SITE SELECTED

Otago Daily Times, Issue 27025, 9 March 1949, Page 4

SITE SELECTED

Dam for Roxburgh Scheme PLACING OF CONTRACT The site of the dam for the Roxburgh Gorge power development project will be at Tamblyn’s Orchard practically at the outlet of the gorge. Because of the need for urgency in the completion of the scheme, the biggest in the southern hemisphere, and because of the great call on the construction capacity of the country, the Government is exploring the possibility of entering into an overseas contract for the huge undertaking.

This information was released to the Daily Times yesterday morning by the Minister of \V orks, Mr Semple, after he had gazed down from a rocky headland on to the Clutha River at the spot where it will be harnessed to produce more than 300,000 kilowatts. With Mr Semple were Mr C. W. O. Turner, assistant engineer-in-chief of the Ministry of Works, Wellington, and Mr G. Hallewell, engineer-in-charge at Roxburgh Gorge, and other engineers connected with the scheme.

“The choice of this site has involved a great deal of work which has been done as rapidly as possible,” said the Minister, “ It has involved a thorough and' complete study of the hydrology of the whole catchment of the Clutha and of the lakes which are tributary to it. There was little initial study of this immense problem. In addition to the hydrological studies, an extensive, survey of the geology of the region, and particular and detailed investigations of the possible dam sites •have been made. The completion of these investigations and of the preliminary design studies have culminated in the choice of the dam site and the development of the layout for the works by the department. “ The scheme is a very large one—the largest in the southern hemisphere”—Mr Semple said, “and will produce over 300,000 kw. Each generator will produce nearly as much power as three of the machines at Waitaki.

“ The Government is well aware of the need for urgency,” he stated, “ and because of the great call on the construction capacity of the country, is at present vigorously exploring the possibility of entering into an overseas contract.”

In December last Mr Semple discussed the two projected sites for the dam—at Pleasant Valley several miles up the gorge and at Tamblyn’s Orchard. At that time he explained that for the Pleasant Valley site a design could be arranged to use a minimum of cement and steel, but, on the other Hand, this design would require fleets of construction vehicles and machines, most of which would be obtainable only from dollar countries.

As the dam will be at the outlet of the gorge before it debouches on to the flat around Roxburgh, road and rail access will be comparatively simple, whereas the Pleasant Vajley site offered many difficulties. Apart from constructional advantages, the new site should, produce a greater number of kilowatts than a station further up the gorge. Some idea of the vast undertaking was gained by a Daily Times reporter who visited the site yesterday. The crest of the great dam which will stretch across the gorge will be 1000 feet in length and from foundation to crest it will rise 2000 feet. The level of the river will be raised 145 feet and a great lake will ultimately hank up behind the dam. The power house will be constructed along the face of the dam, with a spillway • on the right bank to carry surplus water back to the river just above the outdoor station. Details of construction have not yet been completed, but it is probable that while the dam is being built the river will be diverted through the orchard site.

As the Minister previously announced, a construction township will be built on the left bank of the river and a small permanent village will be erected for the station operating staff on the right bank on the undulating hillside near the existing main highway. Meanwhile there is considerable activity in the area. Drilling operations are still in progress on the chosen site, the temporary camp continues to grow and a broad road is being formed on the left bank to meet the Bailey bridge that spans the Clutha. There is still plenty to be done before the main construction work begins.