Bureau Meteorology
AN OBSERVATION OF THE CONFLUENCE OF STATISTICAL ABERRATIONS, DAM RATIOS, TIMING AND UNCOMMON RAINFALL EVENTS THAT COMBINED TO HAVE OUR LEADERS DRAW INCORRECT CONCLUSIONS. THEIR INFLUENCE ON ACTIONS TAKEN.

Author : J. V. Hodgkinson F. C. A. Chartered Accountant : Aug 2006 to November 2013    

The principal thrust of this website is
FLOOD PROOFING BRISBANE from damaging floods to the point of extinction. MITIGATING flooding in Ipswich and Gympie. Putting REAL MEANING into "Drought proofing SEQ" and ensuring our water supplies by natural means well into the future

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

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May 2009 Largely as it was in August 2007

The Bureau definition of a drought has changed from "acute shortage of water". This old definition was used by the QWC and applied to the depleted dam. It ignored the hydrological situation ( source meeting with Minister Hinchliffe and QWC officers 31st January 2009)

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Initial look at the Bureau's hydrology maps that formed the basis of the "drought"

2003 to 2006 Decile map BOM.jpg (132650 bytes)The Bureau of Meteorology is the chief recorder of Rainfall and other items related to weather. In August 2006, their rainfall maps were my first observation point. A click on the "drought" heading for the last three years to July 2006 showed a decile map which grades rainfall from 1 to 10 and recorded that it was in the category of "lowest on record" for the catchments of the Dams. 

2003 to 2006 Percentage map BOM.jpg (152348 bytes)I then clicked on the "percentage" map for the same period and rainfall to observe how much rain fell. It showed that the catchments had received 80 % of the long term average 1961 to 1990.

BOM e mail 25 08 06 Page 1.jpg (131735 bytes)The diversity of the answers for exactly the same rainfall required explanation. You will see from the attached e-mail from a Climatologist from the Bureau of Meteorology National Climate Centre that the two results are compatible. The Dam catchments had received close to 80% of the long term average and that 80% was the "lowest on record". They later confirmed that District 40 in which the catchments reside is a stable rainfall area and permits this Statistical aberration.


The deficiency of 20% in both Somerset_65_06_Sum_and_Non.jpg (317322 bytes)Wivenhoe_65_06_Sum_Non_Sum.jpg (267816 bytes)catchments was in the non-summer months which normally create little inflow.



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May 2009 Additions added

Definition of a drought

In the B.O.M. glossary of terms, Drought is described as "Prolonged absence of marked deficiency of precipitation (rain).

In "living with drought" the Bureau states that "Meteorologists monitor the extent and severity of drought in terms of rainfall deficiency".

Our Leaders have placed before us the Meteorology definition of a drought. It was contained in the "Decile" map delivered to our homes in SEQ. "Decile maps" grade rainfall in section 1 to 10 with  1 being the lowest on record and 10 being the highest on record. 

It was used by the QCCCE when documenting the "drought" to January 2007. The base was on rainfall as no hydrology report was available at that time distance.

THE LAST TWO YEARS ( to March 2009)

A look at the available maps (in the bureau website) for the last two years reveals that

The "drought" map showed no drought in SEQ in the last two years.
The "decile" map shows that the rainfall for the last two years is in the 4 to 7 category. In other words average rainfall.
The "percentage" map shows that the rainfall percentage compared to the long term average of 1961 to 1990 was 100%.
 

APPARENT DEPARTURE FROM METEOROLOGICAL DEFINITION IN THE LAST TWO YEARS

We are all aware that the definition of a "drought" is now tied to the dam levels with 60% ( now 74% May 2009) being the end of the "drought". This is a significant change to a "social expectations and perceptions" view of a drought.

In my view, departure from the meteorological definition obscures the underlying reason for the depletion of our dams and as a consequence the view of all solutions to it.