Quote:Earth is a blue watery planet.
70% of its surface is covered by oceans of salt water, some of which are extremely
deep. These oceans contain about 97% of Earth’s water. Another 2% is locked up in
snow, ice caps and glaciers. That leaves just 1% of Earth’s surface water in inland
seas, lakes, rivers and dams. We have plenty of water, but not much to drink.
In addition to these vast surface water supplies, water vapour is the fourth most abundant gas in the atmosphere, after nitrogen (76%), oxygen (21%) and Argon (1%).
Moisture in the atmosphere varies from almost zero over deserts and ice caps up to
4% over the wet tropics. (Carbon dioxide is a miniscule 0.04%).
Then there are the large and unmeasured supplies of hidden underground water –
“renewable” water from rain soaking into alluvial sands and gravels; artesian water in
deeper permeable rocks; hydro-thermal water associated with volcanic and igneous
activity; and primary water originating deep in Earth’s crust which feeds many natural
springs and is sometimes discovered in unexpected places in very large quantities.
With this abundance of water, why do humans ever find themselves short of fresh water? Three reasons – insufficient water is conserved when it is abundant, too much
water is wasted, and power costs make desalination unattractive.
The biggest water-wasters are those towns and cities which supply unlimited free or
subsidised water to large and growing populations. Everything supplied “free” is wasted. Then when drought comes and water is most needed, it must be rationed.
Under-priced or free water will be wasted watering lawns and golf courses so they can
be mowed again, sprinkling decorative gardens, supplying fish ponds and water
features, washing cars and footpaths, filling swimming pools, indulging long showers,
and ignoring dripping taps and leaking pipes. If every user in every town and city were
metered, and had to pay the full cost of water, it would be used much more carefully.
For example, back in the 1980’s, the Central Queensland coal town of Moranbah, water was un-metered and water was supplied “free” by the coal company. But in droughts Moranbah water had to be rationed – gardens one side of the street could
use water today, the other side tomorrow. Another town, Dalby, in the same climatic
district was metered and self-regulated. No watering restrictions were imposed. The
water consumption per resident in Dalby was half that of Moranbah (and gardens were
just as good).
How should we charge for water? “Charge what it costs” sends the right signals to users. Maybe each user should pay a fixed base charge for water to cover essential
needs. This should be related to the capital costs of the water infrastructure. Usage
above this should be charged at a variable rate which would increase as the water levels in dams dropped. This would remove the need for water restrictions and
generate public support for building more dams.
Lucky Australia has a “Great Artesian Basin” and many grazing properties and inland
towns have relied heavily on artesian water that flows to the surface from deep bores.
Again this “free” water has been badly wasted by allowing the bores to flow unchecked
into open bore drains subject to heavy losses by evaporation and soakage. There is a
program to case and cap these bores to reduce wastage. Some of the government
funding frittered on global warming “research” and green energy gambles would be
better devoted to conserving artesian waters.
Some places like Perth in Western Australia with low rainfall and high evaporation
rates have made good use of artificial desalination plants, but desalination is generally
the last resort without abundant cheap electricity.
The nuclear energy of the sun powers the greatest desalination plant on earth using
mainly sea water to create all of Earth’s clouds, rain, hail and snow. Unfortunately it
delivers these products in cycles of floods and droughts. Therefore dams are needed
to improve water security in droughts, and to moderate the severity of floods.
Water storage is an important part of the water equation which every farmer understands. There is no point allowing immense floods of fresh water to erode the
land and spew into the seas – the oceans are not short of water (but offshore sea life
like prawns and corals can benefit from nutrients and minerals delivered offshore in
floods).
When the inevitable droughts return and the dams are drained, cities are faced with
severe rationing, re-treating waste water or de-salting sea water in expensive power-
hungry desalination plants. Australia has immense deserts and many of our “rive
rs” (including the mighty Murray-Darling) flow intermittently. Normally “creeks” flo
w into “rivers”, but in the dry inland it takes two “rivers” (the Thompson and the Barcoo) to service Coopers “Creek”, and still Lake Eyre is usually dry.
Quote:Sensible people try to conserve water when it is abundant, but every dam proposal soon attracts fierce and organised opposition. This means that most of Australia’s dams were completed decades ago - Warragamba NSW 1960, Eungella Qld 1969, Ord River WA 1971, Beardmore Qld 1972, Fairbairn Qld 1972, Snowy River Vic-NSW 1974, Gordon Tasmania 1974, Hinze Qld 1976, North Pine Qld 1976, Fred Haigh Qld 1978, Wivenhoe Qld 1984, Thompson WA 1984, Burdekin Qld 1987, Barambah Qld 1988.
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Build more dams (Read 4506 times)
