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




May 2009 : Since August 2007 the QWC has applied restriction measures and the requirements are now generally available to the public. This section is now redundant in favour of the updated requirements that we must adhere to.


Now redundant but retained for interest

Our normal water requirements

The final calculation is slightly in excess of 1000ML per day. The SEQ Regional Plan part B uses the expression " business as usual "term which to my understanding means - without restrictions of any kind and before the "Emergency measures" as described and Legislated in the Water Commission's web-site. The Requirements are measured on that basis.

In the first instance, the Population serviced by the Requirements.jpg (201573 bytes)Wivenhoe and Somerset Dams were determined. Examination of the SEQ Plan part B indicated the percentages of the areas described as SEQ. The SEQWater web site describes the areas covered by the 3 Dams which includes the North Pine. The calculation comes to 85% of the 2.8 million population. The North Pine population is excised on the basis of Dam capacities. The result is a Population serviced by the two Dams at 2,113,983 or around 2.1 million.

The second requirement was to adopt the SEQ RP Part B method being "per person including Commercial and Industrial at 450 litres per day each". There are adjustments made by me to cater for the Commercial and Industrial from the main Dams. The revision is 474 litres per person per day. The break-up is 300 litres Domestic and 174 Commercial and Industrial.

The third aspect of the Requirements was to measure the calculation with annual depletion of the Dams together with minor estimates of rainfall. These estimates are fully covered in " Rainfall 2001-06" button. You will see from the attached document that the requirement calculations are within tolerance of the annual totals of the depleted Dams together with rainfall in both "low" and "high" yield years.

It was interesting and understandable that in a high rainfall year as 2004, the requirements dip by as much as 6% of capacity. This could well have been the situation in the years 1986 to 2000 covering up to 5 uncommon events. The year 2004 has an accurate assessment of the Megalitres that inflow created. See "Wivenhoe Dam" button.

Confirmation from the South East Queensland Regional Water Supply

The SEQRWSS stage 2 interim report attached confirms Yield Wiv and Som SEQRWSSS Stage 2 interim.jpg (187097 bytes)the water allocation from the Wivenhoe/Somerset Dams is 374,000 ML per annum. This is the volume allocated and required but as we have seen, not capable of being supplied without "uncommon events". It confirms the calculations made above. If reading of the small print is difficult, it is on their web-site page 8 of the SEQRWSS stage 2 interim report. They do qualify their calculations to the extent that effects of a "drought" are not taken into account.

This 374,000ML a year converts to 1024ML per day which agrees with my calculated requirements. The supply from Shortfall.jpg (162076 bytes)these Dams in normal times without "uncommon events" is 481ML per day or 176,000ML annually. Uncommon events we have seen are rare and unpredictable. The South East Queensland regional Water Supply report is based on this 374,000ML. From my reading of copious other reports, particularly of the Mary Valley Traveston Dam proposal, they are all based on this calculation. It may be correct over a great many years but is irrelevant for around 20 year periods.

This amounts to a shortfall of 198,000ML each year until uncommon events. Those who follow the "drought" mantra, without thought, will have their calculations severely distorted.

300 Litres Domestic. Further considerations.

Attached is an extract from a water tank supplier's brochure. They have been in operation for 14 years and service an area from Bundaberg to the Victorian border principally to Country clients. The relevant part is the normal household requirements to be calculated when determining the size of your water tank.

It reveals to us that the normal requirements per person is Rain tanks.jpg (233954 bytes)more than twice the current allowance of 140 litres per day. This is not a revelation to us all. It supports the selection of the SEQ RP part B. However, their main sales are Country and Country people are practiced in water conservation.

The calculations are also available for those who aspire to self sufficiency. There has been a recent move by our Brisbane Lord Mayor to limit the rebate on water tanks to those who link them into household use ( June 2007 ). This is entirely compatible with these conclusions.

Water Commission

The public stated aim of the Water Commission is to reduce the level of water use to 700ML per day. They are Releases into Bne River.jpg (229567 bytes) achieving this through tough water restrictions in operation since May 2005. The Dam releases by SEQWater indicate that they have been reduced to around 50% of normal. It further indicates that the normal requirement is in the region of 1400ML per day and my calculation of our needs may be conservative.

I have not studied the surrounding aspects of water releases but it obviously plays a part. The calculated 1003ML per day requirement is maintained.


The current water requirements from the Wivenhoe and Somerset Dams to resume normal living is a conservative 1003ML per day.