Geomorphology
Mojtaba Yamani; Shahnaz joudaki
Abstract
Terraces are important archives for paleontology. In this research, the paleotemperature changes and discharge frequency of Jajroud basin in the northeast of Tehran have been investigated based on the sedimentology and geochemistry characteristics of the reservoirs. First, the sediment samples were analyzed ...
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Terraces are important archives for paleontology. In this research, the paleotemperature changes and discharge frequency of Jajroud basin in the northeast of Tehran have been investigated based on the sedimentology and geochemistry characteristics of the reservoirs. First, the sediment samples were analyzed with calcimetry, EC, XRF, and PH techniques, and then these data were correlated with the indices of salinity, chemical weathering, acidity, and maturity of the sedimentary layers of the defenses. The results show three periods of flow changes, during the alternation of cold and warm periods of the river. One is at the peak of the glacial period, when the accumulation of snow and ice in the mountainous part has reduced the discharge (before the Holocene). In the second stage, by passing from the glacial period to the warm period (11 to 8 thousand years ago), Jajrud has experienced its highest discharge. Because the melting of glaciers has been accompanied by rainfall. The existence of very coarse layering in the early Holocene terraces indicates the occurrence of floods in this period. In the third stage, the dominance of recent hot and dry conditions (8 thousand years ago until now) and the lack of glacial deposits have led to a decrease in river flow. Based on this, the geochemical studies of the reservoirs can provide valuable data to recover the dynamic changes of flow and discharge during the Quaternary period and can be generalized to other similar basins.
Geomorphology
Shahnaz Alizadeh; Mojtaba Yamani; Mohammad Reza sarvati; Manijeh Ghahroudi Tali
Abstract
Neglecting coastal erosion can lead to environmental hazards that are among the main factors affecting human communities and facilities. Paleontology researches demonstrate tens of meters fluctuation in water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use ...
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Neglecting coastal erosion can lead to environmental hazards that are among the main factors affecting human communities and facilities. Paleontology researches demonstrate tens of meters fluctuation in water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use including lowlands (estuaries of rivers, gulfs and progradation) and sandy uplands. In this study, spatiotemporal analysis was used to analyze the changes in sandy coasts in relation to land use changes and the adaptation of the coastal line in the study area within the framework of coastal cells. Land use data for the years 1975 and 2020 were extracted using SAGA and ENVI software, and land use changes were analyzed using IDRISI software. The results showed that 68 kilometers of the coast have been unstable, with the majority of these areas experiencing erosion due to human activities (land use changes), including cells 10 and 3. Also, the erosion of unstable cells 5, 6, and 1 is of natural erosion type (sea level changes), and the erosion of unstable cells 9 and 2 is of natural-human erosion type. The remaining 24 kilometers of the studied coastline have been stable coasts, with the majority of coastal areas experiencing natural erosion (sea level changes), including cells 7 and 8. Cell 4 has had sustainable coasts with erosion of a natural-human type.
Hamid Amounia; Siavosh Shayan; Mojtaba Yamani
Abstract
1-IntroductionBeaches, due to environmental (natural-human) conditions, have many changes in the spatial-temporal dimension. Due to this fact, coastal areas are really important. Beaches are part of the complex system of the planet Earth, which occupies only 10% of the total area of the universe ...
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1-IntroductionBeaches, due to environmental (natural-human) conditions, have many changes in the spatial-temporal dimension. Due to this fact, coastal areas are really important. Beaches are part of the complex system of the planet Earth, which occupies only 10% of the total area of the universe (Cai et al., 2009). The majority of human beings choose beaches as their habitat so that about 60% of communities are located in coastal areas (Cracknell, 1999). Shoreline is an extension where exactly seawater intersects with land (Bird, 2008: 2). In international waters, the shoreline is defined as the line that connects the mean points between the maximum tide and the minimum tide. Regarding the dynamic nature of water and land, the coastline situation is not always stable in the short or long term. These shoreline changes can have adverse effects on the environment, natural resources, ecosystems, socio-economic, cultural, and ultimately defense security (Thoai, et al., 2019). A change in coastal land-use patterns can directly affect changes in coastal position (Griffiths, 1988). The coastline can change due to erosion and sedimentation (Rio et al., 2013) and by changing the pattern of land use near the coast, erosion or sedimentation occurs which leads to a change in the coastline (Erickson, 2006; Ahmed, 2011). This study aims to compare the shoreline changes in the digital shoreline analysis system and land use maps for 42 years, between the shoreline changes with the development of human activities and land uses, and then to analyze the relationship between the changes. Coastal land use during periods of the impact of Caspian Sea level fluctuations on coastline changes.2-MethodologyThe data used in this study are in two parts:Sea level data that have been used to draw the Caspian Sea level chart of and its basis is Anzali.Data including Landsat satellite images on TM and OLI sensors have been used to map historic coastlines and map coastal land uses. After registration, these images were downloaded from https://earthexplorer.usgs.gov. Sea level data was processed and analyzed with the help of Microsoft Office Excel software, and data related to satellite images were pre-processed and processed by Envi5.3 software. Coastline analyzes have been performed in GIS software (ArcGIS10.7) as well as the Coastal Line Digital Analysis System (DSAS) plugin. The present research method is analytical - comparison between data and sea-level information, shoreline changes, and land use maps. The land is 42 years old. After receiving the data from the Caspian Sea Research Center (CASPCOM), sea level data have been used to show the trend of changes in the Caspian Sea level at Anzali station.3-Results and DiscussionIn this study, first, the findings related to shoreline changes extracted through a digital analysis system; were analyzed and interpreted, and then the findings related to coastal land uses were presented and these findings were also interpreted.To study the changes in the Babolrood coastline, regarding the trend of fluctuations in the Caspian Sea water level, the periods 1976 to 1995 have been selected as the period of increasing the level and 1995 to 2017 as the period of decreasing the level of water. In the first period, according to the Net Shoreline Movement (NSM) statistics in the shoreline digital analysis system, all transects along with the shoreline show negative numbers. This means that in this period, the coastline has retreated to the mainland, and in this way, in this period, the coastal lands have been associated with a decrease in area. In the second period, when the trend has been decreasing, the majority of the Net Shoreline Movement (NSM) statistics are positive. In the map of these two periods, which shows the trend of changes during the interval; In the first period, in the whole range of the level trend, the level increase was the same as the shoreline movement process, which varies from -139 meters to -33 meters. But in the second period, it is observed that due to the decreasing trend of sea level, it has been receded. In the map from 1976 to 1994, shoreline movements show the same trend as sea level data. But in the map of 1994 to 2017, in some parts, such as the estuary of the Babolrood River, where people have made changes in the coastline by constructing piers, the coastline has receded at a high level. This can show the relationship between land use and shoreline changes.In the present study, land use maps for the three years 1976, 1995, and 2018 have been prepared. After preparing the land use map and evaluating its accuracy, the area of six land use classes for each of the years in the study area was calculated. The results of the changes show that in the period from 1976 to 2018, the man-made use area and water compared to other uses has been increasing during this time, and in the meantime, the area of use of the rangeland has reached zero. To elucidate the type and percentage of changes from one use to another and to keep the same uses constant during the periods 1976 to 1995 and 1995 to 2018, diagrams of these changes have been drawn.The percentage change graph between 1997 and 1995; reveals that most of the area in this period includes the same man-made land uses. In the second period, i.e. from 1995 to 2018, this trend continued, although in this period, man-made lands had the largest area in the total area; but other uses (which had a smaller percentage of the area); have been transformed into man-made uses, with barren lands showing the greatest value during this period.A Diagram of the trend of land use changes reveals that man-made land uses have been increasing in both periods (first and second). Most other uses have become the same man-made uses at this time. This diagram also discloses the ineffectiveness of land uses from the fluctuations of the Caspian Sea water level fluctuations. Because, if this trend is affected, we should see a decrease in the area of man-made land uses, especially in the first period (when the shoreline progress conditions prevailed). The reason for this was a kind of shoreline management with the construction of dams and coastal walls.4-Conclusion(s)The findings of this study indicate the existence of a relationship between coastline changes and land-use changes and vice versa, they indicate no relationship, especially in the second period with the sea level elevation trend in the study area. In the study period, the water level of the Caspian Sea has an upward trend (1976 to 1995) and a downward trend (1995 to 2017). The trend of changes extracted from the drawing of coastlines in the same years and their digital analysis shows the lack of coordination between some of these trends with the way forward and backward coastline in the study area. From the combination of two diagrams of sea level and man-made use, it can be seen that this lack of coordination also exists in this field. More importantly, it has been determined that man was able to manage the coastline in his favor during these 42 years by creating constructions. In a way, man has been able to succeed against the advance of the sea towards the land.Keywords: Caspian Sea shoreline, land-use, DSAS, Babolrood, Babolsar.5- References Cai, F.; Liu, J.; Bing, L.;& Gang. L (2009) Coastal erosion in China under the condition of global climate change and measures for its prevention. Progress in Natural Science, 19(4), 415-426.Cracknell, A.P. (1999). Remote Sensing Techniques in Estuaries and Coastal Zones- an Update, International Journal of Remote Sensing, 19(3), 485-495.Thoai,D.T; Dang, A.N; & Oanh, N. T. K. (2019).Analysis of coastline change in relation to meteorological conditions and human activities in Ca mau cape, Viet Nam. Ocean & Coastal Management, 171(1), 56-65.Griffiths, C.J. (1988) The impact of Sand Extraction from Seasonal Streams on Erosion of Kunduchi Beach. In Beach Erosion along Kunduchi Beach, North of Dar es Salaam; A Report for NEMC by Beach Erosion Monitoring Committee, 55.Rio, L.D.; Gracia, F.J.; & Benaventae, J. (2013).Shoreline change patterns in sandy coasts. A case study in SW Spain. J Geomorphol., 196, 252–266.Ericson, J.P.; Vörösmarty, C.J.; Dingman, S.L.; Ward, L.G.;& Meybeck, M. (2006). Effective sea-level rise and deltas: Causes of change and human dimension implications. J Glob Planet Change, 50, 63–82.Ahmed, A. (2011). Some of the major environmental problems relating to land-use changes in the coastal areas of Bangladesh. J. Geogr. Reg. Plan, 4,1–8.
fatemeh parhizkar; Masume Rajabi; Mojtaba Yamani; Davoud Mokhtari
Abstract
1-Introduction For thousands of years, mangrove forests have played a significant role in the economy and sustainable livelihoods of human societies. Therefore, identifying and measuring changes in the boundaries of mangroves over time can play an important role in planning and conducting effective protection ...
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1-Introduction For thousands of years, mangrove forests have played a significant role in the economy and sustainable livelihoods of human societies. Therefore, identifying and measuring changes in the boundaries of mangroves over time can play an important role in planning and conducting effective protection measures and reducing the vulnerability of mangroves to natural and human hazards. This study aimed to investigate changes in mangrove forests and the relationship between these changes and marine hydrodynamics and coastal morphology in parts of the north and east of the Strait of Hormuz for 47 years. 2-Methodology In this study, Landsat satellite images, MSS, TM, ETM +, OLI sensors from 1972 to 2019 were used to monitoring mangrove forest changes in the west of the Hormuz Strait. In the next step, the necessary preprocesses (radiometric and atmospheric corrections) were applied to the images in ENVI 5.3 software. And the classification of images was done by SVM, MLC, and ANN methods, and considering that to finalize the land use map, all classification accuracy indicators should be adjusted with one or more valid statistical indicators. The kappa index and general accuracy are among the statistical methods used. Post-processing operations also included the integration of classes that were applied to make the land use map more eloquent and eliminate single pixels on different classes. In the next step, the Change Detection method was used to detect changes and tell the results of the classifications. The next step is to convert the classified image to polygon and transfer it to the Arc GIS environment to manage the classes. Of course, the class that is most important to us here is the Mangrove Forest class, which was examined in the period 1972-2019. After the changes in the mangrove forests were identified, with the help of 1: 25000 topographic maps, contours of 2 meters of the range were prepared and the slope map was prepared using DEM images of the area. Also, using the half-hour tide data, the minimum, maximum, and average tide rates of Jask, Shahid Rajaee, Hormoz, and Sirik stations were calculated and finally, these data and maps were prepared to examine the development potential of mangrove forests. 3-Results and Discussion Land use maps were developed using Landsat images using three pixel-based classification algorithms (MLC, SVM, ANN) and the accuracy of the results was assessed using random points. The results showed that the highest overall accuracy and kappa coefficient were 99.44 and 0.99 for region A, and 98.41, 0.97, for region B, for SVM, respectively. Our study showed that SVM could be the most appropriate classification method for this study area. Therefore, SVM land use maps were prepared for the study area for 1972, 1987, 2002, and 2019. After preparing the land-use change map, it was stated that mangrove forests in region A accounted for 55.84% and in region B for 36.18%, tidal areas in region A accounted for 27.63%, and in Area B is 36.58 percent, Water Areas A is 3.04 percent, Area B is 1.78 percent, dry land is 15.37 percent and region B is 99.99. 7% have changed over the past 47 years. To explore the potential for the expansion of mangrove forests, we examined the slope of the region and its relationship with the average tide in the region. Comparing the results of the increasing and decreasing trend of mangrove forests with curves corresponding to the average tidal level and morphological features of the region, we conclude that the study area is about the hydrodynamic characteristics of the sea such as the average tidal area and extent. The catchment area, the height of the waves, and the coastal morphology such as slope and sediments and the water entering the areas from the Hasanlangi River and the Gaz and Hivi rivers have a very high potential for further development of mangrove forests. 4-Conclusion The results show that in the northern part of the Strait of Hormuz, the area of mangrove forests has increased in all the years, but in the eastern part of the study, we have always faced a decreasing and increasing trend and we don't see this part significant development during these 47 years in mangroves. However, according to the study of the geomorphic features of the region such as slope, topography, and the presence of Sabkha and Firth and sediments from the rivers of Hassan Langi, Gaz, and Hivi, as well as the average tide of the region and the vast area it covers, The study has the potential to develop mangrove forests. The results of this study can provide significant information about the progress or regression of mangroves in different coastal areas, can significantly help to implement protection measures and rehabilitate Iranian mangroves.
Mojtaba Yamani; Hamid Ganjaeian; Lila Garoso; Mahnaz Javedan
Abstract
1-Introduction Today, geomorphic studies are considered as the base of studies on natural resources. Recognizing the processes and active mechanisms on these landforms and their characteristics, as well as understanding the type of use of these units in using the natural environment and sustainable development ...
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1-Introduction Today, geomorphic studies are considered as the base of studies on natural resources. Recognizing the processes and active mechanisms on these landforms and their characteristics, as well as understanding the type of use of these units in using the natural environment and sustainable development is important. Many of Iranian towns and villages are on plains and alluvialfans and as a result, exploitation of the plains has become diverse and growing; but there are problems and limitations in the use of these areas. For a successful farming, consideration of climatic and environmental conditions is of tremendous importance. Therefore, the designation of geomorphic units is a suitable method for detailed studies of natural resources planning and management and environmental hazards. According to some experts, the assessment of environmental power is an instrument for identifying a land for activities such as agriculture and forestry (Quang minh et al, 2003). The agricultural sector of Sanandaj Province is especially important among the economic sectors of the province since in terms of production and employment, it is ranked second after the services sector. The geographical and climatic conditions and abundant water resources provide the potential benefits of agricultural production in the city. In recent years, with the adoption of new software and hardware methods, many efforts have been made to determine the capability and management of land leading to fruitful results. 2-Methodology The purpose of this study is to assess land suitability for agricultural activities in Sanandaj based on hydrogeomorphological parameters. To this end, the research method is based on descriptive-analytic methods. Research data includes statistical information (information on the status of groundwater and climate parameters), information layers, information extracted from satellite imagery (land use), as well as library information. Software used in the research includes ARCGIS (providing information layers, fuzzy, final output), IDRISI (implementation of the OWA model), Google Earth (validation of results), and SuperDecisione (weighting to criteria). The data layers of this research are soil, land type, geology, slope, altitude, precipitation, river, temperature, groundwater status, and groundwater chemical quality. Since the value and importance of the parameters are not the same for the desired purposes, the parameters were evaluated using expert opinion (5 geomorphic experts) by the ANP method and fuzzy by using the fuzzy function in ArcGIS software. Afterwards, standardized layers are entered into the IDRISI software and then combined with the ANP model using the OWA model based on the obtained values. Finally, the final map is made. After drawing up the final map to verify the results, 50 random samples were used to validate the result. 3-Results and Discussion In this research, ten parameters have been used for the development of agricultural lands in Sanandaj. The parameters are assigned in three clusters: Geomorphologic parameters (elevation, slope and geomorphology units), hydroclamite (river, underground water, chemical water quality, temperature and precipitation), and land cover (soil and lithology). In this research, after providing information layers, these layers are standardized using ARCGIS software. The geomorphological parameters are standardized in such a way that the altitude, the lower height means that the pixel is worth more And also in terms of slope, areas with a lower slope are worth more. In terms of geomorphology units, the lake and mountain units are of the lowest value. In terms of hydro-climatic parameters, regions with higher rainfall and temperatures near the river have lower groundwater depths and areas with lower EC values are of higher value. In addition, the areas with inspetisol are of higher value and lithologically, the areas with alluvial lithology are more valuable. The value of the criteria was then calculated using the ANP model. Finally, the obtained value was applied to the layers and in the end, using the OWA model, the final map is obtained. 4- Conclusion(S) Since agriculture makes a major contribution to the economy of Sanandaj, and given the great potential of the city in terms of water resources, it is necessary to make proper planning and location in this area. In the present study, according to studies conducted and hydrogeomorphological survey related to the study area regarding zoning the area for the development of agricultural lands, it has been attempted to identify suitable areas for the desired purposes. The results of zoning using integrated network analysis and sequential weighted averaging model have been verified using integrated network analysis model and random sampling method is verified. The confirmed results indicate that the final map has 86 percent accuracy. The results of the present study indicate that the major part of Sanandaj does not have the proper level of agricultural activities so 1587 km2 of the city area is in the inappropriate class and the relatively suitable and suitable class area is 801 and 579 square kilometers, respectively. According to the results, about 53% of Sanandaj area is not suitable for agricultural activities, especially for water crops.
Abdolkarim Veysi; ebrahim moghimi; Mehran Maghsoudi; Mojtaba Yamani; Sayed Musa Hosseini
Volume 6, Issue 19 , September 2019, , Pages 101-123
Abstract
Yamani[1], Sayed Musa Hosseini[2] Introduction Shahu karstic aquifers are the main sources of drinking and agricultural water in Paveh, Javanrood and Ravansar cities. Therefore, according to the important role of karst aquifers in supplying water to local communities in Kermanshah Province, recognizing ...
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Yamani[1], Sayed Musa Hosseini[2] Introduction Shahu karstic aquifers are the main sources of drinking and agricultural water in Paveh, Javanrood and Ravansar cities. Therefore, according to the important role of karst aquifers in supplying water to local communities in Kermanshah Province, recognizing their hydrodynamic characteristics for qualitative and quantitative management plays an important role in water policy planning in the province. The aim of this study was to identify and analyze the characteristics of karstic Dolines in the Shahu area and its relationship to the hydrodynamic characteristics of the water resources of the region. The identification of the sinkholes and their dispersion along with the morphometric analysis of these forms in the study area can be used in discussions on morphological characteristics and environmental hazards assessment and provide usable data for environmental planning. Methodology The purpose of this study was to evaluate the hydrogeological characteristics of Kavat and Holi springs in connection with the development of Karst geomorphology, which is based on library, field, and applied research. To this end, CCL, elongation index, sinusoidal index, D/H ratio, the analysis of the nearest neighbor in order to analyze the Dolin characteristics of the region and time series analysis methods were used. In addition, automatic correlation and spectral density were used in order to study the hydrodynamic characteristics of aquifers in the study area. The data on discharge and precipitation of hydrometric stations and rain stations of the Ministry of Energy were also used during the period of 2003-2014. The sinkholes identified in the Karst Shahu area were derived from 10-meter digital elevation model. Extensive field activities were carried out to check identified forms. A descriptive table including location, geology and morphometric characteristics for each doline were calculated. The doline morphometric characteristics were recorded. Then the data were analyzed by statistical methods in SPSS software. In this study, parameters including density, area, diameter, depth, slope and distance from faults were analyzed. The analysis of the hydrograph subsidence curve was used to evaluate the type of flow system in the karstic aquifers of the study. Finally, to evaluate the results obtained from the time series analysis, the results of the hydrograph curve analysis and karst geomorphological features in Shahu area were considered and the hydrodynamic features in the study aquifer was determined. Result According to CCL method, 104 dolins were identified in the shahu area. These dolines covered 11km2. The majority of the dolines were located in the central and northwestern parts of the study area. The mean depth of dolines in Shahu was 15m. The morphometry of the hollows generally tended to be elliptical or stretched. In the Shahu area, elliptical dolines were predominant forms. This indicated the significant role of rock mass in the evolution of the dolines. Semi-circular hollows were the lowest type of hollows in the study area. These types of dolines represented the initial forms of the dolines and were in a young stage. The number of dolines associated with distance from fault showed that the farthest doline was located in 3400 km, while more than 60 percent of Dolines were located within 0 to 500 m of faults in the region. Dolin density was related to the area of Karsts and the number of dolin in the study area. Dolin density in the study area reached over 1.5 per km2. The results of the analysis of the nearest neighbor showed that the mean of the nearest neighbor for Dolines in the study area was 0.86, which indicated the cluster distribution of Dolin. The cluster distribution of the Dolines indicated the evolution of the karstic system of the Shahu area. Correlogram of Kavat Spring had three distinct sections. In the first section, there was a quick drop in flow and within 10 days. This represented a quick flow in the karstic conduit. In the second part, the fluctuation was in the upper range of 2%. It is indicative of a semi-fast current in large fractures. In the third section, the fluctuation was mainly in the range between -2 and 2 and had a roughly uniform shape indicating a basic flow and a low inertia and low dynamic reserve in the aquifer. The Holy Spring Correlogram also showed almost the same situation and consisted of three distinct sections. Consequently, the aquifers showed the behavior of a developed karst. The spectral density function of both studied fountains provided a broad spectral band at frequencies below 17% and less than 15%. Ravansar spring at frequencies above 17% had a good filtering effect. And this value for a holly spring was higher than 15%. Indeed, distinct peaks at different frequencies over a period of time led to the identification of periodic events and, thus, to the recognition of the characteristics of the karstic system. The spectral density function indicated low inertia of studied aquifers, poor filtering, rapid flow and expansion of karstic channel networks in this aquifer. Discussion and conclusion The comparative evaluation of the karst geomorphology in relation to the hydrodynamic properties of aquifers in the study area suggested the development of the karst system in Shahu area. The results showed that relatively large parts of the shahu karst area were covered with dolines. The Dolin morphmetery features helped to recognize Dolines origin. More than 90 % of the Dolin area was elliptical doline which had a dissolution origin. The high dolin density in this region indicated the development of karst system. Differences in the Dolin morphometric characteristics indicated that the Dolin type was different from the origin of formation, the conditions and the time of formation. The analysis of the hydrodynamic characteristics of the Kavat and Holi springs also indicated the development of Shah's karstic system. The analysis of the hydrograph of the studied springs suggested a high degree of karstfication and the presence of a quick flow and the presence of karst coundit in Shahu area. The automatic correlation function of the springs confirmed the multiplicity of the behavior of the karstic system, the rapid response to precipitation, and the small volume of dynamic reservoir of aquifers. Accordingly, the existence of the developed karst forms, the multiplicity of elliptical dolin, their high density, the presence of joints, the abundant fracture in karstic masses, the presence of large karst conduit in the Shahu area indicated the development of the karst system and was confirmed by hydrodynamic surveys. [1]- Professor, Factualy of Geography, University of Tehran, Tehran, Iran. [2]- Associate Professor, Factualy of Geography, University of Tehran, Tehran, Iran.
Abolghasem goorabi; Mojtaba Yamani; Seyyed Javad Hoseini
Volume 5, Issue 16 , December 2018, , Pages 81-100
Abstract
Abstract
Introduction
Rivers' pattern is seldom stable and is always subject to change. Rivers' banks have long been the most important areas of population settlement, especially in the semi-arid regions of Iran. This has made the recognition and assessment of the geometric deformation of rivers an ...
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Abstract
Introduction
Rivers' pattern is seldom stable and is always subject to change. Rivers' banks have long been the most important areas of population settlement, especially in the semi-arid regions of Iran. This has made the recognition and assessment of the geometric deformation of rivers an important applied topics. Alluvial beds of a river are divided into two groups of stable and unstable. While in a stable bed, the walls and the floor are stabilized, in the unstable bed, the walls and the floor are not constant and have a changing state. Zanjanrood is regarded as the natural bio-economical artery of Zanjan province. In the present study, by recognizing the temporal and the spatial hydro-geomorphological changes of Zanjanrood during the years 1955 and 2011, and in the western part of the river, which is more important for agriculture, the amount of morphological changes is calculated and presented in the form of a map.
Methodology
The method of the study was analytical by spatial-local comparison based on the direct and the indirect observations using satellite images, aerial photos, and maps.
In this method, the intervals were classified into distinct parts based on the morphology-hydrodynamic similarity. Then, by applying spatial analysis on the raster maps, the pattern and variation of the changes were estimated by plotting tangential transects on the extension and restriction areas in the right and left sides. By determining the extension and restriction areas in river sides, the type and amount of stream’s variation in various reaches was determined. Afterwards, the total areas of extension and restriction on both sides of the stream were computed. Transects are rectangles with constant angles whose area variations indicate the changes of the river banks in different time ranges. This technique was used to determine the area dominated every progression and regression area in order to analysis and assess of the main factor(s) affecting this change.
Result
The results of the study showed that the outcome of the action-reaction of the factors affecting Znjanrood changes in the studied area had been a stable trend over the past 56 years. The most important factors involved in this trend were the development of the agricultural activities, the increase of management actions to stabilizing the river for agriculture and infrastructure proposes, and dam construction. However, the effect of slope and geological conditions (neo-tectonic) should not be neglected as well.
Discussion and conclusion
The results indicated that the overall trend was to reduce the width of the channel to its axis. However, the process has increased from the first period (1955-1985) to the second (1985-2011) and the third periods (1985-2011), so that at the end of the given time intervals, there was an increase in the relative stability of the stream. The change in flow to the outlet reduced the erosion power of the river flow and increased the stability and relative stabilization of the bed. The development of the fairly stable gardening activities dispersed on the flood bed played an important role in the stability of the stream in the studied area, so that the gardens and fields on the stable river main bed sides exhibited great changes in the images and photographs.
The role of the human factors in the Zanjanrood Basin due to its relative geographical position (east to northwest transit), has been the basis for the development and launch of several road construction projects (railways, roads and freeways) during the period of 1955 to 2011 in Zanjanrood and caused the change of Hydro-geomorphological-Hydrodynamic systems. A quantitative assessment of the Zanjanrood river bed changes shows that the rate of change, overcoming the general trend of stability and stabilization, has increased from the first period to the last period. Indeed, while the stabilization rate in the first period was 0.16 km2, in the second and final periods, it was respectively 1.91 and 2.01 km2. Progressions are concentrated in the beginning and end of the research (Transects 1, 2, 6, and 9 to 13), which affects the lands of the villages of Nikpey, Darelik, Dolanab, Naji, Idalou, and Baghloja and Saifabad. The recessions are also focused on transects 3 to 8, excluding transect number 6. Based on the results, Zanjanroud shows the overall stability trend. The adjacent area of the upper and lower parts of the studied research (the areas around the villages of Nikpey and Baghloja) are among the most sensitive areas of the research.
Shahram Roostaei; Samad Azimirad; Davood Mokhtari; Seyed Asadollah Hejazi; Mojtaba Yamani
Volume 5, Issue 16 , December 2018, , Pages 119-138
Abstract
Abstract
Introduction
Saymarreh landslide is one of the known largest landslides in the world that is located in the southwest of Iran. The purpose of this study was to compare the characteristics and geomorphological influences of this landslide with the largest landslides of the world. Saymarreh ...
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Abstract
Introduction
Saymarreh landslide is one of the known largest landslides in the world that is located in the southwest of Iran. The purpose of this study was to compare the characteristics and geomorphological influences of this landslide with the largest landslides of the world. Saymarreh landslide is one of those large landslides that have undergone significant geomorphological, historical, and cultural changes during the Holocene era. The evolutionary trend of this landslide is highly complicated; in fact, it is one of the most important characteristics of large landslides. This landslide formed several dam lakes, and their formation were frequently repeated. However, it is not clear that whether the formation and evolution of the lakes were due to the river erosion sequences or the repetition of Saymarreh landslide.
Methodology
A large number of researchers believe that Saymarreh landslide is the largest landslide in the world, but some researchers do not believe so and introduce other landslides as the largest ones. Thus, by performing detailed investigations into the region, the geomorphic features of this landslide and its evolution was probed. To achieve this goal, ETM2002 satellite images, IRS of PAN and LISS III satellite images of 2004 and 2006, topographic maps, geological maps of SRTM DEM, and ArcGIS software were employed. The research method was empirical and it was based on the analysis of the field data. In this regard, the process of the landslide formation, its causes and morphometric characteristics in three classes of slide area, mass movement and displacement parameters along with deposited materials in Saymarreh Dam lakes were studied.
Result
The results relevant to the morphometry of the landslide indicated that various factors were involved in the occurrence of Saymarreh landslide. Among these factors, undercutting of the Asmari limestone layers made by Saymarreh and Kashkan Rivers, particularly in front of the landslide, was the most important cause of the landslide occurrence. The landslide had formed a large lake behind the slide mass and had formed sequential terraces due to repeated slides. The results of the morphometry of the lake, particularly through the estimation of its water (45.642 Gm3) and sediment volume (23.422 Gm3), and comparison of the time taken for filling of the water volume (19.8 years) with the time required for deposition of the whole sediment volume (1888 years) showed that the sediments have not been deposited only during one stabile period of the lake and the lake has been renewed at least at several stages. As a result, the reoccurrence of Saymarreh landslide at several times led to the obstruction of the Saymarreh River. Stratigraphy studies on the lake sediments and the age of its terraces clearly implied the renewal of the lake at least at 4 stages. The sequences of the lake terraces and other evidences confirmed the different scales of the reoccurrence of the large Saymarreh landslide.
Discussion and conclusion
This landslide obstructed the Saymarreh and Kashkan rivers and led to the formation a large lake in that region. The lake depleted after destructing the landslide mass, and there was a change in the direction of the Kashkan River.
The main triggering factor for this landslide was undercutting of Saymarreh and Kashkan rivers. Other factors included the direction and the angle of the slope, steep structural slopes, and gravity. The results obtained from the morphometry of Saymarreh Lake and stratigraphy of the lake sediments demonstrateed that Saymarreh landslide had been reactive several times and led to formation of the lake at several stages.
Mojtaba Yamani; Abolghasem Goorabi; Shirin Mohammadkhan; Hamid Ganjaeian
Volume 4, Issue 12 , December 2017, , Pages 1-23
Abstract
Introduction Qorveh, one of the cities of Kordestan province, has high amount of precipitation and, consequently, a significant resource of water. Geological surveys, physiography and hydrology, and in particular field studies, have revealed rivers' significant role and influence on the formation ...
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Introduction Qorveh, one of the cities of Kordestan province, has high amount of precipitation and, consequently, a significant resource of water. Geological surveys, physiography and hydrology, and in particular field studies, have revealed rivers' significant role and influence on the formation of human activities and settlements. Unfortunately, much of the locally carried out planning has ignored hydro-geomorphological factors. In addition, population growth and the growth in residential and industrial areas have caused uneven progress of the residential areas towards the riverside which has, consequently, changed the natural shape of the river such as its width, length, slope, sediment, and the like. These problems shows the importance and necessity of thorough hydro-geomorphological studies. Therefore, the main objective of this study was to investigate the hydro-geomorphological status of the Shoor River's basin and evaluate the its lands' capabilities to develop urban areas, determine the optimum location based on hydro-geomorphological criteria, minimize the undesirable impacts of inhabitants of cities and villages on the highlands, especially the catchment areas, and minimize the harmful effects of the environmental hazards on agricultural products and inhabitants. Materials and methods The study is based on field, library, and software methods. Firstly, using the topographic maps, the study area of the basin was specified. In this study, 8 factors of lithology, faults, slope, aspect, elevation, distance from the river, vegetation, and land use were used in order to evaluate and zone suitable areas for urban development of Qorveh. After the preparation of the information layers, the coefficients and their values were estimated by the use of ANP model. In this model, like AHP, the measurement of the amount of the relative importance is done by pairwise comparisons with the help of the range of 1 to 9. Number 1 represents the equal importance of two factors and 9 represents the extreme importance of one factor over the other. To this end, for each model, a total of 15 questionnaires were distributed among specialists (5 Land use planning, 5 urban planning, and 5 geomorphology specialists) to rate each of the factors. After analyzing the questionnaires, to calculate the final weights of each criteria and subcriteria (according to the internal relations), Super Decisions software was used for the ANP model. Then, indicators and variables affecting urban development, using the Fuzzy function, were sub-Fuzzed and all layers of the study were standardized and compared. The coefficients were transmitted to the GIS polygonal descriptive databases to make them more quantitative and comparable. Finally, the final maps were made by overlaying the information layers maps. Discussion and results In the present study, to locate suitable areas for urban development, 8 factors were used and the classification was done. On this basis, the suitable areas for future development of the city have a slope of less than 11 %, the lithology persistent for building, low elevation, barren land use, and the changeable vegetation. In addition, they are distant from the fault lines and they are near the riverside. Additionally, the map of each criteria was prepared and the final map was obtained by combining the information layers, based on the weight obtained through ANP. Conclusion The ANP Model, because of having features such as simplicity, flexibility, simultaneous use of qualitative and quantitative criteria and final ranking of the options, can provide a suitable framework for analyzing the issue and determining the final ranking of the options. However, since allocating evaluation weights cannot provide enough reliability, the use of fuzzy logic, for more integration between layers and fixing possible errors, is needed. Finally, the study area was divided into five regions in terms of available potential and the ability for the purposes of the urban development. According to the criteria which was considered in this zoning, it can be said that, areas with the highest score, are located in ideal areas and away from danger. However, it should be noted that the significant presence of the geomorphologic phenomena, such as Bader and Parishan mounts in the southern parts of the study area, as well as the existence of faults in the southwest and southeast of the area have caused the basin to be in a very inappropriate class in relation to the development of the space. The results of this study indicate that the Shoor River's basin has a high potential for spatial development and urban planning in the future.
Siavash Shayan; Mojtaba Yamani; Manizheh Yadegari
Volume 3, Issue 9 , March 2017, , Pages 139-158
Abstract
Geomorphological features are the basis of natural resources evaluation in the watersheds. These features are affected by many factors such as climate and soil, hydrology, ecology, geology etc. Drainage network in this area was different according to the amount and performance of processes and has different ...
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Geomorphological features are the basis of natural resources evaluation in the watersheds. These features are affected by many factors such as climate and soil, hydrology, ecology, geology etc. Drainage network in this area was different according to the amount and performance of processes and has different effects on their surroundings. Sinkholes are located on the way of this drainage network. In association with the occurrence, the researchers have counting on this subject that the change of soil parameters, indiscriminate harvesting from groundwater, drilling of illegal wells and activity of Shahid-Mofateh thermal power plant are the most important factors for the appearance of these profound sinkholes in the plains of this state. The aim of this study is examining the characteristics of the drainage networks in this region, and study their role in the creating of subsidence in this region. For this purpose all information on geology, hydrology, hydrogeological and geographical data in this area were collected and analyzed. Drainage networks, lithology, slope and elevation of this region were drawn by using of digital topographic maps of 1:50000, geological of 1:100000, DEM and also pictures of Google Earth. Then to evaluate annual changes of runoff we used experimental method of Justin and Katain. The results indicate that the dissimilar changes in morphometric data of drainage network in this area due to the climatic and geological conditions, were most important factors in the intensification of decrease of soil humidity, subterranean water and occurrence of subsidence in this region. Human factors and the over use of water sources were effective in the intensification of subsidence.
Mojtaba Yamani; Abolghasem Gourabi; Zahra Abedini
Volume 2, Issue 3 , January 2017, , Pages 137-157
Abstract
Rivers are dynamic systems and their space-time characteristics are constantly changing. This change and displacement creates problems in the human and ecological functions and the study of such changes are the main issues in the fluvial geomorphology. In this study, survey morphological changes in one ...
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Rivers are dynamic systems and their space-time characteristics are constantly changing. This change and displacement creates problems in the human and ecological functions and the study of such changes are the main issues in the fluvial geomorphology. In this study, survey morphological changes in one section of the Babolroud (Bobol River) will be examined during the time period of 1334-93 from Babol city to Kardgarkola village within 18/45 km. Using aerial photo from 1334 and 1383 and satellite images Landsat 8, 1393 the path of the river was digitalized in three time periods with Arc GIS software. To determine the type of changes in each of the beaches spatial and temporal interval were studied and the position of the coastline was compared to the previous coastline. Then, for each beach in each period shifts named layer was prepared and its surface was measured. Then for each time interval (period) studied, the spatial interval was specified. The statistical tables were considered for each time interval to provide possible comparisons between the spatial intervals. Finally, changes in the left and right of each interval in each period was compared to the period before. For a detailed analysis, changes in the stream in each of the study periods were considered after determining the thalweg, the fixed line and the taken transects within the interval of 1000 to 1000 meters. Then, in the Arc GIS, after the determining the transects and thalwegs, and creating a polygon, the area of polygon was compared to the previous periods. Finally, through the implementation of existing disputes, thalweg changes in the riverbed, which determined the cause of the change, was found in each transect. The results show that the interval in the regression process has three periods. The second interval depicted the greatest change. The main reason for this fact in the period of change is excessive land use and human intervention.
Alireza Salehipour Milani; Mojtaba Yamani; Ebrahim Mogimi; Rziye Lak; Maksour Jafarbeiglou
Volume 2, Issue 4 , January 2017, , Pages 143-170
Abstract
Alireza Salehipour Milani[1] Mojtaba Yamani[2]* Mansour Jafarbeiglou[3] Raziye Lak[4] Ebrahim Mogimi[5] Abstract During recent years, with the construction dam on main rivers, the occurrence of hydroecological drought during the last decades, and high evaporation of water reservoirs, the extent of the ...
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Alireza Salehipour Milani[1] Mojtaba Yamani[2]* Mansour Jafarbeiglou[3] Raziye Lak[4] Ebrahim Mogimi[5] Abstract During recent years, with the construction dam on main rivers, the occurrence of hydroecological drought during the last decades, and high evaporation of water reservoirs, the extent of the Urmia Lake has considerably decreased. Besides, salinity rate has increased to 650 milligram per liter. According to this hydrological situation organism cannot live in the Urmia Lakes. There is a lot of information about current chemical characteristics of Urmia Lake but we don’t have sufficient information about paleo hydrology and paleo salinity of the Lake especially in Quaternary. Investigation of The Urmia Paleo Lake terraces, their evolution and changes in elevations and changes in biostratigarphy characteristics are evidences for paleo environments of this lake. Dominant shell fragments of the Urmia Lake terraces are Gostropoda, Ostracoda, Foraminifera and Bivalves. In this study, type and spacious of shell fragments are investigated and the living environment situations of the organisms during formation of each lake terraces are determined. Using biostratigraphic study results and correlation between these environmental changes with elevation changes of lake terraces, Hydrological and ecological situations of The Urmia Lake during Quaternary was reconstructed. The results of biostratigraphy shows, in contrast to the current situation of water in the Urmia Lake (Hyper saline), most of the organisms lived in brackish and fresh water during formation of the lake terraces. [1]- Ph.D in Marine Geology Management; Geological Survey of Iran. [2]- Professor in Geogarphy University of Tehran (Corresponding author, Email:myamani@ut.ac.ir. [3]- Professor in Geogarphy University of Tehran. [4]- Associate Prof. of Research Institure for Earth science Geological Survey of Iran. [5]- Expert of Geological Survey of Iran.
Volume 1, Issue 1 , January 2015, , Pages 131-144
Abstract
Abstract
Ground water is one of important freshwater sources for human. Since surface water sources are limited in most regions, groundwater can be considered as one of the most available resources for supplying water. This research tries to identify regions which have the most groundwater resources ...
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Abstract
Ground water is one of important freshwater sources for human. Since surface water sources are limited in most regions, groundwater can be considered as one of the most available resources for supplying water. This research tries to identify regions which have the most groundwater resources by analyzing effective geology, topology, hydrology and climate parameters in Abadeh – Eghlid basin. Abadeh - Eghlid basin with 2871 Km² area is one of sub- basins in Abargho- Sirjan desert. This area placed on north east of Fars state and its climate semiarid. In order to find potential groundwater resources in Abadeh - Eghlid, climate information and statistics from synoptic stations in Abadeh and Eghlid (1977-2010) gathered and geology, topology and hydrology information acquired from numeral geological maps with 1: 100000 scale and topographical mps with 1: 50000 scale and by using Analytical Hierarchy Processes (AHP) method in software environment Arc GIS the most suitable regions according to their groundwater sources have been recognized, determined, described and classified. The most area of this basin has good and moderate potential, and high and good potential regions placed in south and southeast areas of basin and also there some areas in northwest of basin
