Drought: Auckland would have mandatory water restrictions if not for Covid-19

Wednesday, 8 April 2020

Auckland's Upper Nihotupu Dam reservoir in the Waitakere Ranges at the depth of the drought. (Video April 2020)

Auckland could be just weeks away from mandatory water restrictions, as drought depletes supply lakes to levels not seen for nearly two decades.

Reservoirs are below 52 per cent full, 25 per cent below normal and their lowest since Auckland's water crisis in 1992.

Council water company Watercare said were it not for the Coronavirus lockdown, mandatory water use restrictions would be in place now.

'Once it drops significantly below 50 per cent, we will have to consider mandatory restrictions,' Mayor Phil Goff told Stuff.

Upper Nihotupu Dam in the Waitakere Ranges in June 2019 after the driest first half year on record .

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Watercare chief executive Raveen Jaduram.

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'We go down by 1 per cent every three days - if rain doesn't come in May, we'll be in significant problems,' he said.

Auckland Mayor Phil Goff says water restrictions may be needed

Watercare said in addition to drought conditions, the lockdown was adding to consumption woes.

'People are home and therefore their outdoor consumption seems to have increased, so demand has gone up,' said chief executive Raveen Jaduram.

Wairoa Dam in Auckland's Hunua Ranges on April 1.

Consumption had risen slightly in the past week, compared with a week earlier.

'People are feeling anxious and worried already because of Covid-19 and we don't want to add to the stress by putting restrictions,' he said.

Water levels at Watercare Upper Nihotipu Dam in Auckland's Waitakere Ranges, as at July 7, 2019, as levels fell due to a shortage of rain.

Goff said that restraint might not last much longer.

'We're not moving yet, we know there's probably not much rain coming in April but May looks a better month from the long term forecast from the MetService,' he said.

Water levels at the Mangatangi Dam in Auckland's Hunua Ranges, in July 2019, as levels declined due to a shortage of rain.

'If Aucklanders continue to use a lot of water, then we will have no choice but to introduce water restrictions, possibly by the end of the month,' said Jaduram.

The April storage levels are the worst since Auckland's water crisis in the early 1990s when levels fell to the mid-30 per cents, before heavy winter rainfall arrived.

That prompted the construction of a pipeline and pumping station to take a continuous additional supply from the Waikato River, which now supplies an average 17 per cent of the city's needs.

Watercare has negotiated a new additional resource consent that applies when the Waikato River is above its median levels, bringing an extra 25 million litres of treated water through the network.

However the river has not yet risen sufficiently from its summer lows to allow that additional supply to be taken.

About $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 the city has, and on being able to treat higher volumes of water.

Aucklanders are being urged to maintain Covid-19 advice such as regular hand-washing, but take other measures such as restricting showers to four minutes or less.

Watercare wants an end to outdoor use such as washing cars or houses, and watering gardens.

Climate agency NIWA has forecast normal or below normal rainfall for Auckland and the upper North Island over the next three months, with a 40 per cent likelihood of normal rain, and 35 per cent chance of below normal.

'We are at the mercy of the weather here - we need to change our behaviours,' said Jaduram.