Today, cities must also be able to cope with heavy rainfall, heat waves, and increasing soil sealing. As a result, squares, paths, courtyards, and parks are no longer merely transportation or recreational spaces, but are becoming active components of climate-resilient urban planning.
A key issue here is the management of rainwater. For a long time, the primary planning task was to drain precipitation as quickly as possible. Today, the focus is increasingly on keeping water where it falls: storing it, allowing it to infiltrate, letting it evaporate, or channeling it away in a controlled manner. The so-called “sponge city” conceives of urban space as a system that absorbs rainwater and releases it gradually—much like a sponge.
Paving clinker can play an important role in this context. This is because it combines robust functionality with a natural, durable materiality. When properly planned, the paving becomes not just a paved surface, but a building block of rainwater management.
Rainwater as a Planning Challenge
As heavy rainfall events become more frequent, traditional drainage systems are reaching their limits more quickly. Impervious surfaces direct precipitation directly into the sewer system. There, large volumes of water converge within a short period of time—making flooding, backflow, or local damage more likely.
Modern open-space planning therefore starts earlier. It doesn’t wait until the end of a project to address drainage, but integrates rainwater management into the design from the very beginning. What matters isn’t just whether an area can absorb water. Equally important is how water is guided, slowed, distributed, and connected to green spaces.
Paved outdoor areas in particular offer great potential here. They can be constructed to allow for infiltration, direct water into adjacent planting areas, or be part of a larger retention system. Pure drainage becomes a design and technical task that integrates materials, topography, and use.
Paving Clinkers Designed as a System
Paving clinkers are a ceramic-fired building material. Their strength lies in the combination of durability, high load-bearing capacity, and a natural coloration resulting from the firing process. However, a key factor for stormwater management is that the water management function is not provided by the stone alone, but by the entire structure.
In the case of permeable paving clinker surfaces, rainwater generally enters the subsoil through widened joints. This requires a suitable joint filler, a water-permeable bedding layer, and a properly dimensioned base course. Only when these layers are coordinated can rainwater be permanently absorbed and conveyed.
Another option is drainage clinker. These feature recesses or openings that are filled with water-permeable material. Here, too, the paving becomes part of a system that does not immediately drain water away but instead directs it into the subgrade on-site.
For planners, this means: paving clinker is not an isolated surface material. It is a component of a structure. Joint spacing, slope, subgrade, traffic load, cleaning, maintenance, and connection to green or retention areas must be considered together. Only then can a surface be created that functions effectively both aesthetically and technically over the long term.
Sponge City: Rethinking Paved Surfaces
The sponge city principle expands on this approach. Not every surface needs to be fully permeable to contribute to stormwater management. Controlled water flow is just as important. Paths, plazas, and curbs can be designed to absorb, channel, or direct rainfall into adjacent depressions, flower beds, tree trenches, and retention areas.
This is precisely where the design quality of paving clinkers comes into play. Through formats, laying patterns, colors, and surfaces, water-conducting areas can be precisely integrated into the open space. Lines, directions, and gradients can be made visible. The paving not only serves a technical function but also shapes the spatial perception.
Karens Minde Aksen in Copenhagen: A Park Designed as a Water-Retaining Landscape
An impressive example of this approach is Karens Minde Aksen in the Sydhavn district of Copenhagen. The project combines a green park axis with a comprehensive concept for heavy rain management. Spanning approximately 600 meters, a public space is being created that connects neighborhoods, enhances the quality of life, and can simultaneously absorb large volumes of water.
Due to its low-lying location, the area was particularly prone to flooding. Instead of relying solely on underground drainage systems, a landscape architecture-based infrastructure was developed. Rainwater is visibly channeled through the park, filtered, retained, and integrated into a larger system.
In everyday life, Karens Minde Aksen is a green connecting space: a place for walking, playing, lingering, and meeting. During heavy rain, its function changes. Then the park becomes a water-carrying landscape. The water follows a curved path, is guided through the grounds, and integrated into retention areas.
Image: Kirstine Autzen
The Brick River as the Design Backbone
The clinker paving plays a special role here. It forms a striking, curved path through the park—a so-called “Brick River.” The term aptly describes what it’s all about: The clinker is not just paving. It becomes the visible flow of water.
When dry, the paving serves as a path and an area for movement. During heavy rain, it becomes part of the water flow. The topography, the slope, and the integration with adjacent green spaces make the water flow visible.
The brick makes rainwater management understandable. It shows where water flows, where it is slowed down, and how it becomes part of the park. A necessary technical measure becomes a defining element of the public space.
Image: Kirstine Autzen
Durable Materials
Public outdoor spaces must withstand changing weather conditions, heavy use, cleaning, frost, moisture, and mechanical stress. Especially in areas where water is intentionally channeled, collected, or allowed to drain slowly, materials are needed that can handle these conditions over the long term.
Paving clinker possesses essential properties for this purpose. Its color is created during the ceramic firing process and is not a subsequent coating applied to the surface. As a result, the material’s character is preserved even with intensive use and weathering. Signs of wear, changes in light, and aging alter the paving without diminishing its quality. In Karens Minde Aksen, the clinker simultaneously reinforces the site’s spatial identity: the warm hue stands out clearly against the green of the vegetation and makes the course of the “Brick River” clearly recognizable. At the same time, the material blends naturally into the landscape.
The project demonstrates that stormwater management need not be viewed as a technical add-on implemented after the fact. When water, vegetation, topography, and materials are considered together from the outset, the result is multi-layered public spaces: they protect against flooding, enhance biodiversity, improve connectivity, and create new qualities that make the spaces more inviting. In this way, Karens Minde Aksen exemplifies a trend that is gaining importance in many cities. Outdoor spaces are no longer evaluated solely based on their surface area, but rather on their ability to respond to climatic demands.
Paving clinker can fulfill various functions in this context. It can be designed as a permeable surface, direct rainwater specifically into green spaces or retention areas, structure edges, paths, and open spaces, and make water management functions visible—without compromising on design quality.
Image: Kirstine Autzen
Conclusion: Paving Clinkers as Building Blocks for Climate-Resilient Open Spaces
Rainwater management is one of the central tasks of modern urban and open-space planning. It is not merely a matter of technically managing heavy rainfall events. It is about designing outdoor spaces so that they can absorb, channel, store, and make water an experiential element.
Paving clinker can make an important contribution to this. In permeable constructions, it supports decentralized rainwater management through joints, drainage openings, and water-permeable layers. In projects such as Karens Minde Aksen, it also becomes a visible element of climate-resilient landscape architecture.
The “Brick River” in Copenhagen demonstrates how rainwater management and design can come together. A technical necessity gives rise to a public space with character—robust, usable, and open to the climatic challenges of the city of tomorrow.
