Floating Cities: Innovative Opportunities for Ecology and Sustainability

The construction of a floating city is not only an urban challenge but also presents innovative opportunities for sustainable interaction with nature. A floating city can become an area abundant with possibilities for biodiversity and a healthy soil. How can we incorporate and emphasize the ecological aspects in the construction of floating cities? Landscape designer Michelle de Roo discussed this with ecologist Nick Hofland from Buiting Advies.

Nick Hofland, an ecological expert involved in the research on floating cities, specializes in insects, invertebrates, and the role of vegetation in fostering a balanced ecological system. One of the main reasons for his involvement in this research is the highly innovative nature of the idea, both in urban and ecological contexts.

Michelle: "Where do you see the greatest opportunities when it comes to creating a new ecological area?"

Nick: "The greatest opportunities lie primarily at the water's edges. With the construction of a floating city, we introduce various new elements, such as the building foundations and sidewalls. These elements provide ample surface area for animals and plants to thrive. This is something not commonly found in the Netherlands, where we mostly have sandy substrate, which is relatively unstable. Building floating cities offers an opportunity to explore whether we can create a favorable environment where animals can successfully establish themselves."

M: "How can the natural aspects and urban elements, such as streets, roofs, and balconies, complement each other?"

N: "Having natural elements close to urban areas has a positive impact on people's experience. It brings them joy and happiness. It has also been scientifically proven to be beneficial to health. Additionally, as humans, we provide unique habitats for certain animal species. That is why some species thrive better in urban environments compared to rural areas. Finding the best way to synergize these elements requires considering both ecological and human perspectives without forcing either side."

“By bringing nature and humans so close together, we can create something truly beautiful.”

M: "If a floating city is successfully established, how long would it take for the ecological system to reach a balanced state?"

N: "That depends on the overall design. Vegetation forms the foundation of the ecological system, and its development varies depending on the type. Some plants may emerge within a year, while trees may take decades to reach their full growth potential. In the beginning, there will already be a certain level of balance, but there will always be ongoing changes in the vegetation as succession takes place over the long term."

M: "This succession should occur at the transitions between water and land. Should it be guided through management or left to occur naturally?"

N: "I believe it is beneficial to manage the succession process to a certain some extent, as many people have a specific perception of how nature should look. If left unmanaged, it can become overgrown, and people may quickly perceive it as unkempt. I definitely advocate for a balance between allowing natural growth and controlled management. By managing wisely and developing a combination of more natural areas and more managed areas, you also achieve greater diversity. This promotes the presence of various niches and, consequently, the arrival of different animal species."

M: "Could incorporating green roofs and other building structures contribute significantly to the ecological value?"

N: "Absolutely. Green roofs and vertical greenery can play a vital role in the larger ecological picture. I don't just mean providing habitats for birds but also supporting insect populations, for example. By including plants and herbs that provide nectar for butterflies and bees, we can create a favorable environment. Moreover, in the Netherlands, many insects rely on water, such as dragonflies, stoneflies, and mayflies. By ensuring good shoreline vegetation and water-based vegetation in the direct surroundings of floating cities, we can achieve a lot in ecological terms."

M: "Do you expect human activity to be a problem for the functioning of the ecology in floating cities?"

N: "I think that in relation to humans, we will mainly be dealing with disruption. Many animals are sensitive to human activities in their environment. For example, when we consider the vegetation along the edges where birds breed, such as ducks, animals can be frightened away by people getting too close or making too much noise. However, this is less of a concern for underwater life, as it is a completely different world that is less affected by activities above the water."

M: "Should we establish different zones to distinguish between humans and nature, such as areas without access for pets or boats?"

N: "Ideally, yes. If cats get in areas where birds breed, there is a possibility that they might return with a duckling or something similar prey. One possible solution is to create floating islands with vegetations around the floating cities, protected from pets. Such areas would also provide a habitat for many bird species that rely on tranquility. However, the passage of a speedboat can still disturb the birds and drive them away from their nests. Therefore, it is important to establish zones: within certain zones, people can freely move, but as you move farther away from those zones, nature should be allowed to thrive undisturbed."

M: "So, a certain level of respect for nature is required if you want to live in a floating city?"

N: "Absolutely, it's a delicate balance. People must treat nature with because minimizing disturbances caused by human activities is crucial. However, by bringing nature and humans so close together, we can also create something truly beautiful."

M: "What could be obstacles for a floating city, such as water flow, sedimentation, oxygen-depleted conditions, and pollution?"

N: "The answer to all these impediments largely depends on the specific location. Water flow can indeed pose challenges if barriers are created within the city, impeding the flow. The chosen construction method and the extent to which the city protrudes above the water play a role in this, among other factors. However, additional underwater structures specifically designed for nature can also provide opportunities for flora and fauna. Sedimentation is closely related to water flow. A floating city itself is unlikely to cause significant sedimentation, except for potential pollution. Of course, it is always possible to dredge specific areas to deepen them. However, careful planning is necessary to minimize disruption to wildlife.

Oxygen-depleted conditions are a point of concern. Normally, oxygen enters the water from the air. Therefore, the smaller the surface area, the less oxygen can enter. As a result, the oxygen levels in the water surrounding floating cities may decrease. This effect can be amplified by water warming and the heat released by human activities, leading to rapid algae growth and increased oxygen consumption. To address this, we can implement water circulation to introduce oxygen from above."

“The further you move away from inhabited areas, the greater the opportunity to truly focus on ecology.”

M: "We have recently completed the first phase of the Building from the Soil research at PosadMaxwan. How do you see the role of the soil in floating construction? Does the water become the soil?"

N: "Yes, to some extent, the water becomes the soil. We do add some actual soil, but it's relatively small-scale."

M: "What about underwater vegetation? Do you need to actively introduce it, or does the vegetation naturally emerge once the construction is complete?"

N: "If the location where the floating city is being established is connected to a larger system, vegetation will naturally emerge, just like along the banks of a river where various seeds are transported. However, we can also guide the development of (shoreline) vegetation. For instance, we can sow certain vegetation with native herbs. In zones adjacent to buildings, we can also choose to conduct regular (mowing) management. Nevertheless, I suggest that the further we are from the inhabited areas, the more we should let nature take its course.

M: "Do you see this project as a solution that can be implemented more frequently in the future, and would it enhance or diminish the ecology in the water and green edges?"

N: "Absolutely, I think this technique can be applied more frequently and offers great opportunities. Considering the limited amount of available land in the Netherlands, inhabiting water areas is a viable option. However, I do believe that we should apply it in moderation and carefully consider which locations are suitable and which are not. There are, for instance, places where the ecological balance is already thriving. We should definitely steer clear of those areas. It is essential to prevent any disturbance or harm to vulnerable and valuable natural habitats.

M: "So, primarily, we should consider floating cities as an addition to areas with limited ecological value, such as agricultural regions or areas with low ecological significance, always maintaining a balance between human needs and ecological aspects."

N: "Exactly, the greatest opportunities lie in locations within the city or in rural areas where the ecological value is currently limited. Additionally, floating cities can contribute to future water buffers in the context of climate change. Therefore, it is essential to carefully consider where things are possible and, equally importantly, where they are not. In the immediate vicinity of human settlements, I suggest emphasizing the experiential aspect and then considering what ecological contributions can be made there. The further you move away from inhabited areas, the greater the opportunity to truly focus on ecology. I believe there is a valuable approach in that."

M: "That does indeed sound like a valuable approach What was it like for you to work on a project where so many possibilities are open?”

N: "It is a fascinating project to be involved in and brainstorm together about the various possibilities. I am also very curious about the technical details, which have been addressed by a lot of technical experts from the beginning of the research. Equally important is addressing the question of how to translate all the ideas and outcomes of this research into tangible reality. And as an ecologist, I'm thrilled to explore the vast potential in terms of ecology. I would love to delve deeper into that!”

Regarding the case studies of the research on floating cities, they are focused on exploring the general potential of floating construction. The developed visuals and textual explanations are intended to inspire and stimulate thinking about compelling perspectives for floating construction.

The floating cities research was done in close collaboration with PAS BV, Buiting Advies, Dutch Lotus, Blue Revolution, the municipality of Utrecht, HDSR and the municipality of Rotterdam, and made possible by Stimuleringsfonds Creative Industrie.


The chosen case studies are purely meant as tools to bring these general concepts to life. They are not intended as concrete plans and therefore do not hold any status or impact on ongoing area developments or project implementations (such as the elaboration of the Merwehaven Masterplan). This applies to both the spatial designs and the presented number of residences.