Author : J. V. Hodgkinson F. C. A. Chartered
Accountant : Aug 2006 to April 2013
The principal thrust of this
This is my review based on official
statistics and documents. It is done in conjunction with Ron McMah, grazier
of Imbil and Trevor Herse, retired of the Gold Coast
May 2009 : Retained largely as it was in August 2007.
Our Premier has recently resigned and has been replaced by the Deputy Premier. However their comments at the time are relevant.
Our chief decision makers were firmly of the opinion that a
major drought is the cause of our depleted dams. This was followed by the Water
Commission with similar views and expressed in their advertisements.
This brochure insert appeared in the Courier Mail on the 3rd February 2007. It confirmed that our two chief decision makers at that time were attributing our depleted dams to " the worst drought on record". They also introduced the influence of a rapidly expanding population and its water requirements. The map is 6 year map and important to these observations. It is now expanded for clarity.
The map shown is clearly a decile map. A decile map grades the rainfall in decimal categories of 1 to 10 with 1 being "the lowest on record". The last 6 years may not be the lowest but they are in the lowest 10%.
The stability of district 40 in which the catchments reside permits this 80% to be classified in the lowest on record category because the catchments have never received less than 80%.
It should be recognized at this point that the Qld Govt sponsored "Climate Change Centre of Excellence" reported the catchments as receiving 76.2% and defended it as a "Drought" rivalling the "Federation drought". There was no indication that they were aware that the balance of 23.8% occurred in the low to nil inflow non-summer months which have little impact on dam levels. Refer to "Rainfall deficiency" and the " Federation drought" buttons.
Decile evidence of 6 year periods for both the Wivenhoe and Somerset dams will provide more clarity on that statement. In the Wivenhoe there are 7 periods of 6 years in the last 100 years that are within 66mm ( 693 to 759 mm) mm of the last 6 years. With one exception, there were no "Uncommon event" within those periods.
The 80% of long term average rainfall does not fit within the Bureau of Meteorology definition of a drought being "acute shortage of water" in the context of rainfall.
Press release on recycled water 28th January 2007
Relevant comments on rainfall were made by our leaders when announcing the cancellation of the vote on recycled water. They are contained in "Rainfall 2001-06" button.
Of particular interest is the comment that it may take 5 to 10 years to fill the Wivenhoe to 40 percent. It was made in the context of "below average" rainfall which has been examined in detail in this web-site.