فصلنامه پژوهش های فرسایش محیطی
سال سیزدهم شماره 1 (پیاپی 49، بهار 1402)

The purpose of this study was to investigate the effect of physical and chemical properties of soil on the creation and spread of gully erosion in the region and by providing appropriate solutions to prevent the spread of this type of erosion in the region. In order to identify the natural features of the basin and collect theoretical issues, the basic topographic maps (scale 1: 25000) of the National Mapping Organization and the geological map (scale 1: 100000) of the Geological Survey of Iran were used. Digital elevation model (DEM) and land use map were extracted from Landsat 8 images in 30 by 30 dimensions. The mentioned maps were prepared in ArcGIS10.5 environment. The mentioned maps were prepared in ArcGIS10.5 environment. Then, with field visits, 15 gully were selected and their location was recorded by GPS, and then soil samples were taken from each gully from a depth of 0-30 cm. In the continuation of the work, 5 points were selected from non-gully areas as areas that were not affected by ditch erosion and their location was recorded and soil samples were taken from a depth of 0-30 cm. Soil samples collected from the basin were examined in the laboratory for physical and chemical properties. Then R software was used for statistical analysis. The results showed that there was no discrepancy between the studied variables in the two groups (A: gully areas, B: non-gullyareas). The results of physical properties showed that the normality of sand data in gully and non-gully areas is confirmed (0.880) and (0.484), respectively. Also, the value of leven test (0.499) expresses the homogeneity of variance between the data of the two groups. Finally, sand was able to show a significant difference between the two areas (0.001).

Since the beginning of human civilization, human life has always been threatened by natural disasters. Floods are one of the most severe and dangerous natural events that cause a lot of human and financial losses. Although humans today have realized how they are originated, they are still not able to fully control such natural events (Qanavati et al., 2009). Different definitions of flood and their types have been used in different parts of the world (Chuboklu, 2016; 1). One of these cases is sedimentary currents, which are local hydrological phenomena that occur in small catchments with an area of ​​several square kilometers to several hundred square kilometers with a response time of several hours or less. Therefore, these phenomena are one of the most important natural hazards that have serious casualties and financial losses around the world, especially in mountainous basins (Vilanova et al., 2010) in addition to natural environmental conditions, human activities, and lack of planning. also causes the increase and increase of frequency and volume, as well as financial and human losses caused by deposit flows (Qanavati, 2013). One of the ways that can reduce the damage caused by floods is to determine the areas that produce floods and apply appropriate methods to control them (Ahmadabadi, 1399; 318). These currents are related to torrential rains and are a destructive and common hazard in the study areas. Phenomena such as slipping on a steep slope along a small sloping canal and sediment deposition are of this category (Jacob, Hanger, 2005: 9). Floods of deposit streams can lead to catastrophes that pose a serious threat to the lives and property of individuals and economic development. This doubles the need to assess the vulnerability of areas prone to these currents in the area.

To perform sensitivity analysis and prepare a zoning map of floods with debris flow in the basin, the importance and relationship of each of the factors affecting the debris flow should be evaluated. The most important factors for creating debris flows are the height, slope, and sudden precipitation with a very high flow rate. In this study, according to extensive field studies,10 effective factors in creating debris flow floods were identified and used, including elevation, slope percentage, distance from the stream, drainage density, geology, rainfall, land use, slope direction, soil layer, waterway strength index, and topographic moisture index. To prepare these layers from basic data, 1: 50000 topographic maps and to prepare geological maps and fault maps from 1: 250000 and 1: 100000 scale geological maps published by the Geological Survey of Iran were used. The digital elevation model with a ground separation of 30 meters has been used to prepare factors such as height, slope, slope direction, and slope curvature. Digitization of base maps and functions has been done using ARC GIS 10.5 software and Euclidean distance has been used to prepare lithological factors, distance from the road, and distance from the waterway. The flow rate index indicates the strength of water flow in terms of erosion, which was prepared in the GIS software environment. To prepare the map of total annual rainfall, the hydrometric stations of Strait, Galikesh, Tamar, and Dome of the Nightmare have been used, so that it has been interpolated in ARC GIS 10.5 software using mathematical functions. Land use invoice based on Landsat 7 (2014) satellite images and Google Earth archive, as well as the land use information layer of Golestan province, which had been prepared by the General Department of Natural Resources, had been used. Topographic Humidity Index (TWI) is one of the indicators affecting the occurrence and potential of floods in watersheds (Wooger 2019). To prepare this index, ARC GIS software was used and the TWI index was obtained from Equation One.

For training and experimentation in the artificial neural network model, the data of 605 flood points and 300 non-flood points were used. 0.070 has been used for model training and 0.030 for validation. Usually, the error propagation algorithm with a low learning ratio gives the best answer (Kia, 2010; 229). The number of neurons in the hidden layer was changed between 10 and 20, and by selecting 15 neurons in the hidden layer, the least amount of error was obtained. The final network structure was identified with 10 neurons in the input layer, 15 neurons in the latent layer, and 1 neuron in the output layer, And based on this structure, the final zoning was done. Using the final stage weights related to network training, the whole area, which included 63495 pixels, and each of the pixels had 10 characteristics related to 10 factors influencing the debris flow floods, was included in the network structure. After analyzing this data by the neural network, values ​​between zero and one were obtained based on each of the pixels. Finally, the hazard zoning map was prepared by transferring the weight of the final pixels in the ARC GIS environment into 5 hazard classes: low, very low, medium, high, and very high. In the implementation of the stochastic forest model, the identification of trees is very important in OOB error training and validation. To determine the appropriate number of trees, using the mean square error (MSE) criterion, first, some initial values ​​for the number of trees were determined, and then the model was implemented. By examining the mean square error and the coefficient of determination, the optimal model with the lowest error was designed. The resulting model was obtained with a coefficient of determination of 0.94 and a mean squared error of 0.24 for the training stage. Based on the results of the rocking curve, the area of ​​the curve in the area using the random forest algorithm is estimated to be 0.94.

The results showed that the highest weight with a criterion rank of 2.06 in the random Forest approach and a value of 2.04 in the artificial neural network approach is related to rainfall, which shows the accuracy of the evaluation of the two models in estimating debris flow flood zones. The second factor in creating these movements is the height variable with a weight of 1.68. Since the northern and southeastern parts have the highest points of the region, this factor, along with the rainfall factor, which was in the first category, has been the factor often causing the city to activate the force of gravity and to move the sediment and runoff masses on the slope surfaces. After identifying the core structure in the RF and ANN models and providing the information needed to teach the approaches as well as achieving the promised error, the network prepared to analyze the areas it did not encounter. For this purpose, holding the weights of the final stage related to artificial neural network training with a coefficient of 0.2 along with 15 neurons in the hidden layer of the whole region, which included pixels, was provided to ANN and RF models in order to determine the degree of risk from 0 to 1 for each pixel. By classifying the obtained values ​​and transferring these values ​​to ARC GIS software, the final map obtained was divided into 5 vulnerability classes with intervals of 0.2. Among the proposed solutions, the residential areas of Tangarah villages are formed on parts of cones that are exposed to the flow of materials. These dwellings are formed at the outlet of the basin and should be developed away from the outlet of the basin waterways and should be located in higher areas and very old barracks of the river. Due to the non-resistance capacity of bridges and structures built in this area, most areas are at risk of possible damage.

Soil erosion has been considered as the primary cause of soil degradation because soil erosion leads to the loss of topsoil and soil organic matter, which are essential for the growing of plants. Quantification of soil loss is a significant issue for soil and water conservation practitioners and policy makers. At the watershed level, the two most important hydrological phenomena that can occur from rainfall procedures are surface runoff and soil erosion.There are many models to study the soil erosion. One of the most widely used model for estimating this phenomenon is the Revised Universal Soil Loss Equation (RUSLE). Six factors are included in the RUSLE model: Rainfall erosivity, soil erodibility, slope length and steepness, vegetation cover and management and supporting practices. In this study, multi-sources data are used to generate the necessary parameters of the RUSLE model. Since Surface runoff and soil erosion are the two significant hydrologic reactions, the Soil Conservation Service Curve Number (SCS-CN) model is used to estimate runoff. This study has shown that a strong relationship between the surface runoff estimation and the maximum erosion potential in the study area. The advantage offered by this model is its simplicity and the diversity of the parameters used reflecting the function of runoff under the hydrological system.

In this paper, a bioengineering method for biological stabilization of riverbanks in Gilan region is reviewed and the most appropriate biological method is introduced in terms of plant density and composition. First, using hydraulic information and models such as HEC-RAS, the boundary flow hydraulic conditions and shear stress are evaluated. Vegetation in the form of 5 predicted units including: tree, shrub, shrub, combination of tree and shrub and control, was carried out along the river. Each treatment had 3 replications. In each treatment and its repetitions, from the level of dehydration to the upper edge of the walls, pins perpendicular to the current were hammered. Statistical analysis in this study was performed as a factorial experiment in a completely randomized design. Data analysis was performed using SPSS software. To compare the treatments, Duncan test and significance level were P≥0.05. In this study, in the years of statistics and also statistical analysis showed that the grass cover in the surface has little erosion, this does not indicate that the presence of grass cover has been able to have good protection against erosion. And the vegetation of the tree is more exposed to water flow. For this reason, in the recorded statistics, erosion shows a high number, but during the occurrence of severe floods that cause floods, it was observed in the statistical period that it was observed. . In tree and shrub cover, the walls have maintained their stability. Mechanical and engineering is essential.

The purpose of this study is to identify the shape of ruggedness, activity, physical-chemical and mineralogical characteristics of sands in Kermanshah province. The results showed that the most important form in the desert lands of the study area is the sand arrow and the degree of activity of the sand dunes is semi-active and most of them are unstable.

River canal changes are natural river processes and part of the systematic functioning of rivers that cause the destruction of agricultural land around the river and damage to human facilities and roads. The purpose of this study is to investigate riverbank erosion using Oklahoma Ozark streambank erosion potential index (OSEP). Qaleh Rudkhan watershed is located in the west of Gilan province in Fooman city. This river originates from the northern slopes of the Talesh Mountains and after leaving the mountains in the Fooman region, enters the Gilan Plain and finally flows into the Caspian Sea. In order to investigate the erosion of the river bank, a part of the river with an approximate length of 5 km near Fooman was identified and in 8 reaches, the parameters in the Oklahoma Ozark streambank erosion potential index (OSEP) were examined. In this method, eight factors of bank height, bank angle, percentage of bank height with a bank angle greater than 80 degrees, evidence of recent mass wasting, unconsolidated material, streambank protection, riparian woody-vegetation cover and stream curvature are scored. According to the results of relative score, streambank Protection and Riparian Woody-Vegetation Cover have been the most effective factors in the instability of the left and right shores in Qaleh Rudkhan river. In general, it can be said that instability has prevailed in the banks of Qaleh Rudkhan river, which is due to human intrusion and occupation in this part of the river.

The process of soil erosion and its intensification due to improper management and exploitation causes a lot of damage to the basins of semi-arid and arid regions of Iran every year. Among the various methods of soil erosion studies, morphometric parameter analysis is a cheap, fast and efficient method for soil erosion study.The semi-arid basin of mianrahan is at risk of soil erosion due to the outcrop of different formations, diversity of geomorphological conditions, rugged topography and the prevalence of agricultural and livestock livelihoods.Therefore, zoning of soil erosion potential of this basin is necessary for scientific management and sustainable development.The aim of the present study is to zoning the soil erosion potential in sub-basins, intermediate basins. In this research, WSA and averaging methods are used, which are based on the calculation and ranking of morphometric parameters. The results showed that according to WSA and averaging methods, 47.49% and 65.53% of the area of the mianrahan basin are located in areas with high soil erosion potential and need to implement protection plans.The WSA method is more efficient for soil erosion potential zoning studies due to the use of morphometric, linear and uneven morphometric parameters and the calculation of the correlation coefficient between them.The southern, northern and central sub-basins of the mianrahan basin have low, medium and high potential for soil erosion, respectively. The amount of soil erosion potential in the sub-basins of the mianrahan basin is affected by the roughness and shape of the sub-basins and the parameters related to the shape of the basin and the unevenness of the basin have the greatest impact on the soil erosion potential of the sub-basins.

The shores of the Caspian Sea have different topography and land use, including lowlands associated with the mouths of rivers, bays, or seawater advances on land and relatively higher sandy and sandy beaches. There is a very low slope in the lands behind the beach. Paleontological research shows the rise and fall of the water level of the Caspian Sea in the form of figures of several tens of meters. the purpose of this research is to analyze the degree of vulnerability of 93.4 km of coastlines in three cities of Talesh, Rezvanshahr and Anzali in Gilan province. In this research, four variables were used in the form of 12 subcategories, using the hierarchical analysis method, to achieve the vulnerability index of the coastal area of ​​Talesh to Anzali cities. According to the mentioned references and the purpose of the study, the desired variables include sea level changes, land topography, geomorphology and land use. Landsat satellite images, topographic maps 1:25000 and digital model of 12.5 meters height of the research area as well as SAGA, IDRISI, ENVI, DSAS and Arc GIS software were used for analysis. The results showed that the beaches with low vulnerability belong to the areas around PareSar breakwater, as well as areas strengthened by onshore currents. Therefore, 56.2 km (60%) of the studied coast needs special attention in order to determine management approaches to protect the coast, prevent coastal erosion and strengthen and nourish the beach.

 Soil erosion is a global problem that seriously threatens water and soil resources. Among water, wind and glacial erosions, water erosion causes extensive damage every year around the world.Water erosion is divided into four groups according to the importance and method of formation, including splash erosion, sheet, rill and gully erosion.One of the most important types of water erosion is gully erosion which is a common phenomenon in the climate of arid and semi-arid regions, which affects large areas with different morphological, soil and climatic conditions. In fact, this type of erosion is of special importance due to the production of sediment and soil loss, as well as extensive damage to land, roads and structures. Therefore, to prevent the rapid growth of gullies or to minimize the damages caused by them, it is very important to know the morphology of a gully and how it is formed and the reasons for its growth. In fact, by identifying areas prone to gully erosion and identifying the factors affecting it, the risk of this erosion can be reduced. A large part of the southeastern regions of Fars province due to special topographic and geological conditions, have been affected by this type of water erosion. The main purpose of this study is to prepare a gully erosion susceptibility map using satellite data and using Maxent model to evaluate the ability of this model to predict gully erosion prone areas south of Darab city in Fars province and also to investigate the impact of each factor in this is the type of soil loss.

The study area is located in the Khasoyeh watershed, in Southeast of Fars Province in the Zagros Mountains (ZM) (54, 9' till 54, 42' E and 28, 18'-28, 39' N) and covering ca. 139248ha. In this research, we followed the subsequently mentioned working steps to predict the gully erosion susceptible:In the first step the locations of characteristic gullies were digitized using Google Earth (GE) images, aerial photos and fieldwork. Subsequently, we converted the polygons into equally spaced points, which are congruent with the raster cell centroids.ii) In the second step we prepared the predictor variables that are driving the erosion processes. These continuous predictor variables include; Physiographic indices including, elevation, topograpghic wettness index (TWI), vertical distance to streams, slope, slope direction, hillshade, LS factor, Stream Power Index (SPI), flow concentration with spatial resolution of 12 meters were prepared in SAGA GIS. Before applying the indices, the DEM was preprocessed with low pass filtering to extract artefacts and errors, like local noise and terraces using ArcGIS 10.8 (ESRI, 2010). Then, the DEM was hydrologically corrected eliminating sinks using the algorithm proposed by Planchon & Darboux (2001). The other applied indeice in this research are including, geological maps, land use, morphology, soil texture, were prepare. In the last stage, after preparing all the effective indices (Indepence layers) in the gully erosion of the region, the maximum entropy model was implemented.

 The results of the applied model showed that the elevation index is the most important factor. In the other words, the result indcated that there is an inverse relationship between the elevation and prone areas to gully erosion because the most gullies area are located at a minimum elevation of 900 meters. The reason for this can be reduced soil depth in high areas. The results of the modeling showed that more than 80% of the area is in the very low risk category and most of these areas are located in the northern parts and highlands. The high-risk areasare mostly located in flat and low elevation areas in southeast of the study area. The ROC curves in this study was equal to 0/94 that shows the applied model is considered well distinguish different areas of gully erosion prediction.

Gully erosion is common geomorphological problems in arid and semi-arid regions; therefore, it is essential to develop methods to predict it with simple but highly accurate models. In this research, the spatial prediction of gully erosion in the Khasyoue watershed in Fars province was carried out by means of a stochastic model and a detailed terrain analysis as well as additional environmental variables. The validation of the Maxent model shows that the model prediction for gully is outstanding. Percentage of the important variables for prediction of gully erosion indicates that the most influential parameters on gully erosion in the study area are espectively elevation (57.9%), land use (11.6%), vegetation density (9.8%) respectively and the least effective parameters are the direction of flow and catchment area with (0.1%) slope and vertical distance to streams with (0.2%). The simplicity and the relative low data requirements of the applied method allows an effective method also in other regions.

One of the types of erosions is tunnel erosion, which has been less studied than surface erosion due to its complex formation and measurement problems. Tunnel erosion is one of the water erosions whose occurrence causes significant changes in the earth's landscape and environmental degradation. Cheshmeh Lee village is located 45 km northeast of Kalaleh and 27 km southwest of Maraveh Tappeh in Golestan province. Geoelectric studies in the area of Cheshmehli village with the aim of studying sinkholes, was considered. A total of four profiles named AB, CD, EF and GH were designed in this village, after harvesting the field data, the data obtained from the geoelectric studies were processed. The results of studies performed as geoelectric sections for resistivity data using data inversion using specialized Res2Dinv software. In general, the values of resistivity for the studied profiles showed the trend of changes in the amount of resistivity, mainly affected by the loess units of the region. However, the trend of change has increased or decreased in some parts. Increasing the amount of resistivity is mainly associated with stone units.

Simultaneous use of Geographic Information System (GIS) and methods based on artificial intelligence has always led to good results in research in the field of natural resources. This study was conducted in the same format and in order to prioritize the factors affecting the spread of fire and identify high risk areas in the forests of the Shimbar protected area, in this regard, factors for the artificial neural network method were considered. In implementing the artificial neural network method with factors affecting forest fire, a fire risk zoning map with five classes of very low risk, low risk, medium risk, high risk, very high risk with a total accuracy of 0.83 and RMSE error is prepared. It is 0.75. The results showed that 20% of the area in the middle class, 11% of the area in the upper class and 10% of the area in the very upper class, the potential for fire, also the most important variables affecting the occurrence of fire including distance from the river, type Lands, altitude and minimum temperature. It is concluded that according to the considered factors, the integrated models of artificial neural network (ANN) and spatial information system have a high efficiency in preparing a fire risk zoning map and it is suggested that these models be used to prevent, control and manage fires elsewhere. The country should also be used on a large scale.

The phenomenon of dust is a sign of environmental erosion. Climate change such as lack of rainfall, the presence of erodible soil particles and high wind speeds create the right conditions for the occurrence and severity of dust storms. To better understand the effects of dust, its origin, control and response to its harmful effects, it is necessary to identify and monitor this phenomenon regularly. In this study, with the aim of comparative study of changes in the spatial pattern of dust phenomenon in Tehran province, during 20 years (period 2000-2019) after examining the days with dust phenomenon and extracting related wind roses, using images level 1 of Modis sensor in Terra and Aqua satellites, three indices NDDI, AOD and Dbaael were calculated. Summarizing all the patterns of dust indices in 2000, the main centers of dust density were located in northern Iraq and the plains south of Lake Urmia and the plains on the western slopes of the Zagros. However, the final maps extracted from the 2019 models show that in general, the density of dust particles in Iran has decreased and the dust core in the southern latitudes of Tehran province from Shahrbar to Varamin and Robat Karim and specifically on the late sedimentary landforms. The catchments of Tehran province are concentrated and this can indicate the fundamental changes in land cover during the twenty years of research.

One of the most important environmental challenges in the Middle East and Iran is the phenomenon of dust Coexistence between plants and mycorrhizal fungi can have positive results on vegetation establishment.The aim of this study was to improve plant development in reducing wind erosion. after sampling of rhizosphere soil of Rhizosphere, Haloxylon, Tamarix and Nitraria seedlings in two levels of inoculation with and without mycorrhizal fungi, three levels without water stress, moderate water stress and severe water stress and three standard soil types, Soil No. 1, EC=0.5 and soil No. 2, EC=6 were conducted as a greenhouse in a factorial design.wind tunnel tests, morphological characterization of plants and mycorrhiza colonization experiments on the roots of plants were studied. Mycorrhiza inoculation significantly increased shoot and root fresh and dry weight, root area, root volume, shoot and root length, and decreased soil loss. The results of comparing the mean of Haloxylon (increase of 18 to 40, decrease of 10%) and Tamarix (increase of 1to3% and increase of 1to3%) and Nitraria (increase of 1 to3% and decrease of 1%) indicate the effect of fungus Mycorrhiza has been based on the vegetative traits of the plant and the amount of soil wasted. e interaction of plant species and water stress in Haloxylon plant also had a reduction of about 35% in vegetative traits relative to normal water stress and 15% relative to moderate water stress .Regarding the interaction of plant species and water stress Tamarix, there was a decrease of about 18 to 35% in vegetative traits compared to normal water stress and 9 to 20% relative to water stress. Due to the interaction of plant species and water stress, Nitraria plant also had a reduction of about 25% in vegetative traits relative to normal water stress and 38% relative to moderate water stress.

Topographical conditions of any given area are among the main factors which influence the variations of soil attributes, especially in small spatial scales. The current study was carried out aimed at investigating the influence of slope aspect and position on soil quality considering the local situations via comparing the amounts of soil pH, organic matter (OM), available phosphorus (P), mean geometric diameter of soil aggregates (MGD), and water-dispersible clay (WDC) in the soils located in south-facing and north-facing slopes in five different slope position, including summit, shoulder, backslope, footslope, and toeslope in the forests of Kalpoosh area, Northeast Shahrood. Surface soil samples (0 – 20 cm) were taken up from three different points which were two meters far from each other in every slope position, and after being passed from a 2-mm sieve, their mentioned properties were measured using standard methods. The data were statistically analyzed by applying Duncan test, one-way ANOVA. The results indicated the combined effects of slope aspect and position were significant on most of the selected soil properties (P < 0.01). In contrary to the most of the previous researches, the amounts of OM (2.64 %), P (10.13 mg/kg), MGD (1.30 mm), and WDC (2.23 %), in south-facing slopes were relatively more favorable compared to their corresponding values in north-facing slopes (2.13 %, 8.74 mg/kg, 0.95 mm, and 3.90 %, respectively). Considering that the area under investigation undergoes early coldness in fall as well as heavy snows, low soil temperature in north-facing slopes seemingly hinders plant growth and soil evolution. On the other hand, receiving more radiation, soils located on south-facing slopes can modify the impacts of early coldness so that they provide the appropriate temperature for plant growth and enhancement of soil conditions.