Alternative stormwater management techniques are being explored by Auckland City and will be tested in several new Council developments.
Architects working on Council projects will be asked to incorporate features that provide for the on-site management of stormwater. The first group of Council projects to be involved will be the surface landscape design of the Queen Street Station and the Wesley and Oranga community centres. They will be incorporated into future pensioner housing projects and the Council will talk to its partners in the Western Springs Theatre Project to see if they can be included there also.
The innovative new techniques use a combination of methods, which could include water tanks, shallow depressions in the ground and planting above porous materials, such as sand, stones and scoria. The techniques are an alternative to the traditional method of piping all stormwater off site and discharging it into waterways.
The on-site management of stormwater can have significant economic and environmental benefits because it relieves the pressure on overburdened reticulation systems and reduces the amount of pollutants going into streams and harbours.
City Works Committee chairperson Councillor Doug Astley says the Council is taking an innovative approach to the management of stormwater run off, which is becoming more of a problem as development intensifies.
“Land once open to the natural absorption of water is being covered over with buildings, concrete and paving,” he says. “The city is in danger of developing an impervious shell a bit like a turtle.”
The Council plans to develop a detailed on-site stormwater management manual, which will provide technical details for each particular management measure, taking into account Auckland’s weather and soil characteristics and regulatory controls.
Developers will be able to use the manual to select the most appropriate technique/s for their particular sites at the design phase of their projects, when they can be incorporated without causing significant additional costs and time delays.
Planning and Regulatory Committee chairperson Councillor Juliet Yates says the measures cannot be implemented soon enough from her point of view.
“On-site stormwater management is now being used effectively in some countries and there are examples of multi-unit intensive developments where not one drop of stormwater goes into the public drainage system, nor enters rivers or harbours, which assists harbour water quality,” she says. “Water is ‘harvested’, loses its contaminants through natural filtration processes and is pumped back into the aquifer or used for household purposes, apart from drinking, through a dual pipe system.
“It is encouraging that we are looking at ways to implement these new techniques while land is still available for intensive development in Auckland. We have large scale developments being built now which would be ideal for stormwater harvesting. I would not want to see many more of these taking place without the option of on-site stormwater management being explored.”
Councillor Yates says she would like to think about ways in which the Council could encourage developers to look at on-site stormwater management now.
“Perhaps we could offer incentives, such as enabling developers to implement on-site stormwater management rather than having to pay for new pipe infrastructure,” she says.
Councillor Astley says the Council will continue work on its manual and may then call developers together to tell them where the Council is headed.
“We can outline our work and find out what they’ve done and what they may be prepared to do. The Council, developers and the city as a whole stand to benefit from these alternative techniques. We need to work together to advance them as soon as possible.”