Queensland floods: a local's perspective

Regular ACM contributor Bruce (brc) wrote a lengthy comment on an earlier item which I believe rightly deserves a post of its own. I would like to thank Bruce for his thorough and down to earth assessment of the current Queensland floods which commentators on all sides would do well to imitate:

Look, as a 3rd generation lifelong South East Queensland (“SEQ”) resident, all this
 world wide attention and theories are starting to irk me as talking
 heads start to spout off things of which they appear to have little
 understanding. SEQ (and Queensland in general) is periodically subject to 
intense widespread rain events: 1893, 1974, 2011. They happen. Even
 smaller intense rain events occur at least once a decade. The 1893 
floods were larger, and peaked on 3 separate occasions. Does anyone
 care to tell me how AGW could have done that, given that horseback 
was the primary transportation method at the time, and electricity
 was something played with in laboratories?

If anything, the lower 
levels in 1974 and 2011 is proof that AGW makes the flooding less 
worse (I say with tongue in cheek). There’s also a popular meme 
going around (James Delingpole and Andrew Bolt) that somehow green 
interfering caused the death and destruction. Nothing could be 
further from the truth. And believe me, I love a good outing of
 ridiculous green policy as much as the next person.

Here are the facts:

  • The 
majority of loss of life was caused by flash-flooding in and around
 Toowoomba (700m above sea level) and the Lockyer valley below the 
Toowoomba range. The streams that caused the devastation in
 Toowoomba are normally babbling brooks one can leap with a vigorous 
jump. While some warning may have helped, many deaths were caused 
by people undertaking risky actions like trying to drive across 
flooded bridges.
  • The scrapped Traveston Crossing dam project on 
the Mary river would not have saved Gympie from flooding. It would
 have been 100% full (like every other dam in the region) prior to 
the large rain events – it has been raining steadily for two 
months. In any case, it was the residents of Gympie that campaigned 
the most against the dam. Not because of lungfish (the figleaf that
 the environment minister used) but because it was a bad idea. A 
flat alluvial sandy plain is not the ideal location for a dam. It
 would have been wide and shallow on porous soil. And it would have 
subsumed a huge area of productive farmland. It was correct for the
 dam to be scrapped, and many engineers publicly stated this. That 
it was scrapped under environmental reasons was just the out for an 
embarrassed Federal government saddled with the plans after the 
former premier announced it to save his political hide (Brisbane
 was under severe water restrictions at the time) but then scarpered
 anyway. It was chosen because the area had never, and would never, 
vote for Labor anyway, so it was the best place to put it, safely
away from Brisbane voters. It would have been full, and would not
 have saved Gympie from flooding. And the townspeople in Gympie are 
used to flooding anyway, and go about moving out of the way with a 
cheery disposition.
  • Wivenhoe dam – conceived and built after the 
1974 floods – has done a very good job in extremely difficult
 circumstances. It has managed to keep the peak level of floods 
1m lower than predicted, by delicately balancing the inflows and
 outflows and timing with the low tide in the Brisbane river. It was 
already at 150% (and releasing continually, as it has been for
 months) when this large rainfall event hit. SEQ Water are to be 
commended with the way they handled this, with the Dam balanced 
within 1m of the peak level allowable before dam-protection levees
 give way to protect the wall (with devastating consequences for 
those downstream).

It’s difficult for people who don’t live in 
Queensland to understand the volumes of water we’re talking about
 here. This is not some drizzling Victorian rain or misty English 
weather. This is a proper, tropical summer monsoon rainfall a bit
 further south than it normally is. The written history of Queensland is
 only about 200 years long, but it is peppered with tales of huge
 floods that astound new observers. People see the 1974 markers on
 buildings around Brisbane and think it can’t possibly have 
happened. The puny infrastructure put in the way of these periodic 
deluges is nothing compared with the water volumes. It will happen 
again, at least once per lifetime of the average person. There’s 
nothing that can be done. After all, it’s just weather.

Comments

  1. Simon – thanks for elevating my comment to a post, I hope it gives others some insight to the history of QLD. Interested people might like to check some interesting links available:

    http://www.seqwater.com/public/dam-levels
    This page shows the historical (and current) dam levels. You can used the widget at the bottom to show the historical levels for different dams. This page will show how Wivenhoe was frequently released back to 100% capacity (the water storage capacity) but, from about the 6th January onwards, the inflows were much greater than the outflows (releases) so the dam level climbed sharply to the point where they had to go to full release to keep the dam mitigating as much as possible whilst protecting the integrity of the Dam itself. The peak was at 190%. This page also shows how every other dam in the region was at 100% prior to the large rainfall event that caused the flooding, so no new Dams would have prevented the flooding unless they were of the mitigation type of Wivenhoe, which none of the planned dams have been.

    For QLD flood history, take a look at this link:
    http://www.bom.gov.au/hydro/flood/qld/fld_history/brisbane_history.shtml

    The BOM graph shows quite clearly how we are actually in a time of lower and less frequent floods than in the period from 1850-1900, which would have been an awful time to have riverfront property. This is plenty enough evidence to break the assertion that AGW will cause larger flooding, even if on a less frequent basis. You can look at the Bremer R (Ipswich) for confirmation – there is no flood mitigation on the Bremer River.

  2. Great post Bruce, from another 3rd generation person from Brisbane. After hearing what is coming to light in the Lockyer Valley I don’t think stupidity had much to do with the loss of life. Many of those people interviewed are lucky to be alive with quick thinking, bravery and modern technology aiding their survival.

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