The Council undertakes a specific groundwater investigation where a potential issue has been identified, e.g. elevated nitrate or increased risk of salt water intrusion. There are currently five aquifers in Northland that are subject to further investigation – Ruawai, Taipa, Maungakaramea, Russell and Whatitiri.
Important for: irrigation, stock and public drinking water supply.
Issues: water quality degrading and the risk of saltwater intrusion.
Test results: Ruawai (six bores) saltwater intrusion in the south-eastern zone of the aquifer. No significant increasing trends.
Taipa (four bores) Nitrate levels are below the NZ Standard but elevated and the Council will continue to monitor.
Important for: source of water for domestic use.
Issues: saltwater intrusion.
Test results: (four bores) No increase in saltwater intrusion.
Important for: domestic and stock drinking water and irrigation.
Test Results: elevated nitrate concentrations. The Council is liaising with local property owners in an attempt to reduce levels.
Test Results: (seven bores) high nitrate levels in one isolated bore. The Council has been talking to the landowner regarding fertiliser application.
During 2008-09, 13 bore sites were sampled to determine the average age of groundwater in each. Understanding the mean age of groundwater is important for interpreting the water quality results and the potential effects of land use on groundwater quality.