New tools to increase land recycling – Regional portfolio management



When it comes to curbing urban sprawl, curtailing demand (e.g. by increasing acceptance of dense structures, settlement-oriented locations that do not require further outer development, and by economic means) and improving land recycling processes are promising approaches. Especially the latter promises short- and medium-term success, both because the potential of the reusable areas is considerable and because reusing abandoned areas interferes much less with the fundamental trends of urban development than curtailing space demand entirely would. Such short- and medium-term procedures are also vital because the demand for space will increase significantly in the next 10 to 15 years for demographic reasons (rising number of households and growing living areas).

Aims of the project:

The project ran from September 2007 to February 2010 and aimed to develop the empirical and methodological foundations for municipal or regional portfolio management. In order to do so, we studied building zones in the example region Bonn/Rhine-Sieg/Ahrweiler, especially abandoned areas. The procedure was adapted to the existing administrative structures and political decision-making structures relevant to the planning process.

Contents and structure of the project:

Initially, the interdependencies of land use were analysed and the costs and benefits were quantified (monetarisation) as far as possible using a representative portfolio of potential areas (e.g. arable land on the outskirts of town, recycling areas) and by classifying these areas. The following aspects were considered:

  • The value of the building area to the users
  • Effort/costs required to recycle the area
  • Efforts/costs required for the outer development
  • Efforts/costs required to develop the social infrastructure
  • Positive or negative impact on the surrounding area
  • Damages to the landscape and the environment

Based – among others tools – on the GIS solutions already in use, we then developed an EDP tool to condense these different effects into an impact balance sheet, initially for individual areas, then for a model portfolio and finally for all potential building areas in the region. This made it possible to compare the welfare-economic effects of different regional development or spatial scenarios (e.g. priority inner development). The overall objective of this was to improve the discussion and decision-making basis regarding the control over local and regional settlement and open space development. In addition, this also created the basic structure required to monitor and evaluate the ongoing settlement development.


The project was part of the REFINA program of the Federal Ministry of Education and Research (BMBF).

Project duration:

September 2007 – February 2010

Project partners:

Institute of Urban and Transport Planning (ISB), RWTH Aachen University
empirica Qualitative Marktforschung, Stadt- und Strukturforschung GmbH

gaiac Research Insitute for Ecosystem Analysis and Assessment e.V., RWTH Aachen University

Practice partners:

Regionaler Arbeitskreis Entwicklung, Planung und Verkehr Rhein-Sieg/Ahrweiler (rak)

Contact at the ISB:

Prof. Dr.-Ing. Dirk Vallée

Dipl.-Ing. Anke Ruckes

Claudia Gilles (M.A.)