Our Hawke’s Bay aquifers provide groundwater that we use for drinking, agriculture, industry and the environment.
There are 9 productive aquifer systems in Hawke’s Bay, two large – Heretaunga, Ruataniwha – and seven smaller - Mahia, Nuhaka, Wairoa, Esk, Poukawa, Papanui, Waipukurau/Waipawa.
What we know about aquifer water quality
Water quality in our main Hawke’s Bay aquifers is very good and meets NZ Drinking Water Standards.
HBRC operates more than 100 wells for monitoring short and long term changes in groundwater levels and quality. We monitor key water quality indicators such as nitrate-nitrogen, bacteria levels (Escherichia coli or E. coli), dissolved iron, dissolved manganese, and total hardness.
Some of the smaller northern aquifers have naturally occurring higher levels of iron, manganese and total hardness. This is because the water picks up minerals as it moves through the rocks and aquifer.
The longest monitoring record is near Fernhill where groundwater levels have been measured since 1968. Most of the wells were developed in the early 1990s following the establishment of the regional councils.
We also gather water use data from irrigators and industry, which is invaluable information to help everyone make sound water management decisions.
What we know about the Heretaunga Aquifer
The earliest scientific information for the Heretaunga Plains comes from drilling records at Meeanee 1867 where an artesian bore flowed with a positive pressure of 6 meters above the land surface, which is about the same as today.
In the 1990s the Heretaunga aquifer was investigated by HBRC and the government agency GNS Science. The resulting 1997 report examined drill logs, deep drilling studies and geophysical, chemistry and hydrological data. This work was used to develop our current policies for groundwater management policies in the Hawke’s Bay Regional Resource Management Plan (RRMP).
HBRC is currently working with stakeholders to review land and fresh water management policies for the wider Heretaunga Plains, including the aquifer and the Tutaekuri, Ahuriri, Ngaruroro and Karamū – referred to as the TANK catchments.
HBRC has developed a computer groundwater model of the Heretaunga aquifer. This also feeds data to another computer model which shows how the water flows from groundwater and through rivers and streams on the surface.
These models will help us and the community better understand and decide how water is used in the TANK catchments.
Heretaunga – quick facts
Size: 460 square kilometres
Depth: Productive aquifer system is generally up to 50m in depth, although may be up to 300m deep in some places
Consented volume: The total groundwater use is approximately 161 million cubic metres per year.
Number of consents: 1,687 resource consents are issued to take this water
Management Plan: Review of Regional Resource Management Plan currently in progress (2016-17) for the Tutaekuri, Ahuriri, Ngaruroro and Karamū catchments including the aquifer
What we know about the Ruataniwha Aquifer
HBRC has developed a computer model of the Ruataniwha aquifer system. This was used to develop land and water management policy and rules for the Tukituki Catchment through the Regional Resource Management Plan Change 6. Limits for water allocation and water quality were set so this resource can be used sustainably.
Ruataniwha – quick facts
Size: Approx 800 square kilometres
Depth: Productive aquifer system is up to 60 m in depth, but up to 200 m in places.
Consented volume: Total groundwater allocation is currently set at 28.5 million cubic metres per year.
Number of Consents: 61
Management Plan: Regional Resource Management Plan Change 6 in 2015 set limits for water quality and quantity.
Mahia, Nuhaka, Wairoa, Esk, Poukawa, Papanui, Waipukurau/Waipawa.
These smaller aquifers have lower use – mostly domestic and stock water supply, with some irrigation. Northern aquifers have naturally occurring higher mineral content (calcium, magnesium, iron, manganese) and some sites exceed the NZ Drinking Water Standards.