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 : No change since August 2007.
This is an example of the data provided by the Bureau. It is obtained through identification of the Rainfall Station numbers and then by request to the data section. A small fee is required. You will observe that the information is in EXCEL spread sheet format which gives easy access to assessing the required information.
The Bureau of Meteorology measures rainfall against the 30 year average (or mean) 1961 to 1990. To maintain statistical purity, I have used all the rainfall stations that have been in continuous operation from 1961 to 2006. The remaining stations were mostly closed prior to 2006 but have been inspected for possible aberrations.
These charts were initially used to confirm the rainfall maps. The Qld. Govt. Climate Change Centre for excellence has since confirmed the overall percentage as 76.2%. The relationship of the Somerset and Wivenhoe dams is one of the central ingredients of this examination. The Somerset is on the Stanley river and the Wivenhoe on the Brisbane River at the junction of the Brisbane and Stanley Rivers. It backs up to the foot of the Somerset.
They have separate catchments but as we will see the Somerset is the dominant partner.
The North Pine Dam is completely separate to the other dams. (SEQWater verbal advice). It experiences similar rainfall patterns. A reading of the "water grid" indicates that the proposed Traveston dam will feed into the North Pine dam.
Because it is separate, it is excluded from these observations. The Dam levels quoted contain all three Dams. The North Pine Dam however mirrored the Somerset Dam. It is also much smaller than the Wivenhoe and Somerset and therefore has little influence on all calculations in this web-site. The statistics compared to the total of the three Dams are : Capacity 12.2 % : Yield 10.9 % : Catchment area 4.7 %. Annual Rainfall is listed by SEQWater as : Wivenhoe 940mm : Somerset 1230mm : North Pine 1175mm.