WAITAKI DAM.

Press, Volume LXV, Issue 19785, 25 November 1929, Page 7

WAITAKI DAM.

noaams of works. UwOCT-SAVTHG DEVICES. fitniii to imi raassj OaJ*AKL\ November 22. ' Utt Urn maqktkm of concrete stop lttl»« lac opatmun and downstream ■ft* far 11* eieaTatioaj for the »n----to£*fa*r *pan of the Wartftki- dan. iafNfcHW <rf tie work at tb« eaierkia paaaed a critical *Mk, wafcn the work ot concreting •5 BMBMI to bo carried out ©xpedi- *■% ami with mi*.?, la additwo femaWmg the pauttoa at Ota cofer•••m, Ift* familial txpenae of patftjstli (tap benki wilt bo mow pi J***** tunmfh tb«tr facilitating ■tlllMH, ot oo cither v-L- nf the pcrtiaaw of the rtrer by fcwwftr lf»kn» tto rock foand*- *■»*» A* fcettom of til* rtfw have «B?ara«wl to be of * very satist'ae*w*«Btoff*, aid eminently faitabic t-> yftWWwt the animated weight of the ■* «" tigfei toot to the aqtnre font. *«■»•»»» incwd from ibc nature •■»—Uj, feida in the rork forma* •* •*» aaeontered. Unlike faults ytftlllWtet tkece foid», caused under *■«»•» pmatiTe in bygone days, JJfH asd end ia well-d*'tiu*d pours*!*w"» war* fnfl* explored and cut tour of the fvavatiorw prel"*3» tkearfare, an »n»rm surface. **J"» projections and hol'-nwi were **—»! raiawr than otherwise, pr«keys for the maaai** *JWJ» Will ihCTe ~™*w *ae handling of immense quan- "**•* wcw« «*eh day. tiw ealoe •*■•*•■ atixisg plant « apparent. *■ •aa approve.} labour-savins »■*, tkc Wattaki olant i« t'uliiHinjt all ywaaaapitttad ot h. redwrio*. m it to a minimum. A large **?"*"» H kept aapplied with shin*** ** **d fcy an overhead railway 2* ■ **"* m erane. and thf> cement ■JP *p» wswewi hocn the storage ■** W aa tmdh-rn belt to a gravita2*fcad» which tuppliv* the material **••*!». Th." r«vu«ut.»- amount of ff* far *ach tperi&od ]t>h is reguy*. aataaaaticaUv, and again by glitatian Uw i-...ticrete ia **** ■!*«mi**rw trn.:k< _JI» &Ut«h nt ti.f rri:.'x< r'rnm the *■'•«'» lit «*Ctr-dam is i-4rr;.>d attl in *.*!**» kWaiwM doiag away ■*» tk« WMwitT o* ha ~.'\£.' over the keMjr. asd a>« »-:taiiii*tina g *"tw *• wrrkmen *L-.-agfe the ,C* le » «f rwat<« r» tij.- r.ri-iiC- track. g*.a**t rxB»»T -rark .* raii*d at sh*y «4. aad i ; V- »U*trie aotiv ?**• trifk* 'K- i «';■-* sn--!iß* to T* '■■■lt. tie tTn»'T<i ~.»herirts auft2** •■aeatam A>. \. •-. .•'..!.•' on ■■■> J*atidf(. to rji"- . acr-«* *>•■' 2**» •«* ■ :a-" t" '-i'' T*in», -*i f i.Ti« a"** *■*■«. tka'ipe-:'!-!- :« predated r*|** 'raeki foil. - •■>:■ »n--tb«r !?* *k« treat!* n-«t :*■'.. *<■ fining Sfy? Nt tie m:t»- ' - r» »r -n t track. g*,iw«t » ««.-..t.- . .-.-!-! with P*|jMaaeda, ba; t »•«: :.n mde Jjjltofcte tt to m*»' ,! -« "•JWwar won .is -'i-ure, wbea yftftt ttrer on t v .» «if>-»n<rr.-an» aide ?■* caffer-dans •.--, »)>•>'* *h» larger Z'*. —*li—■ ef •fe- u&jd ij be cob f»«ili:T *•? »aT! ea the urn'ream «de. 2*» "• • **P'b ef IS feet J*** the rrTf-i •» - ■ -~- foundahu V»,, . - . .•.-.;. M.i th» jT***awwic wore i* bow praeeedum g_WB iwri a|[ T v- »■ ■'■-.. l '.-.:;.i»M K-' !«*»ag la* fDs,r-.» lb place «

thoroughly to wash dawn the ««* J oo ' mder a compressed 3*t of water while iron pipe* arp • , * 1 u P n K ht II J . , £ ercM to allow liquid eonerete later to be forced thxougo under pressure to till the interstices, if any, at the foundations. The central span of the dam will not be carried op to »•• ultimate *«**« a * enre, bat only to torn a height •• t« serve for a platform for maelunrrr *p-1 plant for excavating the rlw Wt on either side, la both uiataacw the area to be worked is much larger than that in the pr«nt b«t with the aid of the atop-b***" in the »»««• of the river, provision catr tie .»*« ior doing awav with the necessity of abort* aftd'ataya. thus leaving •« open •pac* to albrn of the working of modera machinery. The exeavationa in the rock at the p»wer-house site are being steadUy proceeded with, and at oae -pot are down to a depth exceeding 40 feet, «ith •till another 20 feet of solid rock to be removed. Progress generally it being kept up to schedule, while every means , oaJuag for safety of the workmen is scrupulously observed The attention of the engineer tn charge, Mr B. H. Pack wood, ha. been drawn to the repeated criticism of the Wsitaki scheme by Mr J B. Hol«"«. who has revived »« poiats he raised •boot twelve months ago. The >»ur*irn of Mr Holmes's criticism >V>" V 1 menace the scheme contains in its interference with a shingle carrying river. Mr Holmes contenda that the dam wi I prevent the ahingte passing, and it will accumulate in tar river channel _ npstream of the dam. eventually raising the riverbed parallel with the present bed bv a height of the dam. i.e.. about TO feet- The result of this, says Mr Holmes, will l»e the inundating of the river fiats affected. The dam, continues Mr Holmes, will reduce the quantity of gravel that is being discharge! by the river into tiie sea to about a quarter of the present quantity. This gravel | at the present time forms a blanket on j the hea.-h along a length of about *'"> , miles. This blanket is being continuously destroyed by the ceaseless action of the sea. and in turn is beine fed by the river with more gravel. If the sv.ppij is Urge I v reduced, says Mr II elm-s. erosion of the seashore mast fellow, as the destructive fnre«>s and supply of gravel are practically balaneed at the present time. When approached oa the subject Mr Paekwood' intimated that the p.iint" rui.ed hv Mr iWrnes had been e.irefnlly ciinsi'!-red and thoroughly invest: gated bv the responsible departmental officers (.-for.- the Waitaki scheme was embarked on. but beyond* that he had no further comment to make. As a m.-t'or of fact in January la»t f the same erincism was aubjeet o- ■ a dis.-us*»o« In which it was jn>.:i:ej ! oat through several papers that of the ! rivers on this cro>—The TVaimnkariri. ! Kuknia. Ranjttatn. and Wr.itaki tlie t Waitaki carries the least qnantity of ° %, ,f.ht»r#> • f if**■■* *3h*** t^r" 1 " 1 " 1 in the Ze-dwaters providing a natural -ieposi'nry *V>r the travel brought de.wn b*- fioo-ls from the mountains. Thu* I was one r.f the factors in favour "f the Waitaki «''V-i:v over tV Waim.-vkariri proposal. IV.r-inr. the Waitaki ur.dirtakit z '» e«»<-r:f.s!ly not a >" , f*C scheme, »■ 'hit r.o appreueajri-r* need be felt <-,,ri.-er!»me th e silting tip 01' the I dam, •* ha* .->*<■> been soegeste-i in Mr j Holmes's crit.,--an.. At its lowest level j the river carries mors thaa saJleitnt ' water to develop electricity to the i fullest capaci'y of the proposed power- ' kow. Arr.p> rvaririn has also been ' prodded foe in th« '*;:j:h <"t ?!;*• *?»'» I way to folly discharge the wuoie of U«" : water of the riveY 'at 'Us highest flood , i level. la any cat*, the most stringent

calculations, based on experiments, showthat the formation of a shingle fan from the beginning of the still water in the lake to the wall of the dam would occupv under the worst possible conditions "at least 120 years, and under average conditions something like Joo years.