POTENTIAL POWER SCHEMES

Press, Volume XCII, Issue 27705, 8 July 1955, Page 10

POTENTIAL POWER SCHEMES

North Canterbury Rivers ADDRESS BY MR A. BUCKINGHAM In the South Island, an increasing unbalance was apparently developing between the location of the main power generating stations and the main load centres, said Mr A. Buckingham, engineer-secretary of the North Canterbury Electric Power Board, when he addressed the council of the Canterbury Chamber of Commerce last evening about the power potential of North Canterbury rivers. He said that the respective figures for generating capacity and consumption in various parts of the South Island were: Nelson and Marlborough, 6 and 10 per cent.; North Canterbury to Mid-Canterbury and the West Coast, 10 and 50 per cent.; South Canterbury, 4 and 6 per cent.; Otago and Southland (including Waitaki and Roxburgh). 80 and 34 per cent. That, said Mr Buckingham, was why some were thinking that consideration should be given to location of'stations nearer the load centre —in North Canterbury. The decision made recently to defer the Braeburn scheme, and to proceed with the alternative scheme of a 220,000 volt transmission line from Islington to Tophouse, was one that greatly enhanced the development of power in North Canterbury, said Mr Buckingham. A scheme on the Hurunui would be 250 miles nearer Nelson than Benmore, site of the proposed next development in the Waitaki. That would result in large savings in costly transmission line construction. large savings in line losses, and greater security against outages.

Untapped Resources The three North Canterbury rivers in view for hydro-electric development were the Hurunui, Waiau, and Clarence, Mr Buckingham said. Apart from some investigation on the Clarence and Waiau undertaken by the Ministry of Works about 14 years ago, little investigation had been done in North Canterbury. Mr Arthur Lush, a retired engineer, had, however, done a great deal of investigation, and had worked out a co-ordinated scheme for the three rivers; and the development that he 'Mr Buckingham) would elaborate largely followed Mr Lush’s proposals. Discussing the Hurunui, Mr Buckingham said that the main argument in favour of the river was that it was a different type to the Waitaki and similar rivers, which flowed quite strongly in the spring and late summer, but dropped in winter when power was most needed. That meant tbat there had to be a great deal of; storage. The Hurunui catchment had a more evenly distributed rainfall than the Waitaki and similar rivers. Residents and travellers would have noted that the flow of the Hurunui was still fairly high in winter. Its lowest flow had been in dry summers.

It was generally agreed that this was because the Hurunui catchment dei rived a good deal of rainfall from the s-outh-west. said Mr Buckingham. This was not the case in the Waitaki. Water from Five Lakes The Hurunui catchment, he said, had an area of about 500 square miles and drained five Jakes, the largest of which was Lake Sumner, more than five square miles in area, and 1725 feet above sea level. The 20 miles from the lake to the gorge outlet had a fall of more than 700 feet, and it was believed that practically all that fall could be developed for hydroelectric purposes. It was also thought that the hydroelectric potential of the river could be still further enhanced by the damming of the outlet of Lake Sumner, said Mr Buckingham. The area had the advantage of beings accessible. There should be no difficulties—as had been experienced at the Cobb, and as certainly would be the case at Benmore—of men having to work under severe climatic conditions. Mr Buckingham said that, at several points along the gorge, heads running up to more than 250 feet could be obtained. Three stations were envisaged, with capacities, subject to confirmation by investigation, of about 22,000 to 23,000 kilowatts (head 175 feet), 45,000 kilowatts (head 210 feet), and 61,000 kilowatts (head 260 feet). The combined capacity of the stations would probably be from 125.000 to 150.000 kilowatts, and that could be increased if it was practicable to dam Lake Sumner at its outlet. Suggested Dam and Canal Mr Lush’s proposal was, then, to have a dam at a point above the Mandamus confluence, and to carry the main flow by a canal 20 miles long from the Hurunui, and drop it down into the Waiau river about four or five miles above Culverden, said Mr Buckingham. This would give a power station a head of 420 feet and a power capacity of about 100.000 kilowatts.

This could be a combined power and irrigation project, said Mr Buckingham, and could provide a good water supply in the northern and western areas of the Waipara County. . The Clarence river had ’ a great advantage in its height above sea level, but there were two disadvantages—the inaccessible nature of the gorge section that could be developed for power purposes, and the susceptibility of the district to earth movements, said Mr Buckingham. This latter characteristic of the country had been the reason why the Ministry of Works ended investigations in this area 14 years ago.

There was, however, a proposal to put a dam at the entrance to * the gorge to dam the river back for eight or nine miles, and to construct a 7£-mile-long tunnel coming out on the Waiau above Hanmer Springs, and giving a fall of 1000 feet and generating capacity of about 170,000 kilowatts, Mr Buckingham said. With the combined flow of the Clarence and Waiau. proposals had been made for a further eight stations, with approximate capacities of 42,800 kilowatts to 115,500 kilowatts. 1,000,000-Kilowatt Potentia. Mr Buckingham said the total power potential of the three rivers was about 1.000,000 to 1,500,000 kilowatts. This was very much greater than, and m\»’it be even twice the power capacity available from the Waikato river developments when completed. The Waiau and Clarence rivers had to be developed together, but the developments in this direction were very indefinite at this stage, and a great deal more investigation was needed; but there was obviously a great power potential there. The Hurunui development was smaller, but it did not involve any costly tunnelling, and was more accessible, Mr Buckingham said. The immediate need, he said, was for the initiation of hydrological investigations, in the Hurunui at first, with the establishment of gauging stations, to assess the power potentialities of the rivers.