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Wind erosion and the formation of sand dunes are common phenomena in many arid regions around the world. More than 100 types of sand dunes have been classified by geomorphologists based on shape and size criteria (Lancaster, 1995). One of the most common and simple types of sand dunes, in areas with one-way winds throughout the year and the inability of sand to cover the entire surface of the area, is the crescent-shaped hills called Barchan (Suerman et al., 2000). Barchan is a single crescent-shaped hill that forms a cohesive and solid surface on the ground, such as a ridge, pediment, or desert pavement (Cook et al. 1993).

To do this research, 11 barchans from the southwest of Mariana Rig were selected, 30 km from Aranbidgol city. Using the images of the Google Earth software archive, the determination of the area of the study area was carried out and then, with field observations, the measurements of the barchans were made. The Google Earth software was used to check and record the amount of displaced barchans over time periods between 2013 and 2019. Also, by using the bar method in 2013 and estimating the amount of displacement relative to the fixed bars in 2019, the measurement of the speed of the barchans along with parameters of area, volume, height, density, periodic variation and length to width ratio Was evaluated and analyzed. Also, in order to investigate the role of wind in the movement of Aeolian sand and Barchans, the 31-year statistics of Kashan meteorological station were used. For this purpose, the desired data was entered in Wrplot 5.0 software and finally the annual flower of Kashan station was drawn. The wind of Kashan station indicates the prevailing northeast wind in this region.

The maximum total total displacement during the years 2019-2013 in Barchan No. 9 has been calculated at 68 meters with an average annual displacement rate of 8.5 per year. The minimum total total displacement during the years 2019-2013 has been calculated in Barchan No. 7 at the rate of 43.9 meters with an average annual rate of 5.5 meters. The rate of 103.5 percent compared to the percentage of negative changes of 93.34, shows the net rate of change of 10.16 percent positive. In other words, during the years 2013 to 2019, the rate of expansion of sand dunes in the study area shows an increasing trend, and on the other hand, the sand zone created during the years 2013 to 2019 has had a lot of area fluctuations. According to the reliability index, the higher the annual displacement of the Barchans, the more unfavorable the reliability index will be. According to Table 8, most of the brooches in the study area with a displacement between 6 to 9 meters are in the category of instability and only one brook is in the category of very low reliability.

The results show that the average displacement speed of selected Barchans is 7.6 meters per year with a range of changes between 5.5 to 8.5 meters per year and the displacement rate in three time periods indicates an increase in displacement in the period 2019-2017 compared to two The period is before that. Pearson correlation test was used to investigate the relationship between volume and cell movement. Pearson correlation between the two variables is calculated to be -19.19 and sig is equal to 0.558, which indicates a very weak negative correlation between the volume and the amount of movement of the selected braces. It is somewhat reduced and this correlation is not completely linear. However, the study of the relationship between length to width ratio with the amount of cell movement shows that by increasing and decreasing the length to width ratio from a numerical value of one, the amount of cell movement decreases significantly. In other words, the maximum displacement of selected Barchans will be when there is a proportion in the ratio of length and width of Barchans. Looking at the periods under study, it can be seen that during the years 2019-2013, when the length-to-width ratio is around one, the highest amount of Barchans movement has occurred. Precipitation also plays a very important role in the rate of cell displacement. The annual precipitation data of Kashan station during the years 2019-2013 indicate the direct effect of rainfall on the displacement of the Barchans, so that in the years with increasing rainfall, the movement of the studied Barchans has increased and in the years with decreasing rainfall, the movement of the Barchans can be significantly Attention has been reduced. The reliability index also indicates the instability of the studied Barchans, so that according to the calculated amount of movement of selected Barchans, this index indicates the average movement of regional Barchans compared to the amount of movement recorded in previous studies in Iran and the world.

The purpose of this study is to investigate the morphology of the sand dunes located in Zarin Erg in the northwest of the city of Yazd and its accordance with the wind data provided by the surrounding synoptic stations. The results showed that the sand dunes have different morphologies, including simple dunes, seif, barchans, star, and complex dunes. The complexity and variety of the dunes indicates the drastic variation of wind regimes seasonally, annually as well as periodically. Also, they do not match with any wind data of the surrounding synoptic stations. The presence of barchans in the quadrilateral erg is indicative of directional winds. The local winds are the main cause of the formation of these dunes and their morphology. Indeed, due to the difference of height between the central Iranian playas and upstream mountainous, the playas of this part of Iran often serve as thermal low-pressure centers on the Earth surface, and their marginal sand dunes are always moved by these winds. The accumulation of large amounts of sand in the southeastern part of the erg and the formation of star dunes with a height of more than 200 meters are signs of prevailing north-west winds in the warm season and the severe winds of the southeast in the cold season. These winds reinforce the power of local convergent winds.

The characteristics of Sistan plain, such as river sedimentation, blowing of erosive winds, especially 120-day winds, and the droughts in the past 20 years have made a suitable situation for wind erosion. One of the concrete symbols of wind erosion is sand displacement. Since the regions of sand displacement in this study were residential, the aim of this study was set to conduct a morphometric analysis of sand dunes, their displacement speed, and their role in posing hazards to these areas. To analyze the role of morphometric parameters in the displacement of barkhans, out of 10 barkhans formed in two wind erosion centers, seven were selected. Then, during the 120-day wind period in Sistan area, their displacement was detected and documented. Afterwards, using the SPSS software, the regression analyses were done on the length, width, height, area, and the displacement of the ​​barkhans. The results indicated a negative correlation between the length of the barkhans and their displacement, while there was no significant correlation between the other parameters and the displacement.

In this article, we analyzed the morphology of barchans (crescentic sand dunes) using morphometric features of seven components of this landform in the west of the Loot desert near Pashoeyeh village. The components were height, width, length of the right side, length of the left side, length of the right wing, length of the left wing, length of the back slope, length of the slip face, width of the barchan, slope of the windward, slope of the slip face, and area of the barchan. These components were calculated and analyzed for all barchans. To do the calculations, we used the SPSS software. Also, topographic maps on the scales of 1:250000 and 1:50000, aerial photos and Google earth images were used. Barchan morphometry showed that, with a decrease of the slope, the elevation of the slip face reduces too. Our study also showed that the biggest barchan was the fifth one. The reason is the position and oldness of the biggest one. The smallest barchan was formed from a tributary of the main barkhan. It was young and had an asymmetric shape. Most of the barchans in the study area, because of topographic barriers on the right and the prevailing wind direction from north and north west, had asymmetric shapes, and their left arms were greater than their right arms. In terms of correlation, the components of barchans proved to be correlated by more than 95%. This suggests that the different parts of a bachan grow in harmony with one another in line with the wind direction in the area. Also, the size of a barchan is correlated to the growth rate of its components.

Introduction Granulometric analysis is a common tool used to understand and determine the origin of wind sands, and is applied in desertification studies; to realize such knowledge, the parameters of sand particles size as well as statistical analysis such as mean, standard deviation, kurtosis, skewness, etc. are used. One of the most common types of sand dunes formed by accumulation of sand in desert areas is crescent-shape dune known as Barchan. The most prominent features of such dunes are mobility and lateral movements which transform them into the heart of crisis and threat to the urban and rural residential areas as well as economic, army and communication centers. Barchans are produced in the lands where the sand fails to fully cover the surface area and the wind action is predominant from one direction. The main location of Barchan dunes is between the original wind source and the main dune concentration areas. They are crescent-shape, and possess two "horns" that face downwind and two gentle and sleeper slopes. There is a ridge in between the two slopes. Barchans are produced by the moving sands, appearing convex, and wind action predominately from one direction, and might gradually migrate. The most prominent features of this phenomenon are mobility and lateral movements with specific annual trends.
MethodologyThe research have investigated the granulometric characteristics of 7 barchans in Pashuiyeh, western Lut. Up to 42 samples have been taken from different parts of the dunes. These parts are right horn, left horn, lee slope, two samples from windward slope, and the crest. From each sample, 100 g of sediments have been separately sieved by the shaker, and then weighed, and the measurements have been transferred into GRADISTAT to analyze the data. In this step, various coefficients and granulometric components of the grains, such as K2f coefficient (chromobin sorting index), percentage of component particle size, uniformity or alignment, middle, faces, mean particle size, bending and stretching of particles using statistical relationships of Folk and Ward (1957) were applied.
ResultsThe greatest mean size belongs to Barchan number 3 (2.502 j). This is because the dunes are located in alluvial fans. The greatest proportion of particle size refers to sand particles. All dunes have good sorting and due to fine grained particles they have also a sym­metrical skewness. All Barchans, from the origin point of view are single-origin with a relatively good particle size and the type of texture in all is sand. The components of Barchans are all single-origin (Single-origin grain stipulates that the sediment, the water, or the wind were single-origin). Flooding from the mountains of the west to the Yardang creates streams in the region with fine-grained sediments which form a part of the sedimentation of the Barchans. For this reason, the chromaticity coefficient is based on the river sediments. The statistical results indicate that Barchans number 1 and 6 are more of a microfiber. Barchan number 6 is smaller than all the others which might be attributed to the fact that it can be split from asymmetrical Barchan behind it. Barchans numbers 2 and 7 contain the highest amount of sand. The reason of this very fact in Barchan 2 might be attributed to the tilled and abandoned farmlands around the village. These lands, which have destroyed the hard surface of the desert and are abandoned, provide a very good source of sand accessible for regional wind, traveling from the northwest. Barchan number 7, in addition to being in line with an asymmetrical and large Barchan, is located in the dry path of the streams caused by a large conifer, which provides a lot of sandy sediments for this Barchan. The least amount of sand belongs to Barchans 4 and 5. These barchans are exposed to the dry, large rivers of the area, and therefore, it is provided with more fine-grained sand material, which confirms the presence of mud aggregates and fine-grains. The amount of mud in Barchans 4 and 5 was higher, first, due to the presence of floods stuck behind these Barchans with fine-grained sediments, leading to an increase in finer materials in these Barchans, and second, due to the fact that these Barchans are on the track or behind the cloves, which are generally fine-grained.
Discussion and ConclusionsAccording to the results, including crumbin coefficient, despite common perceptions of the origin of Barchan sediments, the sediments of under-study Barchans were mostly water and river sediments and due to their location by the end of the alluvial fans, they are mostly fine-grained and mobile. In most of the studies of sand dunes, as it is already known in the background, either types of sand dunes including Barchans is studied in terms of their morphometric and granulometric measurements. Most of these studies consider the source of these desert sand dunes as wind sediments. However, in this research, in addition to the morphometric and granulometric studies of Barchans, the wind sediment element in these dunes was ignored to achieve new results; upon the completion of laboratory and software processes, interesting results were gained which were different from what is attained concerning desert dunes and particle size and grain origins. These results indicate that in the study area, the Barchans have no wind origin but are the results of water and stream sediments. This result, prior to this study, in the desert area of study was unperceivable and the result is achieved through in-depth studies and scrutiny over these sand dunes within the area.

Managemental principles predominated on the development and evolution stages of the geomorphic landscapes are different، because landscape evolution، its relationship with other system components and its response to environmental changes and feedback is varied. One of the most important methods of management of geomorphic landscape are the study and evaluation of morphometric parameters and determining alometry between them. Alometry is the investigation of relative changes between system components، and represent the development of a system component compared with development of entire system or other components، also. Therefore، the study and evaluation of barchan morphometric parameters and alometry between them will help to managers and environmental planners achieve the unified and accurate recognition from landscape، on the one hand، it may be effective in the determination of stability، equilibrium and threshold of barchan system. One of the most important problems of management in arid and semi-arid regions is the identification and application of environmental principles governing on the behavior of Barchan dunes. Barchans are one of the windy depositional features that are forming in regions with medium sand and same direction of privalling wind. The aims of this study are the determination of the most important morphometric parameters of Barchan dunes in the southeast of Haj Ali Gholi playa and the recognition of relationships type، the ratio and alometry between them، in order to identify management principles governing on Barchan dunes. The study area in the research is barchan field that is located in the southeast of Haj Ali Gholi Playa. The area with extent about 25260 hectares، is one of the most important ergs of Haj Ali Gholi playa that is located irregularly along northeastern - southwestern edge of playa with 10 to 12 km length. This region is located at Eastern longitudes between 55° and 55°، 10΄ and at Northern latitudes between 35°، 45΄ and 35°، 50΄. At first، studied area is recognized via topography maps and Google Earth images. Then barchans morphometric parameters are measured along 10 transects that were covering entire extent of the erg. Measurements are based on figure (2). This figure shows types of barchan morphometric parameters and method of their measurement. We define for each barchan dunes، the lengths La، Lb and the widths Wa، Wb independently. Furthermore، this study introduces the length of the slip face Ls and the length Lo from the dune’s toe on the windward side to the brink. Finally، the height of the slip face H is defined at the highest point of the brink، which is the intersection of the brink and the longitudinal centerline of the dune. The total width (W) of a barchan is the sum of the widths Wa & Wb. The overall length (L) of a barchan is the sum of the length (Lo) from the windward foot of the dune to its crest، the length of the slip face (Ls)، and the average of the horn lengths [(La + Lb) / 2]. Then from measurement and determination of morphometric parameters، for recognition of type and intensity of relationships between them، we have been reexamined these relationships using SPSS software and regression analysis technique. Finally، with analysis and evaluation of the obtained relation using mathematical tests، the ratio and the alometry of morphometric parameters of studied Barchans have been defined and determined. Findings and In the study area، several barchans can be observed that they have the same form and shape generally. The barchan dunes of the southeast Haj Ali Goli playa have heights between 1. 2 and 17. 9 m، lengths between 19. 5 and 307. 9 m، and widths between 6. 3 and 165. 6 m، mainly (Table 1). The results obtained from statistical modeling by the regression analysis are presented in tables (2) and (3). Models Summary is described in Table (2)، in which the correlation index، determination index، adjusted determination index and standard deviation of estimation error are reported. Also، the values of model parameters (coefficient and line slope)، t value and their significant level are demonstrated in table (3). Totally In this study، the most important and the most suitable of relationships are following from simple linear relationships. So، in the results part، only، these relationships are presented (figure 3). Comparative evaluation of similar studies results reveals the achievement to different equations in other regions. As، quantitative researches of the morphology studied by other researchers، show the specific relationship between barchan morphometric parameters in their study area. Table (4) presents the results of this study as compared with others. As mentioned previously، Alometry is the investigation of relative changes among system components، and represent the development of a system component compared with development of entire system or other components، also. In the study، to determine the ratio between morphometric parameters of the studied barchan and identification of alometry between them، first was attempt to determine the types of their relationship، and then conclude the ratio from them. The obtained results are illustrated in the table (5). Discussion and The results show that the obtained relationships from relation assessment between morphometric parameters of studied Barchan represent a maximum significant linear relationship of Barchan length and height، with determination index 0. 945 and standard error of estimate 0. 889. Also، the obtained relationships from relation assessment and alometry among Barchan morphometric parameters are statistical and mathematical models reported in this study. The mentioned models provide the possiblity of rapid and accurate calculation of Barchan morphometric parameters، and illustrate the alometry among them. The recognition of morphometric parameters of barchan dunes and their alometry can act as an index in order to determine the condition of barchan system and also shed light on the thier trends. Furthermore recognition and estimate of these indexes is a consequence from rate of threat and distribution and provide for environmental managers with the same، that their investigation determines different region from the view point of environmental management and prioritize them.

A wide variety of barchan dunes are found in south part of Haj Ali GHoli playa، in central part of Semnan province. Barchan dunes of this area have been formed from quick sand، and with maintain of their crescent shape migrate along prevailing wind. Therefore displacement and lateral movements with annual typical trend is the most important of their characteristics.. The Purpose of this Research is Simulation of Barchan movement Using artificial neural networks. Artificial Neural Networks (ANN) is a non-linear model that acts similar to a human neural system. In recent years، artificial neural networks have become one of the most promising tools in order to model complex processes such as movement of phenomenas. In many studies، ANNs have demonstrated superior results compared to alternative methods. Obtained results illustrate that ANN predicting model is an applicable tool in predicting ofmovement of phenomenas. In order to check the sensitivity of the ANN prediction model movement of 100 Barchan measured. %70 for training and %30 for validation. In order to evaluate the accuracy of ANN model، observed and predicted data were compared and analyzed. The best accuracy of the model was 0/996. It indicate that ANN prediction model is an applicable tool in predicting of movement of phenomenas.

Different structures of sand dunes can be observed among sedimentary systems both rich and poor in terms of the amount of sediment load. Barchans are one of the most well-known types of sand dunes which form under unidirectional wind conditions and in the absence of much sand on the ground. The features include individual mobile dunes of crescentic shape، the two horns of which face the direction of dune movement. They are generally regarded as occurring in areas of limited sand supply، on planar surfaces، with low precipitation، sparse vegetation cover، and where winds are narrowly bimodal in direction. Theoretical framework: The earliest studies of sand dunes by geomorphologists were focused on the classification of different types of dunes، and in particular the factors responsible for the wide variability of dune shapes. Three factors controlling the shape of dunes were identified: vegetation، variability of wind direction، and the amount of sand available. The morphological characteristics of Barchan are affected by different temporal and spatial factors. Relationship among Barchan morphometric parameters are closely tied to its three-dimensional morphology. The identification of the relations and representation of their models will be affected in recognition of the behavior and function of this landscape in nature. The purpose of this study is to provide a modeling for the estimation and calculation of Barchan plane geometry parameters، such as perimeter and area، using its morphometric parameters، and by statistical models in south of Chah Jam playa.

The study area is located in the south of Haj Ali Gholi playa، Semnan province، central Iran. Haj Ali Gholi playa، situated in the southwest side of Shahroud city and towards the south of Damghan city، is the most important playa of Semnan province. The playa is influenced by different geomorphic and climatic processes. Chah Jam Erg، with an area of about 25260 hectares، is one of the most important erg of Haj Ali Gholi playa that is located asymmetrically along the northeastern - southwestern edge of the playa with a length of 10 to 12 Km. The study area is located at latitudes between 35° 45 and 35° 50 North، and at longitudes between 54° 40 and 55° 10 East. In order to achieve the goals of this study، first، the most important morphometric parameters of 52 Barchans were measured through linear sampling in the studied field. The most important Barchan morphometric parameters include the following: width of right side، width of left side، length of right horn، length of left horn، length of windward side، length of slip face side، area، and perimeter. These parameters، except for area and perimeter، were measured using the field sampling method in the study area، according to the pattern shown in Figure 2. The estimation method of Barchan area and perimeter is as follows: first، a coordinate system was considered on the earth surface، for each Barchan. Then، the coordinates of 24 points were determined on its perimeter using a mesh network. Sampled points in the field were drawn on graph paper with a scale of 1:200. Finally، the area and perimeter of each Barchan was measured by planimeter and curvimeter، respectively. In the next step، after the formation of a data matrix، the data were modeled using regression analysis in SPSS. For this purpose، first، simple and complex regression were examined. Then، the accuracy assessment of the models is determined through comparing their validity; and finally، the most suitable was selected. The preference indexes of models are the maximum R. Square، R.، Adjusted R. Square، Sig. and the minimum Std. Error of Estimate. Findings and

According to the measurements، Barchans of the study area have a length of between 19. 5 and 307. 85 meters، and a width of between 6. 3 and 165. 6 meters، generally. In order to model the relationships among the plan geometry and morphometric parameters of Barchan، simple and complex regression methods were examined، and the most suitable relationships were reported. The results of the regression analysis between area and perimeter with width، and length of Barchan have been presented in the table below.

Band e Rig Kashan is one the few large sand zones of Iran with various sand forms which is located at the south of salt lake. The area under study is a part of Band e Rig Kashan at south west of Maranjab with an area of 1.272 km2. In this study, thirty typical sand hills were selected. The research method, based on field visits and sampling of sands in front head, tail, right and left arms of the understudy sand hills was performed in the two time periods of August and March 2008, and by the use of grading technique, sand particles were classified and their abundance were verified and analyzed.The aim of this research was review and study of seasonal changes of sand particles diameter and their impact on the geometrical shape of sand hills. The findings show that due to changes of direction, speed and frequency of wind during a year, changes occur on diameter afflection of sand hills in main parts of sand hill which leads to the changes of geometrical shape of forehead and right and left arms of sand hill.

The environmental issues and loss of natural resources are the important causes of management strategies creation of the environment crisis. The influx of quicksand to settlements, communication ways and economical installations in the form of barchan dunes, is one of the most important of environmental problems in the South of Haj Ali Gholi playa. Barchan dunes originate from the characteristics of prevailing wind and little ability to access the sand that is crescentic shape, and have been formed from mobile sand. A side view of a barchan shows a rather flat aerodynamic structure. When viewed from above, a barchan presents a crescentic shape with two horns pointing downwind. A sharp edge divides the dune in two areas: the windward side and the slip face. Because of a boundary layer separation along this sharp edge, a large eddy develops downwind and wind speed decreases dramatically. Therefore, the incoming blown sand is dropped close to the brink line. The aim of this study is the assessment of morphodynamic indices of barchan dunes in Chah Jam Erg using experimental, mathematical and statistical methods. By obtained results, we can comprehend a correct understanding from 3D morphology and morphodynamic characteristics of barchan dunes and their behaviors, to manage the environment of desert regions using systemic approaches.

Introduction The base of analysis of applicative geomorphology is according to systemic stand point. Systemic geomorphology is based on recognition of geomorphic forms and processes and relationships between them. Efficiency of this stand point, when there are linear and non linear reciprocal relationships between parts and elements of system, is very important. The studied feature in this research is Barchan dunes in the south of playa Chah Jam. In studied field, hundreds of barchans can be found; generally all of them have same size and shape. These landscapes are mobile dunes which constitute a considerable threat to infrastructure in study field with their mobile sands. They move over communication ways of region, phone lines and even in to Damghan city, and also disturb agricultural fields and intensify desertification problems in study area. Barchan dunes are open and natural systems and are capable of being modelled in different levels. These dunes are observed where sand availability is low and prevailing wind direction is quite constant. In this paper we have tried to describe morphologic characterizes of the Barchan dune using mathematical and statistical modelling process via morphometric parameters and parabola characterizes. The obtained results from this study can be helpful in the systemic management of desert regions and also can be benefit in the plans of stabiles of trombone sands and recognition of critical regions from view point of windy erosion. Materials and Methods The studied area (Chah Jam erg) is located in the south of playa Haj Aligholi, in central part of Semnan province, Iran. Studied field is bounded between latitudes 350, 45َ to 35َ0, 50َ N and between longitudes 540, 40َ to 550, 10َ E. For measurement of morphological parameters, at first, we have been defended a model, and Barchan morphometric characterize are measured along 10 transects in nature that these transects were covering entire extent of Chah Jam erg. Mathematical modelling of the Barchan shape is performed via its simulation in the coordinate system and using non linear equations of the parabola that it has been gotten two equations for windward side parabola and slip face parabola. Then for recognition of type and intensity of relationships between them, we have studied and reexamined these relationships, using SPSS software and regression analysis techniques. For this achievement, at start, we have reexamined linear and nonlinear, simple and multiple variable regressive analysis technique such as linear, power, exponential, cubic, logarithmic, multiplier and etc, and then we have been selected the most important and the most suitable of relationships. Totally, in this study, the most important and the most suitable of relationships are following from power relationships. Results and Discussion Using Statistical modelling, relationships between mathematical and morphological parameters of Barchan dunes has been determined, that these relationships show a significant power relation with maximum of determination index and minimum of estimation error. One of the most important results of this study is the statistical and mathematical modelling of Barchan dunes and converting of mathematical method to statistical method and vice versa. One of the main characteristics of morphology of Barchan dune is its parabolic shape, that this characteristic is influenced by morphology of crescent and aircraft of Barchan. Therefore for mathematical modelling of Barchan shape can be used parabola equations. On the other words, two-dimensional modelling of Barchan surfaces (regardless from its spatial characteristics) is possible through parabola equations. The recognition of morphologic characteristics of Barchan can act as an index in order to determine the condition of Barchan system and also shed light on its trends. Furthermore, the investigation and exact estimation of these parameters is a consequence from rate of threat, destruction and annual movement that their assessment determines different region from the view point of environmental management and prioritize them. Therefore, obtained results from these methods can be very important for investigation of shape and recognition of behavior of Barchan dunes in nature. Conclusion In this paper we have used statistical and mathematical modeling methods and have represented models that using them, can easily account morphological parameters of Barchan dunes. Therefore the results of this study provide possible of exact and rapid estimation of Barchan morphometric and morphologic parameters. The combination of two methods of statistical and mathematical modelling is a fundamental infrastructure for simulation of Barchan dunes geomorphologic characteristics in the laboratory and imaginary circumferences. Focal distance is one of the important parameters of the parabolas of Barchan dunes that shows its different situations with each other. Results show that if the focal distance of the Barchan dune decreases, its spout becomes closer and the divergent state of Barchan horns decreases, too. Barchan dunes that have farther focal distance are wider and have extensive dimensions and more volume.

Aeolian sand dunes originate from reciprocal interaction between wind flow and sand bed. Barchan dunes are one of the Aeolian compressive forms and are formed in areas that there is not enough sand to cover the entire surface and wind flow comes steadily from the same direction throughout the year. These features have been formed from quick sand. One of the most important of their characteristics is dynamic and lateral movements, that some parts of them are regarded as crisis and threatening focuses for urban and rural settlements, economic and military centers and communication ways. Totally, Barchan dunes move proportionally to the wind velocity and inversely proportionally to their height. Their movement rate is subject to wind velocity, three dimensional morphology and interaction between them. One of the most common of Aeolian features in south of Haj Ali Gholi playa are Barchan dunes. In this study, morphometric parameters of Barchan dunes and their annual movement rate (from 1387/1/10 to 1388/1/10) have been measured via pique. Using regression analysis method, type and intensity of relationship between movement rate and morphometric parameters have been investigated and models have been presented in order to estimate their movement rate. Using these models can assess annual movement rate of Bachan dunes in the field area easily. The obtained results show that relationships between movement rates and morphometric parameters consistent with simple linear, power and exponential relationships. The obtained relationships from relation study between movement rate and Barchan morphometric parameters represents a maximum significant exponential reverse relationships of movement rate with height parameter with determination index of 0.915 and standard error of estimation of 0.133. The recognition of morphometric parameters of barchan can act as an index in order to determine the condition of barchan system and also shed light on the its trends. Furthermore recognition and estimate of these parameters is a consequence from rate of threat and distribution and provide for environmental managers with the same, that their investigation determines different region from the view point of environmental management and prioritize them.

Sistan plain that is located in east of Iran has a dry and unpleasant climate and sand storms and movement of dunes are one of the threatening factors in this area. Draught occurrence in Sistan region and subsequent decrease in vegetation, dryness of the Hamoon Lake and 120- Days wind caused windy erosion and sand storms conditions. These factors caused additional velocity of dunes movement in the region and making plentiful sandy-hills. Kaftaregi and then 6 hills of loess (Barkhan) were chosen as samples in field calculations. The rate of movements was calculated in 3 months and adjusted in a table. The results of field investigations showed that wind in high speed are caused increasing dunes movements and damaged farming fields, villages, roads, irrigation channels, installations. After determining the rate of dunes movement, movement of them will be forecasting for further years. Satellite images and field investigations showed that water storage of Chah Nimeh which is the only drinking water source of people, would be threatened by sand storms in the future, and water storage will be in serious danger, if there isn’t a way to prevent the rushing of sands. In this article, the attempt will be to survey the effect of 120- days wind in producing sand storms, and then mathematical model will be determined between geomorphic parameters. At the end, dunes drifting and damages will be forecasted by satellite images, topographical maps and field investigations.