Worst drought ever for Brisbane dam catchments
In March 2007, the Queensland Climate Change Centre of Excellence (QCCCE) indicated in its report The South East Queensland Drought to 2007 (PDF, 496kB)* that the current drought is the worst on record for the catchments of the Wivenhoe, Somerset and North Pine dams.
The report found that:
- catchment rainfall in the 70 months since 2000–01 (when storages were last full) was 24% less than the historical average over equivalent 70-month periods
- the only other such rainfall deficit, over such a long period, occurred in the so-called Federation drought which, in South East Queensland, lasted 61 months from the end of the wet summer of 1897–8 to April 1903.
- the current drought is more protracted and the rainfall deficit more severe than during the Federation drought.
- there has been a strong drying trend in eastern Queensland since 1950, and a weaker drying trend since 1900.
The report noted that as a number of natural and human-induced factors had possibly influenced the area’s rainfall, it wasn’t clear if the down-trend would continue.
What has caused the current drought?
The drought in South East Queensland has also been associated with a widespread drought across most of eastern Australia (see Figure 2 below), and an ongoing downward trend in rainfall in parts of eastern Queensland (see Figures 4a and 4b in the report). The report considers links between this drought and the El Niño-Southern Oscillation phenomenon, and whether the drought may also be linked to climate change.
Figure 2.0 - Rainfall from April 2001 to January 2007 compared with historical rainfall.
Figure 4a - Ongoing downward trend in rainfall in parts of eastern Queensland 1950-2006
Figure 4b - Ongoing downward trend in rainfall in parts of eastern Queensland 1900-2006
Long term trends
Since the report was prepared, the drought has become even more protracted and rainfall deficits have increased. The following graph is an update of Figure 1 in the report which compares the accumulated rainfall deficit in the catchment area to the west of Brisbane from April 2001 to June 2007, with that in the previous worst drought (from April 1898 to April 1903).
Figure 1 - Accumulated rainfall deficit since April 1898 and April 2001
*Requires Acrobat Reader
Last updated 14 August 2007.