Mahin Hanifapour; Gholamreza Zehtabian; Hasan Ahmadi; Aliakbar Nazari Samani; Hassan Khosravi
Volume 29, Issue 2 , July 2022, , Pages 186-195
Abstract
Wind erosion and dust storms are one of the natural disasters that are increasingly facing the arid and desert areas of central Iran. Improper management in natural resources has also had a high impact on this phenomenon. One of the basic principles of controlling and combating ...
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Wind erosion and dust storms are one of the natural disasters that are increasingly facing the arid and desert areas of central Iran. Improper management in natural resources has also had a high impact on this phenomenon. One of the basic principles of controlling and combating wind erosion is to know the areas of sediment harvesting. The purpose of this study is to identify the areas of wind sediment harvesting in the facies of the Mallard region in the west of Tehran province. Based on topographic maps, satellite imagery, geological map, and field surveys, the geomorphologic facies map was prepared and then the sampling was done and analyzed in a GIS environment. The interpretation of the anemometer data using Windrose & Stormrose showed the wind direction of the dominant and eroding from the northwest. The results obtained from the study's Sandrose indicated that variation in wind direction is low to high, and Qazvin station (the station closest to the critical centers) had high variability and included multi-directional winds with sharp angles. The 83 samples of different facies of the study area are graded by the ASTM (Dry Sieve) method. The granulation results indicate the local origin of the harvest. The prioritization map of the critical centers of the region showed that 16.4% of the area is low intensity, 3.4% medium intensity, and 3% high intensity. Finally, it was found that saline clay with no vegetation cover or with little vegetation covered with saline in the plain had the highest percentage of particles sensitive to wind erosion.
Mohsen Kazemi; Sadat Feiznia; Hasan Khosravi; Hamid Mesbah; Reza Shahbazi
Volume 24, Issue 4 , January 2018, , Pages 815-828
Abstract
Understanding the physical and chemical characteristics of sediments of lakes and wetlands is important for sedimentology and erosion studies. Maharloo Lake is one of the most important lakes of Fars Province. Surface sediments of this lake consist of evaporitic and muddy sediments. For recognition of ...
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Understanding the physical and chemical characteristics of sediments of lakes and wetlands is important for sedimentology and erosion studies. Maharloo Lake is one of the most important lakes of Fars Province. Surface sediments of this lake consist of evaporitic and muddy sediments. For recognition of the nature of the sediments, samples were taken from lake bed and carbonate and evaporitic compositions including calcium-carbonate, calcium-solfate and sodium-chloride were measured. After omitting carbonate and evaporitic compositions, granolumetric analysis of terrigenous fraction was performed using hydrometry method and sediment classification was performed using Pettijohn (1975) Method. The result of the percentage of terrigenous and chemical fractions of surface sediments showed that most of the sediments were fine-grained terrigenous sediment, containing chemical salts. Terrigenous sediments are poorly sorted, skewed toward coarser sizes and have slightly gravelly, sandy mud texture. More than 90 % of sediment minerals in the lake is clay and less than10 % is gypsum, quartz, quartz sandstone, and limestone. Depending on the type of sediment, minerals, salts and frequency of deposits, the sediments of Maharloo Lake are prone to wind erosion and dust generation in the region.
Mohsen Padyab; Sadat Feiznia
Volume 23, Issue 1 , June 2016, , Pages 108-117
Abstract
In order to determine the amount of reduced permeability in the Gachsaran floodwater spreading station, sampling was performed at four points of the first and second strips of both channels and at a depth of 0-15 cm from the ground. Totally, samples were taken at 16 points. In addition, in order to determine ...
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In order to determine the amount of reduced permeability in the Gachsaran floodwater spreading station, sampling was performed at four points of the first and second strips of both channels and at a depth of 0-15 cm from the ground. Totally, samples were taken at 16 points. In addition, in order to determine the permeability changes of the spreading site, random sampling was performed in a place near the study site at four points with the same depth and no water spreading operations.Then, the samples were granulated with a series of standard sieves and the permeability of each point was estimated using the respective tables. According to the obtained results, permeability showed a significant reduction in flood spreading site, on average four times less than that of the start of the project. The reduced permeability of flood spreading areas is the most important limiting factor for implementation and maintenance of this type of artificial recharge projects.
Naser Mashhadi; Hasan Ahmadi
Volume 17, Issue 4 , November 2011, , Pages 499-517
Abstract
The results of wind dynamic are transport of soil or sediment particles and subsequently evolution of desert landforms according to the intensity of either erosion or sedimentation process.Geology, geomorphology and climatology conditions of the Khartouran region create a special situation on the closed ...
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The results of wind dynamic are transport of soil or sediment particles and subsequently evolution of desert landforms according to the intensity of either erosion or sedimentation process.Geology, geomorphology and climatology conditions of the Khartouran region create a special situation on the closed basin of Dasht-e-Kavir. It is evident that the ecosystem balance of the region is affected by anthropogenic exploitation and wind activity, so this area has a geoecological structure with special features. The Khartouran Erg is resulted of wind activity on sand sources. The study area is located on the southwest of Sabzevar city with a total area about 200000 hectares. The study was carried out based on topographic, geologic maps, satellite images, aerial photographs, field observation and sampling. Based on the information and data, the study area was divided into grid cells of 3 km × 3 km. Surface soil or sediment of corner points of each grid was sampled (214 points). The results of granolometry analysis of soil or sediment samples were presented in seven maps. These maps show grain size distribution and consequently determine sand supplement potential of each point in different wind velocities.The granulometry analysis of samples showed that particle size with a range of 0.063 to 0.150 mm (the most vulnerable sand particle size to wind erosion) comprised the most percentage of distribution. Based on the results it may be concluded that these regions were affected by wind erosion in the past more rather than of current time and Khartouran Erg is result of wind activity in the past. Currently, the rate of sand movement intensity and the balance between erosion and sedimentation are dominant factors in shaping geomorphologic facies (Aeolian landforms).
Marzieh Abassi; Sadaat Feiznia; Hamid reza Abassi; Uones Kazemi; Ahmad Gharanjik
Volume 18, Issue 3 , September 2011, , Pages 441-451
Abstract
Source identification of sand dunes is of particular importance in projects of wind erosion control. In this study, the map of geomorphology and inventory map of sand dunes were prepared for five regions of Baluchestan under wind erosion using aerial photos, satellite images and Arc-View ...
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Source identification of sand dunes is of particular importance in projects of wind erosion control. In this study, the map of geomorphology and inventory map of sand dunes were prepared for five regions of Baluchestan under wind erosion using aerial photos, satellite images and Arc-View and Arc-GIS soft wares. Then, 28 samples were collected based on the form of sand dunes and geomorphological facies. The samples were analyzed for Granulometry, morphoscopy and mineralogy in the laboratory. Granulometric analysis was performed using dry–sieving technique and the curves and statistics were drawn and calculated using Gradistat software. The morphoscopic and mineralogic investigation were performed using binocular microscope. Granulometric analyses show that the sediments are well sorted, having better sorting than fluvial sediments, with standard deviation of less than 0.5. Morphoscopic analyses mostly show the effect of Aeolian transport on the grains. Mineralogical studies show that the most abundant particles in the sediments are rock fragments consisting of limestone, quartzite and granodiorite (%84), and the rest are minerals such as quartz, feldspat and calcite. About 94.5 percent of the particles have been transported in saltation. The results of differentiation of sediments according to sedimentary processes indicate that about %71.43 of sediments are transported and deposited by Aeolian processes, %21.42 by fluvial processes and %7.15 by overlapping of Aeolian and fluvial processes.