Zohreh Fanni; Seyyed MohammadReza Ghashami
Abstract
Extended Abstract
Introduction
The natural behaviors of the human life environment where the settlements are constructed without recognizing and studying these behaviors are called hazards. The distinctive features of natural hazards are the changes in the hazard severity in different locations, as ...
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Extended Abstract
Introduction
The natural behaviors of the human life environment where the settlements are constructed without recognizing and studying these behaviors are called hazards. The distinctive features of natural hazards are the changes in the hazard severity in different locations, as in the urban environments, human activities along with greater vulnerability in the environment, aggravate the hazard and the extent of its occurrence. The city and its infrastructure development in providing security and various needs of human are of the most substantial areas for the development of social life. In general, identifying areas prone to hazards is a key tool for decision makers to reduce the damages caused by natural hazards. On the other hand, abstract study of the nature’s behaviors in the form of flood, earthquake, land slide and subsidence has always made managerial decision-makings difficult, so that avoiding the aggravating factors of a hazard has caused to get close to another hazard.
Objectives
The main objective of this study is to evaluate areas affected by these four natural hazards in all 22 Districts of Tehran City. In other words, this research with the aim of comprehensive and integrated zoning of hazards such as flood, earthquake, landslide and subsidence has proceeded to identify, evaluate and adjust the findings in the form of a comprehensive map of the susceptibility of these behaviors under the title of four environmental hazards within the 22 districts of Tehran city.
Discussion
Multiple-risk analysis, including a range of data, provides a more realistic model of the natural environment management. In this regard, studies have been conducted on the various approaches to analyze spatial data, how to create a combination of environmental hazards and how to determine their risk and vulnerability levels. To generate a probabilistic model, the basic assumption is that the risk level is determined by risk factors and possible hazards in the future, and with an emphasis on the past events. In this study, the creating and effective factors in environmental crises are related and calculated with each other with respect to several risks.
Research Methodology
One of the usual algebraic methods is the Analytic Hierarchy Process (AHP), which, as a weighted evaluation method, evaluates different scenarios and selects the best option by combining the qualitative and quantitative factors. The Analytic Hierarchy process as one of the multi-criteria decision-making methods provides the ground for performing applied spatial analyses by examining the effects of different factors in contradiction with each other. The research method is quantitative-analytical, and all the factors affecting the occurrence of each hazard have been identified and digitized in ArcGIS environment and modeled using Frequency Ratio (FR) model. Then, each of the four susceptibility maps was combined in fuzzy method and the final susceptibility map was classified into 5 classes of very high, high, moderate, low and very low susceptibility, and was extracted and presented as a map and a table.
Results
This research resulted in the production of the susceptibility zone map for more probable hazards including flood, earthquake, landslide, and subsidence of Tehran City in the separation of 22 Districts. This map includes several factors such as slope degree, slope direction, slope shape, elevation layers, distance from the river, distance from the road, distance from the fault, geology, land use, and the rain The result show that the effective factors in flood are the distance from the river, and the slope; the most effective factors in the destruction are the wasting of groundwater and eliminating the geotechnical properties of the soil; the most effective factors in the occurrence of earthquake are the distance from the major and minor faults which determine the length of major and minor faults. Based on the results of this research and their analyses in Tehran’s districts, areas with very high, high, moderate, low and very low susceptibility were observed. Then, considering this study, their percentages were calculated in each class and reported in the form of a table. Among the 22 districts of Tehran city, districts 1, 3, 18, 5, and 4 are more susceptible than the rest of districts and districts 9, 10, 11, 12, and 17 are less susceptible in terms of the four aforementioned hazards.
Therefore, it is recommended that the process of reinforcement and standardization of existing facilities and infrastructure to be implemented by prioritizing hazardous zones. Concerning the construction and development of new infrastructure and facilities, the occurrence and exacerbation of these natural hazards within the hazardous areas may be prevented by imposing restriction or not issuing construction permits.
mohammad kazem shams pouya; Jamileh Tavakolinia; Mozaffar Sarrafi; Zohreh Fanni
Abstract
Extended Abstract The concepts of land and land use planning and its objectives have changed over time. These changes include: Changes in the socioeconomic concept, the evolution of the concept of land, physical and new priorities in land use per capita. In addition, seeking to promote the environmental ...
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Extended Abstract The concepts of land and land use planning and its objectives have changed over time. These changes include: Changes in the socioeconomic concept, the evolution of the concept of land, physical and new priorities in land use per capita. In addition, seeking to promote the environmental movement in the 1980s led to the global popularity of the concept of sustainable development, qualitative changes in approaches and methods of planning and urban design. Since then, urbanization goals have changed from physical and functional issues towards the sustainable urban development. In fact, equitable access to land is one of the components of sustainable development. The true role of land and its importance in sustainable development is properly understood when its prerequisites are taken into consideration. One of the most important of these prerequisites can be pointed to good land governance. Alongside this revival of land issues in development policy discourse, is the emergence of a distinct pole in governance discourse, namely, ‘land governance’. The term and notion of ‘land governance’ has gained currency within the mainstream agencies in recent years, and generally means the most efficient way of administration of land issues, such as cadastres, land titling, and so on. Land governance encompasses a range of issues and subjects that the laws and policies of urban land is one of those cases. So, the urban land laws and policies from the perspective of good governance approach Provides good understanding of the policies and rules and patterns of urban land issues. Materials & Methods The main method of this study was a descriptive-analytical approach that has been carried out using a literature review in library data. This research is both fundamental and practical. The main goal of this study is to determine the characteristics and consequences of good and poor governance and the interpretation of laws and policies from the perspective of good land governance model and determining the obstacles to fulfill the requirements of good land governance in Tehran Metropolis. Results & Discussion In the Third Development Plan (1962-1967), the master plan for Tehran Metropolis was prepared. Such plans led to long-term government intervention in the land market. It should be noted that the criterion of 300 meters for land separation in the first comprehensive plan of Tehran was far beyond the average residential land area in the status quo (about 100 meters) and was beyond the capacity of low-income groups.This pattern was repeated in subsequent programs and led to projections of lower income groups to the suburban areas. Whereas good land governance requires knowledge and beyond citizen participation and interest groups in the preparation and implementation of development programs and urban land policies, effectiveness and efficiency is one of the most important criteria for good land governance that must be based on accurate and perfect laws and regulations. In Tehran Metropolis, the lack of adequate and affordable housing, especially for low-income groups led to poor governance of land and housing. Also, given that decision-making process is centralized, the local land management has not been achieved. Conclusion The results showed that, zoning laws, land separation regulations, and housing planning flaws led to speculation of land and housing in Tehran metropolis and ignored low-income groups in urban plans and increased urban sprawl and expansion of the unregulated constructions as a result of poor land governance. Also, it is necessary to mention that the land acquisition and construction by various institutions without permission, the institutional irregularities, centralized decision-making process and the lack of formation of local land management, lack of transparency and unclear land property situation within and outside the cities, all of which are in contradiction with the principles of good land governance. Good land governance is based on transparency of ownership, land tenure security and transparency and so on. This is a very basic issue that also continues. Therefore, the need to revise the governance structure along with subsidiarity and providing the context of popular participation, and institutions such as councils by state are the essential issues. In the end, it must be emphasized that the realization of local land management also depends on good land governance.
