It will take La Nina to KO lingering Big Dry

It may be the case that, given how incredibly dry it was in Auckland earlier this year, that ground is still

not fully replenished.

Ben Noll

Even after months of Auckland downpours, pockets of drought in the region linger from the biggest dry to hit the region in quarter of a century.

But those parched spots are expected soon to be swept away by awarm but wetsummerunder La Nina – and Watercare’s boss says the agency is already in a “strong position” to meet coming demand.

Niwa’s monitoring shows hotspots of excessively dry soils werenowfew and far between around most of the North Island, after the western and central areas received rainfall totalling50mmormore last week.

Although northern spots also receivedsomerain, small to moderate drops in soil moisture were still recorded across Northland, Auckland, the Coromandel and the East Cape – with the driest ground currently found in the Far North.

In the South Island, soils were driest compared to normal for this time of year in lower Westland – and wettest around Nelson.

Drier than normal conditions were still to be found in Auckland region.

Niwa meteorologist Ben Noll said pockets of hydrological drought were still holding on from last summer.

“Hydrological drought is basically howthe moisture in the ground is doing, both near the top of the soil, and all thewaydownto lower depths.

“Sometimes that can be out of synch with meteorological drought, whichwerelate more to rainfall patterns.

“So it maybe the case that, given howincredibly dry it was inauckland earlier this year, that ground is still not fully replenished,” he said.

While big rainfall events were helpful for bringing updamlevels, too muchrain falling at once on parched soils often ran off before it could be properly absorbed into the soil.

Noll said isolated drought pockets remained most visible from the North Shore, south to the Hunuaranges.

“I think inmanywayswehave alleviated [the drought], but there are still lingering reminders of what once was, earlier this year.”

Heexpected that, if a Lanina climate systemnowinfluencing our weather kept delivering its muchneeded moisture to the region, those remnants would be gone by midsummer.

“The furtherweget into summer, it mayeven be we’re looking at the other side of the coin, with respect to flooding events. Aswesaw in Napier, those high-intensity rainfall events can be a hallmark of La Nina, butwhere they land is anyone’s guess.”

At the weekend, Auckland’sdam storage levels were sitting at 72 per cent – well below the 91 per cent normal for this time of year.

Extra water reserves were expected to comefrom several upgrades to bores and reservoirs.

Acompleted Pukekohe East reservoir, would allow the Waikato water treatment plant to draw an extra 25 million litres each day.

Further boosts wouldcomefrom two Pukekohe bores coming back into operation with a newmodular treatment plant, an upgraded Onehunga aquifer, thenewpapakura water treatment plant, and the returned service of the Hays Creek dam.

Watercare also credited efforts by Aucklanders to slash their water use this year.