Council’s groundwater report released

The latest Groundwater Quantity State of the Environment Report has been released.

As the report's name suggests, it looks at the quantity of groundwater in Marlborough’s aquifers, which are described as “generally very good”.

Groundwater plays a crucial role in Marlborough, serving as a vital resource for drinking water for communities and stock, as well as crop irrigation and industrial processing.

Groundwater exists beneath most of the river valleys and floodplains of Marlborough where porous sediments naturally store water as aquifers.

Council’s Senior Groundwater Environmental Scientist, Pete Davidson, told Council’s Environment and Planning Committee the most significant aquifers were associated with the Wairau River floodplain.

“The Wairau Aquifer is the main groundwater system beneath the plain, providing most of our water and playing an essential role in maintaining environmental balance.”

“In early 2024, water levels in this aquifer were the lowest ever recorded. This was mostly due to outside factors, including past flood protection efforts inadvertently narrowing the river and changes in the river’s gravel supply. Lower flows from the Wairau were also a contributing factor, exacerbated by the year-long drought in 2023/24.”

Council's monitoring network also detected indications of climate change impacts, particularly through evidence of rising sea levels affecting the Rārangi Aquifer. So far, there has been no confirmed instance of saline water impacting on a private coastal domestic well.

For more information go to the groundwater section on our website