Wellington submarine pipe to supply water in an emergency

1:30 pm on 16 August 2018

A pipe is to be built under Wellington Harbour, to supply the capital with fresh water in the event of a large earthquake.

All the moisture from recent rainfall in Wellington left some eerie low cloud over the harbour.

Photo: Metservice

Greater Wellington Regional councillors voted today to go ahead with a plan to build the cross-harbour pipe - which would help supply Wellington city with water in an emergency.

The decision came after the drilling of two bores in the harbour found the water couldn't be used for drinking, unless it was treated, which would be expensive.

The Council had been hoped the aquifers would be a cheaper option than building the cross-harbour pipe.

An emergency water supply is needed because the pipes through which water flowed comes from the Hutt Valley, following the line of State Highway 2, and are expected to rupture in a big quake, cutting the capital off.

The cross-harbour pipe plan had been on the council's books for a long time, council chairperson Chris Laidlaw said.

"And it is a practical way of solving a problem which is going to be, if we get the big one, going to be a mammoth challenge. Without some form of emergency bulk water supply for Wellington city, we're really very exposed."

The $115 million pipe was first mooted in 2015, when funding for it was put aside in the Greater Wellington Regional Council's long-term plan.

The council said that price was an estimate, and could change as the project was designed.

The cost so far of the harbour bores investigation was about $5.2 million.