Annual inflow to Perth dams, 1911-2010, showing stepwise changes.

By Chalpat Sonti
November 11, 2010

The equivalent of an extra 17,600 Olympic-sized swimming pools of water will be taken from Perth's aquifers this year, as a prolonged dry spell bites hard on supplies.

The Department of Water has approved the Water Corporation's application to take 165 gigalitres from the Gnangara and Jandakot aquifers.

That is 44 gigalitres, or 44 billion litres, more than last year, though about four gigalitres less than in 2006-07, the last prolonged dry period.

The majority of the drawdown, 151.71 gigalitres, will be from the fragile Gnangara aquifer.

The Water Department's water resource director, Rob Hammond, said the request had been agreed to only after the Water Corporation showed it had maximised the output of the Kwinana desalination plant and ensured demand management measures during dry spells remained in place.

"At the same time last year we had enough water to reduce the draw on Gnangara, and we did significantly," he said.

"However this year following record low inflow into metropolitan dams, the Water Corporation has proved to us they need the water to meet Perth's supply needs."

Dams are about 33 per cent full, compared to 54 per cent last year, an after-effect of one of the driest winters on record.

The Gnangara aquifer had provided about 60 per cent of Perth's scheme water in recent years, but that had reduced to 50 per cent with the advent of the desalination plant, Mr Hammond said.

Dry year sees Perth aquifers drained by a parched city


  1. Anonymous said...

    It is a concern for us Perth residents.

    Lucky for us the aquifers are quite big. The one you are talking about is the Leederville Aquifer.

    interestingly enough the loss of water from the aquifers is causing a measurable compression effect. So suburbs around areas that have had water extracted have sunk by 2 cm or so!

    One idea we have is to use recycled and treated sewage water to inject back into the aquifer. If we were to do that then our water supply problems would be much smaller.




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