General lessons learned
General lessons learned from the Rotterdam and Dordrecht pilots are:
- Application of Building with Nature solutions in urban areas is perfectly possible, but requires special consideration regarding space availability, political processes and high public involvement compared to BwN interventions in regional areas.
- In comparison to traditional interventions special consideration is needed for: uncertainty of ecological development, understanding of the system and a mind shift in maintenance approach.
- A challenge in urban areas is that the available space is limited and scattered, while natural processes often need space to develop any succession or to reach higher levels of service (see also ‘Mallegatpark Rotterdam, coping with space limitations’ below). Understanding of the physical system and the participation/contribution of processes helps to design an intervention that will allow natural processes to develop an ecosystem within the borders set by the urban development. A larger size of the project area may be mimicked by connecting individual Building with Nature interventions (De Jong, 2015b) by creating ‘stepping stones’ of natural areas within the urban region.
- A design has to be adaptable: it must be possible to make small adjustments during the operational phase of the Building with Nature intervention to cope with the unavoidable uncertainties when building with living nature. For example, if the tidal bank system is eroding more than expected or sedimentation processes were underestimated, it should be possible to further close or open the inlet of the parallel dam that protects the foreshore. With a flexible Building with Nature solution one is able to build what is necessary at that moment, and adjust it as the understanding of the system develops or the impact of climate change grows.
- In an urban environment even more stakeholders can be involved than in a regional environment. This can be a drawback because of many conflicting interests and the often long-lasting procedures that follow. However, it is often a strength as well, providing a lot of innovative thinking and creating carrying capacity and awareness. In the three pilots it was found that having a variety of stakeholders also provides willingness for in kind or financial contributions. This really helped to make the projects feasible. In these stakeholder involvement processes it is of importance who you invite to the sessions. The input of people is also highly dependent of individual capacity to express their opinions, sometimes resulting in ‘coloured’ input due to one or two more dominant speakers.
- Good communication is important to give people a good idea of the potential of Building with Nature. Factsheets are created that present an outline of the Building with Nature interventions with costs, benefits, ecosystem services, spatial designing criteria, boundary conditions and a list with the most important current literature concerning the type of intervention. These factsheets can be used by policy makers, engineers, architects and researchers to provide them with ideas that can be used in their projects. All of the factsheets but one are available on the website www.buildingwithnatureinthecity.com. They can be found in Chapter 2 Applications in the picture by selecting a building with nature application and then scroll to the bottom. Further publication of the factsheets is De Jong, B. et al. (2015a) and De Jong, B. et al. (2015b).
A more in-depth exploration of the lessons learned in the pilot project in Dordrecht is described in the evaluation report of Van der Meulen and Hommes (2016).
Mallegatpark, Rotterdam: coping with space limitations
Due to space limitations, the tidal prism (volume water that flows in and out of the system during each tidal cycle) in the Mallegatpark is too small to establish enough tidal dynamics. For a well-functioning tidal ecosystem, a large tidal prism is needed. Therefore, instead of an opening downstream and a closure on the upstream side by the dam, the designed solution had a partly open upstream side as well. This design allows the river to flow through the foreshore area artificially enlarging the tidal dynamics.