Integrating Functions for a Sustainable Urban System: A Review of Multifunctional Land Use and Circular Urban Metabolism

Multifunctional Land Use and Circular Urban Systems

By integrating functions, multiple ecological and socio-economical services can be provided simultaneously and synergies can be developed, which enables greater overall performance and more sustainable development. MLU is about integrating various land use functions in a determined area and time period. An example is green-blue infrastructures where functions as water safety, climate adaptation, green space, and community development are combined (e.g. Roof Park Rotterdam).

CUM is about creating local cycles of material and energy in order to decrease the environmental burden of existing urban areas. Examples are using household waste to produce heat to provide local district heating or supply biogas for cooking or transport (e.g. Hammarby Sjöstad, an urban area in Stockholm).

Challenges and strategies for MLU and CUM

This literature review shows that although MLU and CUM differ in what they integrate, they face partly similar integration challenges. In both fields, the collaboration between actors related to particular functions (water safety, recreation), high investment costs and uncertainties about costs and benefits, and legislation that hampers integration are identified as challenges. In both fields, strategies are proposed to facilitate the collaboration between actors. However, other challenges and strategies are specific. Whilst MLU scholars mostly highlight socio-economic aspects of realizing integration, CUM scholars focus more on technical aspects. We find limited cross-fertilization between both fields so far.

A process perspective to find further solutions

To stimulate discussion and knowledge exchange, we introduce ‘integration of urban functions’ as a shared idea for a sustainable urban system. To find further solutions for integration challenges, we propose conceptualizing MLU or CUM initiatives as processes of change, which requires connecting across previously separate ‘worlds’ and changing previously established monofunctional ways of working. We explore two perspectives that could be used to help deal with the identified integration challenges: focusing on how actors manage (social, cognitive, physical) boundaries in integrative processes, and analyzing integrating functions as a process of integrating multiple socio-technical systems (consisting of technical artifacts, organizations and institutional rules).