Search This Blog

Tuesday, March 22, 2011

The Joint Flood Taskforce Report on the Brisbane flood of 2011

The Joint Flood Taskforce has also released a report on the flood.  On factual matters, it largely confirms the SEQWater report where they overlap, but mostly it concentrates on determining an interim standard for flood levels for council planing.  I don't have much more to say about it at this time.

Sunday, March 20, 2011

The Insurance Council of Australia Reports on South East Queensland Flooding

Belatedly, I have come across the reports prepared by the Insurance Council of Australia by WorleyParsons, Water Matters International, and Water and Environment.  There are three reports, one dealing with theToowoomba flood, one dealing with the local effects of the Brisbane flood, and one dealing with the background and causes of the floods in the Lockyer Valley and Brisbane River.  The later two are in fact part 2 and part 1 (respectively) of a two part report, and of those two parts, it is the first part (and third linked) that interests me most.  That is because it is that report which contains the information relevant to the issue of the Wivenhoe Dam's operations and strategies that are continuing to interest me.

Saturday, March 19, 2011

Mick O'Brien and the Brisbane Flood of 2011

Chemical engineer Mick O'Brien has released his submission to the Queensland Floods Commission of Inquiry. Mick O'Brien has been the chief informant of the Australian's Hedley Thomas, so unsurprisingly, the submission is just a rehash of many of the inaccurate and unwarranted claims that Hedley Thomas has being making over the last few months.  However, there are a number of points that Mick O'Brien raises that I wish to address, and will do so briefly here.  In later posts, I will give a more detailed survey of information now becoming available as part of the preparation of my own submission to the inquiry.

The Greenhouse Effect and the Laws of Thermodynamics

I have just made a comment at Skeptical Science which I believe provides a good summary refutation of the denier claim that the greenhouse effect violates the laws of thermodynamics. Here it is:

Tuesday, March 8, 2011

Reporting on Wivenhoe

SEQ Water have released their initial report on the operations of Wivenhoe and Sommerset Dam during the     Brisbane flood of January, 2011.  I have yet to read it all, but certain things stand out.

The 2011 flood at Wivenhoe, showing inflows (Dark Blue), releases (Light Blue), Dam Levels (Bright Red) and the approximate level of peak flows for the sub catchment in 1974 (Dark Red).  Figure is from the SEQ Water Report, and modified to show 1974 peak.

The key findings are that this was an unusual event, with an Annual Expected return Probability of (possibly) less than 1 in 200, and for some stations, an AEP of less than 1 in 2000 .  That level of rainfall was not predicted in the Bureau Of Meteorology five and three day forecasts, and so was for practical purposes could not have been predicted.  Although the peak inflows to the dam far exceeded 1974 levels (by 200 and 230%), the rise to the peaks was much sharper than in 1974, so that total inflows to the dam only exceeded 1974 levels by 190%.  Peak inflows reached a level with an AEP of approximately 1 in 900.