Aerial mapping project wraps up

Working on the aerial mapping project were, from left, Ben Swart (SkyTEM field manager), Warrick Wright (HeliA1 pilot) and Paul Jardim (SkyTEM field assistant) with the underground water mapping technology used to detect the state of the region’s aquifers. Pictures by Liam Clayton

A major aerial mapping project intended to gather information on the region’s underground water resources concluded with a survey of the Poverty Bay Flats at the weekend.

The project was carried out by Aqua Intel Aotearoa (a partnership between GNS Science and Kānoa, funded by the Provincial Growth Fund) which is working with Gisborne District Council to plan the survey, in discussion with Te Runanganui o Ngāti Porou, Tāmanuhiri Tūtū Poroporo Trust, Te Aitanga a Māhaki Trust and Rongowhakaata Iwi Trust.

The surveying was undertaken by helicopter, using SkyTEM aerial electromagnetic (AEM) technology to “see” under the ground.

“GNS scientists will now begin the lengthy process of analysing the data, while discussions continue with hapū and iwi on arrangements for accessing, storing and using the data,” said Aqua Intel Aotearoa programme director Jane Frances.

“There’s been a fair bit of interest in the helicopter surveying over areas in the north of Tairāwhiti and Poverty Bay flats. I want to reassure everyone that the only aim of this project is to provide Tairāwhiti people with high-quality science and data to support regional decision-making. Knowing more about the region’s aquifers and how the aquifers connect to wetlands, lakes, streams and the ocean, will help people in the region decide how best to care for the wai.

“Conversations are continuing on how to ensure data management arrangements work for hapū, iwi and the council.”

The Gisborne Herald was contacted by one concerned resident after a helicopter flew over her property.

Responding to The Herald yesterday, Jane Frances said the pilots made every effort to avoid flying directly over houses and built-up areas.

“However, I can assure everyone that AEM is safe. Because the helicopter is travelling at high speed there is limited exposure to the magnetic field generated from the equipment. The exposure is safer than watching an LCD  or plasma TV or blow-drying your hair.

“This technology is used safely around the world and has been used to survey aquifers in Northland, Hawke’s Bay, Wairarapa and Southland.”

SkyTEM general manager Steve Johnson said the SkyTEM aerial electromagnetic technology (AEM) used in the survey was safe for people, animals and electronic equipment.

“SkyTEM technology has been safely used around the world since 2003. SkyTEM AEM creates an electromagnetic field which, in turn, produces an electric current and a magnetic field in the ground which is measured to map groundwater and geology.

“Electromagnetic (EM) fields from the AEM system are tiny compared to EM fields generated by household wiring or radio, mobile phone and TV antennas; and the currents generated in the ground are of the order of micro to nanoAmps (a billionth of an Amp). Given the widespread use of electricity, magnetic fields are present everywhere in our daily lives.

“By comparison, the magnetic field from the system (0.4 milligauss) is comparable in strength to the magnetic field experienced by a person standing 20cm outside of an average house, and far less than the magnetic field generated by a household hair dryer (1-70 milligauss). In addition, as EM exposure decreases significantly with distance and time, the altitude and speed at which the helicopter flies past vastly reduces any exposure to EM from the SkyTEM equipment.”