Is Auckland's water supply half-empty or half-full?

Sunday, 16 February 2020

OPINION: Our household has plentiful water again, thanks to the delivery which filled our tank after 40 days without the rainfall we depend on.

Life in Auckland's rural areas, away from the security of mains water, makes you very conscious about how you use it and of the value of a decent bit of rain.

For most of Auckland there is not a supply problem, which raises the question of why the region's water provider Watercare is urging restraint during an almost-record drought.

Aucklanders, they are quick to tell us, are already relatively frugal compared with other major centres, thanks to meters and 'user pays' charging.

**READ MORE: 

* Explainer: There is no water shortage so why are some Auckland tanks running dry?

* Auckland water shortage: Residents urged to take shorter showers

* Auckland water shortage: City warned to cut shower time after dry spell leaves dams depleted

* Critical water shortages: Aucklanders urged to cut consumption after floods​**

So, what is in play for Aucklanders hooked up the mains supply, and who may be wondering whether they need to conserve?

Firstly, the climate forecast for autumn, a time when rainfall begins to climb from its February trough to its July peak, is still too close to call, as Auckland's bulk water dams lower to 70 per cent full, 12 per cent below their average.

Watercare urged caution as recently as July 2019, when the traditional winter rain failed to arrive on time.

In 2017 there was plenty of water, but a storm known as the 'Tasman Tempest' led to so many landslides into the Hunua dams that the treatment plans got clogged and couldn't run at capacity, leading to calls for conservation.

The last imposition of formal restrictions was in Auckland's great water crisis of 1994, before the region tapped into the Waikato River.  

Watercare has been working on new sources of water, the biggest of which will kick in this winter when it ups its daily take from the Waikato River, which supplies on average 17 per cent of Auckland's needs.

Auckland has negotiated a new resource consent that applies when the Waikato River is above its median levels, bringing 25 million litres of treated water through the network, meaning the storage dams can rise closer to full, and remain higher heading into the next dry spell.

The council's water company is also running the line that if Aucklanders can cut back during the summer peak, expensive infrastructure will not have to be built so soon, and there's a website to promote saving.

Can shortening shower durations and not running the tap while cleaning your teeth delay the need to spend hundreds of millions of dollars on a new reservoir or treatment plant?

Watercare said 'yes'. 

Auckland's supply, treatment and distribution network has to be built to cope with the absolute peak demands, and the 2020 summer set a consumption record of 560 million litres a day.

If Auckland could slice off the top of that peak of demand, then the inevitable and costly boosts to supply and treatment could be rolled out more slowly.

Approximately $2.3 billion is due to be spent over two decades on capital works to accommodate Auckland's growing water consumption.

The spending is not just on raw supply, but also cross-region pipelines to make the most of the water we have, and on being able to treat higher volumes of water.

If Auckland's 'townie' majority is not convinced by the fiscal benefit of water conservation, then how about some restraint out of solidarity with the rural Aucklanders who are getting by, tipping buckets of non-drinking water into toilets while waiting for a $200-$300 water delivery?

Watercare does seem to be on top of it all. The reservoirs are more than haf-full - literally -  and the winter supply boost is due to come on stream.

However, winter is not here yet and neither is the rain, so continue to treat water like the precious commodity it is.