21.10.2024

Storm surge protection in an age of uncertainty

How can we plan our coastal cities and landscapes for an unknown future? And why is a nature-led approach pivotal to encompass the complex realities of a changing climate and finding a new balance between cities, humans, landscapes, and water?

We asked SLA project architect and water change expert, PhD. Kristine Holten-Andersen five questions to find out:

Why is storm surge protection one of the most pressing challenges today?

“Our societies are right now facing a ‘Blue Transition’ that will transform how we plan and build: Our landscapes are shaped by water. Our cities are embedded in complex waterscapes. And our infrastructures depend on vast technical and natural water facilities. All these systems will be hugely affected by climate change.

What happens with those systems when precipitation increases, water levels rise, and the frontier between land and ocean shifts? This calls for a transformative change of all landscape practices I can think of. Hence, we are facing a Blue Transition – regardless of whether and how we choose to face it.”

What will the Blue Transition mean for the way we work with coastal landscapes today?

“For centuries, we have strived to control, tame, and disregard our waters when planning our land and building our cities. That approach is outdated. Instead, we must begin to consider water and its processes as the very first thing in our planning and design approaches.

We must also fundamentally change the way we think about water. We must move from thinking of water ‘elements’ as stable and predictable entities to acknowledging water ‘networks’ as dynamic and hugely complex bodies and balances that are fluid, fluctuating, and ever-present. When it comes to mapping our landscapes, we should not ask whether an area is ‘wet or dry?’ but rather ask ‘how wet?’”

What does this mean for the way we approach storm surge protection?

“We have to challenge our habitual ways of working. In our recent work on the comprehensive Storm Surge Study for the Copenhagen Metropolitan Region with Sund&Bælt and Rambøll, we quickly realized that we could not do a traditional feasibility study.

Normally, in preliminary investigations of large infrastructure projects you work with a fixed design object. The task is to place that object in a given landscape and calculate the costs and the effects on the existing environment.

But in this case, the design object was not familiar or given – since storm surge protection can take on a thousand different designs. Furthermore, the existing coast would also face tremendous and unforeseeable change over the coming years due to changing waterscapes. So how do you plan a storm surge defense in those circumstances?

In the Copenhagen Storm Surge Study, we started with each individual locality and its processes of change, starting with a comprehensive analysis of the entire 62-kilometer coastline, mapping its values, characteristics, conditions, and potentials. With that, we formulated a ‘first draft’ of storm surge defenses for each locality that not only seeks to minimize its negative impacts on the existing environment but also aims to promote better conditions for all life – both social, biological, and cultural.”

In the Storm Surge Study for the Copenhagen Metropolitan Region we investigated how different water level scenarios would affect the flooding of Copenhagen.

What kind of innovation did this task require?

Fundamentally, there is no way of knowing how the future climate will be or what the ocean water levels will be in the future. How will Copenhagen’s 62-kilometer coast evolve physically, biologically, culturally, and socially in 50 years time? We simply cannot know. Therefore, it makes less sense to try guessing what the “new water normal” will be and then design a storm surge defense to protect us from that. Because the new normal is change.

Instead of guessing the “new normal,” we may understand the natural and anthropogenic processes reshaping our landscapes. We must design our environments in accordance with these processes to be agile, flexible, and able to adapt to continuous change.

Such designs must start with site-specific readings of the landscape and the complex natural processes that shape it. These must be done in collaboration between many professions: Landscape architects, biologists, hydrogeologists, water engineers, anthropologists, sociologists, cultural and ecological geographers, economists, lawyers, and even philosophers, to name a few. Interdisciplinarity is key, and so is the involvement of citizens. After all, people live by the coast: It is their property, investment, and retirement savings we’re talking about. And on a deeper level: their identity, their history, and their lives.”

Finally, what are the potentials for such a storm surge protection approach?

“When we approach storm surge protection in a nature-based way, we can establish new balances between our lands and our waters. Our coasts are not coastlines but coast zones, which are hundreds of meters wide and whose changes have consequences that extend far into land and out into sea.

What can these coastal zones become? What kinds of new blue-green landscapes, values, experiences, habitats, understandings, and bonds between humans and nature can they provide? And how can we create responsive designs in those zones that do not fortify against the unknown climate realities – but adapt to them and celebrate them?

Those are the questions that an interdisciplinary, value-based, and nature-led approach can ask. And which will be super exciting to explore!”

Contact us to know more

Kristine C.V. Holten-Andersen

Project Architect, Ph.D, cand.arch, Landscape Architect MDL

Perspectives

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