Kariba Sir Malcolm Barrow
Basic Slag E. M. Hopkinson, E. Davison, M. Johnson Treatment or Punishment Frank: Allan Thomson, John Sylvester, John Hipkin Demonstrators: New Style Roy Hiscock, A. F. Blanchard The Centurions Peter Green, Bernard Levin Intrusion Llew Gardner
Americana-1 Henry Pettit
Americana-2 Raymond Postgate KARIBA Sta,—The Kariba Dam has in many respects become the symbol of the tremendous progress that the years of Federation have brought to Central Africa. It is therefore not surprising that the Federation's critics should seek to discredit and to undermine confidence in Kariba by distorting the facts. In so doing, Political commentators like Mrs. Grace Scott (the Spectator, October 6) arrogantly disregard the expert opinions of world-renowned engineers, geologists and economists (including those of the World Bank).
The facts are that examination of both the Kariba and Kafue hydro-electric schemes was started as early as 1947 to 1951 by a special committee set up by the Central African Council. When the decision was taken to proceed with the Kariba scheme, Kariba was hydrologically proven. Kafue was proven only In so far as the first stage was concerned, and proving the second stage to the satisfaction of the consultants and the World Bank involved further observations over a number of years to obtain the necessary hydrological data. Since the demand for power was threatening to overtake the available supply in a very few years, a decision had to be taken urgently.
Estimates for the two schemes in 1955 showed that Kariba (£86 million) would produce more power at a cheaper rate than Kafue (£55 million). At a 74 per cent. load factor, Kariba would produce 1,000 m.w.; Kafue-400 m.w. The cost of power delivered to the receiving stations would be : Kariba--0.254d. per unit; Kafue-0.332d. per unit.
Any suggestion that the decision to build Kariba first was taken because of the possibility of a black government in Northern Rhodesia is pure calumny, as is the statement that Kafue would have been safer. The change of plans was made purely in the best Interests of the economy of the Federation as a whole.
As to safety, the design of Kariba, like many other similar designs, was reviewed after the Malpasset tragedy. In the view of experts, it was not considered that anything that happened at Malpasset was relevant to Kariba. Assurances have been given by the consul- tants with regard to the foundations of rock on which the foundations of the mass of the dam were built to the effect that when the new block has been built the upper third of the dam will also be secure.
The existence of weak rock on the south flank of the dam site where the thrust block is now being constructed was known to the consulting engineers before work started on the dam. The fact that the area of weak rock above 1,500 feet has proved more extensive than was originally believed presents no insurmountable problem. A report by the Northern Rhodesian Geological Department in 1956 referred not to this area of weak rock but to the power station site, 1,200 feet underground. The Northern Rhodesian Department forecast that in excavating this site a great deal of weak rock would be found and advised a different site for the power station. The Federal Power Board naturally considered this warning, but on the advice of their own consultants, rejected it. In the event the power station was con- structed without difficulty and the forebodir,gs of the Northern Rhodesian Geological Department were not realised.
The process of jetting and grouting in order to strengthen areas of rock is a• perfectly normal engineering practice and the total amount expended thereon is by no means abnormal in relation to the total Kariba contract. The abutment block to be constructed is needed only for the top third of the dam wall and the effect of this will be to divert the line of thrust of the dam away from the zone of the weaker rock to the sound rock at a lower level.
The reason why Northern Rhodesians required a special permit to cross the contractors' temporary narrow bridge at Kariba was that the contractors had severely to restrict traffic on the bridge in order not to hold up work on the site. Southern Rhodesians likewise required a special permit to cross the bridge into Northern Rhodesia. Kariba township was sited on the south bank because this was the nearest line of communication to the sea and was the site of the power station in which imported machinery had to be installed. This enabled work to continue on the south bank when the bridge was washed away in the floods of 1957 and 1958. It should be mentioned that all the cement for the huge dam wall came from Chilanga in Northern Rhodesia.
There is now very good reason to believe that had the full Kafue hydro-electric scheme been proceeded with, the authorities might have been guilty of mis- application of capital. This is not because the hydrology of its first and second stages has not been proven (it now has) but because there is a consider- able body of opinion that believes that a portion of the waters of Kafue would be better employed on an irrigation scheme to suoport a large population on the Kafue Flats.
The present question is how to obtain optimum use of the waters of Kafue and what percentage of those waters would be available for electricity genera- tion. In this connection a four-year survey is being planned by the Food and Agriculture Organisation of the United Nations in collaboration with the British, Federal and Territorial Governments at a cost of some £430,000.
To Mrs. Grace Scott, partnership is merely a 'gimmick.' To people of good will in the Federation of Rhodesia and Nyasaland, partnership is a word used with sincerity and pride to describe the spirit of co-operation in which black and white bend their backs and rack their brains together to build great things like Kariba. They are confident that this policy, and the spirit which motivates it, will achieve the goal of a happy, stable society based on practical faith— not negative emotionalism.
MALCOLM BARROW
Minister of Power Federation of Rhodesia and Nyasaland
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