HARNESSING HUNUA FALLS.

Auckland Star, Volume XLV, Issue 8, 9 January 1914, Page 8

HARNESSING HUNUA FALLS.

AN ENGINEER'S REPORT. r A SCHEME TO COST £33,300. Quite recently reference was made in the Australian Press to the wonderful assets possessed by Xew Zealajid in the matter of water power for the jjeneratiou of electricity. In this connection it is ot interest, to note that a special meetin<j of the Manukau County Council has been called for next Tuesday to consider a report by Mr Krnest J. Perm, consulting electrical enjrincer. upon the cost of harnessing Hunua Falls so as to secure electrical lighting and power. Mr Perm states that on December 1 he took readings at the Falls, and found the flow equal to producioff 080 to 800-h.p. He. however, points out that owing to the wet weather for several days' previously, the stream was above its normal flow lie :iKa pointed out that during the winter Mr. Millar, of tie Public Works Department, also took a reading, but a.-» the rainfalHiad been below the average. it coold hardly be considered a correct indication ot the minimum -winter flow over the fa!t. It however. <nve 340-h.p. Mr. Venn points out tJiat it might be wise to assume that hi very dry weather the minimum continuous flow nrtpfht drop to the equivalent <rf lOChh.p. Taking into consideration the tatchmrat area and the nature of the -water. Mr. Perm considers that would be a. saie figure. Hβ also states that by erecting a dam to back itp the stream during , the portions of the- day in viiich, little electricity would be lined, tJ>e po-vver available iould be increased. Such a dam •would enable bhe minimum flow, or :>OO-h.p.. to be available at the drie.it period. During nine -mo-ntruj of -the year <a continuous (low of 300-b_p. could be depended irpon. or, with tie dam 900-h.p. By erecting a larger dam. about 10,000.CKIO cubic ft. of "water could be backed up. which would enable the effective power tiie summer to be increased frum 000 to 400 h.p. and possible 450 U.p. The report points out that with :ue small dam 1.140 units per day could be pec-crated. and with the lurge dam 1.-'ilt) units. Mr. Perm also explains that one unit will light one ."".0 candle power lamp for I<U hours, and small motor.* would use nine-tenths of n unit per h.p. per hour. He states that there are excellent sites for both a dam and a power hou-e. auJ no water races would be required, lie estimates th<> capital expenditure at £33300, including hydraulic works and the larger dam. but that does not allow for the purchase of the land. The power generated would. Mr. Perm e-stim-.ir.ej. return a net profit of .C 717 .j. 1. while only S4O units wer<" utilised of .the 1.320 available, and that would more than cover the capital expenditure charges involved, and, of course, the extensions ivould oniv be carried out if additional business was offering. He considered that 4J per cent would be sufficient to allow for depreciation, as a. considerable portion of the works would be of a very permanent nature.

A smaller scheme might bo adopted, which wouM co*t £S,OOO less, but the larger one would ultimately- be the most economical. I'enn. in conclusion, suggests that a measuring weir be built in tiie river to enable the flow of water during the summer months to be accurately gauged, and adds that the figures he quotes are only approximate, and surveys wonld be necessary to confirm them.