304 Clementi Ave 4, Singapore
To provide green alternative to concrete drains within the park to control, manage and reduce rainwater runoff from the park at source.
VersiTanks were assembled on site and positioned within linear excavations in accordance with the landscape design of the park to allow water to flow and be channeled to outlets where the gradient of the park is lowest for discharge into the local drainage network.
A 100mm layer of coarse sand was first placed at the base of the excavated trenches and compacted. A geotextile was laid to completely envelope VersiTank installed in a continuous row within the trenches. The geotextile filter fabric allows rainwater to percolate through into the tank below but not suspended solids. Sumps were installed at intervals along the length of the swale to facilitate maintenance and easy inspection. The excavations were filled in with coarse sand up to 100mm above the geotextile.
The bioswale allows drainage within the park to be vegetated replacing conventional concrete drains which do not blend into the greenery of the park. Phytoremediation by the plants of the vegetated swale helps to remove organic contaminants and reduce suspended pollutants carried by runoff at source. In addition to allowing the overall landscape design of the park to remain seamlessly green, the system prevents waterlogged grounds and enables the integration of more usable recreational space within the park.
The slow percolation and infiltration process together with the inherent water retention capability of the bioswale network also minimises downstream impact from high volumes of water in downpours that often cause flooding.