Guidelines adopted for artificial wetlands in urban environments
The creation of artificial wetlands in concrete drainage channels in tropical cities can improve water quality. The conditions for these artificial wetlands have been tested and adopted in Singapore. A pilot wetland measuring 50 x 4 metres was created in a channel in Singapore, giving the city the first project of this kind in the world.
Two goals achieved sustainably in a single operation
Concrete drainage channels are common in tropical cities. During the rainy season, extremely large amounts of water are drained out through the channels, preventing flooding. Singapore wants to improve the appearance of the channels, and also to enhance water quality. Creating wetlands makes it possible to achieve both these goals sustainably in a single operation. Ellis Penning: ‘Together with NUS Deltares , we conducted tests in the Van Kleef Centre, the university’s research centre. We conducted experiments that allowed us to identify the most effective types of sand and vegetation.’
Correct design crucial
The next step was to come up with a design for the wetland. Ellis Penning: ‘The drainage channels have to be able to cope with extremely high levels of rainfall, even when the vegetation is in place and so the design has to be just right. If there is too much vegetation, the channel can overflow; if there is too little, the water will not be cleaned adequately. On the basis of the tests, we were able to establish a picture of all the factors needed to ensure the proper functioning of urban wetlands and we can now say whether this is a feasible option in any given location.’