measuring urban sustainability: developing a conceptual framework for bridging the gap between theoretical levels and the operational levels

the issue of sustainable development has been widely acknowledged and spread rapidly after united nations conference on environment and development in rio in 1992. considerable attention is given to urban settlement areas. thus, role of urban development is seen as a challenging issue under circumstances. outcomes of the current patterns of world population growth and industrial development are agreed and reported as major causes of un-sustainability in long term. whereas by turn of century almost half of the world’s population is lived in urban areas; it is expected that this figure will reach to 8.1 billion -60.5% of world population- by year 2030. this is twofold; on the one hand cities are the places of the excessive use of energy and resources, of production of waste and pollution, of crimes and deprivations and socio-cultural un-stability, and so forth. however, some question will arise: is there a simple and universal model of sustainable urban form? how would decision makers be able to assess the rightness of their programs and actions in terms of sustainability of urban forms? and to what extent the concept of urban sustainability can be translated to some measurable elements? this paper therefore, aims to develop a conceptual framework within which the notion of urban sustainability - as a broad conceptual term - can be translated into some quantities which can be measured and evaluated with more assertion. through this model, characteristics of sustainable urban form, systematically are defined and translated into some indicators. it is hoped that this model can provide easement and clarification for researchers and decision-makers in their assessment of cities’ form and function towards achieving sustainability.