Valuing Vertical Green

Abstract

The rapid development of Dutch DC’s near airports pressures the environment. VGS are considered a promising measure toward a more nature-inclusive development of Dutch distribution centers. However, an integral quantitative impact assessment model is needed to retrieve funding and facilitate an evidence-based decision-making process for the implementation of VGS. This research therefore aims to develop a multi-criteria decision model to assess the impact of VGS in Dutch DC’s near airports to enhance the decision-making process for the implementation of VGS. The main research question was formulated as follows: ‘How can a MCDM tool on the quantitative performance of VGS in delivering ecosystem services be developed and applied, in order to facilitate the impact assessment and evidence-based decision-making in the context of Dutch DC’s near airports?’
The research question was answered through a mixed-methods approach including literature research and expert interviews. A case study was used to apply and validate the MCDM model. VGS were found to offer a range of supporting, regulating, provisioning and cultural ecosystem services. The performance of VGS in delivering these services was mainly determined by the plants, substrate and support system. In general, living walls have a higher performance than green façades, among which modular living walls perform best. However, context-specific valuation was considered key. Evaluating VGS on the interaction effects between the main system components and the ecosystem services is an effective approach for developing a MCDM model that enhances decision-making and creates support base for implementation. A context-specific impact assessment can be achieved by weighing the relevance of the ecosystem services. Further research that compares the impact of distinct types of VGS is needed to further develop and validate the model, specifically with regard to grey water treatment, education, and wellbeing.