Major milestone on providing good quality water to residents

Council has given approval for staff to lodge a resource consent application with the Greater Wellington Regional Council for the proposed Waikanae River recharge scheme.

“This is a significant step forward in our goal of providing a dependable high quality supply of treated river water to residents in Waikanae, Paraparaumu and Raumati for the next 50 years,” said Deputy Mayor Roger Booth, who chaired today’s Council meeting.

“Today’s decision is a milestone for a very important project that has been running for several years, and an issue that has been occupying column inches in the local newspapers for many, many years.”

Reports presented to Councillors said there was enough water in the borefield to cover a high population growth scenario and a 50 year drought up to 2060. This was based on extensive research undertaken by Council over the past three years.

The reports indicate there is a risk of saline intrusion, but this is low and will be restricted to the coastal fringe. This will mean the closure of K13, a very productive bore, close to the coast.

Recent investigations show the aquifer systems are inter-connected. This means there could be some impact on private shallow bores in the area during “drawdown” in times of drought. Councillors were told the impact would be localised and reduce with distance from the Council bore.

Modelling indicated 30 to 50 existing private wells could be affected in the shallow aquifers and 10 to 15 deeper wells in the Waimea and Pleistocene aquifer. Project manager Phil Stroud said team members had already been in touch with the bulk of the private bore owners in the area. “Given the information we have gathered, we believe the numbers of bores that could be affected will be less.”

Extensive research has been undertaken on the impact of pumping groundwater into the Waikanae River in times of drought. A recent study suggested there could be some increase in algae growth with some types of algae, but this was considered to have only a minor effect on the river.

The reports presented to Council today also contained feedback and recommendations from the Technical Advisory Group chaired by Don Hunn. TAG concluded that the work undertaken for Council had been “painstaking and well done” and members thought Council was “in a position to make a final decision about whether and when to proceed with staged river recharge.”

Councillors were told key stakeholders, two independent scientists and the Te Āti Awa Water Working Group (WWG) had agreed Council should implement a river monitoring programme which would address any effects as they arose. Talks were now underway with Te Āti Awa on a combined governance structure covering the monitoring of future river conditions and projects designed to improve the upper river catchment. 

Council will lodge its resource consent application with the Greater Wellington Regional Council next month. It will seek approval to take up to a maximum 30,700 cubic metres a day of water from the Waikanae River and at times of low river flows, replace it with ground water.