Author : J. V. Hodgkinson F. C. A. Chartered
Accountant : Aug 2006 to November 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: With the exception of a note it remains as it was in August 2009
Again the deterioration in our Dam levels. Of minor note is that the annual report of SEQWater for the year 2005 was incorrect. The Dam levels at 30th June 2005 were deducted from the 30th June 2003 levels instead of 30th June 2004. It has been adjusted in these figures.
The expected annual rainfall in the Wivenhoe at 940mm and the Somerset at 1,230mm is puzzling. You will see from the charts in the "rainfall stats" section that they both appear too high and would place them permanently in a position of "below average" rainfall. I have requested an explanation in writing but it has understandably been ignored. They are currently busy people and have been most helpful in their public pronouncements. The attached graphs further highlight this minor puzzle.
The other aspect of note is that the Annual water supply is currently under review. This attachment was their previous assessment. It suggests that the annual flow into the Wivenhoe and Somerset dams is 446,900 megalitres. That is 1,224 ML per day. Quite adequate for our unrestricted use as compared to the restrictions now in place. If you examine the "Key features" above, you will see that it currently under review. Reference is SEQWater Environment report 2001-2002 page 2.
Note : May 2009 : QWC has considerable disagreement with these calculations. They have changed their approach from HYNF to Stochastic being "best guess under the circumstances". To me it seems that they are having difficulty coming to grips with "uncommon events" which are the major supplier of our water. Their quite normal but temporary departure has caused them some concern. SEQWater had the benefit of 6 "uncommon events" in their calculations. Of course storage is the answer in the expanded Borumba Dam when they are plentiful.
For those readers who are unfamiliar with the Location of the Dams and their catchments, I have included a contour map available from the SEQWater web-site. I have overlaid the town names and catchment boundaries for readability.