فصلنامه پژوهش های فرسایش محیطی
سال یازدهم شماره 1 (پیاپی 41، بهار 1400)

Arid and semi-arid regions of the world cover more than 30% of the earthchr('39')s surface. Wind, as one of the erosive agents of the earthchr('39')s surface, causes the transport of sand and deformation in arid areas. Wind erosion is directly related to wind speed. The higher the wind speed is above the threshold value, the more increase in wind speed. This issue increases wind erosion and thus, it intensifies wind erosion. The Iranian plateau is one of the most sensitive areas of the world to wind erosion due to its location on the arid belt of the northern hemisphere. The Lut Desert is one of the most active places for changes in wind speed and direction with its huge volume of sand masses. The eastern part of this region, which includes the largest sand mass in Iran, namely Yalan sand, is dominated by 120-day winds, which doubles the importance of studying winds and its shaping role in the wind season. The main purpose and assumption of this study is to analyze the frequency of erosive winds and estimate the potential and final direction of sand transport flow in the Lut plain and to investigate its relationship with the geomorphology of existing wind forms using time series data of wind direction and speed recorded in Synoptic stations are located around this plain.

In this study, in order to analyze the wind situation and study the erosive winds in the Lut plain, the available meteorological data for 4 synoptic stations around this plain were used. WRPLOT view 7 software was used for statistical calculations of wind and drawing of wind rose. Sand Rose Graph 3 software was also used to draw the sand rose of the stations around Lut plain due to the high volume of calculations. To calculate the values of sand transport potential (DP) in different geographical directions, the Freiberger-Dean relationship based on the basic equations of Begnold and Leto-Leto was used. From the sum of DP values in different directions, the total sand carrying capacity (DPt) is obtained and in fact it is an indicator that represents the total wind energy to carry sand to the desired station. RDP stands for the amount or size of the output vector (resulting vector) of sand carrying capacity, which is obtained by summing the DP values in 8 or 16 different directions and shows the final status of sand transport in the study area. RDD indicates the net direction of sand movement (result vector direction) during the year, month or season. In order to determine the amount of sand transferred per unit time, a unit of width is used from the equations presented by Begnold, Xing, 1953, Kawamura, 1964, Hesu, 1973 and Leto-Leto, 1978.

At Shahdad station, about 40% of the winds blow from the north, north-northwest and north-northeast, and the rest of the winds often blow from the east and west. At Nehbandan station, about 20% of the winds blow from the north and northeast, and the rest of the winds have a great variety in the directions. At Bam station, about 36% of the winds blow from the west and west-northwest and the rest of the wind blows from the north and its surroundings. At Nusratabad station, about 31% of the winds blow from the east and southeast, about 27% of the winds from the west and northwest, and the rest of the winds from other directions with great variety. The results of annual hurricanes indicate that winds with north, north-northwest and north-northeast are the dominant winds in Nehbandan and Shahdad stations. At Bam station, in addition to the north directions, these winds also blow from the west and west-northwest directions. At Nusratabad station, there is a great variety of wind directions, but unlike other stations, the wind does not blow from the north. Analysis of net direction of sand movement (RDD) of the studied stations shows that the direction of sand movement in Bam and Shahdad stations is south-southeast, in Nehbandan station to the south and in Nusratabad station is to north-northeast. The analysis of the direction of movement of the sandrose shows the complete correspondence with the hurricane rose of the studied stations. Total sand carrying capacity (DPt) indicates moderate erosion power for Bam and Nusratabad stations and high erosion power for Shahdad and Nehbandan stations. The highest value of vector output of sand carrying capacity (RDP) is related to Shahdad station, followed by Nehbandan, Nusratabad and Bam stations, respectively. For Shahdad, Bam and Nehbandan stations, the maximum amount of one-way winds occurs in autumn and in Nusratabad station in late winter and spring. The maximum amount of sand flow for Bam, Shahdad, Nehbandan and Nusrat Abad stations is 165, 320, 233 and 202 kg/m/s, respectively.

The results indicated that in Shahdad and Nehbandan stations located in the northern half of Lut plain, most of the winds blow from the north, but in Bam and Nusratabad stations located in the southern half of Lut plain, most of the winds are concentrated towards Lut. The highest percentage of occurrence of winds above the threshold speed for Shahdad, Nehbandan and Bam stations occur in summer and the highest percentage of occurrence in Nusratabad station is related to spring. Analysis of net direction of sand movement (RDD) shows that the direction of sand movement in Bam and Shahdad stations is to the south-southeast, in Nehbandan station is to the south and in Nusratabad station is to the north-northeast. Total sand carrying capacity (DPt) indicates moderate erosion power for Bam and Nusratabad stations and high erosion power for Shahdad and Nehbandan stations. The highest value of vector output of sand carrying capacity (RDP) is related to Shahdad station, followed by Nehbandan, Nusratabad and Bam stations, respectively. The study of sand homogeneity index (UDI) indicates one-way winds for Nehbandan station and two-way winds with aperture angle for Bam, Shahdad and Nusratabad stations. The highest flow rate of sand is related to Shahdad station with 320 kg/m/s and the lowest is related to Nusratabad station with 50 kg/m/s.

The Soil surface characteristics have significant effects on the erosion process. The wide areas of watershed soil surfaces are covered with considerable amounts of rocks and pebbles. Surface rock fragments, resulting in water connectivity, change during the erosion process. Rock fragments on the soil surface may increase the infiltration and reduce soil losses because they can act as protective covers. When rainfall and runoff occur, this coating can has an important effect on soil erosion, sediment production, and infiltration processes. Surface rock fragments can protect the soil surface from raindrop impact, which further decrease the overland flow and its transport capacity, thus reducing erosion. But the effect of deployment pattern for these impermeable surfaces on the soil erosion phenomenon is not well known.

In the present study, using a rainfall simulator and soil erosion plots, the effect of impermeable rock surfaces include control (zero), 10, 15 and 20 percent of plot surface coverage, in three surface, semi-embedded and embedded situations and in three replications (30 plots in total) were studied. The experiments were performed in the rainfall and erosion simulation laboratory of the university of Torbat-Heydarieh. The erosion plots were smiliar to a  rectangular with a length of 1 m and a width of 0.5 m. The plots with a constant gradient of 9% for 10 minutes were exposed to rainfall with an intensity of 1.4 mm/min and after each rainfall event, the runoff volume, sediment production, sediment concentration, runoff coefficient, and infiltration rate were sampled and calculated at the plotchr('39')s outlet. Also, the spatial variations of sediment at the surface of plots were measured and compared using Laser roughness meter in different sections before and after each simulation.

The results showed that by increasing the percentage of rocks in the surface situation, the amount of sediment production increases, the volume of produced runoff volume decreases, and the infiltration rate increases. However, if the rock fragments are embedded, the sediment load and volume of produced runoff increase but the infiltration rate decreases. However, the main and interactive effects of treatments on soil erosion processes were not significant. Finally, according to the results of the comparison between pre-and post-roughness data in each treatment, there was a significant difference between the two groups. That, the difference between the groups, were caused by two factors: plot-level drop or the sectional transportation of sediments at the plot area.

In the current simulation study, the runoff and sediment yields were measured in soils with the different surface rock fragments in the laboratory utilizing a rainfall simulator and erosion plots. The most commonly utilized method for studying the influence of rock fragment cover on hydrological processes is to simulate rainfall on disturbed soils under laboratory conditions. The results showed that the difference between soil erosion and sediment production at the erosion plotchr('39')s level is also very considerable. So, the sediment delivery ratio should be seriously considered in erosion studies. It should be noted that the evidence of such differences between sediment analysis results and spatial changes of sediment, presents a new challenge for the erosion modeling and all of these inter-relationships should be perceived well enough that it would be possible to make them into effective erosion models.

Floods are one of the natural events that cause human casualties and damage to buildings, facilities, gardens, fields, and natural resources every year. Urbanization disturbs the balance of slopes through indirect intrusion within watersheds, kills vegetation, soil compaction, and changes in the profile of waterways, increases the severity of floods, and increases the amount of sediment generated. At the foot of the mountain, which includes the citychr('39')s physical fabric expansion area, the natural drainage pattern disrupts and increases the risk of urban flooding. On the one hand, because of its geographical position and the heavy rainfall regime over a short period of time, and on the other hand, because of its significant growth and development, especially during the last decade, and because of its location, the town of Bandar Abbas faces flood problems. On the other hand, flood risk zoning has not been considered so far in order to be used in the planning and management of flood protection and control in Bandar Abbas, and not much work has been done in this area in the form of research and even studies. Flood risk zoning is therefore important in order to forecast the degree of flood damage under various circumstances and the economic and social basis for flood control and containment systems. Risk modeling and flood vulnerability mapping will play an important role in future decision-making, flood management, and land management in the area of the study in some cases.

In general, the first step in the implementation of research in watershed management, environmental, natural resources, agriculture, etc. projects is the preparation of the data used in that project. The data needed to investigate the hazard, vulnerability, and risk of urban floods in Bandar Abbas in the first stage are: 1- Height 2- Land slope 3- Distance from water table 4- Water transport capacity of canal 5- Distance from river 6- Distance from collection network of surface runoff was obtained from Iran Water Resources Management Organization and city demographic data Bandar Abbas was prepared by the Statistics Center of Iran. A map of four key factors, including building quality, urban density, population density and, socio-economic status, has been prepared to examine the vulnerability. Two models of Maximum Entropy (MaxEnt) and Support Vector Machine (SVM) were used to investigate the risk, vulnerability, and risk of flooding and urban flooding in Bandar Abbas. Then, the Area under Curve (AUC) obtained from the curve ROC was used in order to test the modelchr('39')s efficiency. After estimating flood hazard, a hierarchical analysis model was used in order to estimate flood vulnerability in this report. Finally,  the map of flood risk was obtained based on hazard and vulnerability maps.

Based on the Maximum Irregularity Model, the results obtained from the flood risk prediction map showed that the southern parts of Bandar Abbas had a greater likelihood of flooding. It is also likely that parts of Bandar Abbas city center will be flooded. Bandar Abbas western and eastern areas are less likely to be flooded. Support has also shown that the southern, eastern, and southwestern regions are listed as likely to undergo urban flooding in order to help control urban floods. Using the SVM, the flood prediction map shows that the southern, eastern, and southwestern areas are more likely to flood; however, the northern and northwestern parts of Bandar Abbas are less likely to flood. The AUC was used in order to prepare the models. In the two phases of training and validation, the accuracy of the model suggests the highest irregularity. The Maximum Entropy Model, based on these curves, was 99.7% accuracy in the training phase and 94.2% accuracy in the validation phase. Therefore, in both the training and validation phases, the MaxEnt had excellent performance (area under the curve about 90%). The findings of hierarchical analysis have shown that the most important effective criterion for vulnerability is population density. The standard of construction, urban density and socio-economic status were ranked second, and fourth, respectively. Finally, on the basis of the risk map review, it can be claimed that there is a higher degree of risk in the southern parts of Bandar Abbas and parts of Bandar Abbas city center.

The results of the model accuracy evaluation show that SVM has accuracy in flood probability spatial prediction and in identifying areas vulnerable to flooding. It can also be seen that the SVM had better performance than the model of the support vector machine. Since most urban areas such as Bandar Abbas lack reliable hydraulic and hydrological knowledge, a new approach to flood management and urban flooding may be the use of machine learning models and historical urban flooding events. Machine learning models are highly capable of spatial analysis of flood events and urban flooding, as well as extracting the relationships between environmental variables and flood events, based on the tests conducted. The flood risk map revealed in this analysis that the central and southern sections of Bandar Abbas are more susceptible to flood. Prioritization and expert studies have shown that among the factors influencing vulnerability, the population density factor is the most significant. The map of vulnerability based on different factors also showed that there is a greater degree of vulnerability in the central and coastal areas. Comprehensive flood risk analysis has shown that there is a high risk of flooding in the southern and central parts of Bandar Abbas and these areas have a high priority for urban runoff and flood control.

 Topography is one of the effective factors in soil formation and development. Topographical features such as slope aspect and position, by affecting soil temperature, evaporation capacity, soil moisture content, soil organic matter, precipitation, movement, and accumulation of soil solution can impress soil microbial properties. For investigating the effect of land-use change on soil ecosystem functioning because of human activities, it is essential to study the soil processes in disparate land-use systems and to preserve and regenerate the capability of soil to deliver ecosystem services. This study aimed at evaluating the effect of slope aspect and position on soil microbial indices in rangeland and forest areas of Heyran neck.

This experiment was accomplished as factorial on the basis of a randomized complete block design with three treatments containing land use (forest and rangeland), slope aspects (north and south), and three slope positions (shoulder, footslope, toeslope), and four repetitions in Heyran neck, one of the functions of Astara city in Guilan province. Totally, 48 disturbed soil samples were taken from forest and rangeland at two aspects and three slope positions. From soil biological indices, soil microbial population, soil basal, and substrate-induced respiration (BR and SIR), microbial biomass carbon (MBC), and microbial quotient (qmic ) were measured. Soil microbial population was determined by the most probable number method (MPN method). The basal soil respiration was determined by placing 50g of soil in glass jars together with 10mL 0.05N NaOH in 20mL glass vials. All samples were incubated for 24h at 25 ± 1 oC, and the CO2 that evolved and was trapped during the period was determined by titration of the NaOH with 0.1N HCl. Substrate-induced respiration was determined by measuring the CO2 production from 50gr fresh soil. The soil samples included 1% glucose, were first placed in a glass jar. Then, an absorption bottle that was filled with 25ml of 0.1N NaOH was carefully put in the glass jar, and the glass jar was precisely sealed. The jar was then incubated at 25 ± 1 oC for 6h. The evolved CO2 was trapped by NaOH and determined by titration of NaOH with 0.1N HCL. Microbial biomass carbon was estimated by the chloroform fumigation and extraction method. Microbial quotient was calculated by dividing microbial biomass carbon (MBC) with soil organic carbon (SOC). Data’s normality was assessed through Kolmogorov–Smirnov test. The analysis of variance and comparison of means by Duncan test and Pearson correlations were done using SPSS software. Figures were prepared using Excel software.

The results showed that the content of all biological parameters measured in the forest soils was significantly higher than in the rangeland soils. In both land uses and in all slope positions, the highest values of basal soil and substrate-induced respiration, microbial population, and microbial biomass carbon were measured in the north-facing slope. In the studied land uses and slope aspects, all biological indicators except the microbial quotient had the highest value in the shoulder position. In the south-facing slope, the content of microbial quotient in the toeslope position was measured more than in other positions. Still, there was no significant difference from the value of this index in the shoulder position. The highest value of microbial quotient (1.95 mgCmic.g-1Corg) was observed in the north-facing slope on the shoulder, which was not significantly different from the value of this index in the footslope and toeslope positions of north-facing slope and also the shoulder and toeslope of south-facing slope. In forest land use, the content of microbial quotient in both north-facing (1.91 mgCmic.g-1Corg) and south-facing (1.9 mgCmic.g-1Corg) slopes was almost equal, which was significantly different from its value in both slope aspect of rangeland. The correlation between all biological indices at the level of one percent probability was positive and significant. There was the highest correlation between basal soil and substrate-induced respiration (r=0.94**) as well as microbial biomass carbon and substrate-induced respiration (r =0. 89**).

Overall, the results of this study showed that biological indices are dependent largely on landscape and land use, and by affecting the structure of the microbial community, these factors can affect the properties of the soil and its development. Due to the significant role of microorganisms as an integral component in the soil ecosystem and the effect of this component on the physical, chemical and nutritional properties of this ecosystem, by providing suitable conditions for the good activity of these organisms, soil quality can be increased, and thus erosion will be reduced.

Desert dust is formed under the influence of special weather and environmental conditions in desert areas and enters the atmosphere. Local hurricanes caused by surface air instability, passing through dry deserts, remove silt and sand particles from the surface and enter the atmosphere. Desert dust physically, in addition to its ecological effects such as lung-heart disease, disruption of the physiological cycle of the plant and erosion of cultural-structural buildings, contains heavy metals that are deposited on the soil surface, water surface and canopy surfaces of plants which cause chemical changes and physiological damage to environmental ecosystems. Heavy metals are generally referred to as a group of metal elements which have a specific gravity greater than 6 g/cm3 and an atomic weight of more than 50 g. The heavy metals that are important from an environmental point of view include: cadmium, arsenic, cobalt, vanadium, zinc, mercury, iron, manganese, nickel, lead, chromium and copper, which are non-degradable in nature. Furthermore, long life expectancy of the heavy metals is also considered as a very important environmental pollutant. Due to the environmental effects of heavy metals on soils, the present study tries to identify the concentration of heavy metals in Khuzestan province. In addition to monitoring the concentration of heavy metals caused by desert dust at a height of 2 meters above the ground, the concentration of metals in surface soil rangelands were measured.

Several location on Khuzestan province were selected for carrying out the experiment which include the rangelands around the cities of Dezful, Shousha, Ahvaz, Abadan, Ramhormoz, Behbahan, Izeh and Shushtar.  A sediment trap was then installed in these selected locations at a height of 2 meters above the ground to trap the fine dusts after each dust storm. The collected fine dust is then transferred to the laboratory to measure the concentration of heavy metals. The heavy metals that were measured in atmospheric particulate matter included lead, zinc, cadmium and manganese.  Moreover, each time the concentration of heavy metals in the atmospheric fine dust deposited in the trap was measured; the soil of the rangeland ecosystem of the same field was also sampled and transferred to the laboratory for heavy metals measurement.  Finally, in order to evaluate and determine the severity of contamination of atmospheric fine dust and rangeland soil with heavy metals, Geo accumulation Index (Igeo) was used.

The results showed that the maximum Pb metal in atmospheric fine dust of Abadan is (40.3 mg / kg), Zn and cadmium in Ahvaz is (365 and 1.72 mg / kg) and manganese in Abadan is ((548 mg) in kilograms). The pattern of heavy metals in the fine dust and rangeland soils of the region was Mn> Zn> Pb> Cd. The maximum concentrations of Pb, Zn, Cd and Mn were observed in the rangeland soil of Abadan station with the mean of 140.3, 450.16, 0.81 and 561 mg / kg, respectively. The concentration of heavy metals in the atmospheric fine dust of the warm period of the year was higher than the cold period of the year. The results of heavy metal concentration in rangeland soil showed that heavy metals in rangeland soils in the west of Khuzestan province were more than its eastern regions and its maximum was in Abadan rangelands and its minimum was in Izeh.Pollution assessment also showed that the western regions of the province are in a very polluted category in terms of Pb, Zn and Cd; But the eastern regions of Khuzestan province were in a slightly polluted category. Therefore, the entry of desert dust into the region is the main reason for the increase and accumulation of heavy metals in the rangelands of western Khuzestan province.

According to the experiment done on different regions of Khuzestan provience, the desert dust that enters Khuzestan province contains high concentration of heavy metals which can lead to many environmental problems. Desert dust mostly enters Khuzestan from the west and settles in western parts of the country which reduce wind speed and affects its ecosystem negatively. Due to the fact that the concentration of heavy metals in atmospheric dust and soils of the western regions is higher than its eastern regions, it can be concluded that dust deposition is the main reason for the increase in heavy metals in the rangelands of western Khuzestan province.

An examination of the number of floods in recent years shows that floods are no longer a rare sudden disaster, but a growing phenomenon that, at any given time, causes a lot of damage, including life and death. As a result of interference in natural environments, the presence of multiple structures, and the lack of appropriate measures to protect these environments, flood conditions are provided. Also, with the rapid growth of urban development and the creation and development of infrastructure, floods in urban areas have become more and more severe. In our country, especially in the southern regions of the country, due to climatic conditions, floods are frequent and harmful. The growing trend of floods in recent years suggests that most of the countrychr('39')s southern cities are at risk of flooding. According to studies, about 40 large and small floods occur in different parts of the country every year. Experimental and managerial experience of different countries shows that the first step in reducing the harmful effects of floods is to identify flooding areas and zoning of these areas in terms of flood risk so that based on the results obtained with integrated management. And comprehensive urban planning prevented the harmful effects of urban floods as much as possible. This study aims at identifying potential flood areas of Bandar Abbas and Bandar Abbas strategic city using GIS, and adapting this map to the development plan of residential areas obtained from LCM model in remote sensing of satellite images as well as determining the flood risk areas.

In this study, two steps have been taken to achieve the desired goals. In the first stage, using five height parameters, slope, land-use, lithology, and river mile have been used as effective parameters in identifying flood-prone areas. After preparing the information layers for each parameter, the layers are standardized using fuzzy logic. After standardizing the layers, a hierarchical analysis model (AHP) was used to weight the layers. After determining the weight of each layer, in the ArcGIS environment, the weight obtained is applied to that layer, and finally, using fuzzy gamma, the information layers are combined, and the final map of flood-prone areas is prepared. In the second phase, satellite imagery from the 1990s, 2000s, 2010, and 2019 was used to assess the development of residential areas to prone to flood-prone areas. After preparing the images, in the ENVI software, first the necessary pre-processing on the images, including radiometric and atmospheric studies, has been done, and then by using the maximum probability method, land-use maps of the study area related to the 1990s, 2000s, prepared in 2010 and 2019, were presented. After preparing the land use maps, IDRISI software and the LCM (Land Change Modeler) software were used to evaluate the trend of land-use change in residential areas.

Evaluation of the final results of flood-prone areas indicates that a large part of the study area has a high flood-rising potential, so based on the results, the class has a very high potential for floods, 88 km2 (equivalent to 28.7% of the study area). The study area includes mainly areas close to the river, low-slope, and low-lying areas. Also, the class with a very low potential for flooding includes 24 km2 (equivalent to 7.8% of the study area) of the study area, which mainly includes the highlands and the northern slope of the study area. In addition, the results of the assessment of land-use changes indicate that land-use has undergone many changes during the study period, and the use of residential areas has increased. Assessing the trend of changes, shows that the increasing trend of use of residential areas has been due to population growth and construction development. The decrease in the use of vegetation and water area is also due to the development of the use of residential areas, which has caused the destruction of vegetation and the progress towards the coast. Also, the trend of changes in the use of weak pastures and salt marshes has been affected by the development of residential areas and climate change.

The results indicate that the study area has a high potential for flooding, so that about 170 km2 of the study area (equivalent to 55% of the study area) have a high and very high flood potential these areas mainly include low-slope and low-lying areas of the urban area and the suburbs of Bandar Abbas. Therefore, in terms of used parameters, the city of Bandar Abbas has a high potential for flooding. Also, in this research, the trend of land-use changes and residential areas of the study area has been evaluated. According to the results, the use of residential areas (including residential areas and man-made areas) has grown so much that in 1990, this area was 32.2 km2, which in 2000 to 42.9, and in 2010 it increased to 55.7 km2 and in 2019 to 77.4 km2. Assessing the spatial trend of land use changes indicates that a large part of the residential area has moved to areas prone to flooding. According to the results, in 1990, 14.2 km2 of residential areas were located on the potential floor of many floods, which in 2000 to 16.4, in 2010 to 21.9 and in 2019, it has increased to 28.1 km2. Therefore, it can be said that in recent years, a large part of the residential areas has moved to flood-prone areas.

The Hedijan coastal plain around the Zohreh River is a hub for essential agriculture, fisheries, trade, and the military. Any change in the regime and territory of the Zohreh River will have significant economic, social, and security effects in the region. Due to the privation of the region and preserve the available resources and capital, it is necessary to carefully study the hydraulic parameters affecting the morphological changes and the complex pattern of the meandering of the Zohre River. In this study, considering the special conditions of this coastal plain, it has been tried to study geometric features such as curvature coefficient, curvature radius, central angle, and river arc length in three time periods by studying and examining satellite images in a GIS environment.

In this study, to study the morphological changes and meandering pattern of the Zohre River in the coastal plain of Hindijan, Google Earth satellite images from 2000 and 2014 were used. Based on these two images, the old route of the Zohreh River can be identified in the study area. In the next step, to investigate the meandering and morphological changes of the river, the route drawn from Google Earth entered the GIS environment. Using the ArcMap 10.2 software, to examine essential parameters in river morphological changes, circles with a suitable radius tangent to the existing curves in the river path were drawn. In the old route, 35 meanders were detected, and in the 2000 and 2014 routes, 21 meanders were identified and examined.

 Results :

In order to study the morphology and meandering pattern of the Zohre River in the study area, various parameters such as bending coefficient, central angle, arc length, half-wavelength, and radius of curvature were calculated. According to Wolfert (2001), four types of rivers, including direct, sinusoidal, meander, and more meander, have been introduced in terms of the degree of curvature of rivers. According to this criterion, the Zohre River can be placed in a meandering river in the study area. Also, the number of meander from previous years, 2000 and 2014, was 35, 21, and 21. The maximum radius of the meander of this river was 450.1, 661.8, and 632.3 m. The lengths of the arch were 1197, 1118.2, and 1154.6 m, respectively. There have been alternating positive and negative changes in the values of the central angles in all three study periods. The average central angle from the old route to 2000 has been declining, and from 2000 to 2014, it has been increasing. In the old route, based on the size of the central angles, 57.14% of the torsions are in the overdeveloped area, 14.30% of the torsions are in the developed inverted 11.42% are in the undeveloped area. 17.14% was the size of a cowchr('39')s horn, and no percentage was found for quasi-twisting curves. In 2000, based on the size of central angles, 42.86% of turns were over-developed, 14.30% of the turns were over-developed, and 23.80% of the turns were twisted. The average amount of radius in the old path increased from 450.1 to 66.81, and from 2000 to 2014, it decreased to 632.3. In total, this parameter has increased over three time periods. Finally, the obtained values for this parameter indicate that the river is meandering and the morphological changes in these three periods.

The results showed that significant changes have taken place and are taking place over the years under study. During the three times of periods, four significant shortcuts and other significant morphological changes occurred. It is predicted that in the place of the 18th meander at the location of the existing bottleneck, there will be a shortcut in the future, which will eliminate the existing meander and create new ones.Also, according to the Wolfert classification criterion based on the bending coefficient (1.5-2) and the Corneiss classification based on the central angle (158-296), the Zohreh River is located in the Hindijan Plain is in the category of meandering and the meander is overdeveloped.