Wellington water supply situation update – 20 March 2013

Today's data:
Daily target water use (maximum) = 130 million litres (ML)
Yesterday's water use = 122ML
Change from Monday = higher by 9ML

Wellington's households and businesses are still doing a great job with water saving but we need to maintain this low level of water use.

Lower demand helps to preserve our water reserves longer. This is necessary in case we quickly return to pre-rain levels of river water availability.

Yesterday’s water supply came from:
Rivers: 8ML
Hutt aquifer: 77ML
Storage: 37ML (Lake 2 - 31ML, Balancing reservoirs - 6ML)

The water in the Hutt River has now cleaned up enough for us to treat. As of 1.00am this morning the Te Marua treatment plant is back treating water from the Hutt River.

The Wainuiomata treatment plant is expected to be back treating water from the Wainuiomata and Orongorongo rivers some time today.

The rivers coming back on means that we can ease back on use of the Hutt aquifer and start topping up lake 2 to make up for the water taken when river water was too dirty to use. The lake level is currently sitting at 94% but we expect to be able to top this up over the next couple of days.

We'll have a better idea of how useful this rain has been for water supply later this week, when we can assess how quickly water quality and flow rates are returning to pre-rain levels. Current indications are that water available from rivers should stay above pre-rain levels for at least 5 to 7 days.

If we get another rain event like this one over the next couple of weeks we will be discussing the easing of restrictions with the city councils.

The 14-day weather outlook has one possible day of rain before the end of March: Tuesday 26th. The outlook is for mostly fine and dry weather – we need to keep demand low.

The latest supply graph

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