Early last month, the official inquiry into this year’s floods in Queensland began examining the operations of Wivenhoe Dam and its impact on Brisbane, the state capital. The hearings raised crucial questions about the response of the state Labor government, in addition to those raised by last week’s hearings, which featured harrowing first-hand accounts about the lack of emergency warnings in the nearby Lockyer Valley and Toowoomba.
Located about 80 kilometres northwest of Brisbane, Wivenhoe Dam was built in the aftermath of floods that engulfed the city in 1974, killing 14 people and destroying over 6,000 homes. Following its construction in the early 1980s, consecutive Queensland state governments, Labor and Liberal-National alike, along with local councils and property developers, assured Brisbane residents that the dam would protect them from major flooding.
These claims, however, were exposed as patently false in January. The government-owned dam, which is commercially operated by the South East Queensland Water Corporation (SEQW), proved incapable of shielding the city. In fact, Wivenhoe quickly reached its storage limit, threatening its structural integrity and forcing operators on the morning of January 11 to release vast amounts of water.
There had been no controlled, pre-emptive dam releases earlier in the month. Instead, the massive outflow of water—about 7,500 cubic metres a second—inundated an estimated 20,000 homes in low-lying areas of Brisbane, Ipswich and communities in the Brisbane Valley. Infrastructure was seriously damaged, basic services were cut and thousands of residents were forced into evacuation centres.
Brisbane Valley resident Jenny Moore, the first flood victim to testify, told the inquiry on April 11 that she had anxiously observed the increasing water levels in the dam and wondered, “Why won’t they let that water go?”
When the releases occurred, she said that “the speed of the water was phenomenal” and ripped away 40 percent of her family’s 11-acre riverfront farm, including 200-year-old trees that had withstood the 1974 and 1955 floods. Moore added that it took more than a month before she was able to get government authorities to inspect the damage, which has cut her farm’s acreage by almost half.
Counsel assisting the investigation, Peter Callaghan, told the inquiry on April 11 that he would examine a number of questions. These included the impact of the water releases; whether the dam should have been kept at 100 percent water supply during the La Niña weather pattern; the adequacy of the dam’s operating manual; and whether dam operators had been “affected by distractions” with the state government’s emergency control centre.
Whether these and other questions about the state government’s inadequate flood mitigation measures are seriously probed remains to be seen. Nevertheless, testimony by Water Utilities Minister Stephen Robertson and Sunwater senior engineer Robert Ayres in the first Brisbane hearings was revealing.
Robertson’s testimony revealed that the government failed to act on early warnings that massive rainfall from the La Niña weather pattern would hit the region. He told the inquiry that the entire state cabinet had been briefed by Bureau of Meteorology regional director Jim Davidson about the consequences of the La Niña on October 18, two months before the disaster.
Davidson also met with Premier Anna Bligh and briefed water management groups on January 4, warning them that an intense upper-level low pressure system was hovering over southeast Queensland. Davidson predicted several hundred millimetres of rain in the following week. Despite this, the government failed to take any action to pre-emptively release water from Wivenhoe Dam.
Robertson said he wrote to SEQW after the October 18 briefing, asking whether the facility should be lowered to 95 percent capacity in preparation for the predicted downpours. When SEQW replied that future water releases would have a “negligible” impact in the case of moderate to major flooding, he did nothing. Under questioning, Robertson admitted that he did not seek any other opinion from experts in his own department.
The water utilities minister has the authority to directly intervene over dam water levels, but Robertson testified that he was “comfortable” that Wivenhoe’s operation manuals were being followed.
Robert Ayre, a senior engineer with Sunwater, the state agency responsible for Wivenhoe and 25 other Queensland government-owned dams, told the inquiry that pre-emptive lowering of dam levels in response to weather predictions was not effective because of the “uncertainty” of forecasting.
Yet it was obvious that Queensland faced major flooding—the La Niña had already begun to assert itself in March 2010, flooding parts of the state at that time, and there had been record rainfall for the rest of the year. A La Niña event occurs when surface sea temperatures are cooler than normal in the eastern Pacific, and warmer than usual in the western Pacific. This causes a build up of warmer water along Australia’s east coast that drags in moist air and produces massive downpours.
The senior engineer said the dam had a dual purpose—flood mitigation and water supply—and that releasing water if a predicted downpour did not occur would impact on water security. Ayre insisted that it was “best” to rely on a no-rainfall scenario when managing the dam, because this had “been proven to be the most reliable approach in the past.” He asserted that even if SEQW had significantly lowered dam levels in January, this “would still have resulted in flood levels” in Brisbane.
Ayre also revealed that he had emailed SEQW engineers following the massive water releases, suggesting that they “coordinate” their responses to the media. Under cross-examination, he denied attempting to present a false version of events, saying that because there was “a lot of media speculation” about the dam’s operations, he did not want engineers “providing different interpretations of our actions during the course of the flood.”
As yet, nothing has been said in the inquiry about the impact of the commercialisation and privatisation of water supply and other vital services during the past two decades. Nor have any questions been raised about why state and federal governments and the Brisbane city council ignored calls by climate scientists, hydrologists and peak engineering groups in recent years for increased government funds to improve the capacity of Wivenhoe and initiate other flood mitigation measures. (See: “Reports warned of flood dangers to Brisbane”)
“Flooding and Flooding Mitigation”, a position paper released in 2008 by Engineers Australia, for example, called for the urgent development of flood mitigation dams, retarding basins and channel levees.
In 2009, the federal Labor government estimated that natural disasters were responsible for over $1 billion damage each year to Australian homes, businesses and infrastructure. Its response was to allocate just $18 million in Disaster Mitigation funding nationally, with only $5.3 million to Queensland.
Engineers Australia also drew attention to dangerously inappropriate planning and land rezoning on flood plains, and called for public information programs and flood warning systems.
This points to another “elephant in the room” at the inquiry—the political decisions made by federal, state and local authorities to permit property developers, financial institutions and real estate interests to erect low-rise housing, shopping centres and other buildings on flood plains. These areas in and around the state capital were predictably inundated after January 11.
This author also recommends: