Assessment of Influencing Factors on Land Use Changes in Urban Expansion of Metropolis, Case Study: District 22 of Municipality of Tehran

Rapid developments of metropolitans have caused rapid changes in pattern of land uses around these cities. These changes which are most of times irreversible, cause environmental, social and economic problems in many marginal areas of these cities such as disturbance in land uses, lack of services and infrastructure, pollution, etc. One of such problems can be seen in district no. 22 of Tehran, in which the pattern of urban development in the last 2 decades is in the form of scattered urban land uses development, in spite of discrepancy of this type of comprehensive development with fast continuing of detailed policies. Continuation of this trend will cause a number of problems such as: reduced green space, degradation of environment quality, increased trend of non-normative changes in vegetation of area and ignoring limitations and ecological carrying capacity of natural resources in the region. Also, increased rate of these changes has increased social, economic and political problems in Tehran. Therefore, developing a framework for understanding rapid land uses changes in metropolitans and its factors in the past can be of great importance for efficient management of these changes. The present study seeks to identify the main factors and drivers of land use changes in the development trend of metropolitans in order to control and manage these changes. At global level, comprehensive studies have been conducted on these factors and the way they affect changes in land use through an extensive range of economic, social and natural factors. However, in Iran, these factors have never been seriously studied. To this end, for understanding the effective factors on changes in land use of metropolitan cities of Iran, indicators of land use changes (adopted from global experiences and studies and adapted to specific conditions of Iran’s metropolitans) were used which include 12 criteria: access to industrial centers (employment), access to commercial centers, access to urban services centers, ownership, topography and land slop, access to main street, distribution of built urban environment, land uses, and building density. These indicators in conceptual framework of cellular automata (CA) and in the range of district 22 of Tehran have been studied and the contribution of each of these indicators in change of wasteland uses and non-urban land uses in 1996 and urban land uses in 2006 have been calculated. This study has a explanatory- descriptive and quantitative approach with six sections which are: theoretical background; factors and drivers of land use change in the trend of metropolitan development, theoretical framework and research method, introduction of study area, calculation of the score of land use changes indicators, measurement of land use changes indicators in the urban development trend of the area under study with the help of factor analysis and finally concluding section. In this study we tried to select the indicators of land use changes patterns in a proper way regarding to the studies and the existing information in reviewing theories, experiences and existing studies in the field of land use changes factors. With the help of cellular automata logic (CA) and factor analysis method and with the established indicators of land use changes, we tried to identify main factors of land use changes. Research findings indicate that the main factors of land use changes can be categorized in 5 main factors including: access to social service, access to urban centers, proposals of details project, natural location, and incentives for residential construction. Also the results indicate that 53% of the changes in private garden lands and 9% of changes in green spaces lands have been changed into industrial land use that this should be considered as an environmental alerting issue. Most of the changes in land use are from wastelands and non-built lands with private ownership and low residential density lands. Indicators of proximity to commercial centers, proximity to main roads and proposed land use in detailed project have the highest effect on changes of land use. And contrary to what might be imagined at first look, the more near a cell is to industrial use, the probability of urbanization is less. Therefore, in land use plans and urban development plans, the role of the above mentioned factors in creating land use changes should be given serious attention.