Emergency water services planning for Wellington

The supply of water to Wellington city is extremely vulnerable in a major earthquake. The bulk supply lines from the Hutt Valley cross the Wellington fault in five places and restoration of a limited bulk supply to Wellington city following a major rupture of this fault is estimated to take up to 55 days. Functional restoration of the local water network will take up to 30 days longer for the furthest points of the network as there will be limited water available to re-pressurise, test for and repair leaks.

Capacity has been working on earthquake preparedness since its inception in 2004 and has convened a Water Services Emergency Preparedness Group (WSEPG) including representatives from the four city councils WCC, PCC, HCC and UHCC, the Wellington region emergency management office and Greater Wellington regional council. The recent Canterbury earthquakes have increased the focus on this work.

As part of the planning activities this group commissioned MWH to investigate alternative water supply arrangements and to develop a plan for the supply of water following a major earthquake. This investigation covered surface water, groundwater, bottled water, portable desalination and rainwater in addition to the city reservoir storage.