Aquifer mapping promises rich insights for South Wairarapa

South Wairarapa District Council supports the work being done this summer by Greater Wellington Regional Council (GWRC) to map the district’s aquifers.

From late January, a helicopter with special mapping equipment using a loop suspended from cables, will fly over rural parts of the Ruamāhanga Valley to scan aquifers from the air.

The operation will not map ground water as such but look for indicators of it in the geological features of the land.

Aidan Ellims, Chair of the Council’s Infrastructure Committee, said the work was an important project which would allow scientists to build a 3D model of the valley’s potential ground water resources.

Identifying underground aquifers could lead to a greater range of agriculture and horticulture across the Wairarapa, “which could result in more employment and, locally, the identification of a new drinking water source for Martinborough,” he said.

Research into a new water supply for Martinborough in the medium term began when e-coli was detected in the town’s water supply in 2019.

The mapping was meant to take place in 2020 but specialists had to return to Australia due to Covid-19 border controls.

Now the work was able to recommence, Cr Ellims said it would be “great to get this project off the ground and collect data which will help make decisions for not only Martinborough’s future water supply, but the diversification of our primary sector across the Wairarapa.”

SWDC Chief Executive Harry Wilson said most aquifer mapping was modelled and there was little understanding of deep ground water (below 300 metres), “so this is crucial information to our community”.
“Long story short, this is a really significant piece of science that will inform so many decisions about sustainable water use into the future,” Mr Wilson said.

The Council is contributing to the costs of the operation, with the bulk of funding coming from the Provincial Growth Fund.

Why is the survey important?
The survey will provide more information about aquifers, which are layers of gravel or sand that hold or transport water below ground.

Aquifers in the Ruamāhanga Valley provide groundwater for drinking, agriculture, horticulture and industry. They support environmental features like wetlands, lakes and river.

The data gathered is expected to help Greater Wellington to gain a much better picture of what is happening below ground.

Temperatures are projected to rise in future decades, which may lead to greater water shortages. A clearer picture of the interconnections between surface and ground water will help authorities make better decisions about water access and use.

GWRC says it has consulted with iwi on the survey and has given assurances that the technology is safe. It has been used all over the world including Hawke’s Bay and Northland.

During the survey, the pilot will avoid flying over towns and rural houses because metal interferes with the equipment.

The helicopter is not expected to disturb livestock. Noise will be brief and similar to a passing truck.

For more information, visit the GWRC website.

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