Code Red – Safeguarding Supplies from Natural Disaster
Fires in Australia, hurricanes in New Orleans and earthquakes in the California sun have shocked the globe. Dr Gareth Evans looks at how modern-day water infrastructure is equipped to stand up to devastating worldwide events.
As the full costs of Australia's recent bushfires have begun to become apparent, beyond the loss of life, property and infrastructure it seems many of the affected areas will have a further price to pay in terms of water – and for decades to come. Given the already parlous state of many of the country's water reserves after years of sustained drought, the news could hardly come at a worse time.
With the world seemingly locked in a spiral of what UNESCO has described as "a dramatic increase of suffering from the effects of disasters... caused by poor water and land management and possibly by climate change", Australia is clearly not alone in its woes. In February – the month of Victoria's "Black Saturday" bushfires which claimed over 200 lives and destroyed more than 2,000 homes – China announced a raft of novel and innovative approaches to protect its own beleaguered water supplies.
A month later, the European Environment Agency published its report "Water resources across Europe" – highlighting the fact that in some parts of the continent, the current rate of use is driving drought and degrading water quality. Across the globe, whether the threat comes from drought, flood, cyclone, hurricane or earthquake – and irrespective of how much of a human contributory factor there may be – the need to protect water supplies from natural disasters is clear. The challenge is finding the technology to do it.
Shaping defence – construction and infrastructure
Inevitably, the focus has fallen considerably on construction technology. Although none of Melbourne's key water infrastructure was badly damaged, questions have begun to be asked in certain quarters over whether the emphasis in current building regulations on the safe evacuation of personnel, is sufficient.
Mindful of what seems a lucky escape (the bush fires reached the upper reserves of some catchments), some are suggesting that the design of such critical structures should be required to be fire-resistant for much longer periods than current legislation demands, to avoid potentially serious consequences in the future.
Elsewhere in the world, similar pressures to safeguard water infrastructure have driven the uptake of specialist construction measures to protect against other varieties of natural disaster. In southern California, the threat of earthquake – a greater than 99% chance of quake of 6.7 or more within the next 30 years – led San Diego County Water Authority to incorporate state-of-the-art seismic protection into the building of its new Earl Thomas reservoir. Meanwhile, for post-Katrina Mississippi, the lesson of disrupted water supplies has prioritised infrastructure flood defence.
Foretelling the future – prediction technology and water
Designing protection measures into the infrastructure itself has obvious advantages, but it alone is unlikely to offer the complete solution to the vagaries of nature. If, as many believe, natural disasters are going to be increasingly commonplace over the coming years, then the ability to forecast where, when and how badly they will strike, accurately and well in advance, represents a clear benefit for resource protection.
Unsurprisingly, prediction technology is one area that has seen a particular growth in interest. Accordingly, the models used to anticipate major catastrophic events are becoming ever more sophisticated.
Combining data sets from seismology, earthquake geology and geodesy, for instance, enabled a comprehensive model to be developed in California in 2008 that enables earthquake probabilities to be predicted state-wide for the first time. This suggests that the likelihood of a major quake (magnitude 7.5 or greater) occurring within the next 30 years is 46% – and the event is most probable to occur in the southern half of the state – proving the wisdom of San Diego's 2005 decision over its new reservoir.
As Ned Field, a geophysicist with the US Geological Survey and lead scientist on the project explained, this sort of information allows California "to improve public safety and mitigate damage before the next destructive earthquake occurs". With future big earthquakes inevitable, accurate emergency planning and adequate resource protection will be essential.
Flood modelling is another discipline that has seen significant advances, with flow propagation over complex urban landscapes able to be predicted with great resolution and accuracy. Moreover, the door is now open to the development of the first generation of truly integrated models, with multi-user/multi-functionality technology rolled out to full across-the-network applications.
Today's depth-averaged models make full use of 3D laser mapping sensors and enhanced computational capabilities to offer unprecedented levels of information and the potential to achieve major strides in safeguarding key installations and infrastructure during future flood events.
Early warning and good modelling is never going to be enough, however. Climate models predicted February's bush fires but safeguarding supplies evidently calls for more.
A hint of the answer may come from an unexpected direction – and involve the sort of paradigm shift in thinking that Professor Malin Falkenmark of the Stockholm International Water Institute and other proponents of the "peak water" concept would urge.
Borrowing the established precepts from the established peak oil debate, they argue that globally, the era of relatively cheap and easy water access may be about to come to an end and that a time of amplified water scarcity – in part due to natural events – is dawning. The arguments of burgeoning population, aquifer depletion, creeping desertification and run-away demand are, of course, not new – but they are compelling ones in this context.
One thing the peak water concept does make clear is the limitations of considering runoff / groundwater recharge ("blue water") and transpiration / evaporation from vegetation and the soil ("green water") in isolation when it comes to asset management and water resource planning.
Although this approach is useful as an illustration, its artificial simplification ignores the inherent interdependence of the hydrological cycle – and by implication, its intrinsic vulnerability to natural disasters. As environmental consultant Phil Vickery says: "If you're going to protect resources from fire or flood, water's water, wherever it is. If you don't safeguard the 'green' water, in the long run you'll only have to use the 'blue' water to make up the difference – well, that, or starve!"
Back in October 2008, long before the ash run-off from Victoria's ravaged forests threatened to contaminate reservoirs supplying Melbourne for months, the city's water bills were already set to double to fund Melbourne Water's AU$5bn spend on major infrastructure projects. Could this be the first glimpse of peak water? In truth, probably not, but it does seem to indicate that safeguarding supplies – and implementing the technology to achieve it – does not come cheap. It may, nevertheless, be a price we are all simply going to have to get used to paying.