Water Sensitive SA

Permeable paving – 1970s retrofit

King William Road, Unley - permeable paving retrofit

Permeable paving connected to infiltration trench in communal green space

Retrofit of permeable paving in a high-density 1970s residential setting

Utilising water sensitive urban design (WSUD) principles, this high-density1970s residential development’s deteriorating driveway has been repaired using permeable paving in a small section to alleviate water pooling and pavement cracking. Stormwater that soaks through the permeable pavement is temporarily stored within the underlying aggregate before draining into a soakage trench within the shared greenspace within the property.

Project planning & design

The project sought to find a sustainable alternative solution to an existing asphalt pavement in a low-lying section of a residential driveway in an apartment block servicing 37 units. The existing pavement consisted of an aging asphalt surface overlaying a poor subgrade filled with historic building rubble. At the low point of the driveway regular ponding exacerbated the local conditions to form potholes in the driveway surface.

The body corporate moved away from a like-for-like approach to the asset renewal and instead chose a permeable pavement system in a small section of the driveway low point.

The 35m2 permeable paving system consists of the following layers from the surface down to the subgrade:

  • 80mm deep EcoTri-Hex paver
  • 45mm of 5-7mm of screenings
  • 175mm of 20mm single sized aggregate, including an agricultural pipe in the base for drainage
  • a layer of geofabric
  • 100mm of PM2/20 rubble sub base

Permeable paving retrofit - information and site facts

The soakage trench receives stormwater runoff via the agricultural drain within the permeable paving system and comprises:

  • 1m x 1m x 3m excavation, lined with geofabric
  • 800mm deep, 20mm single sized aggregate, wrapped in geofabric
  • 200mm deep top soil.

This system passively irrigates the trees within the central communal green space, enhancing their resilience in the drier summer months.

Acknowledgement of Country

Water Sensitive SA acknowledges Aboriginal people as the First Peoples and Nations of the lands and waters we live and work upon, and we pay our respects to their Elders past, present and emerging. We acknowledge and respect the deep spiritual connection and the relationship that Aboriginal and Torres Strait Islander people have to Country.