An impervious surface is any area on a property where rainwater cannot penetrate and soak into the ground.
These surfaces are typically driveways and paths, roofs, tiled areas, roads and carparks. The rainwater is conveyed by these surfaces collecting anything and everything in its path and carrying it into nearby stormwater networks. As it is not slowed naturally, and directly moves contaminants, this runoff requires stormwater treatment.
In Australia, we are experiencing enormous growth in our cities – and this is often referred to as urban sprawl. These increased areas of impervious surfaces raise the requirements for stormwater management to control water quantity and quality and protect our local environment.