فهرست مطالب فاضل ایرانمنش

  Wind erosion is affected by climate change and several droughts have caused environmental degradation in arid regions. This process causes sand and dust storm (SDS) phenomenon which is one of the most important challenges in fragile areas. This phenomenon is harmful for human health and causes socio-economic problems. Over the past two decades, SDS have been increasing in Iran, particularly in the south-east of the country. Therefore, in order to manage this environmental phenomenon in arid areas, it is an urgent need to identify the dust storm sources. The changes of factors such as vegetation, soil moisture, slope, land temperature, and geological units have effective roles in the occurrence of dust storms. So, investigating the changes in these factors is an effective solution to identify dust storm sources. In this regard, using remote sensing data is one of the effective methods for the detection and mapping of dust storms resource, which combined with field methods, provides a coherent approach to manage and control this phenomenon. This study aimed to identify dust sources and storms in the southeast of Iran with emphasis on the Sistan dust storm by using field work and remote sensing data.

The study area is located in the south east of Iran and contains some of the border areas of Iran and Afghanistan (including some parts of the south Khorasan and Sistan and Baluchestan province in Iran as well as Farah and Nimroz province in Afghanistan with coordinates of 60˚ 16′ - 61˚ 36′ east longitude and 29˚ 8′ - 32˚ 32′ north latitude). In north of the study area, the mountainous and low-altitude areas are intertwined but the southern area is mostly flat and lacks topography and natural features. The most important characteristics of this area is 120-day winds, which sometimes reach speeds of more than 120 kilometers per hour and is accompanied by high intensity of sand and dust storms. In this study, to identify dust storm sources, the combination of remote sensing, field study and wind analysis methods are used. To achieve this purpose, at first effective factors in the occurrence of dust storms such as vegetation, soil moisture, slope, land temperature, and geological units were prepared. In this regard, by using Modis satellite images, map of vegetation, soil moisture and land temperature were prepared by applying Soil Adjusted Vegetation Index (SAVI), integrating temperature vegetation dryness index (TVDI) and Land surface temperature (LST), respectively. Also slope map (using Aster satellite) and geological units were prepared. In the next stage, the fuzzy logic method was employed to combine layers and prepare the map of dust storms source, which is assessed by an error matrix and available dust source map. Detection of sand dust storms were performed by using BTD dust detection indicator. For winds analysis, we used WRplot view 8 Software. In the field study, several dust storms sources were determined and their characteristics were recorded.

    The results showed that the ranges of SAVI index are + 0.6 to -1 and the highest amount of this index coordinate with highest soil moisture (TVDI) and the lowest land surface temperature (LST) area. This area is mostly related to rangeland, combination of wetland-rangeland, hand-planted forests and agricultural lands. The amount of SAVI index and soil moisture reaches its minimum value in the salt marsh lands, abandoned agricultural lands, desert areas and degraded rangeland. By merging the layers and preparing the map of dust storm sources, it was found that the critical dust storms resources coordinate with high land surface temperature and low vegetation and soil moisture areas. In addition, the highest dust source area is in the slopes of 0 to 4 % with geological units such as playa deposits, eolian deposits, alluvium sediment and wet playa deposit. According to the results, the incoming dust storms into the study area come from the east and southeast of south Khorasan province in Iran and the southwest of Farah province in Afghanistan.

  In this study by using effective factors including vegetation, soil moisture, land surface temperature, slope and geological units, the sources of dust production were identified. According to the results, poor vegetation and low soil moisture in flat areas with sensitive formations are the key factors to create dust storm resources in the study area. Also, the most important active hot-spot areas for dust storm is concentrated in the southwest of Afghanistan and north of sistan region (dry lake bed of Hamoon). Therefore, it can be concluded that using satellite images and the studied factors, the dust sources can be properly identified. Furthermore, by using Time series images of modis and the updated dust source maps, a coherent approach can be provided in order to manage and control this phenomenon.

Dust storm is One of the natural phenomena that has a great impact on human life and the environment. Every year, some countries in the world where dust sources are located are affected by soil storms. Also, many more countries that do not have sources of dust particles are affected by the transfer of dust particles. Dust storms damage human health and respiratory system, disrupt power lines, disrupt road and air transportation, and agricultural sector Severely affected. The most important sources of dust production are deserts. After that, dried lakes can be named as the second source of dust production in the world. Glaciers and altered agricultural lands are other sources of dust in the world The largest source of dust in the world is in the Africa that imports large amounts of dust particles into the Earth's atmosphere each year. The Sahara Desert is the largest desert in the world with an area of 9 million square kilometers and is located in 10 countries in North Africa. Kok et al showed that sub-Saharan Africa emits about half of the world's dust. Then, the dust sources in the Middle East and Central Asia are in the second place and 30% of the production sources of global dust storms are located in them. One of the most important dust regions is the East Asian deserts, which emit 11% of the world's dust particles. Therefore, the Middle East is one of the most important regions in the world where many soil sources are located. In the Middle East, most of the sources of dust are located in Iraq, Syria and Saudi Arabia, but some of these sources are located in Iran, although the sources of production in Iraq and Syria are less active, however, these springs affect different parts of Iran by producing dust storms. In addition to scattered domestic springs, the main springs producing dust in Iran include the dried parts of the lake and Hamoon wetland in the southeast, the dried parts of the Horalhvizeh wetland (Hur al-Azim) in the southwest and part Of dried Urmia Lake in northwestern Iran. Sistan and Baluchestan province, which is located in southeastern Iran, in addition to high temperatures and low rainfall, is affected by 120-day winds. Today, the occurrence of dust storms is one of the most important problems of many people in the world and every year it causes a lot of damage in various aspect of human life. Countries in the dust belt are most affected by this environmental problem. As a country in the Middle East, Iran has always been affected by dust storms, which mainly originated from dust sources in other countries. The purpose of this study is to investigate the dust phenomenon in southeastern Iran and the Hamoon region. For this purpose a severe dust case was examined on April 26-28 in the Hamoon Lake region. The investigation from April 26 to 28 showed that in some stations in the region, the horizontal visibility has reached less than 1 kilometer, and the true color images of the Modis sensor and the RGB of the MSG satellite shows well the dust mass in this area. Also, the corrected reflection image of the MODIS sensor has shown the dust mass more clearly. It seems that the optical depth of the particles by using the DT and DB algorithm with a resolution of 10 km overestimated the concentration of dust particles in the study area. Comparing the output of the WRF-Chem model with the MERRA2 model shows that both models show the intensity of dust concentration in the Hamoon area, although the output values of the WRF-Chem model are higher than the output surface concentration values of MERRA2 model. Comparing the output of surface dust concentration of these two models with the PM10 concentration measured in Zabol station, shows that the two models overestimated dust concentration in comparison with the reported station data. Also, in this case study, the mean square error (MSRT) of MERRA2 model in Zahedan station was low, which indicates the acceptable performance of this model in this station in this dust case. Furthermore, the MSE of WRF-Chem model in Zahedan station is high, which indicates the poor performance of this model in Zabol station.

Land cover change is one of the most effective factors of environmental change. So, understanding and predicting the causes, processes and consequences of land cover has become a major challenge. The remote sensing and satellite data technologies can be used effectively to detect and quantify land cover changes and its effects on the environment. This research used the MODIS MCD12Q1 yearly data at 500 m resolution to evaluate the spatio-temporal changes in the national land cover of Iran from 2001 to 2015 in five years periods. Land cover maps of Iran were generated based on 12 classes for years of 2001, 2005, 2010 and 2015 and then evaluated using “Landcover Change Matrix”. Areal distribution analysis showed that the most parts of Iran covered by barren areas (more than 60%). The area of forests, croplands and grasslands were reduced from 0.8, 4.8 and 21.4 percent respectively in the year of 2001 to 0.6, 4.5 and 20.9 percent of Iran’s area in 2015. Furthermore, to evaluate land cover changes in five years’ period, the land cover map of the first and last years of each period were compared using “Landcover Change Matrix”. Results showed that in the five years periods of 2001-2005, 2005-2010 and 2010-2015 land cover of Iran changed increasingly as 2.13, 3.25 and 3.30 percent respectively of Iran’s area. And the overall changes of land cover in Iran from 2001 to 2015 is 6.08 percent of Iran’s area.

Large areas of Khuzestan province are among the most susceptible areas for dust production. There are seven domestic dust producing hotspots in the province. Some of them, like the No.1 Dust hotspot (south Hoor al-Azim), are in fact flood and alluvial plains lowlands of the Persian Gulf and Mesopotamia that have lost contact with large rivers such as Karkhe for many years. Such a problem, along with the subsequent droughts, has made a vast plain southwest of Khuzestan province hotspot dust storms. In this regard, the present study intends to investigate the role of human in relation to morphodynamic changes of Karkheh River and dust hotspots. This research was conducted using Landsat satellite images from 1991, 1998, 2002, Liss sensor from the IRS satellite of 2006, Google Earth images, sediment sampling and field surveys. During the research process, all sedimentary environments and sub-environments of sediments leading to the dust zone were identified and then long-term and mid-term changes in the river were extracted using spatial and spectral indices. The results showed that there were at least three abandoned rivers in the study area. The longest of them is the abandoned Jofier Canal, about 50 kilometers long, which flowed to the south of the Hoor al-Azim in a very long time. This canal is more important than others because of the possibility of feeding the number one dust hotspot. Certainly by restoration this canal, wind erosion combat can be directed towards ways to create and strengthen water harvesting systems that increase soil roughness, soil moisture and vegetation, and increase wind erosion thresholds.

Investigating and understanding the impact of dust storms on wetland vegetation changes can lead to useful information for their optimal management. In this study, the wind rose and hurricane rose diagrams of the research area were prepared using wind statistics of Ahvaz meteorological stations. Changes in vegetation cover of Shadegan wetland were determined using classified soil-adjusted vegetation index (SAVI) maps of MODIS satellite images from 2002 to 2011 and correlations of vegetation changes were analyzed using dust storms data of Ahvaz meteorological station. The results showed that the major winds in the region flow from northwest to west and have the ability to create dust. The trend of changes of the number of stormy days, the concentration of dust and vegetation, were proportional to each other. The correlation between the number of dust days per year and the percentage of area with good vegetation cover showed relatively good relationship (the coefficient of determination was 0.47). The correlation between total dust concentration and vegetation cover, with a coefficient of determination of 0.58, indicated the high effect of dust on vegetation cover in the study area. The trend of changes in dust concentration with vegetation index was decreasing in one, two, three, four, and five months before image date. The relationship between dust concentration one month ago and vegetation percentage (SAVI index) with a coefficient of 0.99 showed the highest correlation. The negative and significant effect of dust storms on vegetation doubles the importance of the issue in Shadegan International Wetland, and on the other hand, the use of satellite images can provide accurate information with less cost and time to manage vegetation water and soil resources for managers.

The most prominent features in the Southwest of Khuzestan province are variety of sedimentary environments. There are usually many questions about the type and origin of sedimentary condition. The study of the morphoscopic and Granulometric evidence is one way to answer these questions. These methods are frequently used to identify the sedimentary condition (Blott & Pye, 2001). Therefore, the present study aimed to determine sedimentary conditions of Karkheh river delta at the upper Holocene. The Holocene Era has not had stable climate conditions and the sea level rise about 6,000 years ago. At this time, Persian Gulf expanded to near Ahwaz and the Hawizeh lagoon (Kennett & Kennett, 2006, 74). During middle Holocene (5500 years ago), coastline started retreating. The Karun Delta has developed and displacements as well as diversion paths are emerging along the Karkheh river bed (Heyvaert and Baeteman, 2007, 167). The development of the Karkheh River Delta has caused changes in particle size and sedimentary conditions (Iranmanesh et al., 2015). However, there is still no conclusive evidence of the sedimentary conditions. This study specifically seeks to respond to the paleo sedimentary conditions using morphoscopic and Granulometric evidence in southwest of Khuzestan province.

The study is based on remote sensing, soil laboratory as well as the soil primary data collected from abandoned channel in Karkheh River. The abandoned channel (Jofeir River) was selected on the basis of nearby karkheh river which has been identified in the beginning through the Landsat data. Field operations on the abandoned Jofeir River were undertaken to completing the required research information such as GPS points and sediment core samples. The six samples were collected from 1-10 m depths. Sediment core collection have been performed by a Drilling Machine and digging a Bore to depth of ten meters from mentioned region. After that, the core samples were transferred to the ground surface and they were placed in special boxes, in depth order. Soil laboratory operation included Granulometric, soil texture, soil bulk density, XRD and morphoscopic tests. Granulometric and soil physical experiments were performed using dry and wet sieve, desiccator and morphoscopic experiments using thin sections, binocular and polarizing microscopy. Grain and texture size analysis was performed using Gradistat and American Hydraulic Properties Calculator. KEView software was used to analysis of morphoscopic properties of Sedimentary particles such as roundness, sphericity, and form.

 The results showed; Sedimentary sequence and features can be divided into two main parts: one from the surface to the depth of 4 meters and another one from depth of 4 meters to depth of 10 meters. The first part includes fine particles of silt loam texture and second part includes coarse particles of sandy loam texture.

The results showed that 77% of the particles in the depth of 1 to 2 meters had high sphericity. The ratio of spherite in the sedimentary sequence decreases with depth and reaches about 30% at 9 to 10 m depth. Roundness of sedimentary particles in the Jofeir area showed that the proportion of sedimentation in the sedimentary sequence increased with depth. As in the depth of 1-2 meters, about 70% of the particles are semi angular and angular, but at a depth of 9-10 meters more than 90% of the particles are very angular.

The samples were mostly mixed phases composed of various minerals including quartz. The absorption frequencies of the peaks in the spectra of each depth in wave number unit are reported. By comparing the observed frequencies, the minerals such as quartz, feldspar, kaolinite, calcite and Vermiculite have been identified.

Research conducted by Kennett & Kennet (2006) found that environmental conditions such as climate and sea level of the Persian Gulf were not constant. Obviously, changes in environmental conditions have a direct impact on the type of sediments and their physical, chemical, mineralogical and morphoscopic properties. Therefore, the present study has investigated the granulometric, mineralogy and morphoscopic properties of sedimentary particles deposited in Karkheh flood plain in Jofeir region. Particles size distribution varies in the vertical sequence, from fine-grained to coarse-grained. Soil texture also changes from silty loam to sandy loam. So, these trend indicate the difference between two depositional environmental. These depositional environments affect not only the granulometric, but also the morphoscopic. The high angularity of the sedimentary particles at depths of 6 to 10 m relative to the depths of 1 to 6 m, together with the increase in darkness and high particle sorting at the same depth, reflects the conditions of the paleo-aeolian environment. Keywords: Khuzestan Plain, Sphericity, roundness, Sedimentary Environment, Morphoscopy.

Tectonic activity affects the formation, deployment and evolution of  landforms as well as erosion processes. The existence of several faults and anticline in the west of Khuzestan Plain has also led to changes in morphology and the establishment of landforms such as sand dunes. Therefore, the research is aimed to determine the effect of tectonic activities on the morphology and behavior of sandy hills in west of Khuzestan Plain. To achieve the above goal, the following information layers were provided. The layers included Ahwaz geological map with a scale of 1: 100,000 and a topography of 1: 25000, field observations, as well as results from the processing of Landsat satellite images and IRS from 1991, 1998, 2002 and 2006. In addition, other GIS layers was used such as faults, anticlines and units, geomorphic units, sedimentary environments and drainage networks. Data analysis was also conducted based on field observations and geomorphic techniques and a comparison method. The results of geomorphologic indices such as coefficient of sinousity and integral hypersometry showed that the study area was strongly influenced by tectonic activity and morphotectonic units such as Hamidyeh-Ahwaz, Zeynol Abbas and Abol Gharib anticlines. However, other secondary factors such as the wind direction and the pattern of the flow of the Karkheh River, change the overall trend of sand dunes. It also causes sediment transfer from sand dunes to flood plains and dust production centers in the west of Khuzestan Plain. Therefore, the findings of this research can lead to the provision of necessary information for soil protection against wind erosion in the province, especially in the center of number one dust (Hooralazim), erosion and sediment sources along the Karkheh River Basin.

The Sistan region has long been known as one of the critical centers of wind erosion due to sand and dust storms. The high sensitivity of the soil to wind erosion, the existence of droughts and regional political disagreements has all limited the way to combat this phenomenon. But along with all the limitations, there are strengths and capabilities in the Sistan region that can be turned into opportunities to combat wind erosion. The identification of these factors was done by using field studies, MODIS and Landsat 7 (ETM+) satellite image processing and expert consultation. Then, using the SWOT analysis, the weight and rate of internal and external factors were evaluated. The results showed that native solutions for decreasing dust concentration in Sistan region can be done in three scenarios based on the strengths and weaknesses as well as the opportunities and threats existing in the scenarios. Among the strengths and weaknesses, respectively, the presence of vegetation on the margin of Lake Saberi Hamoon and the lack of credibility and lack of native skills of communities with soil conservation methods have the highest score in assessing the internal factors. Also, the highest score is in assessing external factors, including renewable energies and regional political disagreements.

Generally, satellite images and climatological and environmental data are used simultaneously in dust storm studies. Most of the processing techniques are limited to a few indices such as brightness temperature differences, normalized dust density index, aerosol optical depth, false color composite and visual image interpretation. Since the reliability of the above-mentioned methods are varied, so an attempt was made to increase the reliability of automatic spatial image clustering by contributing the expert knowledge via visual image interpretation. Therefore, the required satellite images were collected for a period of 2005 to 2008, in Mesopotamian, Syria and south-western provinces of Iran. For doing this, the MODIS color composite images were decomposed into their ordinary bands and then used for further analysis. In this research, spatial image clustering followed by visual image interpretation (hybrid classification) was applied for accurate mapping of geographical extents of dust storm with different intensities. The sources of dust storms were also identified through visual image interpretation by considering the interpretation criteria such as shapes and patterns. Comparison of the previous results and obtained by this research, indicated critical conditions in terms of dust storm occurrence in the region. Image clustering and hybrid classification led to daily dust persistence over the region and then those images compiled in order to prepare annual total heavy dust persistence map. The result of using brightness temperature difference method verified similarity and reliability of obtained results. Therefore, this simple method could be proposed for identification of dust sources, related plumes and their affecting areas, when raw image data are not available.

Deltas are the most important morphological units which have a tremendous effect on agricultural activities, mining, coastal management, etc. Despite appropriate soil and water resources, deltas are influenced by environmental phenomena such as climate change and sea level changes. The effect of these changes will appear on physico-chemical and mineralogical features of delta’s sediments. The current research was conducted to analyze Karkheh delta depositional environments based on the chemical characteristics of ancient sediments. Depositional environments and locations of core were identified using digital data processing, geomorphology mapping, and ​​ initial visit of the area. The coring was carried out using rotary drilling machine continuously down to a depth of 10 m in Jofeir and Rofayeh. Twenty samples were collected from cores for mineralogical and chemical tests. The changes in chemical and mineralogical characteristics revealed that at least three major discontinuities exist between sedimentary layers to a depth of 10 m. In addition, thickness and type of the sediment are not in the same and change depending on the stability of depositional environments. The increasing trend in Mg/Ca, magnesium and salinity; and the decreasing trend in clay particle percentage show that sedimentary environments tend to change toward a dry conditions and high energy environments from depth of 5 to 10 meters. In contrast, at the depth of 5 to 4 and 3 to 0 meter, this trend is towards more humid climate and low energy environments. Therefore, it is concluded that the depositional environment of Karkheh River delta at the upper Holocene is not constant, and this led to recognizable changes in the delta.

Sand dunes developed in 15 provinces with an area of 4.4 million hectares and 56 Citadel, are one of the most important geomorphological features in Iran. Sand and desert stabilization technical office studies, according to project results identify focal and present four regions including Ahvaz, Dasht-e-Azadegan, Susa and the Omidiyeh in Khuzestan province. The mentioned area includes 279505 hectares of land in Khuzestan. This study has used remote sensing technology, GIS techniques and analyzed effective recorded winds data. Toward were reviewed and analyzed the wind regime of the area for direction of source area using Windrose Diagrams. In this study, based on utilizing and composing of image processing techniques such as image enhancement, threshold, false color composition, filtering and analysis and results of wind data analysis, with other investigations is useful to find the source of sand dunes. The results from direction of source area confirm that source of sand dune located in NW to W, notice Windrose in Khuzestan. The source area are flood alluvial fan plain, alluvial fan, agriculture land, meandering rivers and sensitive formation to erosion including Aghajari formation and Bakhtiari formation that located in the in NW to W section.

One of the main characteristics of Azadegan plain in the west of Khuzestan province is active instability of geomorphic features of Karkheh River This instability caused extensive variations in the sedimentary setup in the western parts of this plain، such as buried and abandoned river beds، which are repeated over time. Therefore، these variations should be studied in more details in the upper Holocene، since they can help us to better understand the changes and sedimentation details to reduce the environmental hazards in the region. Morpho dynamic characteristics of this river in the flood plains of Khuzestan are influenced by the sedimentation conditions، climatic changes، and hydraulic base levels of the Persian Gulf and in this context the two dynamic river systems of Karoun and Karkheh in Khuzestan are very important to be studied in much detail (Ramesht، 22، 1382). These rivers have been changed the routes in the past in Khuzestan and consequently caused complex sedimentation systems. The morphologic characteristics of these rivers indicate their longitudinal profiles are higher than the main level of the flood plain of Khuzestan. The Karkheh River changed its route in Hamidieyeh position about 100 yrs ago and at the present is running by Sosangard City in Khuzestan. Diopin (2011) studied the routes of the Karkheh، Karoun and Jarhi Rivers in Khuzestan and he found a good correlation among these river dynamics and human developments in this province. He found four different routes for Karkheh River in his study. The objective of this study was to further lighten the route changes and dynamics of the Karkheh River which will help us to better manage the spatial settings and predict the environmental risk in the province. Study Area: Azadegan plain is located in the west of Khuzestan province. This region is about 7500 km2 bordered from north by Shoush and Ilam cities، Iraq from the west، and Ahvaz City the east. Sosangerd is located in the center and the Karkheh River is the major river which drains this extensive plain. The Karkheh rises from the Zagros Mountains and، after pouring into the plain in the northwest، it crosses the Ahwaz anticline near the village of Hamidiya. The river turns into two parallel channels; both ending in the Hawiza Marshes which are located near the Iraq-Iran border. The area has some low hills، named Alaho-ahakbar and Mishdagh، with 173 m above sea level. Active sand dunes are extended from northwest of the province، i. e.، Fakeh and Mousian area. It contains most part of the plain and develops in west of Karkheh، Molla sani، and Maroon Rivers. The average of annual precipitation and temperature are 266 mm and 31 degrees (C°)، respectively. Annual evaporation in lowlands and coastal areas is 2500 mm، which almost more than 10 times of annual precipitation.

In this research the quantitative data، are grouped into two groups of independent and dependent variables. According to the purpose of the study، the river coarse and sedimentary environments are used as independent variables and some other data including particle size، land use، sand dunes extent، and urban areas as dependent variables. The enhancement of abandoned stream channels and scrutiny of active courses of Karkheh River was conducted by using Landsat satellite images of 1990، 1993، 1998، 2002، as well as IRS LISS images of 2006. In this process we used spectral and spatial enhancement indices and recording index points. One of the main indices، which were used for edge enhancement، was gradient filter. The filter was applied in band 7، due to absorption of wavelengths of 2. 08-2. 35 micrometer due to sensitivity to moisture، vegetation، and soil. Given the direction of flows in the rivers in Azadegan، four linear filters of horizontal، vertical، northwest-southeast، and northeast-southwest have were applied for the enhancement process. To better understand the relationship between the condition of sedimentary environments and the sediment types in river dynamics، drilling operation and core sampling were performed. The coring was done by a rotary drilling method up to the depth of 10 meters in Rafi Area in the vicinity of Hoveyzeh Wetland to represent a lake environment and the abandoned channels of the Karkheh fluvial environment in Jafir Region. From these cores، 20 subsamples were selected for granulometric analysis.

Grain size analysis showed interesting results. The grain size in Roafyeh core indicated the percentage of clay fraction (less 0. 002 mm) showed increasing trend with depth، while on the contrary، the sand fraction showed a decreasing trend with depth. Cristian (1997) and Slina (1998) believed stable condition indicates decreased in flow energy with sedimentation of fine grained particles such as silt and clay particles، while unstable condition shows increase in flow energy with lager particle sizes. The results of grain size analysis on the cores in the area showed a both the stable and unstable sedimentation conditions indicating fluctuations in percentage of particles sizes with depth with Three sedimentary sequences in the depths of (0-3، 4-5 and 6-10 meters) could represent humid conditions at the time of sedimentation and. While two periods of dry climate condition were presented with increased sediment particles size in the depths at 3-4 and 5-6 meters،) can be detected in the Rofayeh core. More arid condition along with recession of sea-level could cause Karoun and Karkheh delta to develop with their channel changes during mid Holocene in the area. However، the changes in the Karkheh route from Hamidieh area to Hovaizeh lagoon along with bed deformation and canal displacements occurred naturally and artificially. Due to rapid changes and shear stresses in the river systems، the bends associated with the expansion of sediment transport phenomena، could cause significant damages to agricultural lands and residential areas.

Morphology of the Karkheh River، bed formation، and its translocations in different parts of the Zagross folding belt are dependent upon a variety of factors such as hydraulics، sediment، and tectonic processes. The morphodynamics of Karkheh in proximity of Azadegan Plain is mainly function of folding types and internal factors of tectonic such as uplifting in the area. Moreover، relative sea level changes in the Persian Gulf and sedimentation in of the Karkheh River delta played a main role in its paleo-morphodynamics. Due to global sea level rise in 6000 years ago in the Persian Gulf area (Kent and Kent، 2006)، shoreline of the Persian Gulf was near Ahvaz City up to Hoveyzeh Wetland. Then، with the beginning of shoreline recession from 5500 years ago، in the middle of Holocene، the Karun River delta was developed and experienced movements over the bed of Karkheh River. The shoreline recession was synchronic with cold climatic conditions in high and middle latitudes and with relatively temperate climatic conditions in low latitudes and coastal areas. In such conditions، sedimentary environments were stable with low energy state that allows deposition of fine particles such as clay. Therefore، the changes in climatic conditions altered the situation of sedimentary environments and river morphology in the area. The hazards caused by these changes had significant influences on natural and human spatial features، i. e.، agriculture، civilization، and geomorphologic features. The extended meanders along the margin of the Karkheh River are cut through the sand dunes، caused the translocation of sand sediments onto the point bars along the river path. This process widened the channel beds through generation of developmental meanders which provided suitable lands for agriculture among the sand dunes. The cuttings are stable until the channel beds are not abandoned.

Since the Wetlands and river and sea are often influenced by variables and changes in ocean dynamics and their impact on river، Recognition these effects lead to a better understanding of planning for maintenance، it will achieve. Arrows or sand dams in front of all the frontal delta and tidal wetlands area are located on the northern coast of Oman. In this study، the hydrodynamic processes of Oman and the processes affecting the environment in times of drought such as the amount of sediment transported by rivers to the coast in Changes periodically، and the arrows in the holy mountain of sand Chalabi in northern Oman has been studied For this purpose، the time period of use of satellite images with the use of Arc GIS software and Ilwis is analyzed. The results show that the morphology of the coastline of this region، the displacement along the coastline is more than other coastal areas. Periodic variation showed the greatest growth in longitudinal sand arrows 11 (from 1371 to 1382) was more than 3300 meters، while in a period of 36 years (from 1335 to 1371) of sand arrows are only 1،500 m be. This growth leads to changes in wetlands and a lagoon bordering the sea in this area has been Chalabi. Intermittent cyclical changes in the tide and waves as well as changes in river discharge and sediment load of streams input to estuaries and river flow changes with arrows moving sand causes these changes and consequently changes in wetlands has been.

Geomorphologic Characteristics are base of study of natural resources in watershed basin. Because, these Characteristics are influenced by many factors such as climate, soil, hydrology, ecology, geology and so on. Doubtless, erosion features will develop with Geomorphologic Characteristics. In this research, effective factors on geomorphologic Characteristics and development of erosion features have analyzed using remote sensing data and GIS and with an integration method. In this way, boundary of basin was clipped using topography map in 1:50000 scales. Then, all layers such as geology, slope, and land use and land capability were digitized. An image of Land sat ETM+ taken in 2002 was also used to discretion of geomorphologic unit, Type and interpretation of erosion features.
The results showed that, Geomorphologic features in the basin separated to mountains, hills and alluvial deposit base on height, slope and morph metric Characteristics. Totally, eight Geomorphologic fancies are recognized. Stone mass with deposited cover from mountain unit with regular slope (1_1_1) have 74 ha (45% from whole area). Also, a lot of surface erosion has developed like white scattered spots and without vegetable or few vegetable. To add natural factors, human factors such as livelihood and sheep keeper can effect on developed erosion features.

Dasht Yari plain is nearly 580,000 hectares which is under engraving gully erosion and unfortunately the gully development rate is increased in the recent decades. Satellite images may provide quick, extensive, and valuable information for the interpretation of morphometric characterstics of gully erosion expansion due to having attributes such as time series, relatively low cost, large coverage, and finally being capable of digital analysis. Therefore, this research was initiated to use these possible capabilities to find a quick and cost effective method to determine the morphometric characteristics of gullies with use of the Landsat ETM+ digital data of Dasht Yari plain in Chabahar county in southeast of Iran. The Landsat 7 data of 2001 and the field data collected from 25 selected gullies from the same area were used as control in this study. After geometric and haze corrections with use of spectral enhancement methods such as linear enhancement and color composites, the images were made ready for visual interpretation and selection field sites for the subsequent field sampling. On the selected 25 gullies, the field data collection including width, length, and height of gullies at 25%, 50%, and 75% cross sections was performed. At the end of the image processing, with use of image interpretation techniques such filtering, fusion and principal component analysis (PCA), morphometric characteristics of the gullies was computed and compared with the field data. Mean comparison and F and t-student tests were used to verify any statistical differences between two set of the data. The results showed that the data set were different at 1 and 5 percent levels. From the image processing methods, the PCA method had the smallest difference with the field collected data. Therefore, we may conclude that PCA method may be used for monitoring the gully expansion in the Dashat Yari plain and similar plains in the southeast of Iran.