Adel Khazaei; Majid Abaspour; Sasan Babaei Kafaky; Lobat Taghavi; Yousef rashidi
Abstract
Introduction: The metropolis of Tehran as the largest capital of the Middle East is faced with phenomena such as environmental degradation, land use change and high concentration of agricultural and industrial disasters. Knowing the changes of land use in the past and predicting its future status is ...
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Introduction: The metropolis of Tehran as the largest capital of the Middle East is faced with phenomena such as environmental degradation, land use change and high concentration of agricultural and industrial disasters. Knowing the changes of land use in the past and predicting its future status is necessary in order to carry out a principled, dynamic planning. In this study, the spatio-temporal dynamics of land use changes in the Tehran in a 20-year period and the prediction of future changes in these land uses in the next 40-year were selected as the general objectives of this study.Material and Methods: After forming a database of Landsat 5 and 8 satellite images for three times of 2001, 2011 and 2021, the land use map of this times were prepared. For the validation of the maps Google Earth images, ground points and accuracy and Kappa coefficients were used. The time period from 2021 to 2061 was considered to predict future changes. In order to zoning and predict the future of land use changes, 6 land use change transfer sub-models with artificial neural network, Markov chain, and LCM model were used. Evaluation of the accuracy of the model was obtained from the comparison of the ground map of 2021, the future map of 2061, and the values of Null success, success, Miss and False Alarm were obtained.Results and Discussion: The results showed that the period from 2001 to 2021 was associated with the expansion of residential areas, the growth of urban areas and the reduction of green spaces including gardens and parks. The expansion of residential areas has been primarily in poor and barren soils and then in gardens and green spaces. This urban growth was clearly in region 5, 21, 22 and its physical development process was linear. The decrease in the level of gardens and green space is very catastrophic and this decrease is especially evident in the central areas of the city due to the high density of buildings. Urban parks are clearly in a complicated condition in the eastern areas of Tehran. The area of rain fed agriculture has increased and the area of barren soils and poor lands has decreased. Most of the changes in land use related to low capacity lands and agricultural lands have occurred. Studying the maps of the future of land cover showed the continuation of the same trend of the past 20 years. Although the growth of residential areas will be slower than the previous period, but the capacity and dimensions of the city will continue to increase, especially in the western, southern and southwestern regions. The decreasing trend of gardens, parks and urban green space is still observed. This process is more intense in the case of parks and they will be destroyed more quickly. The reason for this is besides drought and withering of trees due to climate change, pollution, and conversion of these green land uses to rain fed agriculture, parks, poor rangelands and urban areas. As for the urban green spaces, the 16 and 4 regions have the worst positions, and the 17, 19. 2, 5 and 22 regions will not be safe from this damage either. The decrease in the area of rangelands and cities moved to new areas will increase; the cycle of destruction of vegetation will increase from the outskirts of Tehran.Conclusion: Construction was more in the south of Tehran and the decreasing trend of urban green space will continue to be observed. The central areas of Tehran will be completely devoid of trees due to the predominance of the urban areas, and the point to consider is the destruction of the green belt in the north of Tehran in the future.
kazem rangzan; Alireza Zarasvandi; mostafa kabolizadeh; shahin mohammadi; jasem mayahi
Abstract
Introduction: Particulate matters are one of the main air pollutants in urban areas, which are usually produced from various sources such as urban vehicles, fossil fuels, industrial activities. They may cause respiratory diseases, cardiovascular disease and death. It is, therefore, very important to ...
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Introduction: Particulate matters are one of the main air pollutants in urban areas, which are usually produced from various sources such as urban vehicles, fossil fuels, industrial activities. They may cause respiratory diseases, cardiovascular disease and death. It is, therefore, very important to be aware of spatial changes in these pollutants in areas with high levels of pollution. In this regard, the present study was conducted with the aim of spatio-temporal evaluation of the PM2.5 index in the period 1998 to 2016 in Khuzestan ProvinceMaterial and methods: For this study, first, precipitation, land surface temperature (LST), wind speed, Digital Elevation Model (DEM) and vegetation cover parameters were prepared using four satellites i.e. Terra, Landsat 8, SRTM and GPM, and ground data. Then PM2.5 index for four periods of 1998, 2004, 2010 and 2016 was extracted using satellite products for Khuzestan Province. Also, information on the distribution of the population and industries of the province was received from the relevant organizations. Finally, after providing the spatio-temporal changes of PM2.5 index in Khuzestan Province, the spatial changes of this index were studied with the mentioned parameters to evaluate the effect of each of these parameters on the contamination degree of this index.Results and discussion: The results of the present study showed that the southern cities of the province such as Mahshahr, Abadan and Shadegan are regions with higher potential in terms of particles smaller than 2.5 microns in size. The results of the study of population density and industries of this province showed that most of the cities in which the air pollution rate was high due to the PM2.5 index, had more industries and population density. The results also showed that in all study periods, in the northern and northeastern parts of the province, the amount of air pollution caused by this index was much lower than other regions of the province and the reason for this could be the low density of industries and population of these cities, among which we can mention the cities of Lali and Indika. In addition to the direct relationship between industry and human activities in increasing and decreasing the concentration of PM2.5 index, the relationship between this index and several factors (DEM, wind speed, precipitation, temperature and vegetation cover) was investigated. The correlation results between the mentioned parameters and PM2.5 concentration showed that the highest correlation was between PM2.5 concentration and precipitation and this relationship was inverse.Conclusion: It can be concluded that the concentration of PM2.5 pollutants in the southern and central areas is much higher than other areas and this could be due to the high density of power plants, industries and vehicle pollution in these areas. In addition, environmental and climatic factors can play an important role in the persistence and spread of the air pollution layer of this index. It should be noted that this research can be used as the basis for decision-making for air pollution management, which is an important step towards overcoming the crisis of air pollution.
Morteza Sharif; Saeid Hamzeh
Abstract
Introduction: One of the most important factors that play a major role in reducing soil fertility and agricultural land degradation is soil salinization. Soil salinity problem is more severe in agricultural lands of arid and semi-arid regions. In many cases, human activities and irrigation of agricultural ...
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Introduction: One of the most important factors that play a major role in reducing soil fertility and agricultural land degradation is soil salinization. Soil salinity problem is more severe in agricultural lands of arid and semi-arid regions. In many cases, human activities and irrigation of agricultural lands with saline water are the cause of salinization. This is a serious problem in different regions of Iran, especially in Khuzestan Province. Therefore, the present study was conducted with the aim of monitoring and evaluating the effect of Gotvand Dam on the salinization of the downstream area and changing its plant ecosystem before and after water intake using remote sensing imagery.Material and methods: The time series of two ETM+ and OLI sensors from 2019-1999 were collected using plant indices (NDVI, SAVI), biophysical index of leaf cover (LAI), and salinity indices. The soil was classified by salient decision-making method of changes in halophyte and non-halophyte plants according to the threshold obtained from the indicators used in each year. Then, the final results were evaluated according to the trend of changes obtained from the used indicators and their correlation with changes in the plant ecosystem of the region.Results and discussion: The rate of vegetation changes in the four years of 2018, 2013, 2002, and 1999 was more than other years, which was prepared by the method of supervised classification of the area under normal vegetation and saline plants. According to the results obtained from 1999, the total vegetation area of the groves was about 1117 hectares, of which about 134 hectares were related to halophyte vegetation. However in 2018, these values were estimated at 921 hectares, with areas covered by halophyte changing to 445 hectares and halophyte to 476 hectares.Conclusion: The results of the study indicate the onset of the highest stresses in the plant ecosystem of the region and the simultaneous decline in leaf cover and NDVI with the water intake of Gotvand Dam since 2011. This coincidence, which is due to the salinity of the water of Gotvand Dam Lake and consequently Karun River, has a significant effect on increasing salinity and changes in soil quality of the region and thus increasing halophyte plants as well as high vegetation degradation in the region. These conditions can create more serious challenges for the ecosystem of this area and in the long period change the ecosystem and vegetation cover of this region to halophyte plants.
Mahsa Abdoli; Mohammad Panahandeh
Abstract
Introduction: Over the past few decades, human activity had a significant impact on coastal wetlands around the world. Anzali is one of the 18 Iranian wetlands of international importance listed in Ramsar Convention. This unique ecosystemin the world with high ecological diversity is highly threatened ...
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Introduction: Over the past few decades, human activity had a significant impact on coastal wetlands around the world. Anzali is one of the 18 Iranian wetlands of international importance listed in Ramsar Convention. This unique ecosystemin the world with high ecological diversity is highly threatened by various factors such as pollutants, sedimentation, unauthorized development of urban infrastructure, over-harvesting of wetland resources, land use changes, and invasive species. In this study, we analyze structural and functional changes in the Anzali coastal wetland from 1994 to 2018, using the "drive-pressures-status-effects-responses-(DPSIR)" model and data collected from the Anzali Coastal Wetland. Material and methods: Landsat 5 and 8 TM and OLI sensors for 1994, 2008 and 2018 were used. The land cover maps for these years were prepared in 5 categories of water body, wetland, wetland plants, pasture and agricultural land using the supervised classification with maximum likelihood algorithm in ENVI5.3 software. Changes were identified to assess the current status of the wetland and then the conceptual framework of DPSIR was used to determine the relationship between human activities and environmental activities and to describe environmental problems. Results and discussion: According to the results of the first period (1994-2008), the water body had the highest area change with 7.63% decrease, which was the most influential part of the wetland plants class, with 1045/98 hectares of water body converted into wetland. The wetland plants was second with 3.84 percent. During the second period (2008-2018), the water body had the most change in this period, with a decrease of 14.19%, as in the previous period. Over the entire study period from 1994 to 2018, the water body increased from 4749 hectares in 1994 to 1042 hectares in 2018, the largest conversion to wetland plants. The area of wetland, wetland, pasture and agricultural land uses increased by 10.92%, 0.78%, 4.48% and 5.66%, respectively. The results of maps accuracy assessment show that overall accuracy for year 2018, 96.31, year 2008, 94.14 and for 1994, 90.29% and kappa coefficient were 0.94, 0.92 and 0.87, respectively. Is. Also the driving forces in this research are population growth, industry and tourism. Conclusion: The process of change in the Anzali Wetland is first in a natural sequence and then of human origin. So that the area of the water reservoir is reduced and added to the cover of wetland plants and wetlands and eventually to agricultural lands and the fertilizers and pesticides used in agriculture along with domestic wastewater, industrialization through rivers into the Anzali Wetland. It enters the wetland feed, thereby accelerating the process of wetland destruction. Protecting this wetland requires people's participation, education and culture at the grassroots level.
Mohammad Taghi Razavian; Ali Rahimi
Abstract
Introduction: Nowadays, the urban sprawl phenomenon has become one of the most important concerns of planners and policymakers. The lack of attention to this phenomenon has led to irreparable consequences such as threatening natural resources, and social, economic, physical, and environmental constraints ...
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Introduction: Nowadays, the urban sprawl phenomenon has become one of the most important concerns of planners and policymakers. The lack of attention to this phenomenon has led to irreparable consequences such as threatening natural resources, and social, economic, physical, and environmental constraints and disadvantages. In order to better understand such a model, it is necessary to evaluate and identify the socioeconomic factors affecting it. Material and methods: The methodology in this research was a combination of descriptive and explanatory research, the type of research was applied, and its approach was considered quantitative and qualitative. Data collection was done using library and field survey methods. Also, remote sensing and Landsat satellite images of the studied area during the mentioned period was used. In addition, to analyze Zanjan’s urban sprawl, the method of classified classification, land use classification and cross-feasibility model, the extent of changes in different land uses, and the Holdern model were used. In order to predict the trend of changes and to investigate possible changes in land uses for the 2026 horizon, the Markov chains model was used. Results and discussion: In the studied area, the results of the research indicated that over the past three decades, with uneven development in Zanjan City, the urban area has almost tripled. Theoretical analysis of Zanjan’s urban sprawl according to Heldern model indicated significant urban sprawl domination in the physical development of Zanjan, which always had more effect than the population growth. During the studied years, Zanjan’s urban area had a multiplier increase that in contrast to this expansion, had a significant decrease in orchards and agriculture. In this situation, what made a big difference were the changes in orchard and agricultural land uses. Translation errorThere were many factors involved in this matter, most notably the growth of urban population and urban sprawl. Conclusion: Based on the forecast for 2026, the probability of land use changes to the city over the next 10 years is significant, during which Translation errorthe amount of built-up areas in Zanjan will reach 6311.88 hectares. It should be noted that orchards and Translation erroraaaagricultural lands have only a 23.56% possibility of conversion to urban areas. Therefore, necessary actions are required to prevent over-urbanization. In developed countries, considering the importance of sustainable development, environmental protection and the efficient use of various sources, smart growth, and urban development are highly important. Moreover, preventing the excessive growth of the city's boundaries, the high-ranking agenda, and the use of the compact city pattern, as well as the direction of the expansion of the city towards regolith and abandoned lands with the aim of preventing constructions in agricultural land can be considered.
Abutaleb Sabr; Mazaher Moeinaddini; Hossein Azarnivand
Volume 16, Issue 3 , October 2018, , Pages 79-100
Abstract
Introduction: In recent decades, air quality change and its risks are correlated with the expansion of urban and industrial areas and other land-use changes. One of the important effects of land use/cover changes (LUCC) is wind erosion and as a result, an increase in particulate matter (PM) concentration ...
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Introduction: In recent decades, air quality change and its risks are correlated with the expansion of urban and industrial areas and other land-use changes. One of the important effects of land use/cover changes (LUCC) is wind erosion and as a result, an increase in particulate matter (PM) concentration in residential areas. For this reason, the effects of LUCC on PM concentration in Tehran’s airshed was studied. Material and methods: Data on LUCC and landscape metrics were studied in the years 1985, 2000 and 2014. Then, the relationship between LUCC and PM concentration in Tehran was investigated by trend analysis methods. To find the most important wind directions with strong effects on Tehran’s air quality, conditional probability function (CPF) and directional relative strength (DRS) were used. Results and discussion: LUCC results showed that the area of agricultural land-use has been expanded from 1985 to 2000, yet decreased from 2000 to 2014. The trend was vice versa for barren lands during the mentioned time periods. In addition, the urban area has increased in the whole period. The landscape metric results showed that landscape patches became smaller and the landscape has been fragmented. The results of the PM10 concentration trend analysis revealed that it has been increased dramatically since 2007. Comparison of the average concentration of PM10 before and after 2007 showed a significant difference. The results of CPF and DRS illustrated that no specific wind direction was detected before 2007, but afterwards both increased in specific directions (south to west), which is compatible with most LUCC and fragmented areas in these directions. Conclusion: Our results showed that specific wind directions may lead to an increase in the PM10 concentration which is compatible with LUCC directions. Therefore, LUCC could be a significant reason for the increase in PM10 concentration in Tehran.
Seyed Hossein Pourali; Ali Akbar Matkan; Amin Hosseini-asl
Volume 6, Issue 1 , October 2008
Abstract
Regarding the importance of water sources in Iran, it is necessary to protect better water bodies such as reservoirs. The most efficient way of conserving water sources is to apply proper management to decrease erosion and sedimentation. The first step of this process is to be aware of sediment yield ...
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Regarding the importance of water sources in Iran, it is necessary to protect better water bodies such as reservoirs. The most efficient way of conserving water sources is to apply proper management to decrease erosion and sedimentation. The first step of this process is to be aware of sediment yield and identify erosion hazard areas in upper reach of reservoirs. The present study is the preparation of a map of erosion hazard and sedimentation in Dez watershed (area: 17320 km2) which is to be applied in the rehabilitation project of Dez dam. The inaccessible location and the fact that covers a wide area have made the use of satellite images inevitable. In this study, after examining several erosion and sedimentation modeling methods, the PSIAC - with 9 effective parameters - was selected; it is an empirical model in itself. In order to prepare the first series of data, IRS satellite data, Landsat ETM+, basic maps, the Arial photos, helicopter flights and also field checks were all applied. A calibration model with the data achieved from reservoir studies, and taking account of local characteristics of the area, prepared the opportunity to identify and classify erosive zones with GIS. The results which are presented as maps and erosion statistics, not only identify hazardous erosive areas, but also open a new horizon in the field of watershed management and sediment control by having a special outlook towards executive priorities. Keywords: Erosion, Sedimentation, Remote Sensing, GIS, Dez Dam
