May 2009:
Borumba Dam expansion is an important
component of both the Traveston stage 2 plan and the McMah plan.
As you will read it is currently a small
dam of 45,000ML and yielding 35,000ML annually.
There has been no argument that it can be
expanded to a dam of 2,000,000ML and beyond. This was information provided by
Government appointed engineers GHD. We already own all the land and it is a natural amphitheatre.
The main purpose for expansion to
2,000,000ML, or to be the largest dam in Queensland, is for storage for all of
the dams in South East Queensland principally the Wivenhoe/Somerset. At the same
time all "uncommon events" that now flow over the dam wall will be
trapped increasing the yield beyond the calculation below.
Engineers GHD in their report of the 18/05/06 calculated
an
additional yield of 30,800ML excluding all Weirs. The dam storage capacity used
was 460,000ML or approximately 1/4 of the expanded size to 2,000,000ML. The all
up yield set out in yellow by me comes to 80,500ML. This is compared to
the QWC graph handed to Mr Ron McMah of 51,000ML.
The GHD results were based on the the
Department of Natural Resources HYNF studies done specifically for their report
( Refer to first 2 lines).
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Original website resumes
Yield from stage 2. provided to Mr R McMah
This Dam forms part of the stage 2 of the Traveston Crossing
Dam. The intent is to raise the wall 30 meters and provide an additional yield
40,000ML per annum.
Currently the Dam capacity is 46,000ML and with the wall
raising, the capacity will be 350,000ML. ( Reference is Ministerial media
statement 5th July 2006. The Premier of Queensland. )
This yield statement was handed to Mr Ron McMah as part of 
the
terms of reference to examine his proposal for the Borumba Dam. His submission
to the Senate Enquiry is attached at the end of this section. He refused to sign
off on this statement.
It appears to calculate the yield on the basis of rainfall. If
this is so then there are obvious differences in the approach to rainfall and
clear deficiencies. Ms
Bligh is reported in the Gympie Times on the 4th April 2007 that the records for
the Traveston ( which includes Borumba dam ) area do not go back past 1913. I confirmed this with BOM records.
What it does show is that the expected yield for the second
stage of 40,000ML is based on this yield shown on the statement as 51,000ML.
Official releases from the Borumba Dam from the
Department of Natural Resources web-site.
The
yield from the Borumba Dam for its life shows a different view to the one
provided to Mr McMah. It is in excess of 91,000ML per year and quite possibly in
excess of that in view of the differing information from the same source noted
on the schedule.
Comparison with the North Pine Dam.
The "North Pine Dam" button shows that the
yield from the Borumba Dam is in the region of 73,314ML yearly after catchment
adjustment plus the surplus from floods over the spillway. The North Pine has no
flood mitigation. There is photographic evidence of this in 1999.
SEQWater states that the North Pine Dam has the ability to
provide 150ML per day during the "worst drought on record". See "
North Pine Dam" button. This amounts to 54,750ML each year and
converts to 73,314ML with the catchment adjustment, Borumba being the larger.
Add to that the lack of flood mitigation in the North Pine.
To argue that Borumba Dam's yield is 51,000ML yearly is to
destroy the statement by the professionals at SEQWater. In effect it would guarantee
that the North Pine Dam would not live up to the expectations of the South East
Qld water resources plan.
Requirement of stage 1 of the Traveston Dam proposal.
You will have seen that the requirement of the Traveston
Proposal under the Emergency legislation is 75,000ML a year. See " Traveston
Cross" button.
The Borumba yield matches that proposal.
Mr R. McMah's submission to the Senate Committee is set
out in full.
It is now timely to set out Mr R McMah's proposal. It is done
with his permission.
The concept differs from the stage 2 proposal in that a 300 
metre wall would provide a cold water Dam
with a capacity of 2 million
megalitres. It is a natural amphitheatre with steep rocky sides.
The GHD Report
The Desktop review of identified Dam and Weir sites made to
the South East Qld Regional water supply strategy bulk water task group has
supporting information.
In section 3.12.15 of their report they say " Although a
review 
of further information is required, few factors with a potential to jeopardise
the viability of raising the Borumba Dam have been identified." You will
see that their charts proceed above the 1,000,000ML mark.
A Mr Milligan has also provided a submission to the Senate
enquiry and he has some additions to these charts that may prove useful.
However, it is for the engineers to finally conclude. The
originals by GHD are on page 564 of their report.
May 2009: There is no argument
concerning the raising of the wall to 2,000,000ML
Matching of my knowledge of uncommon events, Mary
Valley, Somerset Dam and Wivenhoe Dam rainfall patterns and Mr McMah's concept
for Borumba Dam.
After reading Mr McMah's submission to the Senate Enquiry, I
sought out Mr McMah. Having traversed the Borumba Dam and part of its catchment
with him it became obvious that with adjacent catchments, the opportunity
for harnessing the surplus waters of the uncommon events of the
Somerset/Wivenhoe system could be feasible and required detailed investigation.
This follows in "Solution/Base" button.
February 2007. Output from the
Government IQQM computer model, covering the 111 years 1890 to 2000, has proven Mr Drury correct. In essence 300mm of
rain in the catchments in a few days is a flood and, in the right circumstances,
can fill the dams from scratch. On the other hand 3 months of 100mm a month is a
comparative
trickle. These facts can be buried in official overall rainfall statistics the
use of which in dam performance can and did throw up statistical aberrations.
records from 1841 reveal that
they occur on average every 3.7 years with most below that average. Therefore
those above can extend well above that average such as the recent period of 2001
to 2007.
Mr Drury also provided dam level charts
which were not published by the Courier Mail. They provided clear evidence of
the importance of "uncommon events" and the inability of the
"Summer wet season" to provide sufficient water from as far back as
1992. 
