Grantham and the media

I haven't written a post on the Queensland 2011 floods for a while.  It is, however, back in the news due to issues relating to events at Grantham.  I have very little to say about that in particular.  Those issues turn on detailed matters of topography and hydrology on which neither I, nor the residents of Grantham have the necessary knowledge to have an informed opinion.  The residents of Grantham do, of course, have the relevant expertise on what they saw; and what they saw must inform any hydrological assessment of the effects of the flood on Grantham.  Knowing what you saw, and interpreting its significance, however, are not the same thing.  Therefore the claims of the Grantham residents do not determine what happened in 2011, and should not by themselves determine the results of the current inquiry.

The task of the inquiry is being made harder by bad reporting on the floods.  I discuss below the fold one such example of bad reporting by Channel Nine, echoed by the Sydney Morning Herald.  Once again I have copied a comment from SkS for convenience, and in this case the first part of the comment is not directly relevant to the issue of bad reporting by media.  I have retained it, however, as it does give useful background on the general situation in the Lockyer Valley at the time of the Grantham flood of Jan 10, 2011.




ryland @4, on January 11th, 2011 I described the Queensland floods saying:

"Of course, and even larger perspective is needed. In March, 2010, Queensland experienced record breaking floods, with many towns experiencing record flood depths, and the greatest area flooded ever reported for Queensland. It was reported that the flood effected area in March was larger than Victoria (area: 240,000 square kilometers, or 92,000 square miles). In the week after Christmas, that record was broken, with a reported flooded extent greater in area than New South Wales (810,000 square kilometers or 313,000 square miles). That is an area about the size of the five largest contiguous US states either under water or cut off, or with crops rotting in the ground two weeks before harvest.
In the last week of December, the floods were mostly confined to the interior behind Rockhampton and Bundaberg (also flooded) and to the Darling Downs and interior. There was minor flooding in Brisbane, and in the north of the state (where at least one woman lost her life). Since then the floods have moved south, flooding Gympie, Maryborough, and of course, Toowoomba and the Lockyer Valley (and soon to be Ipswich and Brisbane). Dalby deserves a special mention, having experience five flood peaks in two weeks."

The post was in connection to the Toowoomba floods, described at the time as an "inland tsunami":

The Toowoomba floods were astonishing in that Toowoomba is literally at the crest of the Great Dividing Range west of Brisbane.  Toowoomba's catchment area lies entirely inside the city limits.
Shortly after the Toowoomba flood, Murphy's Creek was hit by a wall of water, with the water level rising "... about 12 metres in 12 minutes" (Source).

(Source)
That was less surprising in that Murphy's Creek lies at the bottom of the range, hard up against the edge of the Lockyer Valley.  Any flash flood coming down the range would have had no time to disperse before hitting Murhpy's Creek.
Further downstream from Murhpy's Creek (and downstream of the confluence of Murhpy's and Lockyer Creek, on which Helidon sits), at Helidon, the water level rose 8 meters in thirty minutes, with 4 meters of that rise being in ten minutes.  Helidon is downstream of three other streams in addition to Murhpy's Creek.  The rapidity of the water rise at Helidon is astonishing given the relative distance from the valley walls (and hence time and distance for the flood peak to disperse).
Downstream of Helidon (and of Flagstone Creek) lies Grantham.  Further downstream again is Gatton where flood levels 20 meters above Davey's Bridge were recorded:

(Source, see here for video of after flood levels at the same location)
I run through all this to illustrate just how deceptive is your comment @4 that "it is heartening to read in the SMH (May 24 2015) pieces noting the 2011 floods in Queensland were not due to climate change but to human error".  It is deceptive because the 2011 Queensland floods were not restricted to a flood in Grantham.  Nor is the SMH report about the "Queensland floods", but the rather about the floods in "Grantham, Queensland", something made very clear in the article.  It is further deceptive because Grantham certainly would have flooded in any event on January 10th, as is made clear from the generalized flooding both upstream and downstream of Grantham.  Indeed, Grantham had already flooded on Jan 9th, and would do so again in a further flood on Jan 11th when the Grantham water gauge ceased operating at 14 meters (source).
What is at issue in the SMH is whether the collapse of an earth wall in a local quarry made the flood worse in Grantham than it would otherwise have been.  It has no bearing at all on the causes of the flood.  Further, the story is known to be inaccurate (and essentially a beat up by Channel Nine).  The Channel Nine Chopper did not record the "wall of water" through Grantham.  It did not even record the peak of flooding in Grantham, video of which did not emerge until March 18th.  Rather, it responded to reports of the flood which had already peaked by the time it was airbourne.  The "new evidence" on the Sixty Minutes report was not relevant evidence at all.

Even the reports account of what the prior inquiry said is inaccurate.  Channel Nine claims the inquiry "...determined the flood hit the town at 3.15pm".  The SMH reports that as:

"The commission concluded that a wall of flood water hit Grantham between 3.15 and 3.30pm, which fit the timeline of events that suggested the overflowing river upstream was the cause of the devastation."

 The inquiry actually found that:

"While it accepts the submitters’ contention that the road from Gatton to Grantham was clear shortly after 3.00 pm (a conclusion consistent with the Commission’s finding in its interim report that the Grantham flooding occurred between 3.20 pm and 4.00 pm), it does not consider that there is any basis to reject the SES controller’s account as given in his statement referred to in the interim report.  It is supported by statements from the group leader of the Gatton SES unit and members of the SES group which set out to perform the doorknocking task, as well as by the contemporary record in the form of the Gatton SES attendance log."

IMO it is very difficult to mistake 3:20 to 4:00 for 3:15 to 3:30; so Channel Nine and the SMH have directly misrepresented the Commission to beat up a story.  So the "missing hour" is manufactured by dishonest reporting by Channel Nine (and possibly lazy reporting by the SMH).