Facts About the Arnold

Grey River Argus, 22 September 1932, Page 11

Facts About the Arnold

The following particulars of the Arnold scheme, taken from the data of Messrs Vickerman and Lancaster, Consulting Engineers to the Board, when they submitted their comprehensive report on the hydro schemes of Hi,, district at the meeting held on Wednesday, August 17, 1927, will be of interest. The report stated:—The Arnold is of all the other suggested sources of power, the most accessible. Its course.

I which extends from Lake Brunner to I the Grey River, is some 16 miles in i length. The. river grade is flat for I the first four miles from the Lake, : but it becomes steeper in the next two miles and attains its greatest fall of some 25 feet per mile, in the next four miles, that is, from a short distance above Kaimata to the Landing, whence it gradually flattens towards the junction with the Grey River. The fall is thus small for the purpose of hydro electric development, and the banks are low and unfavourable for damming, except along some two miles above Kaimata and even there the height of th e dam must be very much restricted in order to avoid flooding the railway lin e which parallels the river at a height of from 30 feet to 50 feet above it. Fortunately, there arc near Kaimata, several extensive and sharp bends and by conducting the water in a straight <-nurse from what is known as “Perpendicular Bend,” situated about half a mile above Kaimata, across two of these it is possible to secure a fall of some 55 feet in about 95 chains and this fall may bp further augmented by a dam at th e intake and this is, we consider, from your point of view, the most favourable development offering. Tfie area drained above Kaimata is 216 square miles i n extent, of which. 178 square miles drain directly into the Lake and the balance into streams joining the Arnold below the Lake outlet. The best information available appears to indicate that there is, except, possibly very exceptionally, a minimum flow of 800 cusecs and that 1200 cusecs could be ensured by flow control works at the Lake outlet. With this quantity of water and by using the Lake to conserve and control the flow, it would be possible to generate up to 8000 k.w. on a 50 per cent, load factor at the site mentioned. The Consulting Engineers, Messrs Vickerma n and Lancaster, in their first survey of the Arnold hydro scheme estimated the cost, including access, dam. tunnel, race pipes, surge tank, power house, generating machinery and housing, together with flood gates and Lake control when required, as follows:—2000 k.w. £90,000; 2,500 k.w. £100,000; 3000 k.w. £135, 000; 4000 k.w. £182,000; 6000 k.w. £227,000; 8000 k.w. £290,000; the cost thus ranging between £45 and £37 per k.w. They expressed the opinion that the works involved could be undertaken m stages as th e capacity required to be increased.