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The January 2011 flood event that impacted southeast Queensland is amongst the most extensive and severe floods in terms of loss of life and property damage that the region has experienced, despite it being only the eighth highest flood on record at the Brisbane City Gauge. The spring of 2010 was the wettest on record for Queensland, New South Wales, and the Murray-Darling Basin (Bureau of Meteorology 2011a) at that time. The flood mitigation dams in the region, Somerset Dam and Wivenhoe Dam, had to be operated for flood mitigation purposes during October 2010, which was the first occasion since February 2001 that Wivenhoe Dam had been called into action due to the Millennium Drought. The wet October was followed by a very dry November which, in turn, was followed by the wettest December on record for Brisbane. Somerset Dam and Wivenhoe Dam were again pressed into action on three separate occasions during December 2010. The resultant releases ensured that only minor flooding resulted in the Lower Brisbane River during these events. However, on the 5th of January 2011, another rainfall event started to unfold across the catchments of the dams. By the 10th of January 2011, an upper-level low combined with a humid easterly flow to bring very heavy rainfall and flash flooding to southeast Queensland and northeast New South Wales. The heaviest falls were in the areas north and west of Brisbane, with three-day totals exceeding 200 mm over most of the Brisbane River catchment. This rainfall event resulted in a flood of record in the Upper Brisbane River and Upper Lockyer Creek catchments that sadly resulted in a substantial loss of life in Toowoomba and the Lockyer Valley, and which required record releases from Wivenhoe Dam. The resultant downstream flooding saw some 14,000 properties impacted, principally in the Lockyer Valley Regional Council, Somerset Regional Council, Brisbane City Council, and Ipswich City Council local government regions. Flood damage was estimated to be around $2.53 billion. This paper discusses the event as it unfolded and the subsequent judicial inquiries, engineering reviews, and legal proceedings that resulted from the consequences of the operation of Somerset Dam and Wivenhoe Dam. [ABSTRACT FROM AUTHOR]

Residents look to state leaders during high-risk events for advice and guidance. Previous events have reinforced the vital role that governments play in delivering emergency messages. Creating meaningful messages during emergencies is vital to inform affected populations and to encourage them to take appropriate actions. In February 2022, South East Queensland experienced a significant flooding event that resulted in the loss of life and property. This study identified that conflicting information was released due to the uncertainty of the weather event. Many residents used Twitter to post about what was being experienced, creating a real-time display of what was happening. This study analysed the public-facing government media conferences held over 4 days against Situational Crisis Communication Theory1 and compared the response to Twitter posts during the key days of the February flood. The study found an overwhelming use of the theory's denial and diminishment approaches used by some communicators combined with the rebuilding approach used by others. This had great potential to cause conflicting and confusing messages. This research is important because language encourages people to believe that floods can be prevented. Conflicting messaging can cause significant harm by not providing clear direction regarding evacuation and other safety measures. [ABSTRACT FROM AUTHOR]

In the Australian summer season of 2022, exceptional rainfall events occurred in Southeast Queensland and parts of New South Wales, leading to extensive flooding of rural and urban areas. Here, we map the extent of flooding in the city of Brisbane and evaluate the change in electricity usage as a proxy for flood impact using VIIRS nighttime brightness imagery. Scanning a wide range of possible sensors, we used pre-flood and peak-flood PlanetScope imagery to map the inundated areas, using a new spectral index we developed, the Normalized Difference Inundation Index (NDII), which is based on changes in the NIR reflectance due to sediment-laden flood waters. We compared the Capella-Space X-band/HH imaging radar data captured at peak-flood date to the PlanetScope-derived mapping of the inundated areas. We found that in the Capella-Space image, significant flooded areas identified in PlanetScope imagery were omitted. These omission errors may be partly explained by the use of a single-date radar image, by the X-band, which is partly scattered by tree canopy, and by the SAR look angle under which flooded streets may be blocked from the view of the satellite. Using VIIRS nightly imagery, we were able to identify grid cells where electricity usage was impacted due to the floods. These changes in nighttime brightness matched both the inundated areas mapped via PlanetScope data as well as areas corresponding with decreased electricity loads reported by the regional electricity supplier. Altogether we demonstrate that using a variety of optical and radar sensors, as well as nighttime and daytime sensors, enable us to overcome data gaps and better understand the impact of flood events. We also emphasize the importance of high temporal revisit times (at least twice daily) to more accurately monitor flood events. [ABSTRACT FROM AUTHOR]

Devastating floods in southeast Queensland in 2011 were the combination of flash flooding in the Lockyer Valley with riverine flooding in the Brisbane metropolitan area. While there is considerable information about the immediate impact on those affected, there is less understanding of the long-term health effects that follow such events. This study explored the perceptions of health effects and support received by people affected by the 2011 southeast Queensland flood six years after the event. A cross-sectional survey of 327 people was conducted in areas affected by the floods. The questionnaire sought information about the ongoing social, economic, demographic and self-declared physical and mental health effects. The data were analysed through comparison of those unaffected with those directly affected by the floods. Residents whose households were flooded were more likely to score their health negatively than non-affected residents and had higher reported rates of trauma, injury and mental illness. Twenty-six per cent of this group reported that they still experience some adverse health effects from the floods. Managing the longterm health implications of a flood-affected population is an important public policy task. Dissatisfaction with recovery operations and perceived injustices associated with insurance and compensation arrangements may aggravate health consequences. Early recognition and intervention may assist with reducing secondary effects. [ABSTRACT FROM AUTHOR]