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Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Reader Services Ann Jenkinson Advertising Enquiries Leo Simpson Phone (02) 979 5644 Regular Contributors Brendan Akhurst Garry Cratt, VK2YBX Marque Crozman, VK2ZLZ Julian Edgar, Dip.T.(Sec.), B.Ed John Hill Jim Lawler, MTETIA Philip Watson, MIREE, VK2ZPW Jim Yalden, VK2YGY Bob Young Photography Stuart Bryce SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. A.C.N. 003 205 490. All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $49 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 34, 1-3 Jubilee Avenue, Warrie­ wood, NSW 2102. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. PUBLISHER'S LETTER The Gordon Dam must not be emptied It could only happen in a rich democracy: this recent proposal that the Gordon Dam in Tasmania should be emptied so that the original Lake Pedder can be restored. To put it bluntly, this is environmentalism gone crazy. I well remember writing an editorial in the June 1982 issue of “Electronics Australia” opposing the then proposed Gordon River dam scheme. This seemed to be a completely unnecessary scheme and one which was eventual­ly stopped by the Federal Government in 1984. However, the Gordon Dam which flooded the original Lake Pedder is a much larger scheme which was completed in 1976. It was described in detail in the February 1991 issue of SILICON CHIP, as part of the popular series entitled “The Story of Electrical Energy” by Bryan Maher. At present, it has an installed generating capacity of 432 mega­watts and is the major component of Tasmania’s electricity sup­ply. Now I don’t really think that the dam will be emptied but, in today’s topsy turvy world, you never know what crazy scheme might succeed. So let’s look at the proposal objectively. Sure, the original Lake Pedder was a pleasant enough lake although the only aspect that made it unusual was the salmon pink sand beach which showed when the water level was down – when the water level was high, the beach was not visible. Offsetting the subtle colour of the sand was the dirty brown colour of the water, a result of tannin leached from the nut grass which is prevalent in the catchment region. Actually, the water looks like a cola drink. Very few people ever saw the original lake since it was accessi­ble only to trekkers or by plane (which had to land on the beach). Today, we have a much larger body of (still brown) water which is visited by tens of thousands of tourists a year. If it were to be emptied, it would be a financial and environmental disaster. Not only would Tasmania lose a substantial portion of its electricity generating capacity but all the tourist dollars produced by this major attraction would vanish. And how would all the vegetation in the area now covered by water (260,000 square kilometres) be restored? Would the dam wall with its 280,000 tonnes of steel and concrete be demolished and disposed off? What about the two other dams in the scheme which also raise the water level? And what about the very expensive generating plant? Would that be scrapped? And how would Australia then stand in its attempts to reduce carbon dioxide emissions in the years to come, if hydroelectricity has to be replaced by fossil fuels? How would Tasmania cope for water and electricity in the next drought? These questions and many others have very unsatisfactory answers. Or very expensive answers. Really, the whole proposal is crazy and should be dismissed out of hand. Australia may be a rich democracy but we aren’t that rich and nor, I hope, are we that silly! Leo Simpson ISSN 1030-2662 WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 2  Silicon Chip