Use of multi-objective optimization to assess trade-offs of urban expansion in Switzerland

One of the many unwanted side effects of urban growth is the loss of fertile soils since most citizens and villages have been founded in close proximity to fertile soils. Preserving high-quality soils however can conflict with the objective of developing compact urban patterns. A team from researches at the GIScience group, the ETH Zürich and the Michigan State University aims at identifying compromise solutions for municipalities in the canton of Zürich, Switzerland. In a recently published article the authors show that cooperation between municipalities to implement zoning regulations has the potential to lower trade-offs between the two objectives significantly. A multi-objective genetic algorithm has been used to identify Pareto-optimal land use patterns to fulfill anticipated demand for urban expansion in the municipalities. Results show a clear indication that cooperation between municipalities is beneficial from the perspective of the society. However, individual municipalities would have to accept a lower than anticipated growth rate that might call for financial compensation. Results show that cooperation between municipalities is useful at two different stages in the decision-making process. Firstly, municipalities should cooperate when they define their environmental and socio-economic development goals and rank their preferences concerning different goals. Secondly, municipalities should cooperate when deciding on how much agricultural land should be converted into urban land.

Schwaab, J., Deb, K., Goodman, E., Kool, S., Lautenbach, S., Ry, A., Strien, M.J. Van, Grêt-regamey, A., 2018. Using multi-objective optimization to secure fertile soils across municipalities. Appl. Geogr. 97, 75–84.