Watercare: restrictions remain ahead of dry spring

Water restrictions are likely to remain in place this summer.

A long-range weather forecast reaffirming earlier predictions of an extremely dry spring means it’s now more important than ever for Aucklanders to save water, says Watercare.

Auckland received 40 per cent less rainfall than normal in Auckland between November 2019 and May 2020, making it the region’s worst drought on record.

Despite recent rainfall, Auckland’s total dam storage level is currently 60 per cent, when normally at this time of year it would be above 85 per cent.

MetService meteorologist Georgina Griffiths says August looks likely to deliver some decent rainfall to Auckland, but that’s where the good news ends.

“Our long-range models have always been keen on a drier spring for Auckland. The latest forecasts continue to signal an extended run of well-below-normal rainfall between September and December. The main culprit is expected to be frequent high pressure on our weather maps, meaning a lower turnout for the rainmakers.

“There is the possibility of tropical storms providing a good dose of rain early next year, but it really is too early to tell, and even if they do arrive, we would need the rain to fall in the right places.”

Last month, thunderstorms that flooded the Coromandel and Northland almost missed the Hūnua Ranges entirely.

“We can expect some intermittent easterlies, which may bring good amounts of rain, but the Hūnua Ranges are often sheltered from these systems.”

Watercare head of servicing and consents Mark Bourne, who is coordinating the drought response, says the latest seasonal forecast means outdoor water restrictions will likely continue into summer.

“Aucklanders have been making really impressive water savings since restrictions began, and if we can all continue to keep our water usage down, even if we do have a very dry spring, we should start summer with our dams above half full.

“We are also making steady progress on a number of projects that will give us an additional 40 million litres a day by Christmas, compared to what we had available last summer. With these new sources, careful management of our existing sources and continued savings by Aucklanders, we expect to avoid the need for more severe restrictions.”

Upper Mangatawhiri dam from above. Photo:Watercare

This month the completion of the Pukekohe East reservoir will allow the Waikato Water Treatment Plant to treat and deliver 175 million litres of water a day (MLD). Currently, it is treating up to 165MLD, which is up 15MLD from last summer.

An upgrade to the Onehunga Water Treatment Plant, which treats water from an underground aquifer, will also increase production by another 4MLD in December.

Bourne says daily water consumption figures show Aucklanders have been consistently heeding the call to save 20 litres per person every day.

“Our target for August is 405 million litres of water a day, and our rolling weekly average is well below that at 392 million litres a day. That’s a tremendous effort – under normal circumstances we had anticipated daily demand of about 430 million litres at this time of year – so to be under 400 is something to be really proud of.

“We’re also very pleased to see so many businesses in the outdoor cleaning, car-washing and construction industries are supporting our water-saving efforts by using non-potable water in their daily operations.”