Permeable concrete pavements offer a perfect crossroads for those seeking environmentally friendly alternatives in a higher density living environment
A permeable concrete pavement – such as PermCon – is a type of pavement that allows stormwater to pass through the top-wearing course (your traditional concrete surface) and be stored in the open grade basecourse beneath. Here, it can either replenish the natural ground aquifer, by infiltrating the sub grades, or be discharged to the stormwater network via under drains in a measured and controlled manner, reducing the peak flows of a storm event. In essence, it replicates a green fields environment, allowing the stormwater to find its natural paths to either the aquifer or local streams and rivers.
The benefits of using a permeable concrete pavement instead of a traditional impervious pavement are not limited to reducing the stormwater peak flow. Permeable concrete pavements also act as a passive filtration system, improving water quality and reducing the urban heat sink by cooling the environment through evaporation.
Perfect for planning and consenting
There is a myriad of other benefits but a substantial one is that, if a permeable concrete pavement is installed as a ‘passive’ system – which means it is only receiving stormwater that lands directly on it and not from other sources (eg, roofs) – all territorial authorities except two consider it as pervious surface for planning and consenting purposes.
This is an important consideration as New Zealand embraces more and more infill housing and higher density residential construction. A common application in New Zealand is on sites
where an existing property has been removed and replaced with several new dwellings.
In this instance, the installation of a permeable concrete pavement not only acts as the driveway and parking for the properties, but also as a detention device by mitigating run-off and not impacting on the overall site impervious/pervious ratios. This can be scaled up to
assist in multi-unit developments such as JOALs (joint-owned access lots), carparks and driveways, and larger scale commercial car park applications.
Ticking all the boxes
In today’s environment, where we are seeing a desire for higher density living but an increased
focus on sustainability and eco-friendly solutions, a permeable concrete pavement can offer a range of environmental benefits, while helping to minimise onsite hardstand coverage.