Metro weekly water update 8 February 2019

 

	Target	Actual
February water use to date	8 billion litres	8 billion litres
Dam storage levels	N/A	51 per cent
Cumulative streamflow into dams	181 billion litres (Post 1975 May to January average)	149 billion litres
February rainfall to date	13.0 mm (January mean rainfall 1994-2017)   12.5 mm (January average rainfall 1876-2016)	0 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 1.044 billion litres, which was slightly below the forecast of 1.049 billion litres.

 

Daily water use for the last five days
Date	Water use – litres	Forecast – litres
Friday, 8 February 2019	1,080,000,000	1,045,000,000
Thursday, 7 February 2019	1,030,000,000	1,045,000,000
Wednesday, 6 February 2019	1,063,000,000	1,045,000,000
Tuesday, 5 February 2019	1,009,000,000	1,045,000,000
Monday, 4 February 2019	1,092,000,000	1,054,000,000

Note: water use above is calculated up to 8am each day for the previous 24 hour period

 

Since 1 July 2018, we have used 173 billion litres of water - this is 4 billion litres above what we had forecast for this period.  It’s worth noting our 2018-19 demand forecast for the shoulder periods (winter/spring) was more ambitious than previous years and actual total water use is about the same as this time last year.

 

Dam level (total for 15 dams)

 

The dam storage level has decreased slightly over the past week, sitting at 51 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 are no longer an accurate indicator of the health of Perth's water supply situation.

 

Streamflow (total for 15 dams)

 

From 1 May 2018 to 30 January 2019 the dams had received 149 billion litres of streamflow.  The post-1975 average for the May to January period is 181 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 180 warnings and 183 fines this week.  Since 1 January 2019, we have taken a total of 1238 actions (warnings + fines) compared with 1092 actions for the same period in 2018.

 

Annual rainfall

 

Perth has received 7 mm of rainfall since 1 January.  Average rainfall for January and February (1994-2017) is 29.7 mm.

 

General water news

 

When temperatures rise so does our daily water use.

 

The record for the highest daily water use was on 31 January 1991. This was the hottest January day on record in Perth at 45.8C with 1.350 billion litres of water used. That’s the equivalent of 600 Olympic swimming pools of water in one day.

 

With a max temperature of only 38 degrees forecast for tomorrow we’re not expecting to break any records but it is a good reminder to go easy on the outdoor watering.

 

It is estimated that the average person uses around 41,000 litres of drinking water per year on irrigation of household lawns and gardens.  This represents 39% of total residential drinking water use.