The 2010–2011 Queensland floods were a series of major floods that affected much of Queensland, Australia, between December 2010 and January 2011. Prolonged and extensive rainfall fell across large areas of the state on catchments already saturated by a strong La Niña event, following the wettest December on record for Queensland. As of March 2012, 33 deaths had been attributed to the floods, with a further three people missing, later declared deceased by the State Coroner in June 2012. The event ranked among the most destructive disasters in Australian history.
Flooding occurred across much of central and southern Queensland, affecting every major river system south of the Tropic of Capricorn and inundating numerous towns and cities, including Rockhampton, Emerald, Bundaberg, Toowoomba, Ipswich, and Brisbane. More than 200,000 people and 41 local government areas were affected, while over 78 percent of the state was declared a disaster zone, impacting more than 2.5 million people. Approximately 29,000 homes and businesses experienced some degree of inundation. The disaster caused 33 deaths, with a further three people later declared deceased.
The floods caused widespread damage to infrastructure, agriculture, mining, and communities. Insured losses were estimated at A$2.38 billion, while a 2016 assessment estimated the total economic cost at A$14.1 billion, making the disaster one of the costliest in Australian history. The event prompted one of Australia's largest disaster responses, including large-scale evacuations, deployment of the Australian Defence Force, establishment of the Queensland Floods Commission of Inquiry, and the creation of the Queensland Reconstruction Authority. Subsequent litigation over the operation of Wivenhoe Dam resulted in a negligence ruling in 2019 before being overturned on appeal in 2021, with the High Court of Australia refusing a final appeal in 2022.
Background and meteorological history
Brisbane experienced major flooding in 1893 and 1974 as the Brisbane River broke its bank and inundated low-lying areas. Towns, including St. George and Theodore, had dealt with major flooding earlier in 1996. The 2010 La Niña Modoki weather pattern, which brings wetter conditions to eastern Australia, was the strongest since 1973. This La Niña event caused a prolonged event of heavy rainfall over Queensland river catchments. Record or near record sea surface temperatures were recorded off the Queensland coast in late 2010. December 2010 was Queensland's wettest on record, with record-high rainfall totals set in 107 locations for the month. The state's average rainfall level of 209.45 millimetres (8.25 in) exceeded the previous record of 200.1 millimetres (7.88 in) set in 1975. 2010 was also recorded as the state's wettest spring since 1900, and the Australian continent's third-wettest year.
The floods were a result of heavy rainfall caused by Tropical Cyclone Tasha that combined with a trough during the peak of a La Niña Modoki event. Isolated flooding started across parts of the state in early December. On 23 December, a monsoonal trough crossed the coast from the Coral Sea, bringing torrential rain that fell in a broad swath from the Gulf of Carpentaria to the Gold Coast. The Bureau of Meteorology first issued an advisory for a developing tropical low 24 December. The agency declared a cyclone warning for areas between Port Douglas and Lucinda, Queensland. Some parts of Queensland were already suffering from flooding and additional rainfall was expected to worsen the situation. The low intensified into Tropical Cyclone Tasha, which reached its peak intensity on 24 December with winds of 75 km/h (45 mph) and a barometric pressure of 993 mbar (hPa; 29.32 inHg). Hours later, the centre of Tasha made landfall between Cairns and Innisfail at this intensity. Although a relatively weak storm, Tasha produced widespread torrential rains in Queensland, amounting to more than 250 mm (9.8 in) in some areas.
Climate scientist Kevin Trenberth thought climate change was a contributing factor in the unusually high precipitation rates. He attributed a half-degree Celsius rise in ocean temperatures around Australia to global warming (which produces extra water vapour and intensifies the monsoon). Other scientists say that it is too early to draw such a conclusion. Assertions were also made by Professor Hubert Chanson, an expert in dam and reservoir engineering with extensive firsthand knowledge of the Wivenhoe system, that mismanagement of the Wivenhoe Dam might be a contributor to the some flooding in the lower Brisbane valley. While an expert engineer, Michael O'Brien—a senior manager of an ASX-listed resources company and an outside consultant evaluating cause—agrees that "massive releases of water from Wivenhoe Dam on Tuesday, 11 January, did indeed produce most of the flooding in the Brisbane River the following afternoon, with a peak in the early hours of Thursday morning, 13 January. The dam's releases into the Brisbane River also caused the Bremer River, which winds through the city of Ipswich, and the Lockyer Creek to back up and cause much of the flooding outside Brisbane." This was corroborated by a panel of engineers hired by the Insurance Council of Australia. O'Brien also found that the Wivenhoe Dam and Somerset Dam did not hold the maximum capacity they were capable of holding during the crisis period, which would have significantly alleviated flooding. Only one source, Neal Ashkanasy, who specialises in social and organisational psychology (and 35 years ago was involved in the design of Wivenhoe Dam), found fault with these results and instead finds that the dam was operated correctly throughout the time of the storm and the flood that followed, saying the "dam was run with outstanding precision."
Extent
By 28 December, nearly half of Queensland was flooded and preliminary damage estimates exceeded A$1.4 billion. Total economic losses also reached A$6 billion, roughly 0.5% of the nation's gross domestic product. In response to the severe flooding, the Government of Queensland declared numerous towns as disaster areas, allowing for federal funds to be used. By 27 December, flood waters began to recede in Babinda and Gordonvale, leaving behind debris and thick black mud. By 30 December vast areas of Southern and Central Queensland were flooded. The conditions led to a large influx of snakes in the Rockhampton area, as well as some crocodiles.
Flooding was widespread across Queensland and New South Wales from the end of December 2010 to January 2011 with several separate rain events causing rivers to rise over a lengthy period. Many places, including Condamine and Chinchilla were inundated by flood waters on multiple occasions. About 300 roads were closed, including nine major highways.
During the flooding it was reported that more than three-quarters of Queensland was affected by flooding.
Fitzroy River basin
Thousands of hectares of cropland were inundated by floods and many towns and cities were underwater. In Theodore, much of the area was flooded after the Dawson River reached its highest level in 50 years, cresting around 14 m (46 ft). This surpassed the previous record by more than 50 cm (1.6 ft). The flooding forced the evacuation of 1,000 people from Theodore and other towns, some using military helicopters, transporting residents to an evacuation centre at Moura. The evacuation was described as unprecedented by the acting chief officer of the Emergency Management Queensland. The total evacuation of a Queensland town was a first for the state. Major flooding at Theodore persisted for more than two weeks.
Emerald was cut off by road on 29 December as the Nogoa River rose. By the next day, the river surpassed the 2008 flood peak level of 15.36 metres (50.4 ft). At the peak of the flooding, 80% of the town was flooded, the worst the town ever experienced. Twelve hundred Emerald residents registered as evacuees.
Rockhampton had nearly a week to prepare for an expected flood peak from the Fitzroy River, which courses through the centre of the city. The airport was closed on 1 January. A metal flood barrier was erected around the terminal to prevent flood-borne debris from causing damage to the structure. An evacuation centre was set up at the Central Queensland University. The Bruce Highway leading south out of Rockhampton was closed to traffic. The river peaked at 9.2 metres (30 ft), just short of the predicted 9.4-metre (31 ft) maximum.
The Port of Gladstone reduced its export capacity because the coal stockpiles at the port were saturated and further coal deliveries could not be made by rail. The Goonyella railway line which serves a number of coal mines in the Bowen Basin was closed for one week and shipments of grain were also delayed.
Burnett River basin
The central Burnett towns of Gayndah and Mundubbera saw major flooding on 28–29 December. The Burnett River peaked at 18.25 metres (59.9 ft) at Mundubbera—the highest river height since 1942—inundating more than 20 houses. Downstream at Gayndah, the river peaked at 16.1 metres (53 ft) with floodwaters reaching two houses. Both towns were isolated for several days and there was major disruption to the potable water supply and local agricultural production.
Bundaberg experienced severe flooding, the worst in 40 years, after the Burnett River flooded the city, although the Paradise Dam reservoir contributed to some flood mitigation. This resulted in the evacuation of 300 homes. The Bundaberg Port, a major sugar exporting facility, was closed late in December 2010 as flooding deposited silt in the port, forcing its closure. The port re-opened in early March 2011 after successful dredging operations allowed ships to berth.
Condamine/Balonne River basin
Chinchilla and Jericho were also inundated. At least 40 residents were evacuated from Chinchilla.
Flooding in Dalby was the worst since 1981. The town's water purification system was flooded, resulting in water restrictions that hampered clean-up efforts. 112,500 litres (24,700 imp gal; 29,700 US gal) of water were transported to the town of 14,000 residents. Warwick was isolated when all roads into the town were cut off.
The Condamine River reached 14.25 metres (46.8 ft) on 30 December, its highest level ever recorded. Condamine was mandatorily evacuated on 30 December.
A second rain event on 9–10 January saw floodwaters again threaten Chinchilla and Condamine with Chinchilla residents again asked to evacuate.
The Macintyre River, which forms part of the border between the Australian states of New South Wales and Queensland, began to threaten the town of Goondiwindi on 13 January. While the town is protected by an 11-metre (36 ft) levee, the local hospital and aged care home were evacuated as a precaution and an evacuation centre was established.
Mary River basin
Heavy rain in the Mary River catchment on 8–9 January 2011 led to flooding at Maryborough and Gympie. The Mary River at Maryborough was expected to initially peak at 8.5 metres (28 ft) at midday 9 January with some houses and businesses inundated by flood waters.
Toowoomba and the Lockyer Valley
The city of Toowoomba, in the Darling Downs, was hit by flash flooding after more than 160 millimetres (6.3 in) of rain fell in 36 hours to 10 January 2011; this event caused four deaths in a matter of hours. Cars were washed away (see video). Toowoomba sits on the watershed of the Great Dividing Range, some 700 metres (2,300 ft) above sea level. A three-week period where it had rained on all but three days had left the soil around Toowoomba super saturated and when a line of storms hit the city on 10 January, the resulting torrential rain rapidly ran off down gullies and streets. The central business district of the city sits in a small valley where two small water courses—East Creek and West Creek—meet to form Gowrie Creek. Unable to cope with the volume of water heading toward them, the creeks burst their banks, pushing a devastating wall of water through the city centre. This water then headed west—not towards the Lockyer Valley which was also experiencing extreme rainfall that fell on eastern facing slopes.
The surge associated with rainfall which fell on the eastern side of the range passed through the Lockyer Valley town of Withcott, where the force of the water pushed cars into shops and forced the evacuation of hundreds of people. The scene was described by an onlooker as "like Cyclone Tracy has gone through it ... If you dropped an atom bomb on it, you couldn't tell the difference." Nearby Helidon had several homes and farms flooded but did not break the main creek bank and enter the town. It was cut off from all sides by destroyed roads. Grantham was also devastated by the surge of water. Houses were left crumpled by what Premier of Queensland Anna Bligh described as an "inland tsunami". According to local media, the flood waters had reached a height of 7 or 8 metres (23 or 26 ft) by the time it struck Grantham. The peak discharge rate around Withcott and Grantham where Lockyer Creek is joined by Gatton Creek, was estimated to be 3,500 m3 second. At least 100 people were evacuated to the Helidon Community Hall. Nine people were confirmed dead, and many more feared dead among 66 reported missing. The body of one victim washed away at Grantham was recovered 80 kilometres (50 mi) downstream and Queensland Police Commissioner Bob Atkinson warned that some bodies may never be found. Nearby Gatton saw voluntary evacuations as the Lockyer Creek rose to a record height of 18.92 metres (62.1 ft), exceeding the previous record set in the 1893 Queensland floods.
Three people from Grantham listed as missing were officially declared dead by the Coroner on 5 June 2012.