NEW IRRIGATION SCHEME

Press, Volume LXXIII, Issue 22057, 3 April 1937, Page 12

NEW IRRIGATION SCHEME

Rangitata Diversion Begun SERVING 200,000 ACRES LARGEST YET PLANNED IN NEW ZEALAND [THE PRESS Special Service.] TEMUKA, April 2. Work on the largest and most important project of its kind in New Zealand —the Rangitata diversion irrigation scheme—was begun to-day. The purpose of the race which is being constructed is to supply water for the Ashburton-Lynd-hurst irrigation scheme, and also for all anticipated water requirements for the rest of the Ashburton county, including stock water for that part of the county which can be economically served from the race. The total length of the race will be approximately 35 miles, the total area to be served more than 200,000 acres, and the combined cost of the two schemes nearly £1,000,000. The scheme has been worked out with the collaboration of Mr F. Langbein, District Engineer for the Public Works Department in Christchurch, and other senior engineers including Mr J. Wood, Chief Engineer to the Public Works Department. The Jocal engineer in charge is Mr E. C. Smith, and Mr T. G. Beck, resident engineer to,the Public Works Department at Temuka, is directing the work. Course of the Race The race will leave the Rangitata river at Rocky Gorge (where the river emerges on to the plain) and will traverse the plain in a northeasterly direction, passing between the Surrey Hills and Mayfield and across both branches of the Hinds river to the South Ashburton river. On crossing the South Ashburton river through a large flume at an elevation of approximately 980 feet, the capacity, which altogether is 900 cusecs, will be reduced to 450 cusecs, and the race will continue to Boyer’s and Taylor’s streams where, in all probability, flumes will be used to make a crossing. The race will then proceed to the North Ashburton river where a flume will take tfie water into the main race of the Ashburton-Lyndhurst irrigation scheme. Magnitude of Project Some idea of the magnitude of the project can be gathered by comparing its scale with the scale of the existing stock-race. The old stockrace measures 6ft 6in across at the top, 4ft 4in wide at the bottom, and is one foot deep. The new diversion race will measure 60ft across at the top, 20ft wide at the bottom, and will be 10ft deep. The construction work will employ an average of 130 men for about three years, and when the race is completed it will be able to carry sufficient water to supply the irrigation and stock needs of the whole Ashburton county.

Operations at Intake The design for the intake structure has not yet been completed and may involve cutting a shprt drive of from five to six chains, according to Mr T. G. Beck, the department’s engineer at Temuka. During operations at the intake the water will be prevented from entering the existing stock race, and so that no hardship of any kind may fall on the farmers in the lower lying areas, a pumping unit of 300 horse-power will be installed, and the water from the river, by an electric motor of 300 horse-power, will be lifted to a height of 107 ft and discharged in the present stock race. Progress on the scheme will be slow at first till more machinery arrives, Mr Beck told a reporter yesterday, but the speed of constructing will be increased as the necessary machinery is assembled. In the meantime sufficient machinery is at hand for the main job. Tests that were carried out yesterday with an elevating grader and Diesel tractor determined to-day’s proceedings, and at 8 o’clock this morning work on the greatest engineering project of its kind in New Zealand was begun.