فصلنامه پژوهش های فرسایش محیطی
سال یازدهم شماره 4 (پیاپی 44، زمستان 1400)

Changes in river pattern is one of the most important issues of river engineering that affects the activities and structures of the river bank. It is important to study the morphological changes of river channels in order to find appropriate control solutions to solve the dynamic problems of these areas. The morphology of the riverbed pattern over time is a function of various factors such as geological formations, flood discharge, changes caused by human factors, vegetation, topography and tectonic movements. Statistical studies of river patterns have presented the morphology of a number of geostatistical rules. In this regard, the sinusoidal pattern of the riverbed depends on the dominant role of processes and a set of factors that are applied over time. A hydraulic structure refers to a structure in which all or part of the body of water is in contact with water in a way that changes the natural flow of water. These structures are used for purposes such as transmission, energy dissipation and flow cessation. There are different types of hydraulic structures and their use depends on the type of water source and the purpose used. In any case, in general, stair is one of the most important hydraulic structures. The construction of bridges in the course of rivers causes changes in the morphological behavior of rivers.

The two most important rivers in Gilan province are Plorud and Shalmanrud located in the east of Gilan. Data mining algorithm was used to model the effect of hydraulic structures. The algorithm determines the method used to search for the pattern in the data and is, in fact, like a mathematical procedure for solving a particular problem. Data mining algorithms refer to a set of inferences and calculations that provide a model of the data. In order to create a model, the algorithm first analyzes the presented data to search for specific types of patterns or trends. It then uses the results of this analysis several times to achieve the desired parameters to create a data mining model. In the next step, these parameters are used to extract accurate operational patterns and statistical processes in the entire data set. One of the most efficient algorithms used in the data mining process is the use of a priori algorithm. For modeling through a priori algorithm, six parameters of distance from bottom to bottom, cross-sectional area, full cross-section width, maximum full cross-sectional depth, average full cross-sectional depth and width-to-depth ratio were used. Another algorithm used to investigate the effect of constructed structures on the morphological behavior of measured rivers is Veca algorithm. The Weka algorithm consists of a set of methods such as categorization, clustering, and association rules and feature selection. In categorization, each data is assigned to a predefined class, but in clustering there is no information about the classes in the data. Therefore, considering the importance of investigating construction of hydraulic structures on riverbeds, modeling the effect of hydraulic structures on the morphological behavior of Shalmanrud River in Guilan province will be evaluated in this study.

Of the 53 rules obtained, 12 were more attractive and accurate based on the data. Comparison of the rules obtained by using the a priori algorithm showed that among the six indicators measured in data mining operations, the indicators of maximum depth of section with average confidence of 92% and 25% of the participation rates in the extractive laws are in the first place; width to depth ratio with an average confidence of 88% and 24% participation rate in extractive laws is in the second rank; cross-sectional area index with an average confidence of 85%  and 21% participation rate in extraction laws is in the third place; full cross-sectional index with an average 79% confidence and 15% participation rate in extractive laws is in the fourth rank; average depth of full section with an average confidence of 77%  and 10% participation rate in extraction laws is in the fifth rank and downstream distance index with an average confidence of 75% 55 Percentage of participation in extraction laws is in the sixth place. Based on this algorithm, ten rules were extracted from the data set used. The first rule with an accuracy of 0.883 includes river morphology, width-to-depth ratio, cross-sectional area and maximum full cross-sectional depth. The second law with an accuracy of 0.867 includes river morphology, cross-sectional area, full cross-sectional width and distance from the downstream. The third rule with 0.769 accuracy includes river morphology, cross-sectional area, full cross-sectional width and maximum full cross-sectional depth. Based on the results obtained from the accuracy and usefulness of the indicators, the width-to-depth ratio index has the most beneficial mode in the extraction rules.

In order to determine which of the two tested algorithms is more effective, the accuracy, sensitivity and specificity of the two algorithms used were measured along with the accuracy, sensitivity and specificity that can be used for each of the available algorithms. These indices were calculated to determine the accuracy of the classification for each of the categories. In fact, this criterion indicates the success rate of the classifier method in identifying samples related to each category. The call rate with the attribute, which is calculated as the a priori criterion for each of the available categories, shows the percentage of reliability of the output of the classifier method. In general, the results indicated the appropriateness of using the a priori data mining algorithm in modeling the impact of hydraulic structures on the bed of the two rivers Shalmanerood and Plerood because all three indicators of accuracy, sensitivity and specificity of this algorithm were higher than the Weka algorithm.

Soil as a bed of life plays an important role in meeting the nutritional needs of human societies. But due to unscientific poisoning, it is eroding and causing problems for humans, especially in arid areas. Today, a significant part of the soil of these areas is out of use and is practically not suitable for agriculture and exploitation. In addition, by destroying the soil structure, conditions are provided for the movement of soil particles under the influence of wind and water, one of the destructive effects of which is the destruction of the environment. Therefore, since soil is the only source of nutrients, its protection not only reduces evaporation, but also prevents salinization of the soil and also improves plant yield and growth. Therefore, improving the physical and chemical properties of soil and increasing its resistance to corrosive agents (water and wind) is essential. One of the important and efficient methods to improve the physical and chemical properties of soil is the use of mulch, which controls the physic-chemical and biological degradation of soil. Numerous studies have been conducted to investigate the effect of mulch on the physical and chemical properties of soil in and outside the country. One of the arid and desert areas of the country where the decline of natural areas today has caused environmental degradation and also the expansion of erosion centers is Sistan region which has been exposed to soil degradation due to wind erosion and poor vegetation due to lack of water and soil moisture, which in turn has expanded desert areas. This phenomenon has intensified and spread sandstorms and dust. Therefore, due to the importance of studying soil conservation methods and also the urgent need to provide a suitable model compatible with climatic conditions in Sistan region and achieve a principled and efficient management for sustainable use of soil resources in this region, some research studies are needed. Accordingly, the aim of this study was to investigate the long-term effects of using sandy loam and clay nanoparticles on some physical and chemical properties and soil erodibility indices in one of the erosion centers of Nimroz city in Sistan region.

The experiment had been conducted in a randomized complete block design with 3 treatments in 4 replications. The treatments included: nano-clay, sand mulch and witness. In this study, the sand mulch was prepared from windy sediments deposits of the Sistan plain. Also, to prepare nano-clay, sediments from floods that entered Sistan River were used (to pulverize the flood sediments, ball mill were used and to determine the particle size and main elements, DLS and xrf methods were used, respectively). By sampling from each treatment, the physical chemistry characteristics were measured. To study the physical properties of soil, hydrometer method was used and the soil texture was determined. To investigate the chemical characteristics, the soil properties such as organic carbon, acidity (PH), electrical conductivity (EC), sodium absorption ratio (SAR), Na and available P were measured in laboratory. Irrigation of the studied treatments was done by clay method. The pottery used in this research is about 40 cm high and 5 cm in diameter. Sour tea was the plant cultivated in this study. Experimental treatments in this study included: Control treatment, with aerated sand and clay nanoparticles, was coducted in a randomized complete block design with four replications. Statistical analysis of data was performed using SPSS 23 software. The means of the studied parameters were compared using Duncan's multiple range test at the level of 5%.

Based on the results obtained from the particle size distribution, the findings indicated that the percentage of clay, silt and sand at a depth of 0 to 10 cm in the soil of nano-clay treatments and wind sand cover at 5% level significantly differed with the control soil. The highest percentage of sand was in the sandy and nano-clay soil cover treatments, respectively, and the highest percentage of silt was related to the control treatment. Also, the highest values ​​of clay percentage were measured in the nano-clay treatment and the lowest in the wind-blown sandy soil treatment (p>0.05). Particle size in the surface layer of the findings indicated significant changes in the percentage of silt and clay in the treatment of aeolian sand cover. In the same vein, with the preparation of sandy loam soil, the particle size was mainly in the average sand size (0.3 mm), which during the study period was 12.1 and 7.9% of the particles in the average silt (0.031 mm) and clay with > 0.0039 mm, respectively. In analyzing the amount of the above-mentioned parameters in the depths of 10-30 and 30-30 cm of the soil, the findings showed no significant differences between these variables in the treatments of wind-blown sand and control condition. However, the values ​​of these parameters in the nano-clay treatment showed a significant difference compared to other treatments. In control treatments, the percentage of sand, silt and clay decreased by increasing depth of the trend. However, in the treatment of aeolian sand cover, except for the percentage of sand, the trend of changes in the percentage of silt and clay increased. Moreover, in the nano-clay treatment, the studied parameters remained unchanged and, in general, the particle size distribution had the same structure in the studied layers. In the study of the percentage of soil saturation moisture in the treatments, the findings indicated that the rate of this parameter is higher in the nano-clay treatment compared to the two treatments and aerated sand cover. The mean values ​​of this parameter in the mentioned treatments were 33.9, 18.9 and 8.6%, respectively, which are significant at the 95% probability level. The trend of changes in this parameter in other sampling depths compared to the control treatment showed a significant difference. In general, its values ​​in nano-clay and sandy loam treatments are higher than the control treatment. In examining the texture distribution of the collected samples, the findings indicated that in the surface layer (0 to 10 cm) the soil texture was in sandy loam sandy loam treatment.

In this research, which was conducted for the first time in Nimroz city in the north of Sistan region, the long-term effects of nano-clay and aeolian sand cover on physicochemical properties and some soil erodibility indices were investigated. In examining soil physical properties, the results showed that the percentage of clay, silt and sand under the protective effect of soil in the studied treatments are different. In the surface layer, the values ​​of the studied variables in control, nano-clay and aeolian sand cover treatments were significantly different (P <0.05). In fact, with the use of aeolian sand cover on the soil surface with a particle size of 0.316 mm, the soil texture was changed from loamy to sandy loam class and in other sampling depths that did not use sandy loam underwent no significant difference compared to the control treatment. In nano-clay treatment, although changes in the values ​​of the above variables had no effect on soil texture, there was a significant difference in particle size distribution compared to control and aeolian sand cover at all sampling depths. In addition, the presence of nanoparticles among soil particles for increasing the specific surface area had a significant effect on water absorption and thus increased soil moisture. The increase of 1.2 and 1.6 times soil moisture in nano-clay treatment compared to wind-blown sandy soil and control treatments showed a significant difference in the 95% probability level. It has already been found that increasing soil moisture due to the presence of clay nanoparticles in the soil increases the total specific surface area and this in turn increases moisture absorption due to hydrophobicity and high moisture absorption of clay in the soil, which is consistent with the results of this study.

Due to the fact that coastlines have a large part of the world's population and many facilities are located along the coasts, shoreline changes can cause a lot of damage to coastal areas. Coastal changes can be caused by natural and human processes and factors; however, coastal processes are often under human activities, locally or globally. Natural processes can also be enhanced or accelerated by human activities. One of the beaches that has undergone many changes is the shores of the Caspian Sea. Fluctuations in the Caspian Sea are faster than other seas and lakes. The Caspian Sea has experienced several periods of extreme fluctuations in recent decades, and this has led to the shifting of the coastline in each period of alteration. The shores of the Caspian Sea have long been of interest to human societies and numerous activities have taken place along its shores. Changes in the water level of this lake have always changed the lives of the inhabitants of the Caspian Sea and have caused damages and in many cases have led to the relocation of settlements and facilities. Also, changes in the level of the Caspian Sea, in addition to the coastline, have had important effects on Anzali Wetland. Due to past fluctuations in the level of the Caspian Sea, this wetland has been affected by these fluctuations more than other coastal areas of the Caspian Sea. Due to the importance of the issue, in this study, the effects of fluctuations in the Caspian Sea level on the coastline and Anzali wetland have been investigated.

In this study, in order to achieve the desired goals, from 1: 50000 topographic maps, 1: 100000 geological maps, digital model of 12.5 m altitude, Landsat satellite images as well as statistical information related to sea level changes and climate situation Area are used as research data. The instruments used in the research included ArcGIS (in order to prepare the desired maps), ENVI (in order to prepare the desired maps) and IDRISI (in order to analyze the changes that occurred in the coastline and Anzali wetland). Also in this study, LCM models (to analyze land use change information and identify changes in the coastline and Anzali wetland) and a combined model of fuzzy logic and AHP (to identify areas vulnerable to environmental hazards and also identify areas prone to the development of human activities) have been used. This research has been carried out in several stages in accordance with the intended objectives. In the first stage, based on the statistical information of Bandar Anzali metering station, changes in the Caspian Sea level have been evaluated. In the second stage, using Landsat images, the changes of Anzali wetland have been studied. In the third stage, using Landsat images, shoreline changes have been evaluated and in the fourth stage, the relationship between changes in sea level, Anzali Wetland and shoreline has been explored.

In this study, in order to investigate the changes in the Caspian Sea level, information about the leveling station of Bandar Anzali during the years 1990 to 2020 has been used. The results of the evaluation of the changes indicate that the surface of the Caspian Sea has decreased by 51 cm during the study period. Also in this research, using Landsat satellite images, the changes of Anzali wetland have been studied. According to the results, Anzali Wetland has undergone many changes in recent years, to the extent that this wetland in 1990 was about 37.46 square kilometers (wetland water area), which in 1995 increased to 39.24 square kilometers. From this date onwards, the area of the wetland has been decreasing so that the area of the wetland has been reduced in 2000 to 38.59, in 2005 to 37, in 2010 to 35.17, in 2015 to 33.49 and in 2020 to 30.04 square kilometers. The results of the coastline study also indicate that the average shoreline change in the study area from 1990 to 2020 was about 135.4 meters. In fact, during this period of time, under the influence of various natural and human factors, the coastline of the region has experienced a reversal of 135.4 meters.

Declining Caspian Sea level, along with its environmental effects, has caused changes in Anzali Wetland and the coastline. In fact, the declining trend of the Caspian Sea has caused the level of Anzali Wetland to decrease in accordance with this trend and, as a result, the area of the wetland has decreased to the extent that during a period of 30 years, 7.42 square kilometers of wetland area has decreased. This issue has shown a direct effect of sea level decline, although human factors have also played an important role in these changes. Also, the declining trend of the Caspian Sea surface has caused the coastline to regress more rapidly in the study area, so that during a period of 30 years, the coastline of the study area has receded by about 135 meters, part of which is the reason for the decrease in sea level. In addition to sea level changes, human factors have also played an important role in shoreline changes. According to the results, man-made areas have increased by about 20 square kilometers during the years 1990 to 2020; consequently, the increasing trend of population and physical development of Anzali city as well as the development of various infrastructures towards the coastline have caused a change in the coastline and the decline has intensified. Also, human factors have played an important role in the inflow and outflow of water of Anzali wetland, so in changing the size of Anzali wetland these human-related factors have also been effective. According to the mentioned cases, the fluctuations of the Caspian Sea along with human activities have been one of the factors affecting the status of the coastline and Anzali wetland.

Over the past few decades, a variety of methods have been developed to study flooding, including the most important flood risk estimation methods proposed by researchers such as maximum possible flood risk and flood frequency analysis. In addition to the mentioned methods, that are methods which are mainly based on the use of GIS and remote sensing technologies and seek to investigate the flood situation using environmental parameters. It seems that the study of flood risk beyond natural phenomena is also related to human factors. In this regard, studies conducted on multiple floods show that despite the high efficiency of software in assessing hazards, none of these cases in practice has been able to prevent the occurrence of re-floods and the resulting losses. Human factors are also effective in the occurrences of floods. Considering the mentioned cases and the necessity of investigating the possibility of occurrence of floods and also the great importance of investigating the role of human elements along with environmental factors in the happenings of floods, the present study was conducted with the main purpose of investigating and analyzing the role of environmental components and humans in the occurrence of floods in Qaleh Chaie, which was taken from the experiences of floods in 2017.

The present research, in terms of method, has an applied purpose and a descriptive contextualized nature.  To collect the required data for the research, the library and field methods (researcher-made questionnaire in a five-point Likert scale) as well as the experts' questionnaire (Delphi), were used. The implementation process of this research has been done in two general stages: in the first part of the research, the parameters affecting the risk of flood occurrence were environmental. The software used in this section was ARC GIS and ENVI software. Components used in this section include land topography (height), land slope, slope direction, distance from the river, vegetation density, flood characteristics, rainfall, and land use. Also, in the environmental component section, economic, socio-cultural, structural-institutional, and infrastructural variables have been used. The collected data were analyzed using statistical tests.

The results of the analysis of satellite images in the field of topographic parameters of the land slope, slope direction, height, and distance from the Ghaleh Chaie River and others show that there is a big difference in different villages. The first group of villages that are located in the direction of Ghaleh Chaie are prone to floods due to the mountainous type of the region and also the steep slope, and the other group that is located at the end of the Ghaleh Chaie watershed has a very gentle slope due to its plain location and villages are less prone to face floods. Also, the results showed that from 1971 to 2017, 9 floods were reported in the area. In other words, the return periods of the floods are about six years. Also, since 1971, three floods have been reported, which killed four people in 1979, eleven people in 1990, and twenty casualties in 2017.
The results of one-way analysis of variance showed that the difference between 36 villages in terms of four indicators affecting flooding was significant at the level of 0.000, coefficient of 0.05%. Among these, the variables related to economic effects with the value of F = 13.524 have the highest level of expectation from the other three groups, followed by infrastructure, cultural-social and structural-institutional variables, respectively.
The study of the spatial distribution of the villages indicated that the villages near the Qaleh Chain River are vulnerable due to the high slope of the land, the mountainous nature of the region, the melting of snow, and the flow of water due to rainfall on the slopes of Sahand Mountain. Most of these villages are prone to be affected by environmental factors like slope, proximity to the river, mountainous topography, and so on.

As it has been examined in this study, given that floods are recognized as one of the most destructive natural disasters in the world, the identification and investigation of areas vulnerable to floods as well as the identification of all natural and human components that might influence the occurrence of this this phenomenon can be the starting point for practical and effective planning in the field of flood prevention. Accordingly, in this research, the role of environmental and human factors in the occurrence of floods have been investigated simultaneously. The results show that villages located in mountainous areas with high slopes are very vulnerable to flooding. Since environmental parameters are beyond human control, their effects can be reduced by taking preventive measures. The results also showed that there is a relationship between human parameters and the degree of vulnerability of villages to floods, so it is suggested that to manage flood risk in rural areas, human and environmental components be taken into account and studied simultaneously.

     In the last decade, the volatile region of the Middle East, along with all other natural hazards, has been plagued by dust storms. More than anywhere else in the world, global warming and climate change have affected the natural ecosystems of this vulnerable and fragile region. From a synoptic meteorological point of view, storm is a unique destructive phenomenon on synoptic maps that includes a combination of pressure, cloud, rain, wind, et.c (Alijani, 2006; Hosseini, 2000). Dust can be a reaction to changes in land vegetation, according to which the role of human activities along with the natural conditions of geographical environments should be considered (Arimoto, 2000). Burial of residential areas under sand, destruction of agricultural lands and expansion of desert areas (Wang 2005), creation of colored rainfall, disruption of transportation system, disruption of agricultural fields and orchards (Koren et al., 2015), air pollution, respiratory problems and diseases, and the prevalence of infectious diseases are the most important complications and problems caused by dust storms (Goudie and Midelton, 2002). Therefore, it is necessary to identify and analyze dust-generating patterns of prognostic aspects.

     In this research, the synoptic analysis of dust in Kermanshah province has been studied. For this purpose, dust codes for 12 synoptic stations over a period of 30 years (from 1990 to 2017) were received from the Iranian Meteorological Organization. Then, in order to perform the classification operation and further calculations, sea level pressure (SLP) and geopotential height of 500 hPa level data were extracted for grading days by programming in GrADS software. In the next step, in order to classify sea level pressure data and identify representative days, cluster analysis was performed on dusty days and dust generating atmospheric patterns were extracted, and finally the synoptic and dynamic analysess and interpretation of these patterns were performed.

     By performing cluster analysis on sea level pressure events, five patterns for dust occurrence in the western region of Iran can be identified as follows:Pattern1: Indian monsoon low pressure - European migratory high pressure: A study of this model shows that all regions located in southwest Asia to the center of the Mediterranean have become the convergence of currents originating from the monsoon region of South and Southeast Asia. Summer monsoon rotation, the region of South-Southeast Asia, has acted as a large-scale energy source. The regions located in Southwest Asia and the Eastern Mediterranean are the main area of ​​convergence of this flow and, in fact ,are heat wells.
Pattern2: Indian monsoon low pressure integration, Oman Sea - North Caspian high pressure: Like the first pattern, Indian monsoon low pressure system is formed on the northwestern regions of India and on the border with Pakistan, which moves in orbit through the Oman Sea and the Persian Gulf. It has entered the regions of Southwest Asia and covers a large area from the Middle East to North Africa, and has strengthened its coverage of the central to eastern Mediterranean.
Pattern3: Sudan low pressure, European low pressure - North African high pressure: A study of this model shows that at sea level, the Sudanese low pressure system travels from the southern and central parts of the Red Sea to cyclonic and meridional directions. The interior region of Saudi Arabia and the desert of Ruba'at al-Khali have moved and covered all the desert areas of Saudi Arabia, Iraq and Syria in such a way that it has caused the bottom convergence and vertical ascent of the currents over the dust centers. In addition, in the orbital direction and in the vicinity of this system in North Africa (Libya, Egypt and Algeria), a high-pressure system with a central pressure of 1016 hPa prevails, which leads to severe pressure differences and increased instability in dust centers and over-activation. It has resulted in dust hotspots in Saudi Arabia and North Africa.
Pattern4: Sudan low-pressure integration Sudan, Saudi Arabia - Siberian high-pressure: Sudan-origin low-pressure system with high spatial and spatial expansion across the Red Sea is integrated with Saudi low-pressure on one side and on the other; moving northwards with expanded tabs and Indian influence in the eastern and southern parts of Iran has created a huge expanded belt of low pressure centers. In addition, a weak high-pressure system with a central pressure of 1016 hPa over the Mediterranean Sea and North Africa has created atmospheric instability due to the pressure difference created over desert areas.These areas are the focal points of dust and the main generator of dust storms in the Middle East.
Pattern5: Polar low pressure, Sudan low pressure - European high pressure: A study of this model shows that the polar low pressure system along with Sudan and Red Sea penetration low pressure are the main controllers of Iran's atmosphere at sea level in such a way that the cyclonic movement of cold currents in the polar regions towards the lower latitudes and its penetration from the northeast into Iran and then the integration of its tabs with the low pressure tabs of the Red Sea and Sudan cause the corridor to have unstable currents in the polar and tropical regions, or in other words, the polar and subtropical regions, which have dominated the upward vertical currents in a very large area of ​​Iran. However, the dominance of the European high pressure system and its penetration to eastern Turkey in the orbital direction and North Africa in the meridional direction and its confrontation with the infiltration low pressure cause severe compression pattern, instability and transport of dust into the low pressure Sudan and the Red Sea.

   Studying and understanding the synoptic and dynamic state of the atmosphere as well as understanding the local conditions and geomorphology of each region is one of the key topics of interest in atmospheric studies. Dust storms in the western part of Iran are mainly caused by certain weather conditions. Thus, the components of the atmospheric circulation scale at the lower levels play a major role in the occurrence of dust storms. In the patterns of the warm periods of the year, the dominance of the west current with the monsoon origin of India has created the following convergence around the dust centers of southwest and west Asia, which are intensified by the upper convergence caused by the high pressure of the Azores or the western wave. This issue is accompanied by the activation and rising of dust in the dust centers of the region, which eventually extends to the western region of Iran by eastward and orbital currents.  On dusty days occuring in the cold seasons, Sudan and Red Sea thermal low pressures on Saudi Arabia, Iraq and Syria at sea level, and low-lying nuclei and western waves on Europe and the Mediterranean Sea at mid-atmospheric level are the main controllers of climatic conditions in the region. Therefore, in the cold period of the year, due to the heaviness of the cold weather in these days, they are allowed to penetrate to low offerings and place the eastern part of trough on the deserts of North Africa, Saudi Arabia, Iraq and Syria. By creating instability and moving to the east, they direct the generated dust to the west of Iran. However, whenever tabs of Indian monsoon low pressure and Sudan low pressure enter the West Asian region at sea level and the Mediterranean subtropical or high-pressure submarine operates in mid-atmosphere, the upper convergence and the dynamic decrease of air flow causes the amplification and over-activity of surface low pressures, which is accompanied by the activation of dust centers and the rise of dust in the area. In general, Azores high pressure along with migratory systems of western winds is the most important synoptic factor in dust systems in the western regions of Iran. Comparison of research findings showed that thermodynamic processes in the hot season and dynamic processes in the cold season are the most important factors in the formation and transfer of dust to the western half of the country (Kermanshah). Thus, the establishment of low thermal pressure at ground level and low altitude of 850 to 500 hPa in the vicinity of western Iran is effective in generating identified dust during the warm periods of the year, which is consistent with the findings of Azizi et al (2012) in the synoptic study of dust in the western part of the country.

Erosion, especially soil erosion by water, is one of the most important issues in the destruction of environmental resources. To prevent erosion, we need to know its various dimensions. Erosion is a natural and calm phenomenon that has led to the formation of landscapes that are currently considered suitable environmental resources for human life. However, in terms of natural resources, erosion has destroyed fertile soils and has had many negative effects on lives of inhabitants. Soil erosion is the most important cause of land degradation and leads to water and soil wastage. Plants, like other living organisms, are affected by various stresses, including stresses caused by salinity, drought, cold, frost, high temperatures, heavy metals, flooding conditions, UV radiation, and damages caused by deficiency or excess. Soil dryness and water shortages in the city of Maraveh Tappeh, which plays a vital role in ecology, agriculture, industry, tourism and health of the residents, highlight the importance of monitoring this phenomenon. Drought is an irregular rainfall pattern that leads to changes in vegetation, because water is a required factor in plant growth. On the other hand, changes in green cover levels play a dynamic role in balancing energy and water levels. Plants have developed a variety of mechanisms to adapt to dehydration. Molecular genetic aspects have allowed them to respond appropriately and adapt themselves to this stress.

The present study, due to the nature of the issue and the subject under investigation, has a descriptive-analytical design and is of the type of applied studies with an emphasis on quantitative methods. Wet and drought phenomena were used as the key isseues to be examined. The purpose of this study was to measure and analyze the time series of drought-based plant stresses by using remote sensing data and climatic indicators. For this purpose, first by calculating the data of Modis satellite and Telos sensor, the estimation of Vegetation analysis in each pixel was performed based on z distribution. Then, by using parameters involved in plant stress such as humidity, evapotranspiration, temperature and precipitation with a period of 26 years, the reserachers performed time series validation (Mankendal) method. In this study, MODIS satellite images with code (MOD13Q1) from 2010 to 2017 were received from the EarthData website and pre-processing and other necessary processing such as geometric and radiometric corrections were performed on them. The Kendall Man test is one of the most common and widely used non-parametric methods that can be used to analyze the trend of time series. In order to get acquainted with the study area and conduct a correct principled planning for erosion studies, the Maravah-e-Tappeh area was visited and. finally, by using EPM experimental method the erosion rate in the studied area was estimated. 

The results show that the quality of erosion varies in different coatings, but with the influence of other factors, the effectiveness of this factor also changes. The highest rate of erosion in the region, according to the studied model, is estimated in the southeast, north and northeast of the basin. In general, it can be said that due to the topographic conditions of Maraveh Tappeh region and also due to the importance of agriculture in this region, plain lands and slopes have been allocated to agricultural lands that have had an effective role in sediment production. The existing rangelands, which form the bulk of the area, have eroded in steep and erosion-prone areas contrary to the expectations. Due to non-observance of grazing issues and prohibition of exploitation of erosion in sensitive areas, especially the growing conversion of land use to agriculture and loss of rangeland cover, compaction has even caused water wastage and intensified washing of leaf and soil. Consequently, the slopes are completely bare and very severe groove erosions are visible in most places, which has created a very bad secneray and unfavorable shapes. Finally, it should be said that most non-biological stresses such as water stress and temperature stress affect plant cells.

The results of this study showed that the evaluated climatic indicators can be consdidred as strong parameters in the analysis of plant stresses. Remote sensing indicators have good accuracy in monitoring plant stress. Extractable plant indicators have been developed from satellite imagery to assess plant stress status by using remote sensing data. Most of these indicators are based on the measurement of spectral reflectances in different bands and can be calculated in each pixel. These indicators had several advantages over other climatic indicators, including covering a large area of land.

Soil is the most important foundation of any country's civilization, without which human life is endangered. Since man has lived on this planet, natural resources have undoubtedly been the most important source for satisfying his/her needs. With the increase in population, the amount of human use of natural resources has multiplied and more and more destruction is taking place in nature. Erosion is mong the most common phenomena that are seen in most parts of the world and Iran is the occurrence of erosion and instability of roadside slopes. Construction and maintenance of forest roads has been considered as a prominent feature of economic development for decades. In designing thes types of roads, in addition to paying attention to the main objectives, timber transportation and forestry objectives, maintenance of health and cleanliness of water outflows of a watershed against sediment should also be considered. Nowadays, the distribution of forest road network density for the implementation of forestry projects is an important issue that has been less considered by potential researchers as a potential source of sediment and runoff production. The upstream slope of the road is called the excavation trench, which is often located at the bottom of the side atmosphere. Side air can carry sediments produced from different parts of the road. Erosion of forest roads reduces the useful life of road constructions, increases the cost of protection and maintenance of vehicles and leads to the destruction of the environment of aquatic life. Many methods have been proposed to prevent soil erosion and stabilization in the walls/sides of forest roads. These methods generally include three biological methods, mechanical methods and biotechnical methods, each of which can be applied according to the existing conditions. The use of inanimate structures or biological structures is one of the most widely used methods to protect roads and maintain slope stability. So far, many bioengineering methods have been used to stabilize roadside walls and slopes in the world. The purpose of this study was to investigate the effect of some bioengineering treatments including installation of water absorption bags, dead leaves and cell stabilization (geocell) on the sedimentation rate of forest road trenches under rainfall and their efficiency and performance as protective mechanisms. In addition, in this research, by comparing the costs of preparation, installation, implementation and maintenance of each of the treatments used in stabilizing road trenches, the best treatment is determined. Conducting this study and similar studies can help us to gain the necessary knowledge and insight into the role of bioengineering treatments in the protection of forest areas and ultimately the correct and sustainable management of roads in forest areas.

To investigate the effect of sedimentation on forest road trenches, bioengineering treatments of water absorption bags, dead leaves and cell stabilization methods were used. For this purpose, in the forest roads of a series of forestry plan of Dr. Bahramnia, the location of soil trenches prone to erosion and thrust was recorded with the help of GPS in the summer of 2020. Then 12 trenches, each with a minimum usable area of 30 square meters, were selected randomly and for each of the trenches, except for the control treatment, bioengineering treatments of water uptake bags, dead leaves and cell stabilization were performed. Trench status was monitored and rainfall and sediment data were collected after each rainfall during the two seasons of autumn and winter. Soil erosion and sediment delivery were examined by being trapped in the side atmosphere at the beginning and end of the treated and controlled trenches. Trapping involved digging a cylindrical pit 0.4 m in diameter and 0.6 m depth to collect sediment. A calibrated index was installed in the center of each to estimate the sediment height. Upon each visit, sediment height (meters) and sedimentation level (square meters) were measured to calculate sediment volume. To calculate the specific gravity of sediment, three soil samples were prepared at the end of each period by the ring method and were dried in an oven for 24 hours and then the weight of the samples was measured. Data analysis was performed in a randomized block design with two blocks of 4 treatments and 3 replications in SAS software.

The results obtained from the analysis of variance of the effect of different treatments on reducing the amount of sediment from excavated trenches of forest roads showed that all the bioengineering treatments significantly reduced sediment (p<0.0001). Also, there was no significant difference between the amount of sediment obtained from the slopes treated with dead caper and the controlled slope. However, a significant difference was observed in the comparison of water and control bag absorption treatment at  ٪5 probabilitylevel and in the comparison of cell stabilization and control treatment at probability level of ٪99. The amount of sediment from the dead treatments of water uptake bag and cell stabilization were 4787, 7309, 8798 g, respectively, compared to the controlled treatment condition.

In the study of the effectiveness of different engineering treatments in different rainfall events, the results showed that the water absorption bag treatment is more efficient than the other two treatments: cell stabilization and dead leaf treatments. The reason for this is the hemp structure and water absorption properties of this type of treatment, which makes the rate of erosion and sediment production in the lateral atmosphere less than the other treatments. Another reason for the better performance of the water absorption bag in reducing sedimentation is that the treatment itself needs less digging and soil corrosion during execution and installation. Dead caper treatments, water uptake and cell stabilization treatments reduced soil loss at 20.30, 46.13 and 40.24, respectively. The reduction of soil loss in the mentioned treatments compared to the control treatment is due to the fact that each of these treatments acted as a retaining wall and reduced the water flow rate. In general, the study and monitoring of various treatments showed that the use of bioengineering treatments can have a significant effect on reducing the sedimentation rate of forest roads. Among the applied bioengineering treatments, water absorption bag treatment due to having hemp structure caused more water absorption and penetration in the soil. Erosion and sedimentation of forest road excavation walls were significantly reduced by increasing water uptake and reducing water flow.