Water, water … nowhere

Melbourne Water’s operations manager, John Woodland, says it would take seven or eight years of average rain to refill the Thomson dam, the city’s largest storage, which is now just 42.7 per cent full.

Worst hit is the O’Shannassy catchment, where rainfall is down 37 per cent, the streams a trickle at 71 per cent below average. The O’Shannassy catchment is an indicator of the outcome for an ongoing drought. The groundwater store is used up and a stream flow falls further than that of the decline in rainfall.

Over the past 30 years rainfall in the Hydro catchments has been in decline, now 10% below the average of the previous 70 years.

Combined with one year where rainfall has been below average across Tasmania, this trend has seen the possibility of power rationing raised. The 3 month outlook [August to October] for the populated and agricultural parts of Tasmania from the weather Bureau is for a 35 to 40% chance of rainfall exceeding the median, a high chance of the below average rainfall continuing into the traditional high rainfall period.

At least it is warmer you may say, trying desperately to put a positive spin on the weather. Increasing evaporation and transpirational losses come with above average temperatures and the same experts say that is 55% likely for the same period. And so in Tasmania we are facing a prediction of another 2 and a half times reduction in rainfall on top of the 10% that the Hydro has already recorded over the last 30 years.

Along with a reduction in available water due to a further loss of 10% caused by increased temperatures, the future for the semi arid Midlands may be one of camels and dates at the oasis.

What solution do the leading lights in the Tasmanian government offer? To replace the lost hydro generating capacity we see the greenhouse polluting coal fired power from Victoria along with a 40 year supply of gas.

The difficulty with increasing use of carbon dioxide emitting energy sources is that they contribute to the processes driving the change to the climate and so we are adding to the process that generates that same decline in rainfall that causes us to turn to those greenhouse polluting energy sources.

I hope that carbon sequestration is well and truly in place by that time, not just a dream looking for a reality, as its research status makes it today.

Wind farms

Yes, wind farms may dot the landscape. Heavens, they might even heat the water with the sun now the tropics have drifted a few degrees closer to Tasmania. The Meander Dam may assist in supplying water to a thirsty Midlands.

David Leahman may even be shocked as forestry and the hydro are brought under a new Water Act that acts as a planning instrument, his predictions finally penetrating the thick skulls of vested interest by the very conflicts between users that a major deficit in available run-off generates, and allocations between competing users rationed out.

Perhaps, by this time the phenomenon will also be biting globally with, for example, water deficits expanding the Sahara, sub Saharan systems of agriculture collapsing and hungry Africans displaced into exploiting fewer and fewer local resouces.

Glacier fed rivers will be presenting problems about long-term surety of supply if their feedstock has not been entirely liquified. It may be masked by an increasing rate of melt coinciding with a fall in runoff leading to a lack of pressure for governments to act.

However, once the glaciers are gone the future for the 5 great rivers that feed south and eastern Asia, our regional neighbours, will be one of less water for more people.

In Tasmania we still await a greenhouse strategy from government.

phill Parsons waits with baited breath for the new Tasmanian Greenhouse Strategy, its gestation under Minister Jackson taking an extraordianrily long time. He does not expect it to be coordinated with the new Water Act, the planning capacity of the government enthralled by cargo cultism, one of those beliefs that needs to be changed. He watches the cigarette butt free beaches at Manly shrink to the end result of being free of all butts but that of the Wobegong as his winters in Tasmania become more like that of his boyhood home.