Auckland trials permeable pavement

A new type of road surface that is gaining in popularity because of its environmental benefits has been successfully trialled in the Auckland suburb of Birkdale.

Called ‘permeable pavement’, it is made up of interlocking concrete blocks designed to soak up stormwater and reduce contaminants in water that flows to streams and eventually to the harbour.

Dr Elizabeth Fassman and Samuel Blackbourn, a mechanical engineering student from the University of Auckland’s Department of Civil and Environmental Engineering, monitored the effectiveness of the surface on a 200m² section of road over two years.

Results showed it decreased stormwater run-off at peak flow by an average of 75 per cent during most storms and reduced the volume of total run-off by about 40 per cent when compared to run-off from asphalt on the same road.

Storms with less than 7mm rainfall produced only a slow trickle of run-off that was too low to measure accurately. Run-off from the permeable pavement had on average 70 to 80 per cent less sediment, copper, and zinc.