MWDw and all terrain attributes derived from the DEM, but significant correlations were obtained between MWDd and some terrain attributes. Most covariates derived from Landsat images had significant correlation with both MWDw and MWDd. ANN and TR had relatively high and almost the same accuracy in predicting MWDw, but in predicting MWDd, ANN was superior to RT. In general, the findings showed good performance of DSM techniques in predicting and spatial mapping of MWD.
moslem dehdari far; Mohammad Faraji; Mohammad Salehi veisi; Jahangir Ehsani
Abstract
Data on the resistance of rocks to erosion and weathering and their voluntary ratings are key information in erosion and sediment studies. Despite the importance, rock resistance to weathering is not well studied in Iran and the conducted studies are more qualitative rather than quantitative. In this ...
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Data on the resistance of rocks to erosion and weathering and their voluntary ratings are key information in erosion and sediment studies. Despite the importance, rock resistance to weathering is not well studied in Iran and the conducted studies are more qualitative rather than quantitative. In this study rock mass resistances of Asmari formation (limestone) and Fars formations including Mishian (marl limestone), Aghajari (Calcareous sandstone) and Gachsaran (anhydrite) were assessed using rock mass rating (RMR) method in Behbahan, Gachsaran, Deylam and Dehdasht regions. ANOVA and Tukey,s analysis of resistances of 81 collected rock samples showed there were significant differences (P<0.05) between geological formations in term of rock resistance. According to RMR rating, rock mass resistances were in order of Asmari limestone> Mishan limestone> Aghajari calcareous sandstone> Gachsaran anhydrite. Results also indicated there were no significant differences between rock resistances of Fars formations but rock resistance of Fars formations differed significantly from Asmari formation.
leila abdollahi; Mohammad Faraji; ali haghizadh; Somayeh Dehdari
Abstract
Abstract The effects of droughts on surface water and groundwater resources reduce the amount of water available to different sectors. Hydrological drought initially begins with decreasing rainfall and is usually associated with lower levels of lakes and reservoirs. To this end, in order to ma ke appropriate ...
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Abstract The effects of droughts on surface water and groundwater resources reduce the amount of water available to different sectors. Hydrological drought initially begins with decreasing rainfall and is usually associated with lower levels of lakes and reservoirs. To this end, in order to ma ke appropriate management decisions to prevent the harmful effects of drought, it is necessary to assess the characteristics of this phenomenon by assessing and monitoring the drought. In this research, the time series analysis and SDI shaking technique were used to evaluate the hydrological drought at the hydrometric station at the Marian River during the period from 1982 to 2015. The results of hydrological drought on the sunshine station showed that the highest frequency of droughts was related to mild droughts with 29.41% and severe drought with 11.74% and medium drought of 2.94%. Also, the results of self-correlation series analysis, which showed significant correlation for all months except Azar, before the analysis of its effect was removed by Hamed and Rao (modified by Mann-Kendal), and in December, the ordinary Mann-Kendall test used. In all months of the station, except for the month of Aban and Azar (non significant), during the period of 1982-2015, gradual changes are significant at 5% level, and the sudden changes of the time series are significant at 5% level and have a decreasing trend. Also, the results of the Paty's homogeneity test showed that the sudden changes in the time series were significant at all levels at the 5% level.
Azam Tayebi; Mohammad Faraji; Shahram Yousefi khanghah
Abstract
This study with purpose analysis the effect of Maroun՚ dam construction on land use changes using Landsat satellite images taken. For this study two The Landsat satellite image of in 16-year period (1999-2014) and maps Topography was used by applying geometric and atmospheric correction. Then using ...
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This study with purpose analysis the effect of Maroun՚ dam construction on land use changes using Landsat satellite images taken. For this study two The Landsat satellite image of in 16-year period (1999-2014) and maps Topography was used by applying geometric and atmospheric correction. Then using the software ENVI maximum likelihood supervised classification land use map to 7 ClassesRiver, Rangeland , Agriculture, Woodlands and gardens, villages, Palms and Bayer, respectively, with an Kappa coffecient of 75% and 86% were classified . Results classified maps years (1999- 2014) showed that during this period due to dam construction, Agricultural lands, Woodlands and gardens, Village, Palms, Rangeland , increased area and River and Bayer levels was reduced. So by comparing the studing periods of use map, the map changes, represents the maximum land use changes, Agricultural conversion to Rangeland is the equivalent 2875/270 hectares, the lowest changed into Bayer to the village with an area of 0/19 hectares. Overall findings showed that the establishment of Maroon Dam improves the user in the region. Therefore, investigation account the cost of building the dam, construction of the dam has been a lot of positive effects, and in the long run lead to positive economic growth in the region . Changes in cross-river bed also shows that in 1999 the average width bed, 106/10 meters but in 2014 115/89meters and an average of about 7/79 Kilometers been reached. These changes represent a reduction of width and curvature of the river was in 2014.
