Evaluation and spatial Measurement of urban environment with green city approach (Case Study: Tehran Metropolis)

Nowadays cities play a pivotal role in the destruction of the environment that cause human and natural environment is unstable ecosystem. Planning and urban management approach in Green city, as an essential part and comprehensive of urban strategies, based on the ecological management that with adjustment of environmental indicators of ecological sustainability and sustainable urban development. The purpose of this study was to evaluate the environmental situation in Tehran with green city approach. To identify the size of greener Tehran, compared with Asian cities. After identifying indicators of green city, using fuzzy network analysis models and VIKOR, calculated weight of each indicator, Tehran were prioritized among Asian cities. Then 22 areas in Tehran were ranking. The results showed that Tehran ranked fifteenth among Asian cities and the situation is relatively poor. Regions 8, 4 and 1 in the best and regions 10, 11 and 12 the worst environmental situation with green city approach. With both the rapid growth of the world’s urban population and increasing concern about the environment, the challenge of making urban living more sustainable is in the forefront of the minds of many designers, academics and government officials.
The 3E approach frames city development within the context of economy (The competitive city), equity (the inclusive city), and environment (the Green City). Each initiative sets out the key components for achieving such a city and supports the other, providing the basis for sustainable urban development.
There are many approaches of sustainability including Green city, Eco city and Livable city. Each approach is focusing on specific issues of sustainability. Green cities are defined as the cities striving to lessen their environmental impacts by reducing waste, expanding recycling, lowering emissions, increasing housing density while expanding open space, and encouraging the development of sustainable local businesses
Green City concept in the late twentieth century as one of the solutions to reduce urban environmental problems in cities to achieve sustainable urban development was common. Given that Tehran in critical air pollution, intense focus, rapid population growth and the increasing uncontrolled sources of pollution of the environment, study the status and recognition of the situation in Tehran based on indicators Green City can be a suitable approach for planning and achieving environmental sustainability, ecological and sustainable urban development in the future. The aim of this study was to assess the environmental status of Tehran is using Green City Index. The method used in this study has been designed and developed in two main steps. The first step is to determine and identify the emergence of Tehran, the status of which will be discussed among Asian cities. To this end, identify Green City Index, using fuzzy multi-criteria decision-making models assessed the effect (weight) of each of the index, attempted to prioritize and determine the position of Tehran were among Asian cities. In the second step, after the recognition of green in the city of Tehran, citing specific weights to each of the indices Green City in the first stage, using VIKOR ranking, attempted to rank and prioritize each of the 22 districts of Tehran has the importance of each of the areas identified in the current situation in Tehran. Today, cities play a pivotal role in environmental degradation that has led to an unstable ecosystem is human and natural environment. Planning and urban management approach in green city based on ecological management with the implementation of environmental indicators of ecological sustainability and sustainable urban development.
Results showed that the index weighting of energy and carbon dioxide weighing 0.1836, transportation, weighing 0.1585 and weighing 0.1494 air quality rating among the most important indicator.
Using VIKOR Technic and Fuzzy Analytical Network Process (FANP) for weighting in the index showed that in Tehran in selected Asian cities ranked fifteenth among the relatively unfavorable position is that this status. Tehran in negative factors such as the release of CO2 (8/7 tons / person), population density (12,411 people / km²) and water loss (percent) higher than the average, as well as positive measures such as energy share of GDP (3 / 4) and per capita green area (6/15 m), has access to sewerage, sewage treatment rate has been lower than average. Tehran in indices capita waste generation, water consumption and particulate matter are relatively well compared to the average Asian cities. Among the 22 districts of Tehran by Region 8, 4 and 1 in the highest areas 10, 11 and 12 in the lowest ranking of the environmental status of the green. In other words, Tehran eastern areas to central and western regions of the urban landscape better than green. In contrast, the central city areas due to population density, increased traffic, increased air pollution, carbon dioxide emissions are worse than in other parts of Tehran. Tehran is more in the modernization of large volumes of materials and energy on the one hand and on the other hand is out waste and scrap The major strategies to achieve and reach the green in Tehran, it is possible to reduce municipal solid waste, energy efficiency, conservation of urban ecosystems, the development of sustainable transport, air pollution control, sustainable urbanism and green building and plan for quality improvement environmental cited. We can move toward sustainability principles and practices and achieve green city in the use of public participation, public transport, green and efficient, energy saving, waste management, use of renewable energy, reconstruction of buildings and the use of efficient technologies, development of more pedestrian and cycling routes, local policy, and a council to protect the environment, environmental education of citizens (from primary schools to parents and citizens), a collaboration of institutions and organizations and develop and implement preventive laws outlined.