Improving the Allocation of Flood risk management interventions From a Spatial Quality Perspective

In this publication, the developed integrated method for including spatial quality as an ex-ante criterion in flood risk management strategy development is presented in detail and tested. Based on the results of the earlier research-by-design exercise, as described in the third publication, it is concluded that the key to making spatial quality an ex-ante criterion is to make sure sufficient interchangeable flood risk management interventions, with varying locations, are available, since having multiple effective measures from a flood risk perspective makes selection based on other criteria, such as spatial quality, possible. In this paper, the ways in which a range of interchangeable measures can be included by considering flood risk management interventions at different scale levels (varying from system scale to local scale interventions) and at different flood risk layers (including both flood risk reduction and consequence reduction measures) is described. As a base reference situation, the impact on spatial quality of the ‘business as usual’ flood risk management strategy for this region is assessed. Subsequently, the ways that the flood risk management interventions can be shifted away from the locations in which they have a negative effect on spatial quality, by considering alternatives with a better (preferably neutral or positive) impact on spatial quality is tested. This is done by systematically deploying interventions at different scale levels and safety layers, while assessing their impact on spatial quality. Based on this assessment, the combinations of measures that result in an optimal impact on spatial quality, can be selected for the regional flood risk management strategy. This case study research demonstrates that the developed method, compared to the business as usual reference strategy, allows for spatial quality to become an ex-ante criterion, resulting in the formulation of a flood risk management strategy with an improved impact on spatial quality. The approach includes the following steps: An inventory of the current and potential flood risk protection strategies An inventory of the spatial characteristics, ambition, and potentials of the region A qualitative assessment of the existing situation and (if available) of a reference flood risk management strategy Systematic research-by-design on how flood risk management interventions at different scales can shift the local flood risk management interventions (and a qualitative assessment of this shift) Systematic research-by-design on how interventions in different flood risk intervention layers can shift the flood risk intervention (and a qualitative assessment of this shift

The Synergy Between Flood Risk Reduction and Spatial Quality in Coastal Cities

This paper describes the application of a research-by-design approach that aims for a combined approach for spatial quality enhancementand flood risk reduction, with spatial quality as a decisive exante criterion. In order to achieve this, as in the ‘Room for the River’ programme, a dual flood risk and spatial quality objective is set. This research was performed as part of the ‘Atelier for Coastal Quality’, in which The Hague’s seaside area of ‘Scheveningen’ was selected as a case study location.Here, the future reinforcement of the sea barrier could be combined with addressing the challenges of improving spatial quality, among which are: identity, vitality, attractiveness, and connectivity. A research-by-design approach was deployed in which a single parameter was systematically varied (the flood risk intervention) while fixing other parameters (such as the context and the objectives from a spatial and flood risk perspective). After exploring and defining both the flood risk and spatial objectives for the area, three alternative flood risk reduction strategies (based on three alternative interventions: a boulevard, dunes, and a perpendicular dam) for Scheveningen were developed. In order to facilitate the integrated design process, ‘Delta Ateliers’, in which multidisciplinary experts and stakeholders interactively worked together, were successfully deployed. As a result, it became apparent that the inclusion of a prominent spatial objective is not the main key to including spatial quality as an ex-ante decisive criterion in defining flood risk strategies. The three proposed flood risk reduction interventions had all been successfully embedded with regard to meeting the prescribed spatial criteria, thereby disqualifying the spatial aspects as selection criteria for the flood risk intervention. However, as part of the study, a supporting research-by-design exercise was performed in which three different locations for the positioning of the perpendicular dam, were explored from a spatial perspective. Here, it seemed that providing interchangeable (similarly effective) interventions at different locations did result in very different potentials for spatial quality, thus allowing spatial quality to become a decisive selection criterion. The ‘Room for the River’ principle, which appeared essential in order to include spatial quality as a decisive ex-ante criterion, is the creation of alternative exchangeable options for the flood risk reduction interventions at different locations. Based on these findings, the research-by-design approach deployed is extended to not only systematically test different interventions, but to also systematically vary the location of the intervention. The ‘Delta Atelier’ multidisciplinary workshop approach is continued within the remaining research

Introduction

This thesis report is paper based, and as such contains a series of 7 journal and book chapter publications published as part of my PhD research. Each paper has its own problem statement, research question, theoretical framework, and methods section, which are not repeated in this introduction. Due to the paper-based setup of the dissertation, this introductory section is of a different nature than the traditional introduction found in many thesis books at the Faculty of Architecture. The goal of this introduction is not to give a comprehensive introduction to aspects of the research, but to explain the relation between the different publications, which are subsequently included as chapters

Conclusions

Is it possible to define an integrated method for strategic flood risk management and spatial quality enhancement, in which spatial quality is a decisive ex-ante criterion, and what would be the key elements and steps in such a method? This constitutes the primary research question. The publications that together form this dissertation describe such a method and thus provide a positive answer to the primary research question. A key principle in the approach is the inclusion of multiple interchangeable (effective) flood risk reduction interventions at varying locations, so that the criteria of spatial quality can become decisive in flood risk management strategy development. The ability to assess the impact of different interventions on spatial quality is essential. In order to do so, an assessment framework was developed; it combines the approach of a spatial quality criteria checklist with expert judgement. The checklist supports expert judgement in that it keeps a wide, open perspective while assessing the spatial quality of a conceptual intervention, and thus allows verifiable and reproducible assessments. The method developed employs research-by-design to systematically test different interventions at different locations. It includes the following steps: An inventory of current and potential flood risk protection strategies An inventory of a region’s spatial characteristics, challenges, and potentials A qualitative assessment of existing situations and a spatial impact assessment of reference flood risk strategies, if any exist Systematic research on how flood risk management interventions at different scales can shift the location of a flood risk intervention; this includes qualitative assessments of interventions at various locations Systematic research on how flood risk management interventions in different flood risk layers can shift the location of a flood risk assignment; this includes qualitative assessments of interventions at various locations Selection of a combination of interventions that are preferred from a spatial quality objectiv

The synergy between flood risk protection and spatial quality in coastal cities

Coastal regions throughout the world are subject to flood risk challenges. This paper concentrates on the Netherlands; its coastline fulfils an important role in the protection of the Dutch delta. Due to the expected sea level rise, part of the Dutch coastline will have to be reinforced. Along most of the sparsely occupied coastline, the space needed for the reinforcement of the flood risk protection infrastructure can be found easily, either on the seaside or inland. However, some segments of the coastline have been built upon and are difficult to reinforce; buildings have limited the adaptability of the originally flexible coast. One of these locations is Scheveningen, a borough of the city The Hague and a seaside mass-tourism resort operating on a national scale. It is difficult to reinforce the borough’s flood risk infrastructure without significant restructuring. In addition to water-safety issues, Scheveningen faces social-economic challenges and needs a qualitative programmatic and spatial impulse. An integrated approach to spatial and flood risk design is essential to come to a qualitatively as well as functionally acceptable solution for multifunctional flood defences. This paper describes and demonstrates the approach and application of an integral ‘research by design’ study for flood risk management and spatial quality in Scheveningen. It is the result of a collaborative effort between spatial designers and flood risk engineers, who worked together in so-called ‘Delta ateliers’. Three different flood risk strategies (‘a sandy shore’, ‘a hard protection body’ and ‘a perpendicular dam’) are used as leading principles for integral designs in which both the spatial assignment as well as the long term flood risk protection assignment are addressed. This results in three different designs that are discussed in relation to their spatial potential and hydraulic efficiency. This applied research by design approach was considered very valuable–even essential–to feed the debate regarding the choice of a flood risk intervention. As a result, this approach will be continued throughout the Dutch National ‘Delta Programme’ that focusses on long term flood risk protection

Spatial Quality as a decisive criterion in flood risk strategies:

The role of the designer in flood risk management strategy development is currently often restricted to the important but limited task of optimally embedding technical interventions, which are themselves derivatives of system level flood risk strategies that are developed at an earlier stage, in their local surroundings. During this thesis research, an integrated approach is developed in which spatial quality can already be included in the regional flood risk management strategy development, and thus can become a decisive ‘ex-ante’ aspect of flood risk management strategy development. The key principle to this approach is the inclusion of a range of interchangeable (effective) flood risk reduction interventions at varying locations, so that the criterion of spatial quality can become decisive in flood risk management strategy development. As part of the methodology development, an assessment framework is developed, allowing for the assessment of the impact of the different interventions on spatial quality; research-by-design is employed to systematically evaluate different interventions at different locations. The Rijnmond-Drechtsteden area in The Netherlands is used as a case study area for this research

Integrated Design for Flood Risk and Spatial Quality Enhancement: Examples from the Dutch Delta Programme

The assessment of the impact of a potential flood risk intervention on spatial quality at the local scale is an essential element in the research-by-design methodology developed in this thesis (and demonstrated in the previous chapters). Examples of how to explore this impact of the potential flood risk intervention on spatial quality at the local scale are shown in Chapters 5 and 6. In these research-by-design studies, applied to the Rijnmond and Alblasserwaard-Vijfheerenlanden case study areas, a conceptual representation of several business-as-usual flood risk management interventions is spatially projected on to a cross section of the location. It is mentioned in these chapters that design optimisation can mitigate the potential negative effect of a flood risk intervention on the local scale spatial quality (and thereby influence the assessment). In Chapter 6, some basic examples are shown, however, this topic is not elaborated further. The Scheveningen case described in Chapter 4 elaborately shows a design study in which three different flood risk management interventions are optimally embedded spatially. This study also shows an elaborate analysis of the spatial characteristics, challenges, and ambitions of the area. However, this approach is too elaborate and time consuming to apply as part the research-by-design method in which the impact on the local scale spatial quality of a wide range of potential flood risk management interventions is tested. This last publication shows an overview of some research-by-design studies, performed during this PhD research, that apply different approaches to test the impact of potential flood risk interventions on the local scale spatial quality. They vary from elaborate embedment studies (Scheveningen) to a more condensed research-by-design approach that could be included in the developed method (Sliedrecht & Houston). In the design studies, the following method is applied to a greater or lesser extent: Creation of an inventory of the spatial-economic ambitions and challenges of the location Creation of an overview of possible (and viable) technical options for dike reinforcements Performing a design study for the spatial implementation of each intervention Reflecting on the pros and cons of the applications The spatial ambition map developed for the Alblasserwaard-Vijfheerenlanden case study, which is included in this chapter, is a valuable example of how to inventory the spatial-economic ambitions and challenges of the location

Flood Risk and Spatial Quality

This book chapter describes the current practice with regard to combined approaches for flood risk management and spatial quality enhancement in the Netherlands. Currently, there is a requirement to extend the current flood risk system because of increased flood risk (caused by climate change and increased investments in the protected area) and new insights with regard to acceptable risks. Flood risk measures nowadays need to be implemented in a context in which local stakeholders emphasise aspects such as spatial quality and ecology. In this contemporary context, we see interesting developments with regard to combined approaches for flood risk protection, such as, for instance, the experimental flood proof building programme, the ‘building with nature’ concept (in which natural principles are employed for flood risk protection), the atelier for coastal quality (that as part of the Delta Programme developed integrated designs for coastal protection and quality) and the ‘Room for the River’ project (in which, as an alternative to dike reinforcement, the water load is reduced by creating extra space for the river to expand). For this research, the ‘Room for the River’ project is an important reference. Within the project, which aims to address more extreme river discharges, spatial quality is an important secondary objective. Next to the availability of extra budgets, a ‘Quality Team’ was established to supervise the inclusion of spatial quality objectives. The project addressed the growing resistance against the elevation of traditionallybuilt levees, by offering an alternative option of lowering the water levels by improving the flow capacity of the river (for example, by creating a bypass to widen the river). Within the development of the combined method for flood risk and spatial quality, different aspects have been inspired or based on the ‘Room for the River’ approach. Among such aspects are the dual flood risk and spatial quality objective, the principle of providing alternative options for flood risk management interventions, and the inclusion of a spatial quality assessment

Discussion & Recommendations

The proposed methodology creates opportunities for designers to actively participate in debates concerning the location, layer, and scale of flood risk management interventions, resulting in a more integrated design approach. The systematic approach and the strong connection to variables and data sets provides a framework that makes it easier to communicate designers’ propositions from a spatial point of view to engineers and facilitates interdisciplinary cooperation. The developed sub-method for evaluating interventions at different flood risk levels, to shift flood risk management interventions to the most suitable locations, offers a framework for developing a combined probability and consequence reduction strategy. This method can become a valuable tool for strategy development and decision making in so-called multi-layered flood risk management approaches, in which interventions regarding the probability and the consequential damage of a flood are combined. Multi-layered safety approaches have often been referred to in flood risk management debates in the Netherlands, but so far, consistent methods for achieving a balanced probability and consequence reduction strategy have not been put in place