WAIKAREMOANA POWER

Poverty Bay Herald, Volume LIV, Issue 16622, 14 April 1928, Page 5

WAIKAREMOANA POWER

' •wandered about from point.to point, ob("serving, numerous small details "which 'nevertheless are of considerable importance in the general scheme. The.amount of excavation undertaken in connection with the pipe-line sur- ' prised several members of the party, who, having viewed the line from a distance, had formed the impression that it merely ran down the hill-side on the natural surface. It was found that the laying of the line had necessitated a considerable amount Of digging and filling, the building up of concrete cradles '. to carry the steel tubes, and the designing of extremely heavy anchor blocks ■', - to reinforce the tubes at two points where the direction of the line is changed slightly.. It was further ascertained that of the 7292 ft. of piping comprised in the double line from the surge- - chamber to the power-house, approximately 4000 ft. has been laid to date. Progress in the future should Tie much increased, for until recently, the workers were handicapped by various small difficulties, whereas now they have practically all the material on the spot, and are able to proceed without interruptions. . The vicinity of the surge-cham-ber, at the top of the pipe-line, rings constantly with the clatter of the pneumatic riveter, which, in the hands of • an experienced gang of skilled workers, is gradually shaping the steel tubing together. ' 'THE POWER-HOUSE AT TUAL Following the pipe-line down its length, the Gisborne party came upon the power-house site at Tuai', and here, 100, found much that was intensely in- ' toresting. The power-house is-: Beingreared on a foundation comprising about 30CO tons of concrete, laid on columns .built up from the mother rock; above the ground level'the height of " the building is 6,4 ft.,. and. the length of .the building ou the upward "side runs'' to 192 ft., and it v can bo understood that in its "concrete construction titer will be a tremendous weight to carry. Already aJjput 3000 cubic yards of concrete lias been poured into the walls, floors, and columns of the building'above the ground level, making the total weight of the construction to. .'date . about. 6000 tons. , While the Gisborne party was on the site yesterday, a gang of men was busj pouring in the concrete which is to ' form the bed of the first power unit in 'the basement of the building, and it: was explained that the turbine would be placed in position with the assistance of an 80-ton crane, an item which gives some indication of the enormous Weights of the materials. In ; the completed scheme, of which this power-house is the heart, there will fie three, tu/bines, producing 28,0Q0 : horse-power, and developing 20,000 k.v.a. It is from-.this source that the Poverty Bay supply will be • drawn, and the members of the party showed the greatest interest in the. explanation of how the water will be led into the turbine chambers, used, and then discharged into another reservoir Sjust 'below 1 the power-house. There was a technical aspect in which some members of the party showed much interest, •but the majority of the visitors satisfied themselves with an inspection "f the physical side of the operations. ? . ■ SUE-STAITON AMb PO'WEB LINES. The out-door sub-station from which; the power will be distributed north and, ; Lsokth. was the next point visited, this station .occupying an artificial terrace; above the level of the power-house. Here practically every detail has a technical tag, but it was observed that Hie equip, iihent of the station is practically com- ' plete, and that this section of the work • should be ready long before power is available from the scheme, and long be- - fore the power-lines' are ready to carry the power on to Poverty Bay and to the ; scutn. A number of huge transformers already" have been set up, the weight of each being 18 tons, and others of greater . size are still to be erected. The prob- ':■■■ lems of transporting these big details ' of plant were not insignificant, and before they could be taken on the road .'from Wairoa to Tuai' all bridges and - culverts on. the route were submitted, to a rigid inspection. There is a substantial building erected close "to the outdoor' sub-station, and members who. expressed cunousity as '..to its purpose were told that it was -Werelv *a shelter in. which the dryingout arid repairing of transformers would '' : be undertaken, since the work could not

be done in the open air. . , The beginnings' of the tower-line to '■ the south could be seen from the neigh- ' borhood of the building, the line of ".steel structures being visible for some ■distance over the hills in the direction •'.'Of Napier. The cable is being slung on ' 'the. towers as the Work is pushed for- - ward, the wiring gang following close .''■ onithe heels of the erection gang.

This line is much heavier and consequently requires far more material, than ..the pole-line which will carry the power to Poverty Bay, and one of the pnnci- ' pal difficulties., encountered has been in •connection with the delivery of materials ahead of the construction gang. Much • of the country through which the line passes is steep and broken, and ordinary means of transport are quite inadequate. Tracks have had to be cut, bush cleared, and suspension bridges erected '" to enable the deliveries to proceed, and v in some cases cable-cages have had to '■ bo employed in conveying the materials across deep gullies. The utilisation of lowers for ths line has meant, of course, . the possibility of making longer spans, ' and it was stated that in some cases , the spans run beyond three-quarters of a '; mile in length. - V On the Gisborne line, poles will carry "the power-cable and the spans will _be considerably shorter than on the southern route. ' A contract has been let for the' construction of the pole-line, Mr. L. Walker, of Napier, being the success-, - fub tenderer, and this work will be put ; in hand shortlv. ■ . ...',... LINE TO POVERTY BAY The'route of the pole-lino to Poverty Bay will follow a long valley which ■ runs off to the left of the power-house ■ site, gradually rising .to a saddle, from which it will descend.intft .the Buld- ■ turl valley. Beyond that point ,it ' ' '-heads for'the Hangaroa, and proceeds down that valley to the Poverty Bay ■ flats. There is very little country in which difficult conditions are to be en- •■ countered apparently and Mr "Walker's. ■' contract should be completed in plenty 'h of time. It is hoped .that the power ":. will be available by December next, , and iifthc intervening months tho line will be* erected and passed upon. j A brief explanation was made of tho, plans for'future development of the surplus 1 power of Waikaremoana waters, the Gisborne visitors being in- ' v formed that Lake Whakamarino, at the Tuai level, is to be greatly en- . larger!''-by earth dams, and the water led through a tunnel of a mile and a : half to a pipe-line with a fall of 's69ft, This flow of water, will be utilised in \ another powerhouse about .three miles ; below--Tuni, and-the power to be de r .. veloped there is approximately 50,000 ,'■■" k.v.a. Th.ere is also the .third phase ■ ;of the Waikaremoana plan, which will t 'call for the closing of the cracks in thefloor of Waikaremoana itself, so that C- the wholo of the .overflow: can be used i for power production. This last phase Is the most ambitious of all, and . little information of a. definite char- 1 '■:'■ ■ actor fis ' available' regarding the' methods to be used, but even in this V phase, the engineers do not anticipate any great difficulties.

STAFFING THE WORK There- are at present employed on the- pipe-line and powerhouse work, at Kaitawa and Tuai about 400 men, and these are accommodated in the small huts'usually provided f,or temporary camps. When the construction work is complete, and the Tuai powerhouse is producing power for Poverty Bay and Hawke's Bay, there will be a permanent staff of about 30 officials at the station, and permanent quarters for these officials are being provided by .the Public Works Department. A feature recently added to the settlement is the hostel at which single men will mess, and where accommcwlation will be available for visiting .engineers and 'departmental beads. Married men on the permanent stall will be given their own houses,- set upon rising ground from which, tho powerhouse itself will not be visible. The outlook from these, residences,, •when the Whakamarino scheme is complete, should be delightful, and Tuai should bo a haven of quietness and beauty, in strong contrast ,to tho present scene of activity and utilitarian ugliness. An outstanding impression gainer! by the Gisborne visitors .to Waikaremoana 4vas the excellence of the road surface between Wairoa and ,the lake In order to facilitate tho conveyanceof the heavy machinery and other materials, the Public Works Department has strengthened all ,the bridges pft the route, and has laid metal wit'u a topdressing of shingle .which j>vosonts an unusually good surface, for traffic. Above the turn-off to "Lake Kaitawa, the road is not so welT consolidated,- and those who coatiirdo the journey to Lake House tfind ,Jii little roughness in rahe surface, though, the whole of the route is metalled, and well graded. Around the oil/go of the lake itself much good work has been done, and tourist traffic is well catered for in this, respect. The. opening of the hydro-electric works has made Waikaremoana, lar move accessible to the general public, and tho number ,of visitors to tho lake, is in consequence greatly increased.

SCHEME'S RAPID ADVANCE # TUNNEL AND PIPE-LINE \ rORWABD GISBORNE VISITORS IMPRESSED (Herald Special Ecportor.) Even though the technical problems associated with the- scheme may still bo incomprehensible to the lay members of ,tho Poverty Bay Power Board, tho physical aspects of the hydroelectric power development scheme at Waikaremoana must have been thoroughly impressed upon them in the course of the visits paid yesterday to Kaitawa and Tuai, the two points at which extensive work is proceeding. In the course of a three-hour tour of tho works, the members of the Power Board wero shown every detail of material construction, and learned a great deal concerning subjects which hitherto had been mere terms to somo of tho party at least. That tho visit had been most instructive was readily conceded as tho paTty began its homeward journey to Gisbornc, and it is suggested that when Waikaremoana power comes under discussion at tho board table in future such comment as is mado will not lack the quality of understanding. As outlined briefly in yesterday's Herald, tho members ,of tho Poverty Bay Electric-power Board toured the under the ciceronage of officers ""\of tho Government department con- ■ corned in the. exploitation of "Waikarc- . moana power.. Having left Gisborne on Thursday afternoon and spont the Bight at Lake House, ,on the shores of the lake, the party was able to begin its inspection early in the forenoon, tho first point of interest being the outlet from tho lake itself. Here it was found that no water flowed in the nominal channel of the outlet, and it was explained that this was not an uncommon circumstance in the late summer and autumn. At a point a few minutes' walk from the road, however, a considerable ■volume of water gushed from the hillside, emerging .through one of the fissures .which are known to exist in the floor of the lake. The volume of this stream is gradually increased by ■ tributary fissures as it tumbles down Jthe steep gully to tho level of Lake Kaitawa, and at this point the Gisborne party found a river of respectable flow. Lake Kaitawa and the terrace upon which it lies was tha site of the" earliest operations undertaken for exploiting hydro-electric power in the district, for'it is from Lake Kaitawa that water was drawn for the power production plant that to-day serves >S"airoa with currentj while tho lake also is to bo incorporated in tho incomparably greater proposition upon iwhich effort .is now being concentrated. • ; CAPTURING THE OUTLET FLOW Upon -entering the camp at Kaitawa, the Power Board members were met by Messrs F. C. P. Tregertha and G. Cuthbert, the latter a Gisborne boy who after graduating from Canterbury College entered the service and is now associated in the electrical work at Tuai. These' officers' convoyed the visitors ,over the various points of interest at this level, and later conduct- • edr'thoni to Tuai, where, the' greater %fepart of the present activity is con«entrated. At the Lake • Kaitawa level, "the works were found to be well forward, and no technical knowledge was required to undorstand the out* line: of the scheme given by the conductors. • ' T ■ •. The Gisborne party was shown .first the concrete flume through which the waters of the Waikaretaheke river are to be .turned from their original bod into Lake Kaitawa, to build up ■ the "head" of water in that reservoir ' and to eventually find its way through the pipe-line to tho turHno chambers .. at Tuai. This flume .is practically ' complete, and when all sections of the scheme are sufficiently advanced, it will be a simple matter to remove a temporary barrier and allow the water to flow into Kaitawa. A feature of the flume is the spillway through which the surplus water, is to bo eonducted back to the original bed, and • so down to the Tuai level; this valvo is at present used to accommodate the wiiole body of the flow, and as the water sweeps round the right angle into ,the spillway, it presents an excellent impression of force. A permanent concrete- dam is being built across tho old bed of tho stream above the entrance to the flume to replace the sandbag wall which now acts as a deflector in turning the flow into Ihc new channel.' BUILDING UP THE "HEAD" ' It was explained to the visitors that the principle, employed in the manufacture of electric power from water force involves the confining of the water in a pipe-line which descends at such -an angle as to deliver the Jater at high pressure to the turbines the powerhouse. The difference in elevation between the point at which water enters, the pipe and that at which it emerges into the turbine chambers represents the factor of "head," and the physical attributes of the country lend themselves admirably to the production of this factor. From the Lake Kaitawa level to the turbine chambers at Tuai the water will fall 6'45f.t, and will be delivered to the turbines at a pressure of 280 lbs to the square inch. In the development of this «' head,'' as distinct from its actual employment, there arc three main fcatures--the tunnel, the surgechamber, and of course the pipeline • down the hillside. There- is a good deal of subsidiary work which has been done about Lake Kaitawa, such as the building of an earth wall which will add 10ft to the depth of the lake, and incidentally add fractidnally to the amount of head, but it is in ,*the tunnol, surge chamber and pipe-line that the reahy important work shows. , Concrete ovideuco of progress made during recent months was afforded the members of the party at the site of the tunnel, for after clambering down a ladder to the tunnel level, they . were able to pass right under aso lid rock spur and emerge on tho farsidc. ' Concreting work in the tunnel itself is SticaUy complete, and .the finishin* touches are just being applied to the cylindrical passage through which ihe water will pass to f 7»!f «*™; At the upper end ; of the tunnel there is still sonic work .to bo-done about the entrance, but this is insignificant compared with what has Xe before, and it could be completed Sin a very short time if it became necessary. BEAUTY Itf CONCRETE. Of thesurge-chamber, situated on. the; far sule of the spur/the members of ■-"' 'JS rSvdeceived the impression o a the^par W* imil in {orm to that **!& fSar by tales and pictures of Wa llt Rome. Built entirely oi con»nc'en\;TrisinK sheer on all Bjd«,

tunnel, and a three-fold exit, leading to the pipe-lino.- Though strictly utilitarian in purpose, this chamber is quite beautiful in form and proportion, and represents the most interesting feature of tho development scheme at the present time. The level of water in the surge chamber will bo exactly the same &i in Lake Kaitawa, and the flow into tlie pipe-line will be regulated by sluice gates, susceptible to electrical control from the comparative remoteness of the power-house, away down at Tuai. Weighing about three,tons apiece, the gates are already fitted in position, and -the control gear is now being installed, each gate having an individual control ,mf>imtpd above it on the. parapet of the chamber.

From tho singe-chamber to the powerhouse site at Tuai, there is a descent of 645 ff., the average grade-of the pipeline being about one foot in six. Already' a great deal of work has been done on tho pipe-line, and tho contract which a southern firm of engineers has for the construction of the line is well forward.

The visitors saw the beginnings of two lines of steel piping, and were informed that the third )ine would be added later, when the immediate demand for power from Waikaremoana had been satisfied. Full provision for the third line has been made, and it will be n simple inatter to install the steel tube later. Each line of piping is 3646 ft. in length, and in the two now being erect cci tho weight of the steel is about 1750 tons.

To appreciate tho amount of \vo< : iiv'ilveo in drilling, fili-vn'njr. n nd trim porting the sections of the tubes on to the pipe-line, where they are rivetted together, one must see the operations proceeding. The dimensions of the piping vary, as between the top end and the lower, the sections near tho top being 6ft. 6in. in diameter and formed of sheet steel only Jin. thick, whereas those lower down,'where the force of the' water-thrust will be greatest, will have ,a diameter of off. 6in. and a thickness of nearly 1 in. The, necessity for increasing the strength of the pipeline as it approaches the power-house will be understood when it is known that the pressure of the water there is estimated to reach 2801 b. per square inch. DETAILS OF THE PIPE-LINE. This portion of the work absorbed the, attention of the Gisborne party for seme time, the operations of the steelcorkers engaged in fitting and rivet ting tho tubes being full of interest, while at and about the surge-chamber there were ninny details of importance to lnsnect.. 'Some of the visitors saw the haulage engine, which onerates from a point .ihove the pipe-line and has ft cable three-quarters of a mile long, on which are hauled the heavy items of materia used in the work. Others inspected closelv the labors of a warty of Maoris, who emploved a pneumatic tool in breaking thr.nu'h rocky nutcropnings which barred -their excavations. Others agair,