Tag Archive: rain

Queensland Floods

Like everyone, I’ve been absolutely devastated by the floods that have affected most of Queensland over the past few weeks. The sheer volume of water, both in terms of river heights and areas affected, is just mind boggling. With Rockhampton and Central Queensland flooding just before the new year, the Wide Bay region flooding just after, the Fraser Coast not long after that, then inland South East Queensland being smashed by those torrents of water, with the disaster finally culminating in massive flooding of the Brisbane and Ipswich areas earlier this week. Hundreds of kilometres of coastline has been totally devastated by this incredible deluge.

Brisbane itself is a lovely city – located pretty much in a valley, the undulating terrain cosily surrounds the already vast Brisbane River. There are a number of pockets on the river still largely undeveloped, but home to a few absolutely picturesque homes. It is these homes that were first to be flooded when the waters rose a few days ago. Sadly, while the beauty of living in a gorgeous riverside location such as many in Brisbane may be envied most of the time, these houses were simply made victims of their locations.

The Brisvegans were fortunate (believe it or not) in one way that the initial fears of a river peak higher than that of the devastating 1974 floods were never realised. The river peaked in the early hours of yesterday morning at 4.46 metres on the Brisbane City gauge, more than a metre below the levels of 1974, not that anyone was unhappy about that.

Two factors had an impact on the river falling short of those huge levels of 37 years ago, the first being a lucky break with the weather, amazingly enough. The rain had cleared by the morning of the 13th, the day the river was to peak. While there were huge rainfall totals in the days prior, the easing of the weather conditions on Thursday prevented any additional runoff in the river catchment.

The second was a brilliant decision made in the wake of the events of January ’74 – the construction of the Wivenhoe Dam. In 1974, all the runoff from the upstream catchment of the Brisbane River flowed completely unchecked downstream to the city itself, producing the devastating floods they experienced. This time around, the runoff generated could be at least in part controlled through the massive reservoirs of this dam. While some releases were required to protect the integrity of the dam wall, they were controlled to limit as well as possible the floods downstream. Now with the river falling below the minor flood level, the stored floodwater can be gradually released over the course of the next week at a safe rate that will ensure no further flooding. Without Wivenhoe, it is entirely possible that the floods could have and would have been worse than 1974, and far more damaging to property and even life.

Now the attention is turning to the cleanup. Thousands of homes have been inundated, and the receding waters have left behind a trail of destruction. Those with just a thick layer of mud through their homes will consider themselves lucky, there will be many whose houses and belongings have been totally destroyed, or will need to be. It will be months or even years before normality returns to the lives of so many Queenslanders. I wish everyone whose lives have been impacted by this disaster the best of luck in the recovery.


Marge, the rains are ‘ere!

It’s been a very wet weekend here in Melbourne. Anyone who watched the races at Derby Day on Saturday would have seen that. We’ve had roads flooding, dams filling, and one dog has been made particularly happy by all the water. This blogger recorded 77mm of rain in the 24 hours to 12PM today falling in Melbourne’s eastern suburbs, with plenty more having accumulated in the gauge this afternoon too.

In fact, it’s been quite a wet year as a whole. After a prolonged drought for the best part of the last 14 years, it does in fact seem that the current drought episode has ended. Melbourne’s water storage levels, which have copped a real hiding over this period, have been rising steadily over the course of the past six months, and have for the first time since 2006 have reached 50% of their capacity. Geelong’s water storages are a poofteenth shy of being at 70% capacity, which is a significant improvement from the sub 20% levels they were at just last year.

Unfortunately, I fear that while this rain will be of great benefit to our water supplies, and to the agriculture industry so desperately in need of it, it may be used as a weapon by those against the idea of climate change. Despite the 14 years of evidence, it appears that one good year of rain means that the problem is completely gone, and that we should stop worrying about it. It’s a scarily ignorant attitude.

This rain is not inexplicable by a basic understanding of Australia’s climatic history. We’ve been a land of “droughts and flooding rains” since the days of Dorothea McKellar, but when explaining this it’s best to dispose of the Australian literature for something more Spanish.

I’d think most people would have heard the term El Niño before in relation to weather. In short, an El Niño event is a period where sea surface temperatures in the Pacific Ocean are above average, which results in Australia’s east coast experiencing at times significantly reduced rainfall. The opposite event, known as La Niña, produces the opposite anomaly in sea surface temperatures, and as such brings above-average rainfall to eastern Australia. These events aren’t a new occurrence, in fact in the last 14 years of drought, we’ve had at least 3 significant El Niño events (1997, 2002, 2006) that have all contributed to significantly reduced rainfall here. So it should come as little surprise that, being in the grips of what the Bureau of Meteorology describes as a “Moderate to strong La Niña event in Pacific“, we’ve had a year of above average rainfall.

So you might be tempted to think that it’s all a natural part of life and we’ve nothing to worry about. That would be unwise, as this drought has been one of the most serious and prolonged droughts in recorded history. Sure, a natural climatic process has brought some relief for now, but it doesn’t mean we’re out of the woods forever. To be “out of the woods”, we’d probably need another year or two of this above-average rainfall to bring our water systems back to their pre-drought levels. Then we’d need to return to pre-drought long-term average rainfalls in years where no La Niña event is occurring. If these things all do occur, we can then look at saying that things have returned to “normal”.

I hate to rain on everyone’s parade (boom boom) but those are the facts of the situation. The climate change science also seems to predict that future El Niño events may become more frequent and more severe, and rainfall in normal years will continue to decline. I’m not trying to get everyone down while something good has just happened, I’m just trying to convey the point that we need to be mindful of the bigger picture. One good month of rain does not mean climate change is a hoax, as much as there might be people out there trying to convince you that it does.