Electromagnetic signals are analysed to create a 3D model of the hidden. Photo: GNS Science
It's hoped new data on Hawke's Bay's freshwater aquifers can help reduce the risk of drinking water contamination, following the campylobacter crisis in Havelock North eight years ago.
The region relies on underground aquifers for its drinking water and irrigation, and in 2016 more than eight thousand people were infected and four people died from drinking water out of contaminated bores.
The project took four years and was focussed on gaining a better understanding of Hawke's Bay's water sources. Researchers from GNS Science used a large hexagonal loop suspended below a helicopter to map the vast groundwater system beneath the surface to depths of 300 metres.
The GNS Science senior hydro-geophysicist Zara Rawlinson said the level of three-dimensional detail has exceeded expectations.
"This high-resolution spatial detail, combined with existing borehole data such as the age of groundwater, has significantly improved our understanding of the region's aquifer systems.
"This is vital information to support the sustainable management of Hawke's Bay's freshwater," she said.
Data was gathered across 8000 km of flight lines in Hawke's Bay. Photo: Hawke's Bay Regional Council
GNS Science and Hawke's Bay Regional Council (HBRC) have completed an analysis of 8000 kilometres of data, which will inform water management policies and reduce future contamination risk.
HBRC team leader hydrology and groundwater science Simon Harper said the findings are expected to benefit businesses and the public.
"The new models will help the Council make better policy and rules to balance the water demands of industry and agriculture, while not adversely impacting the health of our aquifers," he said.
It provides vital information that can help reduce contamination risk, as Rawlinson said drinking water security is a key priority for the region following the 2016 Havelock North campylobacter outbreak.
"We've refined the mapping of the near-surface clay-rich layer of the aquifer, which helps us understand the vulnerability of the groundwater system to surface contamination.
"The models can be used to improve our knowledge of how contamination flows through the system, and to help define source protection zones for drinking water wells," said Rawlinson.
Data from the survey has been used to update numerical groundwater models for the Heretaunga Plains, Ruataniwha Plains and a Bridge Pa model. The models are the primary tools used by the regional council when they set groundwater allocations and make other management decisions.
Funding for the project included $300,000 from GNS Science, $2.4m from Hawke's Bay Regional Council and $2m from the Provincial Growth Fund.