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.
Nezam Asgharipour Dasht Bozorg; Mohammad Reza Servati; Pervez Kardavani; Siavash Shayan
Volume 5, Issue 17 , March 2019, , Pages 65-84
Abstract
Introduction
Alluvial fans have a great importance in terms of their high efficiency to create natural aquifer and groundwater storage. Increasing the rate of water demand and relying on groundwater has caused a remarkable decline in groundwater resource and aquifer level. On the other hand, flood spreading ...
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Introduction
Alluvial fans have a great importance in terms of their high efficiency to create natural aquifer and groundwater storage. Increasing the rate of water demand and relying on groundwater has caused a remarkable decline in groundwater resource and aquifer level. On the other hand, flood spreading is known as an applicable and an effective method for artificial aquifers recharging in arid and semiarid regions. Sabzab and Gotvand plains (fig. 1), in Khuzestan Province, have experienced vivid decline in groundwater-level due to over pumping of aquifer resources, since last decades. Therefore, these plains have been selected to implement methods of artificial recharging of groundwater, especially flood spreading.
Methodology
The research methodology included comprehensive methods of field observations, application of ArcGIS, 10.3 tools, and modeling. Accordingly, a geographical information system was used for the zoning of the suitable areas to implement artificial recharging by a flood spreading method based on the fuzzy logic model. Imported data for zoning included Landsat ETM+ satellite images (2010, 28.5 m resolution), topographic maps of Gotvand and Sarbishe regions (1:25000 scale), geological map of Dezfol region (1:100000 scale), precipitation data, soil permeability data, and the measurement of the electrical conductivity of floods region. The zoning procedures provided 6 GIS-ready map layers including quaternary deposits of the region, slope, infiltration, electrical conductivity, thickness of alluvium, transmissivity, and drainage density. In the second step, the effective factors were formulated in a fuzzy manner and GIS-Ready layers were overlapped using Sum, and, OR, Product, and Gamma operators. Finally, the zones with high suitability for flood spreading were overlaid over the alluvial fans outcrops.
Results and discussion
Several thematic maps were produced on the basis of the fuzzy method. The suitability zoning as the main objectives of the research was obtained in four classes ranged (fig. 5) from high suitable to unsuitable (table 1). The results showed that high-suitable areas were often at the bottom of the Bakhtiari conglomerate formations and alluvial fans (Fig. 7). In addition, alluvial fans which had mainly composed of coarse size sediments had close genetic relationship with Bakhtiari conglomerate formation and represented the remarkable matching with two high-suitable and suitable classes. The mean rate of 83 % of the different fuzzy operators showed the most comparability with high suitable and suitable areas.
Conclusion
The research hypotheses were successfully confirmed by the resultant data. The present research indicates the importance of geomorphological landforms in terms of artificial groundwater recharge and it should be protected as a source of water. Therefore, incorrect changes to this lands form should be avoided. Furthermore, the fuzzy method has represented a useful manner to find suitable zones for flood spreading. The research method is also recommended to be used in other similar geological conditions in Khuzestan Province.
Mohammad Akbarian; Siavosh Shayan
Volume 4, Issue 13 , March 2018, , Pages 63-78
Abstract
Extended Abstract
Introduction
Each part of a shore should be thouroughly considered with its hydrodynamic, lithodynamic, geological, geomorphological, and other peculiarities. In modern conditions, anthropogenic factors should also be included. Only such a multilateral approach can produce results ...
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Extended Abstract
Introduction
Each part of a shore should be thouroughly considered with its hydrodynamic, lithodynamic, geological, geomorphological, and other peculiarities. In modern conditions, anthropogenic factors should also be included. Only such a multilateral approach can produce results which reflect the actual situation as closely as possible. Arid lands and coastal zones are the most favourable areas for wind processes. The analysis of the forms and coastal conditions provides a valuable key for coastal management. A beach can be composed of a wide variety of materials of many sizes and shapes. The river load is one of the hydrological elements that affects the beach. Particle size windows (PSWs) are interpreted as reflecting different modes of sediment transport and deposition. In a related research on western Makoran coastal plain, Shayan et.al (2014) found that the distribution of the internal sand masses on the plain was affected by the extent of the old beds and floodplain that were exposed to the prevailing wind rather than wind function. The aim of this study was to identify the effect of river’s flows on sedimentological characteristics of the shoreline in the western part of Mokran coastal plain, Iran. The major process that formed coastal plains were fluvial processes. In semi arid areas, the geomorphological impacts of dams are very major. The purpose here was to identify the consequences of dam construction on vegetation and aeolian geomorphology with an emphasis on the ecogeomorphology of the western part of Makran coastal plain. The study area is located at 25o31’-25o50’N, 57o52’-59o02’E, in the western part of the coastal plain of Makoran, the southern part of Iran, the northern part of the Oman Sea, and the eastern part of Strait of Hormoz. In general, the region under research could be assumed a dry land with very low rain, windy, sand storm, torrent shower, thunder-storm, higher humidity, and hazy down (Akbarian et al., 2006). Geologically, it is affected by Mokran (Makoran) region's general construction and it is mainly composed of shaile, marl, and sandstone layers.
Methodology
Research data included spatial distributions of coastal lanforms, rivers' hydrodinamic data, data of surface morphometric specialy slope, and type of vegetation. Maps of geology and topography, satellite imagery, aerial photos, GPS and computer softwares such as Freehand and ArcGIS were used. Morphodynamic changes of the rivers were investigated by using hydrometric station's data, comparing the satelite images and areal photos, and gathering the results of other studies. The Coastal plain's topographical and geological charecteristics, the distribution map of landfoms, the vegetatin cover, and coastal dunes were also studied. Then, based on the geomorphological analysis and information from field works, the possible ecogeomorphological consequences of dam construction were studied.
Discussion
The exploitation of coastal rivers have had an enormously negative impact on coastal zone and a deleterious effect on the natural dynamics of river loads. The basins leading to the Coastal Plains of Sedijch, Gabric, and Jagin have high sedimentation discharge. According to the results, the hydrodynamic effects of these rivers have a special effect on the formation of plain landforms. The sources of the sedimentation of sand masses and the establishment of forest cover on adjacent coastal plain are affected by river’s hydrodynamic. Once dams constructions on these rivers are complete, sediment load virtually comes to an end. In the near future, major changes can be expected at the mouth of the rivers and along the coastal zones of this region. However, dams could cause serious environmental damage in the downstream of these rivers. They may increase the severity of wind erosion, the performance of waves in sediment drift along the coastline. They will also have negative effect on the amount of forest cover on upland of these coastal plains and especially mangrove wetlands.
These results are consistent with the following researchers. According to Nanson and Croke (1992), as a result of environmental modifications on rivers, flood plains affected by major rivers evolve over time. In a study of hydrology, geomorphology and vegetation in the southeastern coastal rivers of the United States, Hop (2000) concluded that the vegetation diversity of the coastal plain has adapted to long flood periods and anaerobic conditions. Based on Berkun (2014), the natural course of fluvial alluvium transport is almost completely altered because of planned and constructed dams and coastal protection measures. Decreasing volume of sediment carried to the sea cause intensification of the shore erosion (Berkun, 2012). Sulimanirad et al. (2011) stated that the habitat of the protected area of Gabrij (the whole range of Gabriel coastal wetlands, Jengin, and Sourgelm) is threatened and possibly destroyed due to the construction of a dam on the Jegin River, camel grazing and the destruction of mangroves.
Conclusion
The present study showed that water and sediment discharge of rivers and their hydrodynamic has a special role in the formation of coastal landforms, specially on aeolian landforms, and the stablishment of mangrove on lagoon and Persian Gulf-Oman(Sahara-Sendi) forest habitat on upland deltas. Lake of fluvial processes in the long period will probably have destructive consequences on the ecology and geomorphology of this coastal region.
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.
