AN OBSERVATION OF THE CONFLUENCE OF STATISTICAL ABERRATIONS, DAM RATIOS, TIMING AND UNCOMMON RAINFALL EVENTS THAT COMBINED TO PRESENT OUR DAMS AS VICTIMS OF A SEVERE DROUGHT. THIS IS NOT THE CASE. THEIR INFLUENCE ON CONCLUSIONS REACHED AND ACTIONS TAKEN.

Author : J. V. Hodgkinson F. C. A. Chartered Accountant
August 2006 to April 2008

  UPDATES : November 2008. This website is maintained as it was in April 2008. Currently the Dam levels are around 40% and, with the addition of the Grid, should be maintained around that percentage. The next "uncommon meteorological event" will fill the Dams to overflow. This event will show that that the actions of "uncommon events", being Monsoons, Cyclones or Large Rainfall Depressions that generally cover all of SEQ, is again misunderstood and that they are the major source of our water supply. Our current storage capacity is insufficient to deal with them. The historical fundamental flaw of the cancellation of the Wolfdene Dam (1989) is being repeated in reverse at Traveston Crossing in the Mary Valley. See "Home" page for further updates.

A few of the principal statistics have been graphed for visual comprehension. This graph shows the Sq Klm of the catchments.

Dam capacities highlight the enormous capacities of our Dams. The Somerset was our mainstay until 1986 when the Wivenhoe was commissioned.

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 SEQWater web-site provides the overall statistics of the dams. Of particular note is the completion dates of the Wivenhoe in 1985 and the Somerset in 1959.

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.