7 May 2024

Decommissioned dam considered to help increase Wellington's water supply

6:43 am on 7 May 2024
The Morton Dam in Wainuiomata.

The Morton Dam was decommissioned in 1988, but may be used again. Photo: Supplied / Greater Wellington Regional Council

Wellington Water could bring a decommissioned 113-year-old dam back into service to increase future water supply.

The 164-metre-long Morton Dam was built between 1908 and 1911 in the Lower Hutt suburb of Wanuiomata, and was decommissioned in 1988.

Heritage New Zealand proposed listing the piece of infrastructure as a Category B heritage site in March, but that proposal was put on hold when it was discovered that Wellington Water was considering reinstating the dam.

Wellington Water told RNZ they'd recently completed a "comprehensive water supply strategy update" which looked at options for long term supply and demand in the region beyond the next 10 years.

One of the options was recommissioning the Morton Dam to to help meet demand from a growing population.

Further investigations into the options are required and are slated for the coming years.

Wellington Water said it will be likely a decade or more before any decisions are reached, and it could not say how much bringing the dam back into service would cost.

The water provider told RNZ that alongside providing advice for councils' long term plans, it was important to consider increased demand on supply in the longer term.

In Hutt City Council's draft long term plan, it allocated $1.5 billion for drinking, storm and wastewater infrastructure over the next 10 years.