Media release 24 December 2010

Christchurch city faces water restrictions

Please reduce outdoor water use

Water restrictions are likely in Christchurch this summer because of earthquake damage to the city's water reticulation network, reservoirs and wells. Christchurch City Council is closely monitoring the situation.

Although normal water supply was restored in the days after the September 4 earthquake, the water supply system has been compromised. On hot summer days, Christchurch uses up to four times the annual daily average, and the compromised water reticulation system may not cope with this peak.

As a result, Christchurch City Council may need to impose water restrictions to protect the water supply. The most preventable form of water over-use is in "domestic irrigation", or people watering their gardens over summer. The situation is also closely tied to weather patterns.

If we go to what is called Level 1 restrictions, this will mean that people with odd- numbered street addresses can water their gardens on odd-numbered days of the month, and those with even- numbered street addresses can water on even-numbered days.

Level 2 restrictions mean hand-held garden watering only; level 3 restricts to hand-held hoses on alternate days; and level 4 bans all watering.

If Level 1 restrictions do not quickly improve the situation, restrictions will be elevated.

Christchurch City Council's acting Unit Manager City Water and Waste Mike Bourke says the goal for the City is to conserve water, and for each household to aim for a 10% reduction in the amount of water they would have used last summer, particularly for outdoors use.

"If restrictions are imposed, and the usage rate doesn't drop, we will be forced to impose stronger restrictions."

The main area of concern is the well fields. Ten per cent of Christchurch's wells are no longer usable, and a further 44 per cent require repair or redevelopment.

Breaks to pipes in the reticulation network have been repaired and the City is now replacing around 19kms of water main and sub-mains. Three reservoirs have been damaged and repairs are underway. These require each reservoir to be taken out of service while work is done.

It is estimated that it will take 18 months to restore the City's well fields to pre-earthquake condition because of summer peak demand period and the time and resource it takes to develop a well.

"Therefore if the City does not limit water consumption over the peak summer period there is a risk that the central zone will be stressed during hot summer days and we may have problems maintaining fire fighting pressures," says Mr Bourke. "Stressing the well fields can then cause water quality issues and secondary failures which would make the situation more challenging."

Tips to conserve water:

* Check taps and your water meter for leaks

* Minimise use of automated irrigation

* Use mulch to keep your garden cool and moist

* Water the garden at cooler times of the day, in the morning or evening, to minimise evaporation and water wastage. Avoid watering in a nor'west wind as it quickly evaporates the water

* Do not hose down paths and driveways; use a broom.

* Use a gun nozzle on your hose - this makes it easier to turn the water on and off, preventing water wastage.

ENDS

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