NEW IRRIGATION DEVICES

Press, Volume XCI, Issue 27641, 23 April 1955, Page 8

NEW IRRIGATION DEVICES

Automatic Operation

Practicable

SUCCESSFUL TRIALS IN CANTERBURY

Trials made in Canterbury recently have shown that by automatic means is practicable. Further experiments are now being conducted to develop a sound practice of water distribution using automatic devices. “It can, however, now be said that it appears that automatic irrigation as a major problem is well on the way to solution,’’ said the District Commissioner of Works, Mr A. E. Clark, yesterday. \ “The labour involved on irrigation is considerable, and these devices, which are designed for use in conjunction with the border- dyke system of land preparation, not only save labour but permit 24-hour irrigation,” he said, explaining the purpose of the investigations. Mr Clark said that for some considerable tipie officers of the Ministry of Works had been considering the de - velopment of automatic irrigation, and last year the Ministry had manufactured the first prototype. At the W inchmore irrigation research farm the Department of Agriculture had also been carrying out investigations and the- ideas of investigators had been co-ordinated in the recentlyestablished inter-departmental irrigation committee, on which were representatives of the Ministry of Works, the Department of Agriculture, the Lands and Survey Department, and the Department of Scientific and Industrial Research. At a trial held recently in the Ashburton area, five sets of automatic gates manufactured by the Ministry of Works—four of the trip gate type and one of the canvas dam type—three sets of canvas dam type developed on the Winchmore irrigation research farm, and one developed by private interests had been tested. “Definitely Possible*’ “All of these showed that they were practical developments and therefore that automatic irrigation is definitely possible,” said Mr Clark. All could be readily manufactured—particularly that of the Department of Agriculture, which could be made at comparatively low cost out of materials which any farmer could reasonably obtain and was an application of the well-under-stood canvas dam. Now, said Mr Clark, experiments were being conducted to determine a sound practice of water distribution using the new devices. Farmers now use canvas dams in head races to bank up water to irrigate border dyked land, but these dams have to be moved, by hand when one section of a paddock has been irrigated sufficiently. The automatic devices seek to overcome the need for close personal supervision of irrigation. The Department of Agriculture’s canvas dam automatic device is an ingenious arrangement. The tripping mechanism includes an alarm clock, a dog chain, and a bomb release of a type used in the Air Force which has been obtained from surplus war stocks. At a predetermined time the alarm clock actuates a trip on the bomb release which eases the tension on the dog chain allowing the canvas dam to drop to the bottom of the race and the water to flow down the race to the next dam, where the process is repeated. The Ministry of Works has also developed a canvas-type dam with a slightly different tripping device. The Ministry has also designed a hinged steel gate set on a sill. The gate is tripped by the flow of a small stream of water into a tripping bucket at the back of the gate. The bucket has an adjustable setting depending on the time required for water to flow down the border.