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Salient. Victoria University Student Newspaper. Volume 33 No. 14. 1970

Manapouri

Manapouri

Only by a full understanding of the forces at work producing the present ecological balance, can an appreciation be reached of the extent of the environmental changes that would be initiated by the rise of lake level.

—A.F. Mark

The ecologist sees the decline of the great natural buffer of wilderness as an element in our danger. Natural wilderness is a factor for world stability, not some remote place inimical to the human being. It is strange that it has been so-long a place of fear to many men, and so something to hate and destroy. Wilderness is not remote or indifferent, but an active agent in maintaining a habitable world, though the co-operation is unconscious. But we ourselves are conscious of what we are doing and capable of forecasting the consequences. Pragmatic man, typified by too many of our politicians and of those considered to have their feet firmly on the ground, has his head in some world of illusion of his own making. What is the use, he asks, of all that forest if it cannot be brought to the service of man? The answer in the service of man if he is willing to accept fellowship with the world of nature.

F.F. Darling

Don't it always seem to go, That you don't know what you've got till it's gone ?"

Recent research by Dr. A.F. Mark, near Lake Te Anau, established that the artificial raising of a water-table does within a period of 9 months, kill mountain beech trees growing on sites where the new water table lies within 9 inches of the ground surface. It seriously weakens trees within 12 inches of the raised water-table. This suggests that mountain beech trees would die under comparable circumstances around the shoreline of either Lakes Manapouri or Te Anau.

An ecological loss could not be denied if the lake were raised, but this had been over-emphasised. There were few unique features and little that would be lost irrevocably.

(The Solicitor General. Mr R.C. Savage September 3 1970)

The 25 islands on which the natural woody vegetation will be destroyed are scientifically, by far the most valuable since, unlike the large islands and the mainland, they have remained relatively free of deer, they now provide the only known examples of virgin forest and scrub in eastern Fiordland. As such they are irreplaceable reference areas.

It was also accepted that all the beaches now around the lake would disappear. Some however, could with care be created at the new lake level, said Mr Savage.

In the experimental bush-clearing site at the head of South Arm Lake Manapouri the shifting of beach material by bulldozer was not a scientific experiment but treated as a sheer physical task, in piling up a mixed gravel and sand to a height of 610 feet simply to show that something of the kind was a possibility. Beach material was unsorted; it was not placed in a scientifically defined profile that could be expected to remain in equilibrium under the force of the waves. No calculation was made as to the need to place material above 610 feet, so as to withstand the storm waves that would inevitably be powerful agents of erosion at times of strong winds. The back slope and underwater shelf of the beach recieved no attention in relation to the stability required. The colossal amount of vegetation to be removed, apart from commercially valuable timber is presumably to be disposed of by dumping into the lake. This amount of organic and soil material (of the order of millions of tons) must have a profound effect on the biology of such a low-production clear-water lake as Manapouri. No" research has as yet been supported on this problem.

It was well established that it was feasible to do the shoreline clearing, he contended. Evidence by the American King Ranch organisation on cost was a good guide for this and at a not unreasonable figure.

The N.Z. Forest Service stated that any investigation of the methods and costs of shoreline clearance to satisfactory standards have been quite inadequate to date, in the 2 experimental clearings. The cost of these ($11,000) cannot be used for assessing total cost of shoreline treatment. The total area to be flooded around the lake is estimated by Dr. C. Burrows, Canterbury University to be almost 4,000 acres rather than the Governments revised estimate of 2,500 acres.

Comparisons have been drawn with Lake Monowai, but nothing was done there, and a great amount of work will be done for the Lake Manapouri scenery.

Lake Manapouri is to be raised 27.5feet. Experience at Lake Monowai 45 years after raising the lake level only 7 feet shows vividly and beyond dispute that damage to the shoreline and its vegetation cover draws attention to such devastation, and utterly destroys the sense of satisfaction derived by the observer from the scene.

If naturalists seem always to be against something it is because they feel a responsibility to share their understanding, and their opposition constitutes a defense of the natural systems to which man is committed as an organic being. Sometimes naturalists propose projects too, but the project approach is itself partly the fault, the need for projects a consequence of linear, compartmental thinking, of machine-like unils to be controlled and manipulated.

P. Shepard