Former regional councillor Chris Turver warns the Kāpiti District Council’s river recharge plan for summer droughts may cause gradual saltwater contamination of pure underground aquifers.
He’s calling for an urgent review of the $14million recharge plan. He says it depends too much on a heavy ‘draw-down’ from the underground aquifers during drought to recharge the volume of water in the Waikanae river.
Productive bore threatened
The KCDC has confirmed it will close the K13 bore in Huiawa Street, Waikanae Beach, but says the risk of saline intrusion is low and will be restricted to the coastal fringe.
He says the KCDC’s admission that one bore is being shut down is a frightening because, once started, saline intrusion is hard to stop.
Mr Turver, who chaired the Greater Wellington Regional Council’s resource consent hearing in late 2004 which granted the KCDC the right to put down the original eight production wells, says the hearing committee built in safeguards to limit the chances of saltwater contamination.
More bores planned
But since then the KCDC has put down more bores and is planning to drill at least a further three large-capacity bores as part of its river recharge plan.
Mr Turver says it’s of particular concern that a KCDC report discloses that the three main aquifer systems in the Waikanae Groundwater Zone are inter-connected, which means that saltwater contamination in one aquifer could spread into the others.
“If that happens, then the worst-case scenario if the river recharge plan goes ahead is that the quality of one or more of the aquifers is gradually compromised and the water could eventually become undrinkable,” says Mr Turver.
The KCDC is soon to lodge a resource consent application with Greater Wellington Regional Council for an increased ‘take’ from the bore-field for the river recharge system.
Mr Turver says the KCDC will have to prove convincingly that saltwater contamination would not be a problem.
The KCDC has already signalled that some private shallow household bores in the area could lose water in times of drought as the aquifer levels fall through draw-down from the production wells.