HYDRO-ELECTRIC POWER.

Taranaki Daily News, 12 February 1919, Page 6

HYDRO-ELECTRIC POWER.

NEW PLYMOUTH EXTENSION fiOHEm SOMii FURTHER I'ARTICULARS. In view of the poll, to 'be taken on Tuesday next, by means of which the Council of the Borough of New Plymouth is asking the authority of the ratepayers to raise a loan of £40,000 for the purpose of the extension of their electrical power development plant, it may not be out of place to put before the ratepayers a summary of the actual proposals as contained in the report of the consulting engineer—Mr. Rlair Mason, M.1.C.E., M.LME., engineer to the New Plymouth Harbor Board. Mr Mason was expressly engaged by the Council, on a request from the Borough electrical engineer (Mr R- H. Bartley) that an outside civil engineer should be asked to report upon the possibilities of power development for the purpose of providing the extensions to the present installation, which the increased demands upon it now make absolutely essential- Mr Mason has gone very exhaustively into the matter, and placed before the Council several alternative schemes, two of which have been adopted, the smaller one being part of the greater. The main scheme is that marked and known as D in the schedule attached to Mr Mason's report, and the lesser part as E 11. Briefly explained the scheme (D) provides for utilizing to the utmost. the head obtained by tapping the Wai--yakaiho at the suggested new intake (about 1} miles above the present intake) and for storage that at the least Will extract all the power that can be got from the source of water supply. This can be secured by building a new dam in the gorge of the Mangamahoe about 30 chains above the existing dam, to such level as will impound the water to the full head of 237 feet above the powerhouse. At this level the waUi would rise two feet above tno saddle about half a mile south of the forebay from whence it would be conveyed by conduit and pipes to the power-house-The dam would necessarily be high and a work of some magnitude. An excellent site exists for the work. _ The estimates are taken out for an earthen dam of massive dimensions with an equally massive ooncrexe core. The dam would impound and raise the water to a level that is hoped will submerge at least 30 acres and with a 10 feet draw off give about 13,000,000 cubic £|et storage. The actual storage required with a load factor of .45 to develop the maximum water power amounts to seven and a -quarter million cubic feet. The provisions of storage over and above this latter quantity will increase the elasticity of the system by affording additional power to meet extraordinary demands or by permanently raising the maximum power if water in excess of the basic quantity "of 160 .cusecs (cubic feet per second) can be obtained. Power.—Allowing for a 10 feet draw off in the reservoir the power furnished for an intake of 150 cusecs would give a maximum of G3OO horse-power. The estimated cost- is £4tf.ooo, or equivalent to £7 10s per horse-potfer-The portion E 11, which is part of the whole of scheme D, provides for the conntructiQn of the weir, intake and tunnel. From the tunnel it is proposed to carry an open earthen race running 50 cusecs about 140 chains to a penstock above the present forebay. From thence the water to be conveyed to the powerhouse through a permanent wood or steel main of large capacity to deliver up to 100 cusecs when required. The working head would be about "230 feet, and would generate 900 horse-power which, added to the present maximum output, would give a total of 1800 horsepower at an estimated cost of £'11,700. Of this sum only £I3OO need be regarded as temporary wor,k, being the estimated cost of race and tlepreciation on flume pipes. The estimated cost of the proposed scheme is divided a sfollows: — Permanent works being portions of scheme D the same as in E, £9513; race to carry 50 cusecs, £100; classed across Mangamahoe (asset), £400; land and allowances, £837; total, £11,700-Horse-power developed 900, horsepower present plant 900, total 1800 horse-power. Equal to a connected load of 9000 horse-power. Full particulars arc advertised to-day in regard to the hours of polling and the polling places. Ratepayers should familiarise themselves with the proposition which the Council is putting before them, and not fail to record their vote on Tuesday next.