Flooding plains, bursting rivers, human suffering

From Griffith REVIEW Edition 35: Surviving
© Copyright Griffith University & the author.

Written by Matthew Condon

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Matthew Condon’s biography and other articles by this writer

Spreading out from that meteorological epicentre in Ann Street is a vast interconnected web of radars, automatic weather stations, river height stations, field observers, storm spotters and satellites that keep a constant eye on weather movements across the state. Paramount on that massive grid - on alert for changes in sea temperatures, wind movements, precipitation, flash floods - are fourteen Weather Watch radars. And chief among those is the Doppler radar at Mount Stapylton, about 40 kilometres south of the city, near Beenleigh. The mountain was named after the surveyor Granville Stapylton, murdered by local Aborigines in 1840. The Doppler now perches atop it, not unlike a giant white teed golf ball surrounded by bush.

The Doppler radar can detect low-level wind and precipitation to a radius of about 150 kilometres: it takes in Brisbane city and even Toowoomba, 127 kilometres west of Brisbane, up on the Great Dividing Range. Another radar in Gympie, north of the capital, also has Doppler capabilities. A third is located in Marburg, sixty kilometres west of the city. All three gaze vigilantly over the greater Brisbane area, and the information gathered feeds into the Regional Forecast Centre and Flood Warning Centre databases.

In June 2010 the bureau's multitudinous feelers began sensing the advent of an unusually volatile La Niña effect. La Niña and its partner, El Niño, are major seesaw shifts in weather patterns across the Pacific Ocean in one- to three-year cycles. With a La Niña over northern Australia you could historically expect low pressures, warm oceans, increased cloudiness, and a high likelihood of rains and tropical cyclones. Combined with northern Australia's annual monsoon season - and depending on the longevity of that season - a La Niña requires a very close eye, especially with summer approaching. And after years of drought in Queensland, local meteorologists were keenly observing anything that suggested significant rain.

The bureau issued a warning that a La Niña was likely by the end of the year. Then, almost to order, it began raining across Queensland. And it kept raining. By October everyone in that bureau on Ann Street, and officers out in the field, and all the weather watchers and storm chasers and amateur meteorologists and farmers attuned to working with weather, knew that something wicked was on its way.

IT'S A TEN-MINUTE walk from the Bureau of Meteorology offices, down George Street heading south, past the law courts and legal cafés and city library and Treasury Casino and the park presided over by a stern Queen Victoria, to the Executive Building that houses the Queensland Premier's Department and numerous other government offices. On 18 October 2010 a small, historic moment took place behind its closed doors. James Davidson, regional director, Bureau of Meteorology, Queensland, briefed the state cabinet. Nobody could recall someone from the bureau ever being called to address cabinet.

Two weeks earlier, on 4 October, the bureau had issued an alert across the state of an impending active summer - weather talk for storms, cyclones and possibly flooding. It held briefings with disaster management authorities. Five days later, on 9 October, dam levels hit, then surpassed, 100 per cent for the first time in years.

As a result, the first flood of the wet season was officially declared. Up to 1600 cubic metres per second of water was released from Wivenhoe Dam, up in the Brisbane Valley, and by the day of Davidson's rendezvous with cabinet the dam was brought back to full, or 100 per cent, capacity. The scientific data collated since the detection of the La Niña months earlier, and the release actions being performed at Wivenhoe, were strong enough indicators to warrant this unprecedented briefing to the Premier and cabinet.

At the meeting James Davidson warned that Queensland could certainly expect a La Niña event, and he briefed those present on projected rainfall for December 2010 and January 2011. The bureau predicted that January would exceed median rainfall, but no specifics could be given on where cyclones might cross the coast or which rivers might flood.

Present that day was Stephen Robertson, the Minister for Natural Resources. Robertson - bespectacled, flinty and the bearer of an often monotone, measured public servant's voice - had entered the ministry in his late thirties, in 1999, and was given the traditional career make-or-break portfolio of health in 2005. Accused of bungles and mismanagement, he was presented with Natural Resources after the election in 2009 as the government - still haunted by the seemingly unending Millennium Drought, as people called it - raced to install a South-East Queensland water grid: a network of two-way pipes and treatment plants that enabled drinking water to be moved, when needed, around the region. Two years earlier the government had begun the wholesale reform of South-East Queensland's urban water supply industry, and the grid was the centrepiece, along with the establishment of the Queensland Water Commission.

By October 2010, when Davidson addressed cabinet, Robertson had already suffered public criticism for the government's spending and waste over the water grid. A month after Robertson took control of his new portfolio, the controversial $1 billion Tugun desalination plant on the Gold Coast had officially opened. Within weeks it was temporarily shut down with technical difficulties. Further faults closed it for three months in 2010. The public dubbed it a white elephant. (On 5 December 2010 Robertson put the plant on ‘stand-by', to be reactivated only when the region's water supply dropped to 60 per cent or lower.) Now he was being told that enough water might be on its way to render the drought-proof grid irrelevant.

Shortly after James Davidson's briefing, Stephen Robertson met with his director-general, John Bradley, to discuss what measures had been put in place for the forthcoming wet season. Because of the rains since June, the city's primary dams - Wivenhoe, North Pine and Somerset - were full. Robertson contacted various water grid managers about lowering the giant Wivenhoe to 95 per cent. There was advice that dropping levels to 95 per cent was possible, but nothing was formally signed off.

Releasing water from Wivenhoe so soon after the so-called Millennium Drought was a perverse idea. Years and billions of dollars had been spent to secure water. Now the same bureaucrats might have to let precious water go, to mitigate potential flooding. The government's mindset was to protect water, to store it, hold on to it. How could anyone contemplate throwing it away?

On 25 October Robertson queried water grid officials: ‘I seek your urgent advice whether this water security provides an opportunity to release the volumes stored in dams as a means of reducing severity, frequency and duration of flooding in downstream areas.' As Robertson issued his memo, the Bureau of Meteorology detected strong bursts of the Madden-Julian Oscillation. This reflects patterns of atmospheric circulation and convection. As it rises it manifests in thunderstorm activity. The MJO was enhancing the monsoons in North Queensland, and was stronger than anyone had seen since the 1980s.

September had already been the wettest on record. Catchments were soaked. And the bureau was predicting more heavy rainfall through to the end of the year, and beyond. The worst-case scenario for the bureau and the government was an aggressive La Niña, a lively MJO, and record rainfalls and soaked catchments unable to absorb any more water all combining at the height of summer. By October a few Queenslanders may have begun to see the ghosts of 1974 - the last great inundation to hit Brisbane. And statisticians, after record rainfall, were also peering gingerly back to data from the great floods of 1893, which swept people and houses and bridges and boats and innumerable tonnes of debris out into Moreton Bay.

Through October and most of November Minister Robertson was satisfied that Wivenhoe was being managed in accordance with the Manual of Operational Procedures for Flood Mitigation - the bible for managing dams in a crisis. In late November, however, the worst aspects of La Niña and the monsoonal rains began to intersect, and Queensland started to go under water.