Key elements of this design approach include re-using stormwater via a ‘third pipe’ system, together with an extensive wetland system and the construction of swales, which are plant-filled surfaces that channel down surface water into the ground and then into the pipe system.

The third pipe system – which is the result of a collaboration between Landco, Metrowater, Auckland City and the consultant team of Wood and Partners and CH2M Beca - will recycle stormwater for use in the toilets and garden irrigation of all dwellings within Stonefields.

Under this system, stormwater runoff and groundwater will collect in the wetlands at the lowest point in the development. From there it will be treated before being pumped to a reservoir at the high point of the site. The treated water will then be reticulated back down through the development in a separate, system to each property. This system will be completely distinct from the drinking water system.

“Stonefields’ design sets an excellent example of sustainable water reuse,” says Landco Development Manager, Aaron Smail, “by reducing runoff and peak flows, protecting natural systems, integrating stormwater treatment into the landscape and protecting water quality to the Waiatarua Reserve. It also lessens demand on Auckland’s potable water supply. ”

Landco is funding, designing and constructing the system, after which it will be vested to Auckland City who will in turn transfer it to Metrowater to own and operate. The third pipe supply is expected to be metered in the same manner as drinking water.

Recent water shortages have made water recycling commonplace in Australia and parts of the U.S., but to date New Zealand’s relative abundance of water has not economically justified the construction of a scheme on this scale. However Stonefields’ unique geography, together with a desire by Landco and Auckland City to take a lead on sustainable water practices, made it a perfect choice for the introduction of this technology.

“I believe this project will be leading edge for New Zealand,” Mr Smail says. “Through the application of best practice urban design and development Stonefields will deliver benefits to both residents and the city as a whole.’