Building with Nature as integrated design of infrastructures

Many people associate Building with Nature with its flagship project, the Sand Motor. This mega-nourishment redefined the role of natural processes in civil engineering projects, demonstrating that instead of ‘do no harm’ as the highest possible supporting goal of coastal infrastructure, the design could incorporate natural processes to attain societal and ecological goals. As such, the Sand Motor represents a key example of the integrated design of civil infrastructures. In this contribution, we pursue an improved understanding of the integrated design of civil infrastructures, by comparing the illustrative example of the Sand Motor against a framework based on transport infrastructures and the occasional flood defence. It turns out that application of a framework from one domain to another - a conscious act of interdisciplinary learning - results in a modification of that framework. Although the domain of Building with Nature fits well with many existing attributes of integrated design for civil infrastructures (the life cycle approach, adaptive design and adding functionalities), its key attribute (dynamics) adds a unique box to the integrality index. This intellectual effort raises two issues. It demonstrates that our understanding of integrated design is rather specific for different infrastructure-domains. Second, it is likely that the bandwidth of uncertainty that is key to the incorporation of natural processes in infrastructure design, and the changing behaviour of the structure itself in the maintenance phase, has implications for the governance regime of such infrastructures.


Introduction
Despite ubiquitous calls for interdisciplinary research, the conscious, strategic pursuit of such learning is often an exception to the rule (INTREPID, 2019). Multidisciplinary research packages remain the trend, and measures to integrate learning throughout the research process are established 'on the go' (DIMI, forthcoming). While on the one hand, multidisciplinary research is often sold as far more ambitious than interdisciplinary research, we suspect it is quite common that many scholars pursue interdisciplinary learning unknowingly. Scholars can also make interdisciplinary cognitive connections on an intrapersonal level (Pfirman & Martin, 2017). Interpersonal, collegial connections in team-collaboration within a university department are also systemic, especially among disciplines that are closely related to one another such as urban planning and urban design. Such curiosity-driven interactions occur daily and are likely the engine behind the creation of new academic disciplines (Lyall, 2008;Gibbons et al., 2010), although, as a rule of thumb, integrative learning is not done explicitly (Tress et al., 2005). It is possible that interdepartmental, cross-field connections on topics that sit at the intersection of multiple disciplines may be the most challenging type and this is where awareness about the methodology of interdisciplinary learning could facilitate integrative learning. This is especially the case when such problem-oriented research engages multiple stakeholders outside of academia, and a full inter-and transdisciplinary research project develops (Pfirman & Martin, 2017;Rhoten & Pfirman 2007;Tress et al., 2005). This chapter therefore aims to explicitly pursue interdisciplinary thinking, with a twofold aim.
1. First, we ask how the application of an integrated design methodology from the domain of civil infrastructure to the concept of building with nature changes the understanding of integrated design.

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Second, by consciously selecting the why and how of an interdisciplinary learning strategy, we reflect on the presumed benefits of such integrative reasoning.
The chapter is structured as follows. In the first section, we outline key notions of interdisciplinary research and its presumed contribution to learning. Second, we explain integrated design methodology as derived from the topic of transportation infrastructures and the occasional flood defence. In the third section, building with nature's flagship example of the Sand Motor will be contrasted with features of different forms of integrated design in the civil infrastructure domain. How does the Sand Motor fit into our current understanding of integrated design of civil infrastructures and should that understanding be adapted? After a discussion of results, we conclude with the implications of this study, including a reflection on interdisciplinary learning.

Interdisciplinarity as a means for research
Interdisciplinary research -which we define as the act of interdependent learning strategies of different academic disciplines -is considered as the key vehicle to pursue knowledge and contributes to the solution of complex (socio-scientific) problems, where one discipline on its own cannot provide an answer (Lyall, 2008). Despite the increase in availability of scientific knowledge, decisive action regarding persistent, complex problems including climate change, biodiversity loss and related issues such as poverty, security and governance has been very slow (Hirsh Hadorn et al., 2008). While transdisciplinary research -learning that involves stakeholders -is considered as a means to overcome the mismatch between knowledge production in academia and knowledge requests for solving societal problems (Hoffman-Riem et al., 2008), interdisciplinary learning targets the knowledge fragmentation that undermines the capacity of society to address its complex problems.
The promise of interdisciplinary research is therefore in delivering what has been called 'systems knowledge' (ProClim, 1997;COST, 2014). However, despite the urgent call for interdisciplinary learning, the organisational barriers for such work within the university's structures are large (Pfirman & Martin, 2017), the rate of progress has been slow (National Academy of Sciences et al., 2005;Krull, 2000) and confusion about the state of the art abounds (Tress et al., 2005), resulting in the term being used as window-dressing for what, in fact, is multidisciplinary research (COST, 2019). Lyall (2008) identified at least seven motivations to pursue interdisciplinary learning, as summed up below: Table 1. Examples of motivations for undertaking interdisciplinary, policy-or practice-oriented research according to Lyall (2008) 1 The nature of the object of research is interdisciplinary (e.g. transport, environment) 2 Researchers are engaged in transferring knowledge from the laboratory to real world applications 3 The research seeks to break down barriers between science and society and encourage social acceptance of technology 4 The research is 'user-driven': either encouraging innovation by connecting technology-based businesses to market demand or involving a practice community, although not necessarily commercially oriented 5 the research may be particularly relevant to policy: many strategic issues can only be effectively addressed by interdisciplinary approaches 6 single discipline research may have encountered a bottle-neck and more than one discipline may be needed to make a breakthrough 7 or, in academically-oriented (mode 1) interdisciplinary research, for more intellectual reasons in order to promote the emergence of new disciplines and modes of thinking.
To summarize, interdisciplinarity can therefore be a means of research in four main cases: for (1) particular objects or domains, (2) knowledge transfer to real-life applications, (3) is user-or stakeholder-driven (transdisciplinary) work or (4) for overcoming academic obstacles.
The objective of this paper fits with the first and the last of these cases. First, the Sand Motor can be considered as an interdisciplinary research object, that can be addressed by a multitude of disciplines like coastal engineering, ecology, landscape architecture and civil infrastructure design. Second, our goal to consider Building with Nature from the perspective of civil infrastructure design purely for the sake of intellectual reasoning -a better understanding of integrated design of civil infrastructures -is purely academically-oriented. Having clarified why the objective of this chapter is interdisciplinary, we can consciously select a learning strategy, again following Lyall (2008).

Integrated design of civil infrastructures
In the larger domain of integrated design, many different understandings of the concept exist (Hertogh et al., 2018;Visser, 2020). In this contribution, we depart from examples of integrated design that were studied in our section -Integrated Design and Management -and were published in a previous publication (Hertogh et al., 2018). It is key to note that all of these case-studies are civil infrastructures, and that our perspective is likely influ-   Our working hypothesis is that different understandings of integrated design from the narrow domain of civil infrastructures can be explained, first, from paradigm shifts in design management: most notably the shift from a deterministic perspective to a complexity perspective (Hertogh & Westerveld, 2010). This paradigm shift puts more emphasis on interrelatedness of design variables, openness, and an acknowledgement that reality is knowable and controllable by a reductionist approach to problem-solving. A second factor that likely determines the differences between notions of integrated design is the design problem that they aim to tackle. Do note that with the exception of the three-layer model, all forms target large-scale (public) transportation or flood defences as examples of civil infrastructures. The three-layer model is applied in spatial decision-making processes, where the competition for space between different land uses is mitigated (ESPON, 2015). Rather than delivering a design itself, the layer-model is used to guide policy that informs the design of future infrastructures and land-use development. Third, it is key to note here that the three-layer model originates from the discipline of landscape architecture (De Hoog et al.,1998), and multifunctional design (of flood defences) is a hybrid between hydraulic engineering and spatial design (Voorendt, 2017). Interdisciplinary synthesis of knowledge in this domain has thus previously resulted in a different understanding of the integrated design of civil infrastructures.  Sophia Rail-tunnel, for example, was deliberately oversized because of its location in two layers with the lowest pace of transformation in the three-layer model: the substratum and networks (Stive, 1999). Acknowledging the higher speed of change in the highest-tier layer (occupation) and the relative inertia of the second layer (networks), the tunnel was designed with a larger diameter. This will accommodate stacked transport if the demand arises in the future. The Sand Motor, when compared with the Sophia-tunnel example, is part of the substratum-layer but was not over-dimensioned to accommodate future changes in the first occupation-layer. Moreover, the design-life of the Sand Motor is a mere twenty years, which is shorter than the speed associated with the third, subsurface layer. Fourth, the Sand Motor does match the type of integrality that we associate with the life-cycle model and the example of Design-Build-Finance-Maintain (DBfM) contracts used in the construction industry. The key issue of DBM is that they incentivize contractors to pursue designs that are costlier to build, but cheaper to maintain. This is also key for the Sand Motor, which acknowledges the maintenance-phase explicitly.

The Sand Motor and the integrality index
The project is oversized compared to the traditional coastal nourishment projects (that occur more often), dispersing the sediment along a larger stretch of coastline using the natural forces of tide, waves and wind. Nourishment therefore has to occur less often. It should be noted however that the Sand Motor's design is not so much driven by the optimisation of maintenance

Results
From  Overall, we can conclude that Building with Nature, when viewed as a particular form of integrated design of infrastructures with the Sand Motor as an example project, it fits particularly well with the lifecycle approach, adaptive design and adding functionalities. However, we argue that Building with Nature deserves to add its own box to the integrality-index (rather than being seen as a subcategory of multifunctional design) due to its unique attribute, dynamics. Obviously, the dynamics of natural forces represents a different form of functionality than precisely engineered co-functions. When reflecting on the presumed benefit of the interdisciplinary learning strategy followed above, this outcome is not surprising. The purpose of applying an existing framework to a new domain is to evaluate it, and in this case, is adds to the scope of a framework that was initially created for infrastructure in the form of hard engineering measures. The upcoming domain of Building with Nature in the flood safety sector is different in this sense. We expect that the bandwidth of uncertainty that is associated with the incorporation of natural processes in the design of civil infrastructures, and the changing behaviour of the structure itself in the maintenance phase, have implications for the governance of such infrastructures.

Implications
Completion of the construction-phase is the default moment when hard infrastructure is assessed against predetermined and rather strict design requirements. After that, the structure is expected to demonstrate limited change, which can be compensated for by a detailed maintenance regime.
Such a span of control seems unlikely for Building with Nature projects. In particular, Building with Nature projects require commissioners of civil infrastructures to acknowledge and perhaps embrace adaptivity in their policy (including legislation and financial agreements), another nudge in the paradigm shift in design management from a deterministic to a complexity perspective. To conclude, it should be noted that such modes of thinking may become more natural to certain academic disciplines.
This may be related to the object of study from which the particular discipline has originated. Landscape architecture, in particular, has traditionally worked with large spatial scales, natural processes and longer planning horizons -all attributes that belong to the landscape as the main object of study.
A merging of landscape and infrastructure design efforts could therefore be a promising means to successfully organize Building with Nature projects.
We can then again expect a redefinition for infrastructure and an expanded scope for its understanding -as Nijhuis and Jauslin already argued in 2015, less utilitarian, but as armatures for the facilitation of functional, social and ecological interaction.