Water Resilience Operative Key Concepts for Climate-resilient Urban Waterfronts

Introduction

The huge impacts provoked by the interaction between climate changes, ecosystem fragility and unplanned urbanization have recently stood out as one of the most relevant topics in the current European (and global) discourse. Higher temperatures, sea-level rise, intense rainfalls, and more frequent floods are constantly challenging our cities, not only representing a threat to human lives but also being a serious economic, social and urban issue 1 2 3. In particular, waterfront areas have been strongly affected by this phenomenon, being constantly forced to cope with an always higher number of water-related disasters, stronger, year after year, for magnitude and frequency 4 5. At the same time, though, the copious and profitable economic opportunities tightly related to the water activities (industrial production, commercial, leisure, logistics, etc…) have also put these areas under the pressure of persistent population growth and, consequentially, urban expansion even in flood-prone areas. Hence, this intrinsic contradiction has now led waterfronts to a severe state of vulnerability, risking compromising almost in an irreversible way their traditional crucial role.

However, despite this condition, an analysis on the development of waterfront contexts in the past decades has revealed how the latter, and specifically urban ones, have always been an evolving context, morphologically but also economically, culturally and urban wise. From fundamental infrastructures to exchange hubs, from productive sites to residential and recreative areas, urban waterfronts present an intrinsic capability of rearranging and shaping their character according to the necessity/opportunities arose time after time within the related cities 6. For this reason, they have been identified as a suitable field for exploring and researching innovative and adaptive design strategies to cope with the always more unpredictable consequences of climate change and global socio-economic transformations.

In this perspective, the research focuses on the unsolved ongoing conflict between flood protection and urban planning in urban waterfronts, reflecting on the possibilities that a more integrated approach between architectural and urban solutions on one side and safety necessities on the other might bring along. In particular, the aim is to investigate which implications responsive and adaptive design principles might have, not only in the physical definition of the space, but also in the urban, social and cultural perception of it; the underlying idea is, indeed, to transform protective measures into an opportunity to increase the quality of the social and urban environment, retrieving and enhancing the traditional relationship between water and urban settlements rather than impeding it.

To achieve that, though, different theoretical fundamentals need to be established.

Water resilience: theoretical background and operative design key concepts

The concept of “resilience” is nowadays widely used in the urban field, although it actually originates from the ecological environment. In one of his most famous papers, the ecologist Crawford Stanley Holling explains the difference between two possible properties of a system: “stability” and “resilience”. “Stability” is defined as “the ability of a system to return to an equilibrium state after a temporary disturbance” (7, p. 17); on the other hand, “resilience” is described as “the measure of the ability of these systems to absorb changes of state variables, driving variables, and parameters, and still persist” (7, p. 17). Bringing these definitions into a more “urban” framework, it could be argued that the main measures currently applied to face natural disasters in waterfront areas (dikes, floodwalls, dams, …) are conceived in order to guarantee the “stability” condition, where water is prevented, with all the means, from coming in contact with the built and human environment. However, the increase of magnitude and frequency of water-related hazards has revealed the current (economic, urban and environmental) un-sustainability of these models and all their intrinsic limits.

For this reason, the research aims to elaborate alternative design pathways, which are rather established on the more complex concept of “resilience”. Yet, how can the latter be related to the waterfront areas and how can we “build up” this condition? The starting point to answer this question is to deeply rethink the relationship between water and urbanisation, replacing the common idea of living separated from the water with the idea of living with the water. Long-term previsions show that, in the coming decades, more and more space will be needed around waterfront areas in order to protect them from water-related disasters. Therefore, only accepting a certain (inevitable) degree of flooding already into the design phase will enable to create a resilient system, able not only to effectively respond to water-related disasters, but also to trigger a wider urban regeneration process.

As a first step in order to achieve this purpose, the research has identified three different operative key concepts, which will represent the essential basis for the accomplishment of the desired design methodology. These concepts, which are deeply intertwined and whose implications strongly affect and are affected by the achievement of the others, can be summarized as following:

• redefining the concept of waterfront as an “active border”. Urban waterfronts cannot be considered anymore as a “boundary” 8, a mono-dimensional and fixed separation between water and land, neither can they become an irrational and uncontrolled space of urbanization processes. On the contrary, they need to be read as a “border” 8, a “thick” edge that has its own identity and acts as a fluid and responsive interface between built and natural, solid and liquid, permanent and temporary. Indeed, rediscovering the concept of “Third Landscape” of Gilles Clément 9, it is exactly in the “undefined” spaces and in their natural tendency to welcome diversity and accept changes that it is possible to realise the maximal potential of adaptability. Hence, instead of “black-or-white” areas (dry-wet, built-unbuilt, natural-urban), the challenge of the design process would be to create a more dynamic, hybrid areas, capable of adapting their nature according to the variable external conditions. In this way, the border becomes “active” and, through a sequence of both architectural, landscape and urban episodes able to both accommodate and react with water, it can actually lead to the creation of a “buffer space” which will be able to actually absorb disturbances and still represent a social and urban opportunity for the city.
• integrating the “temporal component” as fundamental part of the design process. When considering urban waterfronts as ecosystems 10, the traditional anthropocentric attitude which tries to constrain a dynamic reality into a pre-ordinated and fixed scheme appears more and more inapplicable. As waterfront areas are intrinsically evolving contexts, the design research needs to be focused on architectural and urban expressions which can accommodate different temporal pashes and be consistent with additive, transformative and adaptive logics as a response to always-changing external perturbations. In these terms, the assumption “once built, always built” is critically exanimated in favour of a more dynamic interplay between water and urban context over the time, where the alternance between absence/presence of water or the continuous variation of water levels altimetry can become a tool to dynamically shape the space during different moments of the day, month, year or long term periods, creating multiple and changing urban and architectural scenarios and enhancing, as a result, also the identity and the urban quality of a place.
• including landscape and urban mapping and drawing an essential design support. Mapping is indeed seen as a fundamental resource to understand economic, urban and morphological transformations concerning waterfront areas; however, it cannot be considered as a neutral representation of a subject, but as a design process itself 11, capable of proposing innovative contents and shape reality according to established objectives 12. In particular, it becomes an operative tool to combine objective interpretation levels (such as land uses, variation of water levels altimetry, climate change hazards and impacts, population, …) with design key concepts and assumptions (such as future uses, expectations/needs, temporal design phases, etc..) in order to bring to light the inner relations and the intrinsic potentials lying among the different components acting within the waterfront system and define, in this way, possible resilient design pathways.

Case studies

The potentials of these design assumptions have already been investigated in some countries, either as part of national programmes, urban visions or realised projects.

Regarding the concept of “active border”, an interesting interpretation can be found in the guidelines identified by the Rotterdam Climate Adaptation Strategy 13, a framework developed by the Dutch city to ensure its adaptation to climate change in the coming decades. Here, a great attention is paid to the exploration of the possibilities that waterfront areas can have to define the transition between water and urbanization. In particular, water is seen not exclusively as a threat, but also as the fundamental component of the designs: the flood-risk issue is tackled through the design of an (integrated) urban multiscale system of open stepped quays, “floodable” parks and floating structures which creates a protective border that will help to withstand the water pressure in case of raising levels and, at the same time, enable the city to safely and harmoniously experience and live with the dynamics of the delta.

A similar logic, despite the substantial geographical, scalar, morphological and cultural differences, lies in a landscape project designed by the Chinese landscape firm Turenscape, the Yanweizhou Park, a restoration intervention of a local wetland located in the heart of Jinhua (Chiana). In this case, the design strategy chosen to address the severe threats posed by the annual flooding of the scope area deeply reformulates the traditional idea of protection: instead of strengthening the existing hard boundary between land and water through the reinforcement of concrete walls, the proposal of the Chinese architects focuses on the idea of totally dissolving this edge into a system of floodable vegetated terraces, which not only slow eventual flooding down or absorb excessive stormwater, but also create a new, engaging transitional landscape, where iconic suspended bridges, floodable pedestrian paths, pavilions and gardens finally connect, instead of dividing, local people with the nature within the city.

Lastly, regarding the several possibilities according to which the “active border” paradigm can be articulated, it is worth to mention the The BIG U proposal developed by an international and multidisciplinary team led by the Danish firm BIG (Bjarke Ingels Group) for the enhancement and strengthen of the low-lying area of Lower Manhattan in New York 14. Despite the clear intention of ensuring an adequate protection against coming threats such floods and storms, the main target of the proposal is “not (to) separate the community from the (Manhattan’s) waterfront. Rather, the very structures that protect us from the elements will become attractive centres of social and recreational activity that enhance the city and lay a positive groundwork for its future.” (14, p. 9). In the proposal, indeed, the waterfront is considered neither as an entirely built context nor a completely natural system, but it is envisioned as an adaptive transition (active border) which, variously shaped as undulated berms, rain gardens, stormwater buffers, street furniture, pavilions, deployable walls and landform buildings, can work as green infrastructure, create job opportunities, satisfy the neighbourhoods’ necessity of facilities and recreational areas, improve the social security or even represent a vehicle for cultural expression and integration [ 1 ].

In all the describes strategies, though, the achievement of this dynamic transition between water and built-up is deeply linked to the inclusion of the “temporal component” into the design process. This same principle can be effectively analysed, on a smaller scale, in the Dutch example of the “water squares” and, in particular, the Benthemplein project in Rotterdam 15. The idea of creating big urban reservoirs in order to store excess of stormwater has been already tested in different international contexts, such as Sao Paulo, where several “piscinões” (“swimming pools”) have been built in order to mitigate the impacts of severe rainfalls. However, the peculiarity of the Dutch project is the great emphasis given to the idea of converting a necessity (stormwater protection) into a benefit for the urban environment. This target was achieved exactly through the inclusion already into the design phase of the possibility of an evolving perception and space usage of the area over the time. Indeed, this square is shaped in three lowered basins [ 2 ] which perfectly work as sport and theatre area (with zones dedicated for skaters, dancers, football, volleyball and basketball) but, in case of extreme weather conditions, they can easily rearrange into capacious water storages, reducing stormwater pressure and preventing local drainage system from collapsing.

Lastly, it is worth noting how in all the above-mentioned initiatives urban and landscape mapping played a fundamental role in the development of adaptive and resilient design solutions. In The BIG U, several indicators (such as expected surge levels, land use, ethnicity, income, open spaces, social infrastructures, …) were overlapped in order to assess vulnerability and, at the same time, to research possible design pathways which could combine safety needs with residents’ desire for an improved public realm [ 3 ]. Similarly, in the Yanweizhou Park project, mapping was an essential support to combine into systemic vision traditional (and often static) urban features with the extremely fragile and dynamic ecological environment of the Yanweizhou wetland. Finally, in both the “waters quare” projects and the Rotterdam Climate Adaptation Strategy the representation of criticalities became a fundamental tool to research when and at what water level adaptive measures needed to be developed, to investigate possible interventions and finally to evaluate and eventually implement the proposed design principles.

Conclusions

As analysed in the previous paragraphs, the consequences of climate change combined with recent the socio-economic transformations concerning urban waterfronts have arisen new challenges that traditional measures seem to be unable to effectively address. The unpredictability of water-related disasters and the speed with which these phenomena are increasing in magnitude and frequency have led to the necessity to design resilient systems, capable not only to avoid, but also to absorb eventual disturbances and still recover. In order to achieve this condition, though, the paper has identified some key concepts which need to lead the design process, becoming both its theoretical and practical ground: active border, temporal component and urban and landscape mapping. As the analysis of the case studies has demonstrated, indeed, the combination of the proposed key concepts reveals to be a fundamental prerequisite in order to achieve in operative terms that adaptive and responsive condition in waterfront areas that is essential for a resilient behaviour in case of extreme situations. Moreover, in this way, not only is safety accomplished, but also urban waterfronts become, again, attractive areas and a space where to create social, cultural and economic opportunities for the cities.

Therefore, through a further analysis of “best-practice” case-studies (such as the Dutch environment) and the comparison with other contexts which have been recently experiencing the severe consequences of climate change but whose water management and design appears to be still behind if compared to other international experiences (such as in the Mediterranean basin, and in particular the Adriatic and Ionian area), the following step of the research will be the translation of these key concepts into operative architectural and urban design principles and strategies, in order to build a design methodology that can also become a reference for other countries which are still trying to define more suitable resilient means for the development and the protection of their own urban waterfronts.