The Rain Gardens are situated at the lowest point of the road, with the road sloping up and away from the rain gardens in either direction, creating a bowl-like situation. Utilising a variety of hardy, drought tolerant species, the planting palette will also cope well with some inevitable flood events that the road will experience in the future.
Within the project, chamber covers have been integrated, along with distinctive red domes serving as overflow mechanisms, featuring downward-extending pipes. While the designs may vary, the fundamental structure of our rain gardens involves water entering at the surface, permeating the soil, and traversing through a specifically graded stone layer into the ground itself.
The stone layer, intentionally designed with 30% voids, is utilised as a reservoir for floodwater storage. In cases where the volume of water surpasses the surrounding soil’s absorption capacity, the stone layer is filled up first, followed by the soil layer. Eventually, any excess water is allowed to overflow into the sewer system.
To optimise drainage, the soil layer is carefully selected to be free-draining. Intriguingly, the rain gardens are curated to host plants resilient enough to endure prolonged dry spells, ensuring the success of our sustainable and flood-resistant project.
Innovative technologies, like “SuperDrain,” a porous carriageway allowing water to drain through the asphalt surface, complement the rain gardens. The rebuilt substructure with stone layers demonstrates how existing urban spaces can adapt to persistent problems.