Drought prompts call to take care with groundwater use

10 Feb 2017

Northlanders are being urged to take care with ever-dwindling groundwater supplies as the region’s drought continues, despite much-welcome recent rain in many places.

“Groundwater levels, in small coastal aquifers in particular, are getting very low. People need to make sure they use water efficiently to avoid supplies drying up completely,” says Colin Dall, Group Manager Regulatory Services says.

The Minister of Primary Industries last week (Friday 3 February) officially classified the impact of Northland’s drought as a medium-scale adverse event under the Primary Sector Recovery Policy.

Groundwater supplies diminish with ongoing dry spells.

“There’s a perception that the supply’s unlimited because it’s coming out of the ground, but that’s not the case,” Mr Dall says.

Rainwater stored naturally in underground aquifers provides important supply for many people along Northland’s east coast, around Kaikohe and the Far North’s Aupouri Peninsula.

“People should be conserving groundwater supplies,” Mr Dall says.

“The overnight rainfall in parts of Northland on Wednesday will not make a noticeable difference to groundwater levels.

“It’s easy to think that this little bit of rain means everything’s okay now but that’s not the case,” Mr Dall says.

Wednesday’s overnight rain fell much as forecast, with Whangarei to Kaeo receiving 30-50mm.  The Bream Bay – Mangawhai area received 10-20mm, however Northland’s west coast and the more northerly parts of the Far North district only received up to about five millimetres.

The region’s groundwater resource is created when rain falls and trickles into underground aquifers found in parts of Northland with a particular underlying geology.

It can weeks or even months for rainfall to trickle down into aquifers so there is a lag between rain falling and groundwater replenishment.

Depleting groundwater supplies affected the wider community, Mr Dall says.

“There’s knock-on effects from lowering groundwater. Streams flowing out of the underground storage areas can then dry up which will affect downstream users.”

A wide range of people including householders, horticulturists and pastoral farmers typically access underground water supplies using bores or tapping into springs coming to the surface.

“There are many ways we can all conserve water. These include stopping non-essential water use such as refilling the swimming pool, washing cars and managing livestock and crop water supplies for maximum efficiency,” Mr Dall says.

“Everyone can take simple water conservation measures such as finding and fixing leaking taps, taking shorter showers and thinking carefully every time before the tap’s turned on”.

For more water conservation information go to www.nrc.govt.nz/savewater