ELECTRICITY DEPARTMENT

Bay of Plenty Times, Volume L, Issue 7965, 20 April 1922, Page 4

ELECTRICITY DEPARTMENT

PROPOSED WALIK)A EXTENSION. At the meeting of (lie Borough Council on the pJth inst., Cr Jones, for the Electricity Committee, presented the following report : ‘A our committee met several times during tin' month and made one trip to Omanawa to inspect the buildings on the Council s .property there. As a result of the inspection your commit tee recommend that an expenditure of, approximately, £ISOO he authorised for the purpose of erecting new cottages for the stall, repairing verandah of present house erecting outhouses, gates and fencing, and for water supply. Your committee also recommend the expenditure of a small sum for the purpose of re-grassing a portion of the property and also for planting for shelter purposes, the estimated cost of widen is included in the amount asked for. Re Wairoa Extension - As requested some time ago, Mr Mandeno lias compiled estimates of the cost of developing energy at the Wairoa. These estimates, will be laid before von, and your committee suggests that, as the question at issue is of great importance and one largely ahecting the future welfare not’onl} r of the Borough, of Tatiranga but of the greater part of the 1 Bay of Plenty, that a special meeting of the Council should bo held on April 26 to consider the proposals. The committee suggested that the Council as a whole arrange a visit to the Wairoa .Falls. On the motion of Cr Jones, seconded by Cr Whiting, it was decided to hold the special meeting as recommended. BE BOUT OF 11YDBO ELECTBIC DEVELOPMENT OF WAIBOA. As instructed T have to report as | follows on this subject;- ; The urgency of making further provision for power supply beyond the now extended capacity of Omanawa Falls is apparent from the I following 'considerations: - The increase in the demands on the generating station have been in creasing during the last two years at a much faster rate than formerly I as is shown by the following figures I for annual production; -

! Year I'niis I ending general eel I J 917 260,000 .1918 854,000 1919 396,000 1920 486.00 Q i 1921 786,000 i 1922 1,404,000 ; Estimated 1923 2,600,000

I! The import of these figures is f shown more graphically on the (curve attached, ami it is obvious that unless measures are taken to check development that the present plant will soon become inadequate. Ar previously reported to (he Council the precise measurements of the (low made with the recently I imported appliances iu the Omau--awa stream during the summer of last year show that there is not. as much water in the river as the measurements made with the means previously available indicated. In this connection it is perhaps unfor- | lunate that the measuring weir, I authority for the construction of | wind) I applied to the Council some | years ago, was not then constructed, | as accurate records would then have i been available continuously over I the last six years and these would of i course be most valuable now. From the facts as above set out ■ id may be stated that it is essential [ That further provision for power f supplies should be put iu hand at an ; early date. An additional factor i is that now the Government ■ has ; agreed to the formation of a Power Board for the County of Taurauj ga it is important that provision be made to meet its full requirements as soon as it is in a position to take supply for tjto country districts. Although the requirements of the Power Boai*d for purely rural supply will not be very great, there are quite a mi mber of large power consumer in this vicinity who would gladly use. electric power were it available to them on favourable ternts. These include: - Public Works Department which re*quircf>; over lOOh.p. both at its Mount Worirhops and the To Puke qna.rrv. Fla. [milling- Tim industry require:- ;i large amount ol power and 1 w,t- approached only a lew weeks ago bp an owner who was desirou-

of taking power for two mills near Te Puke and who was prepared to guarantee a substantial amount of revenue for 5 years ahead if he could get the power. Timbenuibing --Although this industry is not at present brisk there are 3 mills adjacent- to existing or proposed power lines the management of which are anxious to obtain power for driving all or part of their machinery. Drainage of Swamp Lands - There ii in the Tauranga County an important application for electric power which lias not yet been exploited but some consideration has however been given it in connection with the unwatering of fertile swamps in the Te Puke district which are 100 low to drain properly by gravitation alone. An approximate estimate of the total h.p. of engines in use in the county or at present being put into use for which the Council has been, approached for an equivalent supply of electricity works out at 990 li.p. worth at a low estimate £7OOO per annum. Together with the normal increase in the requirements of consumers already connected it will he seen that there are large power requirements to be met in Tauranga and County. Before committing the district to any scheme for development ol power'it is important that all possible schemes should bo considered. Considered from a broad standpoint it is realised that any scheme now undertaken should be capable of supplying all requirements of I be Tauranga County for some time to come and*possibly also of the whole Bay for a period of years at least until the load warrants the Government bringing in (heir lines lo take over part of the load. On the basis of the one-fifth h.p. per head of population which is the figure on which the Government calculations of power requirements have been based it is calculated that on present population the Bay of .Plenty district would require when fully rotriculated approximately 3000 h.p. Outride of the Councils own plant the only other power stations arc the Opotiki suction gas plant of 50h.p. and the uncompleted 300h.p. plant of the Whakatane Borough, Seeing that the dist rict as a whole is very far from having reached its full settlement, also that the allowance of one-fifth per head of population has been proved in other countries, such as Ontario and Rcandanavia, to be too low already, it mav be stated that an additional oOOOh.p, development is warranted. There are not a great number of sites in the Bay of .Plenty where this amount of power is obtainable. Large power developments are possible on the Kaituna, larawoia and Rangitaiki rivers, ihe full development of the Kaituna or Jaiaweia rivers arc undertakings lar too largo to be usefully employed in the Bay of Plenty and the same applies to the Rangitaiki Falls, the development of which, even, if permitted by the Government would place a heavy burden on its promoteis until the power could be something like fully employed. The only other power sites as far as 1 can find which would meet requirements are on the Wairoa River and on the Omanawa. On the Omanawa it is possible to obtain by impounding the river half mile above the present power house about JlOOh.p. total including present plant capacity on the basis of 60 per cent, load factor. Detailed estimates of this proposal have not been worked out but it may be said, that although* an economical scheme is possible at this site there are obvious advantages in commencing at a new site, especially one where the accessibility is better. Wairoa Proposition. Site The proposed site is at the confluence of Hie Maugakarenga and Mangapapa rivers where there is a fall of approximately 42ft, in height, access being obtained off the Cambridge road through Mr McLaren's property at ihe Lower Kaimai, through which a very fair grade is obtainable down to the site. Surveys ■■■Preliminary surveys have been made by myself during the last two years of the ground around the Falls and last year Mr Sinalllield carried out a survey with special regard to water storage cap-

achy' available;. Measurements of the’How of water in the river have been made on several occasions at different sites—records of flood levels have also been made. In this connection we have been singularly fortunate as the instrument for making measurements of flow came to hand in time to make several measurements during the exceptionallv dry season experienced last year. Also records were made at the time of the flood levels reached during the flood of Juno 6th, 19-0, which is believed to have been almost as severe as anv flood within the memory oi old residents. Proposed met hod of development - The obvious method of harnessing the Falls is by erecting a low spill way dam across the head of the Falls and diverting the water by this means to the Power House which would be located on the west bank of the river two chains below the Falls. By this means about 42 feet of head is obtainable, which would be sufficient to generate 1000 h.p. continuously. This would I believe make quite an economical development but is hardly large enough for requirements. Further study of the site was therefore made and an extremely promising scheme has been located. This involves the erection of a dam across the Mangapapa river where it passes through a deep canyon about M chains above the Falls. By means of this dam it is proposed to raise the water level 40ft, at this point and forming a small lake extending tip stream for three-quarters of a mile. The water not required for generation of power would run to waste from this lake over a low spillwa\ dam built across a shallow 'channel just east of the main dam, this dam of course being estimated so as to safety pass the heaviest flood likely to be experienced. The water for power generation would find Us way along what is now a dry gulley without any excavations whatever to a point about five chains only from the Falls. Here the intake would he built with screens ami headgates, after passing which, the water traverses a tunnel 3 chains in length and Bft. in diameter to the surge chamber, and from here to steel pipes sft. Gin. in diameter and 90ft. long would lead it to the turbines. These would be located on the bottom floor of the powerhouse. This would be a concrete structure about 50 x 60fl ; the turbines being located on the bottom floor and direct coupled (o their corresponding generators on the floor above, while other equipment would be placed on the roof above this. It has been estimated to erect 2 generating sets each of 1500 h.p. but only one set. would bo installed at first, and probably the second set might be increased to 2000h.p. when the time for', its installation arrived. This at slight extra cost would give 3500b.p. bisleacl of 3000h.p. estimated on. The final stage of the works would be the diversion of the Mangaharenga stream into the Mangapapa about IJ, miles above the Falls. This can be readily done by means of a short tunnel under the low saddle between the two rivers. The cost of these works together with, the acquisition of laud, erection of staff cottages, access road, i traffic bridge over Wairoa, etc, is estimated at £70,000 on present prices, but in view of the probable fall in prices the allowance for contingencies is not so large as usually provided. If the erection of one generating set only is undertaken the cost would be reduced t0£46,500. In the latter figure provision _ for one outgoing transmission lino is allowed for while for the full scheme 3 arc provided for. A further item of expenditure essential to the scheme will be tho linking up of the Omanawa and Wairoa stations estimated to cost £3IOO. Beyond this again the cost of transmission lines and substation, lias to be provided for and for this purpose it is suggested that the sum of £25,000 should be provided. This would enable the greater part of the large consumers enumerated above to be connected up and thus ensure sufficient revenue for the success of the undertaking. After creation of the Power Board arrangements could be made for transferring these consumers to the Board. As to the financial prospects of the scheme it may be stated that if a loan of £75,000 is raised at 6 per

cent, the annual costs will be approximately as follows: £ Interest, 6 per cent. 4,500 Depreciation, - per cent. 1,500 Operation of Power Station 1,000 Maintenance of new lines 300 £7,300 h has already been shown that present power used ether than electric can be calculated to contribute i,'7000, while apart from this the profits cf the undertaking' as now exist ine and amounting to over £0.500 should ensure the sheme as a whole being continuously sell-sup-porting. In conclusion it may be pointed out that Tauranga lias already achieved a wide reputation as a district with an abundant electric supply which is available at cheap rates. It cannot be questioned that this reputation is a valuable factor in encouraging further settlement as well as the establishment, of now industries and the question now is whether due provision is to bo made so that- the district may retain its reputation. LLOYD MANDENO.