To cope with the traditional surge in demand over summer, the City Council said it may need to draw water from wells that have not been signed off as secure. If that happens, all water provided from that pump station will need to be chlorinated.
“There is no way to separate the water from the secure wells which doesn’t need to be chlorinated from that supplied from the unsecure below ground well heads, which will need to be treated,” said city council water supply improvement manager Helen Beaumont.
“What’s important for people to understand is we need them to reduce how much water they use so we can keep working on upgrading well heads. Being able to work over summer is essential if we’re going to have any chance of removing chlorine within the 12 month deadline.”
If consumption isn’t reduced enough, the Council will consider introducing water restrictions.
“We’re hopeful we won’t need to go that far because the community has indicated it was prepared to save water this summer if it means we can get the work done and end temporary chlorination sooner.
The Council did a survey and about two-thirds of people said they would be prepared to reduce water use while nearly 80 per cent were in favour of restrictions.
There are nine unchlorinated pump stations around Christchurch, primarily in the east and nor-west of the city. Most of these pump stations have more than one well.
“Over winter, we have been able to rely on the secure above ground well heads at these pump stations. However when usage goes up, we need to reintroduce the below ground wells that are yet to be upgraded, which means the water requires chlorination.”
There are four sites with only above ground well heads — Gardiners, Estuary, Keyes and Prestons. Water from these will not be chlorinated.
The Council is encouraging hand-held watering only for lawns and gardens on alternate days. Watering should take place between 9pm and 7am.