Towards sustainable settlement growth: a new multi-criteria assessment for implementing environmental targets into strategic urban planning

For nearly one decade, the German political and research-agenda has been to a large extent determined by the ongoing question of how to limit the expansion of settlement areas around cities in order to preserve natural resources, make settlement growth more sustainable and to strengthen the re-use of existing inner-urban areas (see a.o. Kötter et al. 2009a, 2010; Schetke et al. 2009, 2010b). What is already under discussion within the international literature are the recommendations of the German Council for Sustainability to quantitatively reduce the daily greenfield consumption from the current rate of over 100 ha per day to a rate of 30 ha per day in 2020 and to bring urban infill development up to a ratio of 3:1 with greenfield development (German Council for Sustainability, 2004).). This paper addresses the added value beyond those abstract political targets and presents an innovative, multi-criteria assessment (MCA) of greenfield and infill sites to evaluate their sustainability and resource efficiency. MCA development and its incorporation into a Decision Support System (DSS) were accomplished by utilising a stakeholder-driven approach. The resulting tool can be applied in preparing and revising land-use plans. The paper presents the concept and the development process of the MCA-DSS. Test runs with planners prove that the evaluation of potential housing sites using individually weighted environmental indicators helps to identify those strategies of housing development that accord most closely with sustainability goals. The tests further show that the development of greenfield sites generally exhibits less sustainability than that of infill sites.