Science Bl

Valuing our precious supply
Peter Schwerdtfeger is Emeritus Professor of Meteorology, Flinders University.
21 March 2007

Peter Schwerdtfeger’s distinguished career has included becoming Foundation Professor of Meteorology at Flinders University and currently Emeritus Professor. He is also a former member of the Australian Bureau of Meteorology Advisory Board and a member of the Antarctic Science Advisory Committee as well as senior advisor at Airborne Research Australia, a major National Research Facility at Flinders University.

In this blog Peter discusses a number of ways to move forward during our water crisis and although he lives in South Australia many of the solutions he proposes here are relevant all over Australia.

Urban run-off
Adelaide and Perth are two southern state capitals which have expanded over their vital catchments or aquifers. Perth has sullied its substantial underground resources and allowed its Darling Ranges catchments to become increasingly salinised by excessive land clearance in the SW region.

At the same time Adelaide has allowed its urban development to ever expand over the southern Mount Lofty Ranges. This was the area that Colonel Light saw as being the reliable source of Adelaide's water supplies. Since the 1960s every South Australian Government has been aware of the relentless destruction of the water catchments as greed-driven ever closer development progressed.

We have become so inured to this level of environmental irresponsibility that no one comments any more that the Hope Valley and Happy Valley Reservoirs are completely surrounded by "moats" to prevent the entrance of local rainfall runoff. However we must not allow the less publicly visible and larger storages to also become isolated from local flow!

Householders too have become removed from personal responsibility around their use of local rainfall. The construction of the Murray pipelines in the 1950s allowed SA's citizens to sink into excessively wasteful habits. In most years, all households should be able to store sufficient rain water for drinking and cooking. If most urban runoff were directed into the Adelaide Plains aquifer through expanded wetlands, reasonable irrigation of gardens would be possible. This would leave the Mt. Lofty Ranges storages substantially free for other purposes, including domestic washing, and industry.

Intelligent water use
With regard to water restrictions, intelligent use should be made of water meters, with which all connections to a reticulated water supply are equipped. An equitable allocation could then be made for each household. SA's present rationing scheme allows unlimited water to be used when the use cannot be publicly witnessed!

Desalination
Adelaide's water storage and supply infra-structure has remained unchanged for half a century, during which time the population has more than doubled. Therefore if the Government wishes to persits with plans to increase the population even further, then extra water needs to be found. Building a weir at Wellington would have almost irreversible environmental consequences for the Lakes Alexandrina and Albert as well as the Coorong. Suggestions that a structure costing more than $100Million could be regarded as temporary are completely absurd. Far better that this sum would be spent on the down-payment for a desalination plant at a location such as Port Stanvac, where access to sufficiently deep water may be sufficient to deal with the problem of the waste saline "sludge".

Recycle for industry
It may be some time before the Australian public will accept the idea of recycling waste water for human consumption, even though overseas travellers may have unwittingly consumed such products in many other countries. On the other hand, there is no reason why many industrial processes require clinically purified water, especially when so much urban run-off is drained away to sea.

Efficient irrigation
While Adelaide currently faces a severe water supply deficiency, it must be recalled that irrigation schemes draw most of the Murray River water. Airborne and satellite imagery reveal varying levels of wastefulness as well as some "text-book" examples of efficiency. It is important that the Government builds up more competence in such monitoring skills so it can offer sympathetic advice and constructive assistance to growers.

The principal mechanism for the loss of water is by evaporation. With the relentless de-emphasising of measurement practices and rigorous sciences in many of the nation's universities, the need for experts who actually know how to measure evaporation rather than just talk about it has never been greater. Monitoring of agricultural water use by airborne facilities could prove beneficial to irrigators as well as help identify wasteful practices.

Senseless and wasteful extension of irrigated areas into semi-arid zones, particularly by "faceless" investment schemes, should be strongly discouraged. Without pausing to consider the long-term consequences, in the last 20 years, SA Governments of both shades have endorsed three new irrigation schemes in regions which had existed productively without externally supplied water for many decades.

Shared resource
Australia's rainfall, surface and undergroundwater need to be thoroughly understood and monitored by ever continuing investigations. Without such information, the thorny question of water allocations cannot be dealt with equitably. Most aquifers can cope with modest windmills supplying farm animals with water, but vast fields growing fodder for export, relying on huge quantities of pumped underground water can affect the sustainability of entire regions. Once water has left the surface of any private property either as defined stream-flow or to reach an underground aquifer, it should be regarded as a national or state resource, just as minerals are. Allocation of such resources should not be a matter of political patronage and certainly not free from time constraints, especially as belief in climate change grows.

The entire philosophy of water allocations must be thoroughly and openly re-examined. In particular, the absurd concept that water can beJanuary 9, 2008 system without any consideration of the environmental consequences must be stopped once and for all.

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