Dutch shipping hub Rotterdam is a testing ground for ambitious new projects in flood management, as Giovanna Dunmall discovers.
It’s like living in a bathtub that constantly needs to be monitored. When it fills up too much you have to pump the water out, and when you get low on water you have to pump it back in.”
So says Dirk van Peijpe of life in the Dutch city of Rotterdam. Founder of landscape architecture firm De Urbanisten, he explains how his low-lying city is constantly under threat of flooding. In January 2018, for the very first time, all five of the Netherlands’ main storm surge barriers had to be closed at once due to strong winds and high seas.
Even in a city where 80 per cent of the land sits below sea level, this is unusual.
De Urbanisten has just launched a two-year research and design project entitled The City as a Sponge. It comprises a circular garden where the city’s three main soil types are being investigated for their sponge-like qualities. “It will be interesting to see how vegetation and other biological materials can also be used to increase the ability of the city to perform as a sponge,” says van Peijpe. “Can the city soak up water, store water and then give it back to its environment in the same way a sponge naturally does?”
De Urbanisten has been involved in many of the more intriguing water management projects around Rotterdam, Europe’s largest port. It is also the firm behind the first, largest and most famous water square in the city (some say the world), which opened in 2013. Called Benthemplein, it eloquently showed how functionality could work alongside aesthetics. The square, which is planted with trees, long grasses and wildflowers, has a sunken sports pitch in the centre with stepped seating on both sides, and two basins nearby that can be used for biking and skateboarding in dry weather. Following a sudden rainstorm, the pitch and basins turn into water receptacles that can hold an impressive 1.7 million litres of water.
In order to emphasise the square’s purpose, the designers created oversized stainless steel gutters, bringing water from nearby surfaces and rooftops into the collection ponds. “We also have a water wall in the largest basin that releases the water in an orchestrated way, and a rain well that brings water into the square in an almost mystical way from below,” van Peijpe adds.
Arnoud Molenaar has the rather interesting job title of chief resilience officer for Rotterdam. “This is about climate resilience yes, but it’s also about adding urban quality and investing in social cohesion,” he says of Benthemplein water square which used money earmarked for sewage works and pumps to improve public space. “Our new philosophy is to do things in a multi-functional way and not look at climate change only as a problem. Every city wants to become a more attractive and greener city. We can combine all these ambitions.”
Above: A satellite view of Rotterdam shows how low-lying land is prone to flooding.