The Daily News. THURSDAY, JULY 20, 1922. HYDRO-ELECTRIC EXTENSIONS.

Taranaki Daily News, 20 July 1922, Page 4

The Daily News. THURSDAY, JULY 20, 1922. HYDRO-ELECTRIC EXTENSIONS.

The report which has been presented to the New Plymouth Borough Council by Messrs, gladden and Palmer, who were employed by the Council to examine the possible means of increasing the present water power con nected with the hydro-elecrrie, works, apparently gives reliable information concerning the utilisation of one or more of the streams that rise in the vicinity of Mount Egmont. To the lay mind the report reveals a very careful examination of these streams from the point of view of their utility in generating electric power additional to that provided for in the present scheme, the first portion of which is nearing completion. It appears to be quite evident that considerable water power is available for the required purpose, but the question of the utilisation of the various sources of supply mentioned in the report necessarily turns on the cost involved. This has been set out clearly by the engineers. Their report bears out the . contention of Messrs. Blair Mason and Lee, the council’s consulting engineers, that it is possible to augment the present supplies (from the Waiwakaiho and the Mangamahoe) by diverting the waters of the Mangorei and the Henui into the valley of the Mangamahoe by means of tunnels at a cost that may be regarded as economically practicable. It Will be remembered that as the result of strong representations, culminating in a vote of ratepayers, it was decided to enlarge the diameter of the second tunnel in connec'ion with the scheme now being carried out in order to provide for further water supplies that might be diverted into the Mangamahoe. Messrs. Sladden and Palmer’s report justifies this provision, for they show that the power can be materially increased by utilising the streams mentioned. They also show—and this appears to be the most valuable feature of their report—that it is possible to utilise the waters of the Waiwakaiho a second time below the Mangorei river, and obtain thereby an additional 3375 horse-power, at a cost of £43 per h.p,, a comparatively low figure. They regard this as a possible augmentation of power well worthy of consideration. The present scheme when fully developed will provide 9000 h.p. The section now under construction will give a little over 3000 h.p The extra 6000 is to be obtained by the erection of a dam above the second tunnel and storage of the water of the two rivers. Doubt has been expressed regarding the water supply in times of lengthy spells of dry weather, but it is admitted that 6000 h.p. can be relied upon under the most adverse conditions. What such a supply means may be better realised when it is stated that the Lake Coleridge works supplying Christchurch and other parts of Canterbury up till recently only developed 6000 h.p., so that , even under the most adverse conditions New Plymouth will have, when the present scheme is completed, I ample power to serve the needs of the greater part of Taranaki. Messrs. Sladden and Palmer have investigated the possibilities of Bell’s Falls and Stony River, sources of power that have fl equently been discussed, and estimate that, they can supply 1000 h p with a fall of 500 feet, or with a 1000 ft head a corresponding increase.. The Oakura and Kiri rivers have also been examined, and. as a result, it is estimated 600 h.p. can be generated, and more if the waters are used a second time. Altogether the report is a very valuable one, showing as it does the possibilities of the development of hydro„l«>trip.ity in Northern Taranaki,

and justifies the action of the Council in having the report made. For the present, of course, no action can be taken in regard to the engineers’ recommendations, for the power available when the partial scheme is completed will have to be disposed of before the full scheme is undertaken. It is satisfactory, however, to have the assurance that on top of the 9000 h.p. scheme, further hydro power may be obtained at a reasonable cost, power sufficient to meet the requirements of the whole province for many a year. Summarised, the possible works mentioned by Messrs. Sladden and Palmer and their cost would be somewhat as follows: — Mangamahoe Valley—Three dams to impound 18,890,000 cubic feet giving an extra 140 h.p., at a cost of £34,150, or £244 per h.p., plus the price of about 27 acres of land that would be required. Kaiaui Valley.—Not a very satisfactory site, but capable of , storing 7,000.000 cubic feet of water by means of a dam 40ft high,, giving an extra 60 h.p. at a cost of £12,000, or £2OO per h.p., plus eleven acres of land. Mangaraka. Stream.—This could be diverted by a tunnel into the Waiwakaiho at a cost of £l3OO, or £26 .per h.p., and might give an extra 50 h.p. Mangorei and Henui.—The Henui ' could bo diverted into the Mangorei by a tunnel, and the fi.tter also diverted by a tunnel into the Mangamahoe basin, giving a combined weight of 760 h.p.. the Mangorei tunnel costing £45,000, or £75 per h.p.. and the Henui tunnel £5OOO, or £3l per h.p. Utilising the water in the Waiwakaiho and Mangorei a second time—a scheme which is recommended as worthy of consideration —at a c"»st of £48,420 for machinery, or a total cost of £145,750, being £43 per h.p., the increase in h.p. bringing the total to 3375." Ponaki Basin. —It is possible to get 1000 h.p. from this source, but the cost is not mentioned, the proposal being one for future consideration. Oakura and Kiri.—Using these waters below the ji.action would probably give about 600 h.p., and the water could be used a second time if necessary, but no estimate of cost is given.