It will be some time before the Northland Regional Council's independent commissioners make a decision regarding 24 applications to take up to 6.2 million cubic metres of water from the Aupōuri aquifer annually, but the the Ministry of Education clearly shares the concerns expressed by many private bore owners on the peninsula.
The ministry is calling for closer monitoring of groundwater at some Far North schools to ensure that their bores don't run dry due to avocado irrigation. And if any school bores do run dry, or suffer salt water intrusion, it wants orchardists to stump up for the costs of setting up alternative water supplies.
The regional council's commissioners are due to complete three days of hearing submissions for and against 24 applications by the Aupōuri Aquifer Water Users' Group to draw up to 6.2 million cubic metres a year at Te Ahu, in Kaitaia, today. The water would mainly be used for to irrigate avocado orchards, which are burgeoning in the Houhora area.
Submitters include the Ministry of Education, which has seven schools (at Ngataki, Pukenui, Waiharara, Paparore, Awanui, Pukepoto and Ahipara) that largely rely upon the aquifer for water.
Hydrogeologist Kenneth 'Keg' Alexander said overall the council's proposals for monitoring the aquifer for salt water intrusion and groundwater depletion were ''relevant and robust,'' but he called for extra monitoring of some school bores, especially those drawing from the shallow aquifer, which had not been assessed as thoroughly as the deeper shell bed aquifer.
Speaking on behalf of the ministry on Tuesday, Alexander said Ngataki School's 18m shallow aquifer bore needed to be monitored to make sure it wasn't affected by pumping from the deep aquifer at orchard bores 1.4km and 1.9km away.
Waiharara School, with a 38m bore in the shallow aquifer, was just 200m away from a proposed deep aquifer bore, yet no monitoring of the shallow aquifer near the school was planned.
At Pukenui School, on the other hand, he believed the proposed monitoring regime was sufficient, and he expected the other schools would be unaffected because th
ey were far enough away from proposed orchard bores.
Ahipara School was 4.5km from the nearest extraction bore, but because it was just 800m from the coast, its bores were at risk of saline intrusion. They also needed to be monitored for salt levels.
Alexander, who described his recommendations as "relatively small and prudent," told the commissioners that if any school bore became unusable due to salt water intrusion the consent holders should be required to immediately provide the school with a temporary water supply until a permanent alternative could be provided, at the consent holders' expense.
Last year the council said it considered that the potential adverse effects of the 24 applications on the environment, including saline intrusion and surface water features such as wetlands, would be no more than minor, but could lower the water level in the aquifer to a point that would adversely affect the ability of some people between Ngataki and Ahipara to take water from existing bores or surface water bodies.
The timing and magnitude of any potential adverse effect would depend upon bore depth and construction, the nature of the surface body from which water was taken, and the severity of any future drought