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.

The changing climate pressures the resilience of cities and nature all over the world, putting the position of historically valuable urban and natural environments at risk. The province of South-Holland has economically evolved around the unique triple delta landscape. In order to keep its economically competitive position and take environmental responsibility, the province aims to be circular by 2050. However, the province is facing a number of environmental challenges, such as salinization, soil subsidence and the risk of flooding, that are further aggravated by the intensification of land use and climate change. At the same time, however, the region faces an enormous housing demand. Therefore, this strategic vision was created with the aim to propose a way to answer the high demand for space in South-Holland while preserving the delta environment. Three themes were identified as key drivers to reach the use of adaptive delta water management, the transformation to sponge cities and a shift towards water circularity were identified as key drivers. Implementing interventions along these themes will preserve and redefine both the natural and the urban environment. This strategic vision provides the roadmap towards a circular delta environment in 2050. This vision involves the transformation of export-oriented agricultural land into wetland area, the densification and expansion of urban areas and a shift towards a biobased port. The strategic pathway towards 2050 starts by involving a wide range of stakeholders. Water boards were identified as a fundamental partner. Besides, local stakeholders, such as farmers and citizens, are empowered in order to secure social justice and to increase impact. The interventions are then being implemented in collaboration with these stakeholders. Pilot projects are the first step of implementation, after which the interventions are being implemented on a larger scale. The main interventions are: implementing wetlands and blue-green networks, implementing a separated water system and water retaining structures within urban areas, executing urban development projects and the development of a blue-green hydrogen network. Finally, these implemented interventions are connected to create a circular system. Based on this projects the main recommendations to foster the shift towards circular water flows are: the implementation of a separated water system as an aspect in the shift towards sponge cities, the implementation of large scale wetland areas that are connected to the water system and finally the implementation of water reuse technologies within the port, greenports and agriculture.