Published 23/04/2024
Wainuiomata Water Treatment Plant temporarily shutdown due to low river levels
Lower river levels over the past weekend, which forced the temporary shutdown of the Wainuiomata water treatment plant, have been a timely reminder for the need for level 2 Water restrictions, even though summer has ended.
“We’ve gotten through a tricky summer by working together,’ says Charles Barker, Wellington Water’s Director of Regulatory Services. “We knew this summer could have a long tail, and even though we’re moving into colder weather, this goes to show how important it is that people are still conscious of their water use and following Level 2 water restrictions. That means no sprinklers or irrigation systems – just water your garden by hand.”
The running of the Wainuiomata Water Treatment Plant is a key consideration when Wellington Water assesses the need for tighter water restrictions.
“Had this occurred (the low river levels) earlier in the summer, it is likely it would have resulted in a move to tighter water restriction levels," says Charles.
"However, as we head into winter, demand is down due to shorter days and low temperatures. This helps us manage supply and has enabled us to remain at Level 2 water restrictions."
Available supply is also affected by the low level of Te Awa Kairangi/Hutt River. To continue supplying enough drinking water, we’re relying on the Waiwhetū Aquifer and using the storage lakes to supplement supply. The storage lakes are vital to a resilient supply of safe drinking water. Level 2 water restrictions help us manage water supply, ensuring the lakes aren't drawn down on too quickly.
The shutdown of Wainuiomata Water Treatment Plant is a risk every summer. Operational improvements meant that we could continue to draw from the Wainuiomata and Orongorongo rivers at lower levels than previous years.
Recent heavy rain provided a short, sharp increase in river levels, but these dropped away quickly. Steady and continuous rainfall over a number of weeks is needed to get the rivers back up to more sustainable levels, which will be a key factor in moving down to Level 1. With no significant rain forecast for the next ten days, we are monitoring the situation closely and will continue to keep people updated.
Editor notes
Wellington Water is owned and fully funded by Wellington City Council, Hutt City Council, Porirua City Council, and Upper Hutt City Council, Greater Wellington Regional Council and South Wairarapa District Council. All six councils are equal shareholders.
Our councils own the water infrastructure in the region, and they task us to manage the infrastructure and deliver water services to our communities.
Wellington Water is governed by a Board of Directors. The Board and our organisation receive overall leadership and direction from the Wellington Water Committee, which are also responsible for appointing members to the Board.
The Wellington Water Committee is made up of representatives from our council owners and mana whenua.