Metro weekly water update 21 December 2018

	Target	Actual
December water use to date	20 billion litres	20 billion litres
Dam storage levels	N/A	55 per cent
Cumulative streamflow into dams	178 billion litres (Post 1975 May to December average)	146 billion litres
December rainfall to date	11.7 mm (December mean rainfall 1994-2017)   13.1mm (December average rainfall 1876-2016)	1.6 mm

Note: 1 billion litres = approx. 400 Olympic swimming pools.  Please note these figures are rounded (except for rainfall) to the nearest whole number.

 

Water use

 

Average daily water use over the last week was 981 million litres, which was below the forecast of 991 million litres. 

 

Since 1 July 2018, we have used 123 billion litres of water - this is 6 billion litres above what we had forecast for this period.  While we have been more ambitious in our forecast this year, water use is around the same as this time last year.

 

Dam level (total for 15 dams)

 

The dam storage level has remained steady over the past week sitting at 55 per cent* of full capacity.

 

*Please note some dams are filled from different sources - dam levels include the transfer of groundwater and desalinated seawater from treatment plants as well as streamflow (that comes from rainfall).  Dam levels should therefore not be used as a single measure to represent the true water supply situation for Perth.

 

Streamflow (total for 15 dams)

 

From 1 May 2018 to 20 December 2018 the dams have received 146 billion litres of streamflow.  The post-1975 average for the May to December period is 178 billion litres.

 

Sprinkler roster compliance

 

The two-day-a-week sprinkler roster now applies across Perth, so make sure your sprinklers are programmed for your rostered water days and only to come on once, either before 9am or after 6pm.

 

Our team of inspectors issued 140 warnings and 98 fines this week.  Since 1 January 2018, we have taken a total of 8522 actions (warnings + fines) compared with 9867 actions for the same period in 2017.

 

Annual rainfall

 

Perth has received 741.4 mm of rainfall since January this year.  The cumulative average rainfall for January to December is 732.8 mm.

 

General water news

 

The Bureau of Meteorology and CSIRO released the State of the Climate 2018 report this week which draws on the latest monitoring, science and projection information to describe the impacts of climate change across Australia’s climate.

 

Climate change continues to impact our water supplies here in Perth, the report notes:

• The drying trend is particularly strong between May to July over southwest Western Australia, with rainfall since 1970 around 20 per cent less than the average.

• Since 1999, this reduction has increased to around 26 per cent.

With that in mind, we wish you all a happy – and waterwise – festive season!