Overall dam levels since November 2001
Sydney's overall dam level has gradually dropped since it was last full in 1998.
This figure shows the data since November 2001 for overall dam levels.
You can see this in more detail in the year-by-year figure below.
This figure shows the overall dam levels for the last few years. Each line represents how full the
dams are for that year. From this figure we can see that the large drops in dam levels (since
November 2001) came in the second half of 2002 and first half or 2004. The rest of the time
the levels appear fairly steady. As no two lines meet each other, we can say that in every 365 day period since 2001, the dam levels have gone down.
Are Warragamba dam's levels dropping faster or slower than Sydney's other dams?
In the following graph you can see the total amount of water available in Sydney's various dams since 2001.
The thick line is the total system water available. It is obviously just how large a part of Sydney's entire system
is made up by Warragamba.
Since 2001 the total water in Sydney's dams other than Warragamba has remained relatively
constant (whilst Warragamba's level has dropped). This is obvious from the following diagram.
This difference is explained primarily by Sydney Water management primarily using Warragamba Dam water for
Sydney's water needs (for several reasons). The fact that the droughts in NSW tend not to affect the coast significantly is also a factor.