Study On Evaluation Method Of Eco-city Based On Emergy And Ecological Footprint Model

This article had a study on evaluation of eco-city based on Emergy and Ecological Footprint model, aiming to grasp the status and future trends of urban ecological construction accurately, explore the undesirable conditions in the changing process and do a warning, thereby ensure the well ecology and provide scientific basis of social-economic-environmental sustainable development of city. The main works are following:First of all, this paper reviewed the status of construction and evaluation of domestic and international eco-city and analyzed the emphasis and difficulty, also the advantages and disadvantages of evaluation. Then different types of methods were compared to explore a way which can reflect the ecological situation of city truly.Secondly, this paper analyzed and generalized the traditional Ecological Footprint model in order to find the advantages and disadvantages of model in quantitative evaluation of eco-city. The traditional model has a few defects, such us based on static and closed system assumptions, ignore the differences between the orientation of regional function, based on space mutual exclusion hypothesis, and underestimate the role of human initiative. In order to overcome these flaws, this article used Emergy theory to modify the traditional model and formed the calculation method based on Emergy and Ecological Footprint model.The improved model considered lots of factors, such as the open of urban ecosystem, the initiative and destructive role of people, input and output of material and so on. In the calculation of ecological carrying capacity, the article proposed and quantitative calculated the artificial ecological carrying capacity and ecological carrying capacity of virtual product supply based on the natural ecological carrying capacity and the ecological carrying capacity of product output, which could reflect a real status of the ecological carrying capacity and study the functional orientation differences and comparative advantages between different regions. In the calculation of ecological footprint, the ecological footprint of waste discharge which was also included in the evaluation system made the result of ecological footprint more comprehensive. Then the article took the statistics of Tianjin, Shanghai, Chongqing in 2007 as cases to calculate and analyze the three cities'ecological footprint, on this basis, we tested the improved model. The results showed that the improved model could overcome some shortcomings of the traditional Ecological Footprint to some extent, and reflected the cities'sustainable development objectively.Finally, the Emergy and Ecological Footprint model was applied to assess the eco-city construction results of Tianjin in 2001-2008. This article made a dynamic analysis from bio-products, energy and other accounts, and a series of evaluation index, such as ecological footprint diversity index, on Tianjin's ecological carrying capacity and ecological footprint and achieved satisfying results.