I am standing in the middle of an unusual public square in Rotterdam. To my left is a drama school with a grand concrete entrance and a huge plaza. To my right are a trio of large sunken squares, each surrounded by a few steps.
On a regular day like today, these squares can be used as basketball and volleyball courts, skateboarding rinks, amphitheaters, or even as celebrations for a nearby church. But when it rains, the squares can fill up and hold 450,000 gallons of water.
The Water Square (Waterplein in Dutch) was designed by the local urbanism and landscape architecture firm De Urbanisten. It was completed in 2013, and it marked a change in the firm’s mission. Since then, architects have researched water management issues in Mexico City; Antwerp, Belgium; And even New York City after Hurricane Sandy. They have built another water square in the Dutch city of Tiel, a sponge garden outside their office in Rotterdam, and are now working on two major projects elsewhere in Rotterdam: a tidal park that was designed for flooding, and a climate-adaptive version of Manhattan’s High Line, complete with a water-purifying landscape.
At the core of de Urbaniston’s practice is the belief that landscape architecture can help mitigate climate change by moving away from obsolete drainage systems and toward more natural approaches such as rain gardens and permeable surfaces.
Studio work is particularly important in Rotterdam, much of which is below sea level. But as climate change leads to flash floods and excessive rainfall more likely Worldwide, it offers an exemplary model that extends far beyond city limits.
“Drainage city is a 19th century concept that was elaborated in the 20th century, but we are not going to bring it into the 21st century,” says Dirk van Pijpe, founder of D’Urbanisten. “We may still need a little bit of these pipes and pumps, but we need to start investing in the system of the future which is a nature-based system with mud and blue-green infrastructure.”
In 2019, d’Urbaniston created a small sponge garden designed to quickly absorb rainwater, hold it temporarily, and release it slowly back into the ground. For the past three years, architects have been using the garden as a testing ground, testing various plants and soil compositions such as clay, rubble and peat.
Agate Kalanpure, the firm’s architect and landscape designer, who took me on a tour of the Sponge Garden, says the garden is not connected to the city’s sewage system. Instead, it can collect and absorb storm water without anyone having to water the plants. The concept can be extended and replicated in a wild variety of urban landscapes, from residential gardens to landscaped strips along highways.
Not far from the Sponge Garden, d’Urbaniston is working on a tidal park. Situated on a riverbank in a former port, the park or parts of it were designed to flood with tides approximately twice a day. The concept was developed with the Municipality of Rotterdam as a blueprint for a comprehensive initiative that would convert very large sections of the river into a tidal park.
Rotterdam has more than 220 miles of river banks, but 70% of them are lined with hard quarries and built-up residential areas at the water’s edge. The tidal park would provide what van Pijpe called a “soft ecological space,” with increased biodiversity that was pushed out by a polluting port.
It will also increase flood resilience because the steep, vegetated slope of the river bank can help break up waves when water levels are high. On a regular day, parts of the park will be accessible at low tide, allowing citizens to reconnect with the river and a renewed diversity of animals that will make for underwater life.
This level of coexistence is important and suggests that public spaces can perform double duty. A park can also provide natural protection against flooding, and a set of public squares can also act as rainwater storage.
Back at Water Square, the architects had to disconnect the plaza from the city’s sewage system. During flash floods, a network of large stainless steel gutters built into the pavement channel rainwater into three ponds, then into an underground infiltration basin that filters pollutants and allows the water to soak back into the soil.
Wait a few years, and Water Square will be part of a much larger network of public spaces and parks connected by a green spine hovering over the city. Rotterdam’s version of the High Line is called the Hofbogenpark, and will sit on top of a 1.2-mile abandoned railway viaduct.
When the park is complete, it will have a robust, circular water management system: rainwater will be naturally purified through soil on the roof, then sent through underground drainage pipes to an aquifer, where it will be stored. and then reused for irrigation. Park landscape. Most parks will also have a water stream for children to play in.
Eventually, van Pijpe envisioned, something would happen in what he calls a “rainwater spring” scheme, where rainwater would be collected and slowly absorbed at various points throughout the city – first on the roof, then around the building. The water slowly seeps into the ground and disappears, through a variety of systems, from water squares to sponge parks, through gardens, then pavements along permeable surfaces, and then through a variety of systems.