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.
Hamed Eskandari Damaneh; Gholamreza Zehtabian; Hassan Khosravi; Hosein Azarnivand; Aliakbar Barati
Volume 28, Issue 3 , October 2021, , Pages 520-536
Abstract
In the present study, the existing land uses in the Minab plain were simulated using the CA-Markov combined method. For this purpose, land use maps for the years 2000, 2010 and 2020 were generated using Landsat satellite images using the maximum probability classification method and after evaluating ...
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In the present study, the existing land uses in the Minab plain were simulated using the CA-Markov combined method. For this purpose, land use maps for the years 2000, 2010 and 2020 were generated using Landsat satellite images using the maximum probability classification method and after evaluating the model, the land use map for 2030 and 2040 was predicted using the combined CA-Markov method. Analysis of land use change patterns in Minab plain showed that during the statistical period 2000-2020 in the level of land uses in this area has changed significantly so that during this 20-year period the area of agricultural land use, urban and man-made areas, saline lands and rangelands and barren lands respectively from 38.91, 25.99, 20.09 and 15 % in 2000 to 40.75, 40.02, 12.44 and 6.80 percent in 2020. Evaluation of the model using kappa index above 90% indicates the high accuracy of the model for predicting land uses. Prediction of changes in 2030 and 2040 show that the use of agricultural lands and urban areas and man-made are increasing at a rate of 0.05 and 0.39 %, respectively, which are advancing from the east of the plain to the west; Meanwhile, the uses of saline areas, rangelands and barren lands are decreasing at a rate of 0.44%, which is more evident in the west and northwest of this plain. Finally, one of the most important executive strategies of planners and officials to prevent land use change and ultimately land degradation in this area, can be to improve the cultivation pattern, new irrigation methods, nourish the bed of this plain and maintain and restore native vegetation.
Tayebeh Mesbahzadeh; Farshad Soleimani Sardoo; Ali Salajeghe; Gholamreza Zehtabian; Abbas Ranjbar; Mario Marcello Miglietta
Volume 27, Issue 4 , December 2020, , Pages 752-762
Abstract
The dust phenomenon is of particular importance because of its close association with public health. Many researchers are looking for ways to reduce the harmful effects of this phenomenon. To this end, having information about the nature of the spatial and temporal pattern of this phenomenon is of particular ...
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The dust phenomenon is of particular importance because of its close association with public health. Many researchers are looking for ways to reduce the harmful effects of this phenomenon. To this end, having information about the nature of the spatial and temporal pattern of this phenomenon is of particular importance to all researchers. Dust is one of the natural hazards of the central Iranian plateau. In this study, statistical analysis was performed on a yearly and monthly basis in the period 2006 to 2018 using codes 06 and 07 obtained from 50 synoptic stations located in the study area. Also the spatial pattern of dust days with horizontal views less than 1000 m, 1000 to 1500 m and 1500 to 3000 m in the study area was plotted. The results also showed that Tabas synoptic stations with 661 days, Arak with 528 days and Zahedan with 511 days with 1500 to 3000 m horizontal view were more important in the study period. Also, the results of seasonal survey of dust days in the statistical period showed that spring with more than 42% had the highest occurrence of dust. The results showed that in the horizontal view of less than 1000 m, Zahedan station with 113 days and Tabas station with 91 days of dust had higher frequency. Meanwhile, Zahedan and Shahreza stations with 91 and 55 days of dust with a horizontal view of 1000 to 1500 meters also had the highest frequency of dust days in the study area. Monthly statistical analysis revealed that most of the dust events were recorded in June and May. The results of spatial variation of dust days showed that there is no regular spatial pattern due to the extent of the area but in general in all three classes of horizontal view the focus of this phenomenon is most of the southeastern part of the study area.
Shima Javadi; Gholam Reza Zehtabian; Mohammad Jafari; Hassan Khosravi; Azam Abolhasani
Volume 27, Issue 2 , June 2020, , Pages 248-261
Abstract
Regarding population growth, increasing agricultural land is necessary to provide food and meet existing needs. This issue has led to land degradation because of mismanagement and excessive exploitation. Therefore, much research must be done to determine whether agriculture leads to land degradation ...
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Regarding population growth, increasing agricultural land is necessary to provide food and meet existing needs. This issue has led to land degradation because of mismanagement and excessive exploitation. Therefore, much research must be done to determine whether agriculture leads to land degradation or not. Regarding the importance of this issue in arid and semi-arid regions, the Eshtehard region was selected as the study area in this research. Different maps of the area including soil map, altitudes, and land-use were prepared using ArcGIS 9.3 and ENVI software. After visiting the area and determining the main land-uses including rangeland (as control sample), fallow lands, monoculture lands, multicultural lands, and garden lands, soil sampling was carried out in two depths of 0-30 and 30-60 centimeters with three replications for each treatment. Finally, 35 soil samples were transferred to the laboratory, and soil degradation factors such as salinity, sodium, sodium adsorption ratio, and acidity were measured in each soil sample. After determining the normality of the data using the Shapiro test, the study of factors with non-parametric Tukey test showed that there was a significant difference between treatments in the region. Then, a comparison of surface and subsurface layers for each factor was done using a t-test in SPSS software. The results showed that multicultural treatment with the highest score was the most desirable treatment and fallow treatment with the lowest score was the most undesirable treatment, leading to soil degradation in the region.
Sara Nakhaie Nejad; Gholamreza zehtabian; Arash Malekian; Hassan Khosravi
Volume 24, Issue 2 , July 2017, , Pages 268-279
Abstract
Nowadays, due to water scarcity in the country, especially in arid and semi-arid areas, optimal management of groundwater resources is necessary. This study investigates the quality and quantity of underground water of the Sarayan plain in the northwest of South Khorasan Province in a 14-year period ...
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Nowadays, due to water scarcity in the country, especially in arid and semi-arid areas, optimal management of groundwater resources is necessary. This study investigates the quality and quantity of underground water of the Sarayan plain in the northwest of South Khorasan Province in a 14-year period (1998-2012) using statistical methods. The number of samples studied included 20 wells, six qanats and three springs. Then, using GS + software, appropriate statistical methods were selected. Results showed that Kriging method was suitable for zoning of the factors. Using interpolation methods, appropriate spatial maps for each of the groundwater quality parameters (EC, TDS, and SAR) were obtained in three years (beginning, middle and end of the fourteen-year period). The results of the spatial variations of the TDS and SAR showed that the reduction of these two parameters was more severe in the middle and southern parts of the study area. To evaluate changes in groundwater depth in the plains, the depth maps of the ground water resources were prepared during the study period by the use of the results of measuring the depth of water in each of the observation wells. Results showed that in 1998, in the eastern and southern plains, the water was at a closer distance to the ground and with the advance toward the West and especially to the north, water was available in deeper parts of the ground. In the study area, the average amount of rainfall is less than the average amount of the whole of Iran and groundwater resources in agricultural water supply plays a fundamental role. Therefore, the sustainability of water resources is affected by sustainable management of underground water resources in the agricultural sector.
Mina Arast; Gholamreza zehtabian; Mohammad Jafari; hasan khosravi; saeed shojaee
Volume 23, Issue 3 , January 2017, , Pages 543-554
Abstract
The used of unconventional waters in the agricultural lands not only reduces the environmental hazards but also increases the productivity. This research was aimed to assess the effects of wastewater, saline water and brackish water on some soil properties including organic matter, bulk density, and ...
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The used of unconventional waters in the agricultural lands not only reduces the environmental hazards but also increases the productivity. This research was aimed to assess the effects of wastewater, saline water and brackish water on some soil properties including organic matter, bulk density, and electrical conductivity. Therefore, five study sites were selected. The treatments consisted of control, irrigation with saline water, brackish water, and wastewater as well as mixed irrigation of wastewater and saline water. Five profiles were dug in the study sites. In each profile, two samples were taken from two depths of 0-30 cm and 30-60 cm. The results showed that irrigating with wastewater led to improved soil properties in terms of organic matter and bulk density, as compared with other treatments. There was no significant difference in pH among all treatments. However, the amount of Electrical Conductivity of saline water in surface and deep layers of soil was 17.57 ds/m and 5.5 ds/m, respectively. This large difference between the two depths in saline water treatment represents the EC downward trend from surface to depth. This trend was constant for the brackish water and wastewater treatments.
hasan khosravi; Esamaeel Heydari; Gholamreza Zehtabian; Javad Bazrafshan
Volume 22, Issue 4 , March 2015, , Pages 711-720
Abstract
Yazd-Ardakan plain has been faced with significant reduction of groundwater level in recent years. Therefore, it is expected that studying hydro-geological drought can help the right management of this aquifer. Groundwater Resources Index was used to study hydro-geological drought in Yazd-Ardakan plain. ...
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Yazd-Ardakan plain has been faced with significant reduction of groundwater level in recent years. Therefore, it is expected that studying hydro-geological drought can help the right management of this aquifer. Groundwater Resources Index was used to study hydro-geological drought in Yazd-Ardakan plain. At first, 30 piezometric wells with the same 10-year period (2002-2012) were selected. Then, the zonation maps of annual groundwater level, average groundwater level, and standard deviation were provided by ArcGIS9.3. Finally, GRI map was provided using these maps and GRI relation. According to the obtained results, the most serious annual hydro-geological drought occurred in 2011 with an average GRI of 0.79. According to the GRI zonation map, hydro-geological drought severity is high in northern and southern parts of the study area. It can be due to concentration of population, industrial centers, and excessive harvesting of groundwater in these areas. In addition, the GRI temporal changes indicate the deterioration of Yazd-Ardakan aquifer.
Mehdi Jafari; Gholam Reza Zehtabian; Amir Houshang Ehsani
Volume 20, Issue 1 , June 2013, , Pages 72-87
Abstract
Today, remote sensing data can provide the latest information for the study of land cover and land uses These images are of utmost importance due to the providing updated information, variety of forms and the possibility of processing for making land use maps. Determining the location of each land use ...
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Today, remote sensing data can provide the latest information for the study of land cover and land uses These images are of utmost importance due to the providing updated information, variety of forms and the possibility of processing for making land use maps. Determining the location of each land use together with land cover helps managers in making decisions. Also, the current status of the land cover can be studied by using land use maps at different levels. In order to evaluate the ability of multitemporal satellite data of TM and ETM + in land use classification and the effect of the thermal band on increasing the accuracy of the land use maps, Landsat TM digital data relating to the September 27, 1990 and Landsat ETM + digital data of 10 July 2002 from Kashan were analyzed. Initial studies were performed on images in terms of the presence of geometric errors. In order to prepare the images for digital processing, improved operation and image enhancement were applied on the images. Ground truth map was prepared in the same stage. Then, the supervised classification of satellite images with algorithms and different approaches including a variety of bands were tested and the accuracy of each of the methods and approaches were investigated. The results showed that the highest Kappa accuracy in both Landsat TM and ETM + with all the bands were 86.34 and 83.21, respectively. While the elimination of the thermal band decreases the accuracy to 82.46 and 79.93 % The results of this study showed that using thermal bonding caused an increase of 4 percent in Kappa accuracy, and the highest accuracy was occurred in the classes of clay plains, flood plains, mountains and puffy salt lands. Therefore, despite the lower spectral resolution, the use of thermal bonding is recommended in such studies.
Saeedeh Nateghi; Gholam reza Zehtabian; Hasan Ahmadi
Volume 19, Issue 4 , March 2013, , Pages 590-600
Abstract
Segzi plain is one of the most critical areas of the province in terms of the extent and severity of desertification process. This area has a special strategic position due to the industrial centers, Shahid Babaee airport, Shahid Beheshti International Airport, railroads, transit road of Bandar Abbas- ...
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Segzi plain is one of the most critical areas of the province in terms of the extent and severity of desertification process. This area has a special strategic position due to the industrial centers, Shahid Babaee airport, Shahid Beheshti International Airport, railroads, transit road of Bandar Abbas- Esfahan, agricultural centers and vicinity to historical city of Esfahan. Consequently, investigation on the main cause of desertification phenomenon is the main objective of this study. Therefore, the IMDPA model was used to study desertification intensity in Segzi plain. In this research, two criteria including geology – geomorphology and soil, consisting of seven indicators (sensitivity of the formation, land use, and slope based upon geology–geomorphology criterion, and soil texture, soil depth, percentage of stone and gravel, and EC based upon soil criterion) were studied. Desertification intensity map was generated by using geometric mean of criteria. With regard to the geometric mean of criteria, soil criterion, with a numerical value of 3.4, and geology – geomorphology criterion, with a numerical value of 3 were classified in severe desertification class. Finally, the severity of desertification (DS) was calculated to be 3.26 indicating that the region was in severe desertification class. Results showed that EC, with an average value of 3.75, was classified as very intense indicator and had the most impact on desertification of the region.