عنوان مقاله [English]
The growth and expansion of urbanization in the contemporary era and the emergence of metropolitan areas as places in which large number of people live together and capital and assets are accumulated have recently attracted the attention of many planners, governments and nations topotential natural hazards and the importance of crisis management in these areas.In this regard, land use planning is considered to be critical due to its importance for sustainable development, optimal configuration, and crisis management.
Materials & Methods
The present study primarily seeks to design a spatial model for spatial evaluation of urban land use in district 19 of Tehran Municipalityusing a crisis management approach. In this descriptive-analytical study,necessary information were collected through library research methods and the analysis of quantitative and qualitative indicators.In quantitative index analysis, per capita land use of the district was compared to the country’s standard level, and in qualitative index analysis, three criteria of compatibility, capacity and desirability have been evaluated. One of the goals of urban land use planning is proper site selection for different land uses and separation of incompatible land uses from each other which is achieved through collection of necessary information about the current situation and evaluation of the collected information. For example, attempts are made to find a proper site forland uses producing pollutants such as smoke, odors, and noise away from residential, cultural, and social areas.In contrast, activities that complement each other are located in vicinity of each other. ArcGIS was used to evaluate and model the compatibility level of neighboring land uses. The proposed model inthe present study aims to evaluate the proximity of activities in order to determine their level of compatibility from the perspective of crisis management. Results of this model can be used for land use planning. This model is based on two principles: the logic behindland uses’ compatibility, and spatial neighborhood relationship and models of this relationship in GIS environment. Model Builder, a visual programming language at the Arc Info Editor Level which is undoubtedly one of the most important features offered in this program has been used to achieve the desired goal in this study. This modeler is actually an interface which forms the input-output parameters and processing functions in the processor. In this interface, the user can call several functions in a sequence and the processes will be performed one after the other. The input parameters includeeverysupported format in ArcGIS. Processing functions include all functionsused in the spatial analysis network. Outputs can be stored and used in later steps.
Results & Discussion
Qualitative analysis of land uses in District 19 of Tehran Municipality
Evaluating the compatibility of land uses in District 19
In order to analyze the compatibility levelofneighboring land uses, the number of neighbors in each parcel is determined.Then,a binary compatibility relationship is stipulated for each pair and finally a fixed number is reached in the process of comparing land uses. As required by the land use compatibility matrix, urban uses are hypothetically classified into 5 groupsbased on their current situation: fully compatible, relatively compatible, indifferent, completely incompatible, and relatively incompatible. Following the production of compatibility matrix, details oflandusescollected during the field study have been analyzed and presented as maps. Then, the model is run in Arc GIS and the level of each land use’s compatibility is presented with anespecialcolor. Results indicate that except for Velayat park which is not compatible with the surrounding land uses, most of the incompatible land uses are located in the western and southwestern parts of the district. These incompatible land uses are presented with 5 different color ranges.
Investigating the capacity of different land uses in district 19 of Tehran Municipality
Qualitative analysis of accessibility zone in the capacity matrix
In this matrix, the performance of each major land use in service provision and performance coverage is determined based on the urban population and its area of influence, and the results are presented in the relevant tables and on a map produced using Euclidean analysis in Arc GIS. The basic level of performance for each land use at the regional level and its area of direct influenceis identified based on the population required for standard performance of that specific land use in this area. This identified level of performance was used as the basis for further calculations.
According to the proposed model and considering the accessibility zone, a special buffer zone is identified for each land use and its census blocks are determined. Finally,population within the blocks is determined separately for each land use (in this section, a few maps of buffer zones are provided for some land usesas an example). This model determines whether the rules of accessibility have been complied in different land uses. Based on the accessibility zone and censusblocks, decision making about the necessity of different land uses is made possible.
Investigating the desirability of land uses in district 19
To reach the desired goal, a land use layerto which a new field of desirability has been added will be consideredaccording to the model (Figures 5 and 7) and the existing rules for specific land uses. Results are exhibited in two different classes (desirable, undesirable). According to the existing rules and maps, the desired parts of the area are marked in green and the undesirable parts of the area are marked in red.
As one of the most important tools and a major goal of urban planning,land use planning has a vital role in risk mitigation duringurban development. Thus, improving methods and processes of realizing this goal is of great importance and priority. Physical and functional characteristicsof land use have a significant effect on the number of casualties in different urban crisis. Therefore, land use planning is considered to be an important principle of urban planning and an urban planner is primarily expected to make the right decisions and to properly monitor land uses.On the other hand, crisis management and resilience approach have become a pervasive topic of debate in the present decade. Many researchers consider resilience to be the internal ability of a system, community or element to withstand the effects of a natural or social event. In order to determine the level of resilience, land uses in this area are investigated based on different aspects of crisis management. A major difference is observed between the findings of the present study and that of other researchers: most of dimensions, criteria or the main indicator in the present study are related to each other.The dimensions proposed in this model cover all physical and non-physical aspects and the proposed criteria or indicators also show important factors in each dimension. Moreover, the vulnerability of each dimension affects other dimensionsdirectly or indirectly. In fact, a district of Tehran municipality may be more resilient than other districts in some dimensions, but this does not suffice by its own and vulnerability in one dimension reduces the resilience of the whole district.Therefore, a resilient city or district needs to reduce its vulnerability in all dimensions and achieve resilience and crisis management in their real sense. One of the main concerns in the study of urban issues and urban planning is the issue of quantitative and qualitative analysis of the city and urban land uses. In the present study, an attempt has been made to perform quantitative index analysis of urban land uses under the topic of fair distribution of land uses per capita.And for the analysis of quality index, urban land uses were separately investigated based on their compatibility, capacity, and desirability level.This is another innovation of the present study which makes it different from other researches.In the discussion of compatibility,a model has been developed in ArcGIS environmentbased on the rules of urban planning to determine the compatibility of neighboring land uses. The highest level of incompatibility between neighboring land uses was observed in the western and southwestern part of the district. In terms of capacity, a model has been designed for existing uses in the area based on the standard accessibility zone. Regarding desirability, appropriateness of spatial conditions (slope, pollution, odor, location ...) and the land uses in a particular place have been considered as important criterion used to distinguish desirable and undesirable areas.The present studyinvestigates appropriateness of land uses based on standard slope. As previously mentioned, a model has been developed for each case in the GIS environment and the results are provided as a map at the end of each section. Following qualitative analysis, the most incompatible land uses were identified. Finally, the following solutions and suggestions are provided to improve and manage land use and for the managementof possible future crisis:
Using empty spaces in the district and worthless lands in the southern and southwestern areas of the district to prevent the physical expansion and encroachment of the district on Tehran and Islamshahr.
Considering a special zone around high-risk land uses such as gas stations and applying additional rules and regulations to prohibit increased density in these zones.
Collecting physical and environmental data as much as possible, combining these data with each other, and using them statistically.
Assessing earthquake risk and including the results in land use planning to mitigate risk and manage possiblecrisis.
Distributingthe population in this districtbased on identified hazards in the area.
Properly distributing parks and green spaces in the district, maintaining them for the times of possible crisis, ensuring easier access and equitable distribution among citizens.
Increasing the quality of buildings in accordance with construction and urban planning standards, planning for the reconstruction and repairing of worn out buildings.