The climate is changing: the rain is getting heavier, and the dry periods are lasting longer. How can we moderate these two extremes? Rainwater currently drains through sewers and increases the problem of drought. In the future, there will be even a need for larger sewers. The mechanism of how a sponge can work follows a threefold sequence of collecting water, storing it for a certain period and then returning the water into the ecosystem. This ‘Collect – Store – Return’ sequence implies that the concept of a sponge is, in essence, a system. Our research focused specifically on the city of Rotterdam. In Sponge Garden we test out our research in practice. Here we have realized a test site for simple and practical ‘natural’ solutions to maximize water resources in the city during heavy rainfalls and periods of extreme drought while creating a context for enhancing biodiversity. In the garden, three methods are being tested:
Soil cubicles – Rotterdam soils. Improving water retention of four characteristic Rotterdam districts. Low maintenance planting and effective soil enhancements for small areas like private gardens to encourage owners to contribute to climate measures and increase the overall amount of green spaces.
Waving wadi – capillary infiltration. It demonstrates how public space can be used to collect rainwater from a local catchment area of 4 to 5 times their size and to return their water slowly. These spaces can be effective for immediate buffering of heavy rainfalls. They subsequently retain the water for longer periods in order to be usable in extended periods of drought. It is divided in four subconcepts to offer diverse public use and aesthetics in urban contexts.
Depave garden – super infiltration. Immediate and simple ways to enlarge planted spaces and reduce the area of paved spaces. It is the most low-key intervention to depave hard infrastructure is being tested on its potential to function as a planter or even as a small garden.
The layout of the Sponge garden follows the design of the Food garden (Voedseltuin) where planting is organised in circles. There is a meeting space in the middle of the Sponge garden, and the outer doughnut is split into three parts, each dedicated to a different experiment. The garden is a pleasant collective space, well enjoyed by nearby office and Food garden workers, visitors and local residents. Educational and professional visits take place regularly.
The research and project is our own office initiative, in collaboration with the municipality of Rotterdam and with the support of Water boards, foundations and private parties. We planted, and we maintain the garden ourselves. A simulation of heavy rainfall has been carried out, and monitoring is taking place.
Sponge Garden shows that designing flourishing public spaces can go hand in hand with researching new concepts for collecting, retaining and returning rainwater to the natural environment. It is an experimental garden where planting, and maintenance are adjusted over time, and extreme rainfalls are simulated.
Location | Rotterdam, The Netherlands
Sponsors and Support | Water Sensitive Rotterdam, Stichting Voedseltuin Rotterdam, Gemeente Rotterdam, Hoogheemraadschap Delfland, Provincie Zuid-Holland, EFL Stichting, Binder Groenprojecten, Kim Kogelman, Lapinus
Collaboration | Stichting Voedseltuin Rotterdam, Municipality of Rotterdam
Images Credit | De Urbanisten