Brisbane Floods 2011: Analysis and Impacts
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RUNNING HEAD: EXPRESS OF INTERESTABC ENGINEERSP.O. BOX. XXXXXTEL. XXXXXXTO PREMIER,GOVERNMENT OF QUEENSLANDPHONE: 13 QGOV (13 74 68)/ +617 3405 0985AUGUST 25TH, 2017Dear Sir/Madam,RE: EXPRESSIONS OF INTEREST TO CONSTRUCT A BUFFER DAMIn January 2011, the state of Queensland experienced the biggest natural disaster witnessed over the last decade. The floods begun as early as December 10th, occurring in various parts of the state but themost damage occurred when the Brisbane River flooded between the 10th and 13th of January. The aftermath of this was widespread havoc which resulted in loss of life and property of some of the resident of the areas surrounding the river. Up to date, 37 deaths have been recorded in relation to the floods while the financial damage caused, both in properties lost and in flood mitigation costs exceeded 10 billion AUD. With a commission having been set up to investigate the causes of the flooding and provide a managerial way forward, a lot of information has been collected which details the cases of the floods and the extent of the damage. CAUSES OF THE FLOODINGIn early 2010, meteorologist reports were released warning of the impending La Nina rains. The La Nina is naturally associated with heavy rainfall and during this period, the state witnessed an average precipitation level of 4.04m. These were the highest precipitation levels recorded since the 1975 flooding (van den Honert and McAneney, 2011). The la Nina fears were later qualified when CycloneTasha, a tropical cyclone hit the North Western part of Australia, roughly 1,600 kilometers from Brisbane, heading south towards Brisbane. The cyclone led to increased levels of rainfall with this water accumulating over time behind the Somerset and Wivenhoe dams. Up till then, the main flood protection system in Brisbane had been Wivenhoe and Somerset dams which reached their capacity sooner, owing to the prolonged rainfall season.By December 2010, the cyclone had brought about so much rain that troughs joining the Brisbane andBremer Rivers at different points had significantly increased the water level of the two rivers. This contributed to the creek rising and flash flooding of the surrounding areas when the intense localized rains came. The damage caused by this rainfall was spread over Eastern Australia and as the cyclone and La Nina rains moved towards Queensland, the more severe the effects of these flooding became. Between 10th and 13th January, having accumulated excess water from the rainfall and the River’s capacity, Somerset and Wivenhoe dams gave way causing downstream flooding along the river. The flooding of these dams contributed to 59% of the recorded damage. So far, the flash flooding of riversdue to heavy rain and the downstream flooding of the dams have been the only recorded causes of the flood.EFFECTS OF THE FLOODThe effects of the flooding include loss of life and property. With a total of 37 record deaths over the entire flooding event, 23 occurred in the Toowoomba and Lockyer Valley which were nearest to the
RUNNING HEAD: EXPRESS OF INTERESTdam location. The flood contributed to loss of property where over 26,000 residential properties were affected with 60% of the figure being destroyed completely that was a staggering 4.2% of the entire city’s population. The financial implication of the flooding was roughly 12.5 billion AUD which includes economic losses (van den Honert and McAneney, 2011). Another great effect of the event was the realization of the poor mitigating measures that the state of Queensland had put up in order combat such an event. It exposed various flaws in the various Australia’s disaster management systems it had in place. With people unprepared for the flooding, the effects of the floods were greatly felt as there was a very tiny response window [ CITATION Sto12 \l 1033 ]. With the “dam release flood” itself happening over the whole duration of the whole 3 days, people had very little time to secure property and belongings. The insurance industry also suffered huge losses due to payouts in some areas where individuals had lost property and those that needed environmental healthcare services too.FLOOD ENQUIRY REPORTSNumerous flood enquiry reports have been published by engineers and other professionals. A study ofthe interim report for instance suggests that the warning about the La Nina floods had been carried outby the meteorological department as early as June [ CITATION OBr11 \l 1033 ]. It however generalizes the 2 causes of flooding into one suggesting that the same heavy rainfall that caused the flash floodinghad direct influence on the “dam release floods”. It suggests that the rainfall was too intense that, as it caused the rivers to swell, these in turn fed the dams at a much faster rate than it had the capacity for.Engineers John Hayes and Ashantha Goonetilleke suggest that the spatial information systems had notbeen fully utilized and therefore could not be of much help in resident protection apart from assisting in obtaining weather information (Hayes & Goonetilleke, 2012). They suggested the implementation of a system that would map out the flood lines and the extent of the flooding. The Queensland Surveying and Spatial Sciences Joint Natural Disaster Response Committee suggested through their report, a system where individual property owners would be able to access spatial data in order to be able to make the necessary arrangements should a similar flood occur (Q. S. S. S. J. N. D. R. C, 2011). While it may not stop the floods, their report argues that having this information would help them be ready.In his submission, Alex Stoney. Points out that having more flow cross sections of the various streamsand rivers would be helpful to any flooding related planning that would be concerned with the volumes of water flowing [ CITATION Sto12 \l 1033 ]. He also suggests deepening the channels by cutting trenches in the river’s lower extents much like dredging is done on artificial harbors to increase their depth for easy ship accommodation. A report by John Craig suggests the modification of dam itself by increasing the capacity to mitigate floods by increasing its wall height. Should that fail, he suggests reducing the amount of water coming into the dam itself. Should that fail too, a new dam would be constructed[ CITATION Cra11 \l 1033 ].COSTING OF THE PROJECTOur expression of interest to build a buffer dam is because we believe it would be more cost effective approach to protecting the individuals and households of areas prone to flooding. We believe that such a dam would be able to alleviate the pressure on the 2 dams and water could be redirected to it. The reason we believe it would be cost effective is that it can be regarded as a permanent solution. This would permanently reduce the amount of water coming into the dam. Pricing information is as follows:
RUNNING HEAD: EXPRESS OF INTEREST
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