DRAINAGE OF LAKES.

Otago Witness, Issue 3808, 8 March 1927, Page 36

DRAINAGE OF LAKES.

' OPERATIONS AT KAITANGATA. A SUCCESSFUL DEMONSTRATION. In the past 50 years many schemes have been formula.ed • ith a view to draining Lakes Kaitangata and Tuakitoto. Lying in the centre of the large and fertile plain • between Lovelli Flat and Kaitangata, these two lakes, which are, in reality (particularly in the case of the former), only glorified swamps, serve no other useful purpose than as a sanctuary for wildfowl, -. although residents of tne district have : long been convinced that these two lakes, if drained, •muld make available some 2400 acres of splendid arable land. In the ( case-of Lake Kaitangata especially little - surface water remains, but some 800 or 900 acres of bog land lie waiting to be thoroughly drained end to come, eventually under cultivation. There at present ■ exists a canal which was cut by the Public Works Department some nine years ago from Lake Tuakitoto through Lake Kai- , tangata. to the flood gates 0” the Clutha River, but of late this as become so silted ’ up and choked with v eeds as to be almost ■ useless excepting in the case of flood, when • it serves the . urpose of keeping the surrounding country free of surface water. ’ Visualising the possibilities of the large - ■ tract of rich ai.d valuable land which now lies idle for the want of adequate drainage a syndicate of four residents of Lovell’s Flat and Benhar districts (Messrs P. M'Skimming, D. Rovd. W. Robinson, and 8. Nelson), who own •‘he leasehold of the i Jake be<’a. as well as the land adjacent to them, have now undertaken to reclaim the are; under water, and, i- identally, thoroughly to dry out the swamps surrounding them. The project is undoubtedly an ambitious one, but there apnears to be no doubt of its ultimate fulfilment, and when it is remembered .that for generations the rich silt from the surrounding hills has been draining i.-to the two lakes ? the value of the tract of land thus laid bare immediately becomes apparent. Nearlv 50 years have elapsed since the | late Mi- Robert Lee first suggested a scheme for the drainage of the two lakes. ’’ Careful surveys were made, and elaborate ■ ’ plans of the proposed work prepared, but nothing Was done, owing to the gicat cost involved. Now, however, by means of the hydraulic rivar sleeper it would seem as if ’all these difficulties will be smoothed away, and rhe channel from Lake Tuakitoto to the lock gates at the Clutha River so cleared, widened, and deepened, that the water from both lakes will be afforded an easy getaway. One of these machines •' is now operating on the canal, and our representative was enabled to view the work it can do during a demonstration run which was given last week in the presence of a large number of interested spectators, including'Messrs J. R. - Marks and R. W. M'Curdy, who attended on behalf of the Public Works Department, Messrs <7. Horn, M.P., and F. Waite, M.P. M essrs A. Renton and R. Bateman, representing the Bruce County Council, Mr J. C. Collins (Otago Power Board), and-a number of ladies. . ■j- The ‘‘river sweeper,” which is the invention of Mr R. T. Stewart, of Dunedin, is exactly what its name would imply, excepting that, instead of with a broom, the sweeping is done with rowerful jets of water. It is principally intended to be used for cleaning the weedy and. silted beds of streams or ditches expeditiously and economically ,and in this connection it will be remembered that one was tried out with marked success on the Avon River, in Christchurch, a few months ago. The machine is accommodated on a pontoon, and is driven by two powerful electric motors driving a pair of centrifugal pumps capable of lifting and delivering 48,000 gallons of water an hour at a pressure of 6010 to the square inch. Power is conveyed by flexible cable from the Otago Power Board's lines. The water of the stream, or the ditch, is lifted from the up-stream end of the pontoon and delivered through pipes which terminate in patented nozzles reaching into the water at the forward end of the punt. Through these nozzles the ■water is directed through a sleeve of air which protects it from the resistance of the water of the stream. The jets of water, on coming in contact with the mud and weeds on the bed of the stream, break up ■f. ■ their accompanying sleeve of air and force .. it in the form of globules into the material, and this, along with the high-powered stream of water, causes a rapid disintegration of the material, which then rises to , the surface. The weeds are torn from their bed, and washed in the process, enabling them to be carried away with the stream. The mud and silt, which, of course, remain in suspension in the water, are also carried ■ away. The pontoon is guided in any direction which may be desired by winches and drawing wires attached to the banks., The demonstration given last week was i entirely successful, and those present ex • pressed themselves as delighted with the work done by the “sweeper.” A particularly difficult stretch of the canal was chosen for the, test, and, despite the fact that it was barely six feet wide and no more than two feet deep, besides being so badly choked by weeds that there Was no trace of a current in the stream, an hour’s work by the sweeper changed it into a splendid, clear stream quite 15ft in width and with an average depth of 4ft 6in. TOASTS HONOURED. At the conclusion of the trial the party adjourned to the Cabaret Tea Rooms, at the invitation of Mr Stewart, where several toasts, including the loyal toast, were honoured. Mr Marks occupied the chair. Mr Marks proposed the.toast of the host, who, he said, was well known as an eminent hydraulic engineer throughout the Dominion. Mr Marks said that, although he had heard of Mr Stewart’s plant, he had never seen it in operation until that afternoon, and the demonstration had convinced him that it was safe to predict its complete success. Further, he could see a definite scope for such a plant in the deepening of navigable rivers or removing shoals, particularly in the case of a river like the Clutha. He wished to compliment Mr Stewart on the well-deserved success of the plant. -Mr Stewart thanked those present for their attendance, and also Mr Marks for his. remarks. He stressed the fact that the ’success of his machine that afternoonwas due more than anything else to his

being able to obtain electric power, and he considered that Otago generally owed a debt of gratitude to the Electric Power Board which had made this possible. The Otago Expansion League was also a body to whom praise was due for its unflagging work in the interests of the province. •Mr Stewart went on to refer to his machine, and stated that by means of a larger one on similar lines it might yet be possible to allow, steamers to come right up to Kaitangata. Mr Bateman proposed the toast of the syndicate which was responsible for establishing the plant. Mr M'Skimming replied and paid a tribute to the foresight and energy displayed by Mr Stewart in designing and erecting . it. When the matter had been discussed they had been promised electric power by the Otago Power Board, and he was bound to say that the power was available as soon as the machine was ready. He considered that the widening and deepening of the canal with the consequent draining of the lakes would be a good thing, not only for himself and his fellow-directors but for the district generally. He could see in the machine they had seen working that day a beginning of greater things. Mr D. Boyd also spoke briefly and pointed out that anything which overcame the difficulty of economicaUy draining land was a public benefit. Their thanks were due in a large measure to Mr A. C. Buchanan, who was responsible for the electrical installation, as well as to Mr Stewart, both of whom had worked early and late to ensure the success of the scheme. Mr Boyd referred to the demonstration which they had witnessed, and said he considered that in the future Mr Stewart’s invention would be used on a larger scale with ultimate benefit to districts served by navigable rivers. Mr Waite, M.P., proposed the toast "of the- Bruce County Council, and made eulogistic reference to the work done by that body. Although, he said, county councils were harshly criticised at times, there could be no doubt that its members, who gave their services freely and without hope of reward, were deserving of great praise., Mr Renton replied briefly on behalf of the council. Other toasts honoured were, “The Otago Power Board,” proposed by Mr M’Curdy and replied to by Mr Collins; “the Public Works Department,” proposed by Mr J. Horn, M.P., and replied to by Messrs Marks and M'Curdy; “Parliament,” pronosed by Mr Renton and replied to by Messrs Waite and Horn; and “The Ladies,” proposed by Mr A. Buchanan and replied to by Mr Stewart. Th© gathering concluded with, a vote of thanks to the chair.