Blue-Green-Sponges in Urbanization – My Lifelong Engagement for Climate Resilient Cities
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My Approach
The reopened Kalang river corridor is the backbone for climate resilience within the restored Bishan-Ang Mo Kio Parc. With increasing biodiversity, the biophilia effect to people and the new beauty it is a destination not only for locals. Photo: Herbert Dreiseitl
Green spaces like parks, green roofs, green facades, bioswales, and pocket parks are the answer to tackle climate stress and stabilize climate resilience – they are the Blue/Green Infrastructure tools to make cities climate resilient. While the climate crisis was denied in parts of our society some decades ago, fast melting glaciers, extreme temperatures with droughts, brutal storms, rising sea levels and other challenges are hitting us today with greater frequency and intensity. In this light Blue/Green Infrastructure is becoming more and more important.
I opened my first office called Atelier Dreiseitl in 1980. We focused on water projects in Swiss and German cities, celebrating rainwater harvesting, integrated stormwater management, systematically combined in urban settings with a special care to produce meaningful beauty. In villages, suburbs and cities we managed to integrate stormwater by collecting it in open swales, cleaning and treating polluted water runoff, then infiltrating, evaporating and releasing it into the environment.
Still, I remember at this time many people and so called ‘experts’ were making jokes about my early projects and my attitude. They were thinking that water needs to be centralized, controlled, covered and hidden from the public; like “out of sight – out of mind”. In those days it was not easy to convince stakeholders, politicians and clients to think differently and to invest in climate resilient projects based using nature-based solutions. In the early nineteen-eighties, the term “sustainable” was almost unknown and the word “sponge-city” was not even invented. But soon my projects were trendsetters and many professionals, academics and government officials took notice and to my surprise I had to be a guide on many excursions and was invited as speaker to conferences. I could show that our systems avoid floods, create cooling air in summer months, increase biodiversity and are, by the way, beautiful.
Within the last 40 years I have been lucky to create many milestone projects. Together with my teams and partners we created projects like the Urban Waters at the “Potsdamer Platz” in Central Berlin, Chicago’s old “City Hall Rooftop Garden”, the “Tanner Springs Park” in Portland, the “Solar City” in Linz Austria, “Kronsberg” for the World Expo 2000 in Hannover, the “Cloudburst Program” for Copenhagen and the “ABC-Waters Program” with its pilot project “Bishan-Ang Mo Kio Park” for Singapore. With such programs and successfully executed projects, I could inspire many professionals, organizations and cities to follow.
Today I do consult institutions, help cities to develop more in regenerative plans, influence urban planning, and work on selected water projects with my wife Bettina and a small team. Based on my experience and observation I am convinced, it all starts with our attitude, our imagination and consciousness. I call this “Fluid Thinking” and I am teaching this subject in many international and local workshops and at several academic institutions.
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Thinking Fluid
Blue/Green Infrastructure in nature is never static. It is always in a state of constant flux. This dynamic of water and greenery is the environment’s resilient language, a continuum of potential to create living systems, enhance evolution and give the opportunities for life on this planet. In short: it is the living landscape in motion. To work in harmony with this ever-changing dynamic, we need fluid thinking and imagination.
Stormwater swales at the Solar City in Linz are easy to maintain and collect, infiltrate and evaporate water in open on site. Photo: Herbert Dreiseitl
This flexibility has always been challenging for the human race, with our habits and desire for comfort in life, to independence and to freedom. In this light it is interesting how the first shelters and structures were invented by ancient people and finally our imaginations and desires to be more independent created the gray infrastructure and architecture we know and live with today.
In the urban fabric today, infrastructure and buildings, whatever function they might contain, are mostly built as shelters and protectors. They define, separate and fix solid space from the ever-flexible constantly changing environment. Here are the defined controlled conditions of such urban rooms, and there, are the uncontrolled “wild” places, with unforeseen and unpredictable surprises of instability like temperature-extremes, and weather conditions like wind and rain. We might not be fully aware of this strict separation but the benefits of this relief from nature created our human civilization. But I am convinced we can only survive, if we are learning and implementing healthier regenerative and fluid processes.
Urbanization in Environmental Context
With the improvement of infrastructure like roads, railways, and buildings …, we have created cities like perfect machines and the supporting structures seem to make the natural environment a by-product. Our dependence on nature seems to be like a relic of the past.
The climate crisis, loss of resources, and growing weather instability are increasing today and probably will even more in the future, and so we are beginning to recognize how much we really do rely on the environment. We are not independent but are embedded and supported by our environment and to say this clearly; this is great. We are not isolated but connected, and we have a responsibility to keep our environment and natural resources in good condition not only for us but also for the next generations to come. We are not self-sufficient but need the environment for food, water, air, energy and other basic needs that support our standard of living.
Cities are highly dependent on importing resources to supply and feed the urban system to get water, air, comfort, energy, and virtual information from outside of its borders. Consumers in buildings rely on natural resources that are basically brought from outside and this also includes our daily food system. Urban dwellers rely on minerals, nutrients, good soil for agriculture, products from forests, oceans and so on – usually resources that come from far outside and are transported into the urban fabric to feed each building and each customer. This flow of resources is needed to support livability in densely populated urban areas.
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The Solar City in Linz, Austria has not only an energy plus concept but also an integrated water management as an early sponge city to respond for climate resiliency. Photo: City Linz
Turning Points
Looking into the environmental damages and problems that we are confronted with in our cities, it seems today we are on a turning point. Looking at the urban fabric in isolation is simply not beneficial. Missing the interaction of the interior of buildings to the environment is creating more and more challenges not only physical but also mental and cultural in the society. This approach is highly risky and will fail sooner or later.
Working in many cities around the world, I have seen so much irritation, destruction and damage by the involvement with people’s irrelevant fears and bizarre expectations about the environment. Emotions like fear, tell a lot about people’s confidence in life. They show how far we have already separated ourselves from the natural context in which we are living. A lack of trust and missing values are often the reasons for doubtful behavior, for vandalism, self-destruction and for putting our society at a high risk.
Buildings and cities tell stories and shape our awareness. Like in many cities, children often have not only a limited idea of how their food is produced, how a tomato grows and where cheese comes from. They also see water and earth as unaesthetic and dangerous subjects - that are better to observe on television than to touch with one’s own hand in reality.
Connecting Inside and Outside
How can new architecture bridge the divide between the inside and the outside?
Already in the last few decades this topic was for innovative architects, landscape architects and engineers very relevant and a burning question. How to bring the green factors in buildings by creating a win-win situation for better air, for the acoustics, for biodiversity and finally for livability were subjects of increasing interest. Pilot projects brought awareness and did encourage planners to overcome the traditional separation of silos in the profession.
Architecture, industry and customers in our times are on a true paradigm shift and are making steps forward towards a sustainable, climate resilient and more regenerative cities by exploring more the larger context. This trend is absolutely needed as Blue/Green Infrastructure is becoming more and more important as a key to solve the environmental challenges and adapt to the increasing climate crisis.
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People enjoy the transformed waterway from a concrete monsoon canal into an integrated naturalized river-corridor in Singapore. Here people can touch and experience a river in the middle of a big city. Photo: Herbert Dreiseitl
Rediscovering Natural Infrastructures
For decades cities have been turning their back on green corridors and especially water bodies. Waterways, rivers and streams are often unattractive and poorly treated in our cities. Why do they often seem so problematic?
The rapid growth of urban sprawl in many parts of the world will continue to cover the earth’s surface with asphalt and concrete, creating direct run-off affecting large amounts of water at the same time to the same place, creating flooding. This also has a significant side effect on microclimates.
The lack of Blue/Green Infrastructure limits filtration and fails to hold back the microscopic, wind-blown particles. The consequence of this is an increase in dust particle concentrations that contribute to unhealthy living conditions. Awareness of the problem of air pollution is growing, and research shows that in city centers with fewer green spaces and water bodies the concentration of dust particles is significantly higher. Streets and buildings with greenery and trees have lower dust particle concentrations than those without. According to the World Health Organization, 7.1 million people died in 2012 as a result of air pollution.
To create a livable atmosphere in the modernistic City Neu Ulm in Germany, water is the key-element. It separates the traffic and protects the urban life at the plaza. Photo: Herbert Dreiseitl
Where water is absent, we find temperature extremes; this phenomenon is well known in hot deserts where temperatures are very high during daytime but at night can easily drop below the freezing point. Similar microclimatic effects are observed in cities, where city centers temperatures can easily deviate from that of the surrounding landscape by up to 10° Celsius or more - the urban heat island effect. Water and vegetation are the buffers that help to regulate these worsening temperature extremes.
Inflexible buildings and urban structures cannot really cope with the dynamic forces of change; not only in the unpredictable rhythms of the environment, but also within the fields of socio-economic and political trends and their influences on human society, where change processes are also getting more and more dynamic.
By comparing structures in the natural environment with structures from an urban setting in most cities today, a significant difference appears: natural structures work with flexible spaces and resilient principles over time responding with dynamic reactions and balance to any event from a soft change to an unexpected disaster – including extreme climate conditions. Ultimately, it’s all about processes over time and having integrated space, such as wetlands, that are available to operate as a buffer.
From Horizontal to Vertical
In most cities we are simply running out of space and this is one of the biggest challenges we are confronted with today. Growing populations and the resulting demand for housing is in conflict with the different needs of infrastructures on the remaining spaces. It is an ongoing fight for priorities and ownership. All too often the loser is the Blue/ Green Infrastructure in this competition. Simply put, most stakeholders and developers in the private sectors can make more money with buildings but less with the green terrain. On top it is often more challenging to build for the public domain, it needs special care and ongoing maintenance and is for the investors considered riskier.
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Strong advocates came often out of the environmental movements; the discussion has been going on for many decades about ethics and environmental values, but not strong enough on socio and economic aspects that drive developers’ decisions. Almost everybody agrees with the arguments that it would be nice to have more Blue/Green Infrastructure, but unfortunately it can not be done because of all kinds of reasons. But looking into the future this is an attitude we cannot afford anymore.
Therefore Blue/Green Infrastructure just on the remaining spots in cities on the ground floor is too little. To keep cities healthy and to react to climate change with mitigation and adaptation, we have to discover other opportunities. One is to occupy the building envelope itself.
Blue-Green Infrastructure can be seamless integrated in the Urban Fabric of Singapore. The ABC-Waters Program has here a great prototype to be followed. Photo: Herbert Dreiseitl
All buildings have some kind of skin between the inside and outside. It can be the roof and/or the facade as well and those structures have a big variation in form and function. In the last centuries of modernity building envelops were most likely in bricks, concrete, glass and steel and there was no space for plants and water. In fact, the opposite was true, and water was seen as one of the biggest enemies and grass and moss were signs of deterioration. This has changed and today we all know of many examples of architecture in history where we find green roofs and breathing walls with willow bushes and trees.
Vertical structures (green walls) with Blue/Green Infrastructure components are on the rise and in cities like Singapore where we see a new trend of innovations that completely modify our imaginations of what can be done. With buildings like the Park Royal Hotel, the Treehouse in District 23 or the Khoo Teck Puat Hospital we see a new generation of vertical layers of green in the city. This goes together with the topic of water for irrigation of the plants, it means evaporation and filtration with many side effects of the Blue/Green Infrastructure in the Urban structure.
Even if these examples are breathtaking, we might have seen just the beginning of a Blue/Green Infrastructure revolution in architecture and it is easy to imagine much more could be done in the near future. Especially the water component, which needs to be integrated even more actively to accomplish a truly sustainable in the architecture of the future.
Engineering and Beyond
A lot of research and development today has gone into engineering such as mathematical models for hydraulics, flood risk analysis and settlement protection, energy efficiency and other topics. We have knowledge regarding many specific details and methods, we have developed countless engineering tools and planning instruments but we know very little about how an urban society can integrate and live in harmony with its natural environment. A big part of the solution is the Blue-Green Infrastructure resources with good water quality and rich green landscapes. But what kind of water systems are adequate and will work effectively over the long term? What kind of infrastructure fits to the scale of individual buildings with their specific functions and users? What can be maintained and easily handed from this generation to the next?
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Without a proper management of water systems and green structures on a larger scale but also with the implementation of small-scale solutions on building level, there is no basis for a truly long-term sustainability. Maintenance is the DNA for any healthy urban development and the medicine to keep cities alive and vibrant.
In my personal view, having worked on urban landscape and water issues for more than four decades in many different regions and climate zones, the challenges and questions are often similar. Yet there is no patented recipe that works everywhere. Principles and guidelines can help but since Blue/Green Infrastructure is alive, the solutions have to be individually adapted.
Blue/Green Infrastructure is different everywhere and has to fit to the climatic conditions of a region. Climate zones with high humidity, much rain and warm temperatures have advantages and work well for a lush greenery, but there is a higher risk that traditional engineering with water and green frequently fails in projects and cities of arid regions. It is not only critical but also unrealistic to expect the same intense green in Abu Dhabi like in the Garden City of Singapore. Instead of pushing this nonlocal vegetation with enormous water consumption and nutrient inputs, it would be better to use local plants with their specific, sensitive and adapted characteristics. But this will look different and needs a special appreciation of the different esthetics on desert plants with their subtle forms, colors and particular beauty.
Beside honesty and courage to accept the local conditions on water and vegetative ecotypes, we have to turn a challenge into an opportunity. In addition to climatic conditions, increasingly dense situations are the challenge today and will be even more in future. It demands engineering adopt a new language and awareness regarding Blue-Green Infrastructure. We cannot separate work tracks anymore, and have to go beyond traditional engineering that is often dominated by silo thinking. This might include pre-eminent strategic policy-making tools and new, integrating governance structures.
To give an example: One of the first pilot-projects, by far the largest, is the transformation of 3.2 km of the Kallang River in combination with the restoration of 62 hectares of Bishan-Ang Mo Kio Park. This is a classic Blue-Green Infrastructure project (BGI) with a strong social component with over 3 million visitors per year.
A before and after to better explain the transformation at Bishan-Ang Mo Kio Parc in Singapore. The after photo speaks for itself. Photo: Herbert Dreiseitl
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The design was carried out under my leadership with our local studio called Atelier Dreiseitl Asia at this time. In an interdisciplinary planning process including test studies on site, hydraulic modeling with flow simulations, this BGI was designed to accommodate the dynamic process of a monsoon river system, which includes fluctuating water levels and widths to make sure there are no unexpected problems. A focus was taken on security by creating a special safety system in case of sudden water level rise in the open river valley. Elements from the concrete canal – that was previously on the site – were recycled and reused as substrate for the riverbed and a specially formed hill to build a platform for artwork.
The local industry was open to integrate young citizens in the production of the plaza in Neu Ulm. Local young people with immigrant backgrounds were proud to design the structures. Photo: Herbert Dreiseitl
At the design process we conducted several workshops with different stakeholders like organisations from the municipality, grassroots people and children from local schools. These workshops turned out to be very helpful as our clients could ask questions, get confidence and we learned to understand the unspoken questions between the lines. Later we had to train the workers as this special technique with soft bio-engineering has never been used in this part of the world. Fluid thinking was here in high demand not only for the workers but also from our side.
Today we can be proud of the result that got many international awards, is published intensely, and is a trendsetter for many following projects in the city and for other regions. It is a vibrant and naturalized urban river, which feels like a natural environment but is still formed and shaped by a human signature. Aspects of better hydrological capacities, upgrading parameters of limnology, efficient erosion control and others were possible through suitable bioengineering techniques and reshaping of the river profile.
Plants and bedding materials were used to stabilize the banks to withstand the erosive energy of high flows, while at the same time creating diverse stream habitats for native plants and animals. Not only is there a significant increase of biodiversity, there is also a completely new atmosphere that resulted in a very active social life. Socioeconomic factors play into this development and together with National University of Singapore we made a study on the effects of the BGI on human welfare, but also the impact on real estate, which is a sensitive factor.
Beside the return of almost extinct animals and plants coming back to the heart of Singapore on the river and park corridor we have seen a change in social behavior. There is more interaction and trust between people and the apartments and condominiums around the park are very popular and high in demand. Last but not least, this case has enormous value for the image and symbolic capital for Singapore. You will find images of this park in almost all magazines, brochures and official publications from government agencies, books down to flight magazines, business and tourist advertisement.
The Kallang River Bishan Park project could be seen as a new vision for how to shape cities that address the dual needs of water supply and flood management while creating open spaces for people and nature in the city.
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Blue Green Technique and Factors on Buildings
As this new waterway can handle extreme storms, elegant bridges make the crossing easy in rainy days. Photo: Herbert Dreiseitl
Vertical structures with plants on the roofs and walls of buildings are starting to become a megatrend not only in places like Singapore but also worldwide. They act as a symbol for green architecture. In the last decade many architects, landscape architects and engineers have discovered how to integrate plants as a green element to give buildings an environment friendly face and character.
The separation to the natural environment by enclosed and encapsulated objects is breaking up. There is no doubt this is a very positive step and development in architecture. But there are also critical sides of this trend that need to be addressed. Often projects look good in the first years but have serious problems in functionality and maintenance in the following ones and sometimes fail completely in the long run. What often is overseen; plant structures are living systems that are very complex in their specific environmental needs, growth patterns, rhythms and lifecycle.
We have to think differently to mimic the natural conditions of plants like the processes of change including growth, aging and renewal. This challenge is even much more complex by implementing Blue/Green Infrastructure on more exposed vertical and stackable positions.
In the 1960s the green roof movement in Germany, Switzerland and Austria established great knowledge and set international standards for green roofs. The vertical green structures of today go beyond their complexity. We know more about plant performance, substrate and structures to stabilize but still we have to learn more about their sustainable integration within the water cycle.
The best Blue Infrastructure is a combination of decentralized and centralized systems. Why is this so: Water is often very unevenly contributed by nature. We can see this in the structure of rain patterns and the possible storage needs. Where in natural landscapes water can be retained in open lakes, swamps, rivers, streams and in groundwater, the capacity in cities is limited as all water is drained as quickly as possible out of the city. Water becomes scarce and is limited both in time and space and this is getting even more extreme by the conditions of climate change.
Where water is, there is life, so flora and fauna and biodiversity can increase. The effects and values are rich and multiplex. Better air quality, notice reduction, cooler temperatures just to mention some benefits go parallel with the psychological effects of wellbeing, stress reduction and have therapeutic effects.
The challenge is not only the technology but also its implementation within the surrounding urban fabric. Blue-Green Infrastructure is most often in the public realm and so at the forefront of public awareness. As we can all see and experience how space in vibrant cities is getting tighter and tighter, there is a growing competition between functions, programming and jobs. Instead of a competition where the loudest and most brutal, but not necessarily the most important voices often win, better ways of sharing and multi-functional structures need to be developed.
Water-curtains in the German City Neu Ulm filter the city and illuminate a plaza at night. A project in the city centre with the intense involvements of local young people. Photo: Herbert Dreiseitl
A good example to summarize this topic is the Heiner Metzger Platz in the German City Neu Ulm. A big part of the City’s population are young immigrants. To me it was a given to integrate this part of the society in the redesign and construction of a central square. The area was troubled, with some vandalism and uncontrolled potential areas for crime. I could convince our client, the municipality, to start with public workshops and to involve the final users of the plaza early on in the project.
Based on ideas of “fluid thinking” I included in this workshop more than 50 young students and we studied water phenomena in my studio, making sketches and discussed possible options for the plaza design, art-features and a water installation. With enthusiasm, this young group gave inspiration and were involved in the execution. The firms were happy to integrate with the students on implementation, as they were in the need to get a next generation. Including the final users was a big success. Not only the media like TV and Newspapers were interested, but with the final decision in the city parliament, all deputy members voted with a ‘yes’.
The installation is using metal membranes where water can glide and is forming a curtain. This is helping to reduce the traffic noise and provides an inner shelter and protection for the young people but does not cut them off. The plaza today is safe and vibrant, it is used by all generations. The young people are now adults and they are proud to show their co-work to their children and may be grandchildren.
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What has been a monsoon drain embedded in concrete and steel is today an attractive livable and climate stabilizing river as Blue-Green Infrastructure for biodiversity and people in the city. Photo: Herbert Dreiseitl
The Challenges and Opportunities to Livability
Increasing population density is forcing us to better understand and quantify the values that can give even a higher priority to Blue/Green Infrastructure systems. With climate change, we are forced to make the urban fabric more dynamic and resilient with living systems that can filter, buffer and store strong rain events but also survive dry periods and heat waves. Not to react in this way will cost more. Many studies like one in Copenhagen, show doing nothing is expensive and not to react is more costly already now. The costs of inaction will become greater and bring great troubles to the next generation. It is not just about avoiding flooding, but to also create better opportunities for health like better air quality, food security and biodiversity.
The character of cities is strongly influenced by Blue/Green Infrastructure development because it acts in the public realm. As we can experience in many examples, water and green spaces interact with buildings and establish the ‘genius loci’; they may be amongst the most important factors for any human settlement. Blue/Green spaces offer possibilities for humans to coexist with flora and fauna, even within a dense city. They create a platform for modern society to address human needs and they provide opportunities for interaction.
In my early career, I started as an art therapist by helping young people, often with drug problems, ridden by fears and lack of self-confidence to find stability in their life. Using methods of drawings like my exercises of “Fluid Thinking” with water-forms did open up new perceptions and overwhelming opportunities. Later I used the inspiration of water structures to start public involvement workshops and co-creations, often with hundreds of people at the same time. The results were design solutions for suburbs, townships, parks and artworks with a broad political robust consensus. All my design ideas were based on sensitive research with this “Fluid Thinking” to create nature based regenerative solutions to essentially make our world more livable and somehow healthier for the future.
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Herbert Dreiseitl is Landscape Architect, Artist, Urban Designer for Regenerative Water Sensitive Cities. He is a Harvard GSD Loeb Fellow and a Professor in Praxis, based in Germany and working in many continents with his firm DREISEITLconsulting GmbH. Mr. Dreiseitl was born in Ulm, Germany. He started his career in 1980 by creating a park and fountain for blind people in his hometown. His early artwork was already combined with topics like celebrating rainwater and interacting society with the environment. He started the water sensitive design movement and the sponge city concept and created with his team of Atelier Dreiseitl trend setting projects around the world like the Urban Waters at Potsdamer Platz Berlin, Kronsberg at World Expo Hannover 2000, Solar City Linz Austria, Tanner Springs Park Portland, Bishan-Ang Mo Kio Park Singapore, Paragon McLaren London and others. Mr. Dreiseitl is living and working with DREISEITLconsulting GmbH out of Überlingen in Germany, at the Lake of Constance.
Visit his website here.
Selected Publications:
Waterscapes Innovation: Planning, Building and Designing with Water, Dreiseitl, H. and Grau, D. (eds.) Design Media Publishing Limited (ISBN 978-988-12969-3-1)
Recent Waterscapes: Planning, Building and Designing with Water, Dreiseitl, H. and Grau, D. (eds.) Birkhäuser (ISBN 978-3-7643-8984-0)
Biophilia for healthy Cities - Blue-green infrastructure as DNA for healthy urban development, Topos
Liveable Cities; The Art of Integrating Today What We Need Tomorrow. FuturArc Journal, BCI Asia
Cities as living systems, Urban Solutions, CLC Magazin Singapore
Active Beautiful Clean Waters, Design Guidelines 4th Edition, PUB
Dreiseitl, H., D., Wanschura, Wörlen, “Strengthening Blue-Green Infrastructure in our cities. Enhancing blue-green infrastructure and social performance in high-density urban environments”. Funded by the Ramboll Foundation.
