HEADRACE DRY.

Auckland Star, Volume LXI, Issue 140, 16 June 1930, Page 9

HEADRACE DRY.

ARA PUNI DISCLOSURES.

ALL SEEPAGE DISAPPEARS.

<(TILT v TOWARDS POWERHOUSE.

MANY MEN DISCHARGED

HUNDKEDS OF VISITORS

Tn bright sunshine yesterday Arapuni , the'appcarancc of being the centre "'inafillfete rather than the scene !f a national disaster. From early Sinn" until late afternoon hundreds "2r cars converged on the little Lvnship and slowly wended their way l g the main road to the huge dan, .impounding the titers of the h Waikato. A toucn or eolom ;-as ...t-dal IV the gaudy uniforms ot foutuaa, teaniV-wliJch contended for euprcmacr ■ on the'village green. -•Buses Crowded with sightseers cauie from Hamilton, Cambridge, ami otmuplaces even,a, far afield as Rttorua. Over one'hundred people arrived from the thermal district by tins means oi transport; while the Railway Oepartran a special train at excursion fares from Aueklamu It carried 160 passengers to Putaxurn/ the nearest railhead, and conveyed then, by special buses from there to Arapuai. As usual on such occasions, there Vas a fly in (he ointment. Sightseers were not allowed on the affected area, They were permitted a view of the dam, the surrounding country and the water boiling out of the diversion tunnel into the Ampuni Go-go. Th*y were also permitted a distant view of Hie powerhouse and the river from a vantage point on the east bank of the gorge. ...This was all Attempts to get closer tfere firmly resisted by' a strong tend, of picket? etationed at, every point winch would give access, to the works » the vicinity of the headrace, powerliquse or suspension brWjre over (he rivjsv. This restriction was placed on viarors in their own interests. -It' would have been 'unsafe as well as unwise iff the public to have had-access to the country which lias ' "tilted"' and -where.'remedial measures are being carried ov throughout tho day and night. : fro Tumps Used. Contrary' tii. expectations, the headrace -was miito 4y Iry eight o'clock on Saturday ni«ll''Arrangements' had been , complete! to ami syphon the water "'ad. of the 1 ' headrace whan it reached*, level too low to allow it to rim off 'thvoigii' tlio penstock intakes.. This happ.' ; rfcl s on Saturday after noon, but it ■ was tle'n discovered that tho flow was filing mt so quickly through the fractures "thai v pumping was unnecessary. . By 3 p.m.' the headrace was ' dry and "' a* tliirough inspection was commenced disclosure? have been made. ThJ "t'ault"°is more serious than anticipated. It commences some chains up tie headrace channel and carries down itreain in the bed oi the new river paral- • leling the walk of the penstock intakes some six feet out-, and pinching in to the -north-east corner where the spillway joins the penstock -structure. From this" point it runs diagonally into the bank between the old and new channels and bends in again and comes to an end in the vicinity of the falls above the submerged forest. The fissure varies in width from one. to two inches. Numerous smaller cracks have also appeared running in various directions. The shaft which was run into the bank from below the spillway intercepted the crevice at a depth some eight feet below the headrace bed. This took practically the whole flow of water after the penstock intakes had refused to act. This tunnel will be lined and act in future as a seepage canal. Headrace Silted. The bed of the. headrace, close to the spillway, has silted up to a depth of ten feet with a mixture of sand-and pumice, while' the intake screens for some" distance up from their base are . covered with, silt and rocks. Dead trout litter the bed of the headrace towards the spillway. They had no means of escape. -A gang of twenty men are busy in the bed of the headrace clearing awjiy the silt and following up the, fissure from " the weir towards the dam. It will take some time before the inspection is completed, as tho engineers will have to make "'a-'most minute examination. Shafts will- be driven below the fissures to ascertain their extent and depth. -- With the complete dewatering of the headrace, all the seepage in the face - above the powerhouse and through the bank facing the gorge road has disap- . pearai, but" interesting experiments are • being carried out by pouring red dye into the "fault" with a view to tracing the point or points from which it may emerge. There were no results of the test yesterday. .' . •■ • ' Lake-Hajf Empty! | Lake- Arapuni has new discharged: half its waters through the diversion tunnel, which has stood without -signs of .deterioration the great strain imposed or> it. All danger of it carrying away, may now be dismissed, as the pressure is not nearly so great as when it was opened eight days. ago. Then it was only safe to lift the gates 2ffc_#n. Now Hit gates are up nearly Bft. They will be lifted more each day a?>_ the lake recedes. The tunnel is 24ft by ' 24ft. There wa3 considerable doubt .when the trouble' was first discovered as to which direction the earth movement had taken —whether towards the power station in 'the gorge, or towards the spillway weir. By careful-surveys, and checking from old pegs it has been aseer- ■ tained it-at. the "tilt" is slightly towards the power house, the movement being given as two millimetres. 'This is only a\niinuis fraction, but the data was most .'necessary- to the engineers- ■ "The; taniwim has only shaken his head so far," remarked an educated Maori yesterday, with ft smile. "Goodness knows what will happen' when he shake a his whole body." Many Men Discharged. '. In the. meantime. SO single men wHo were engaged in. excavating the ne# penstocks for. additional power units 1 have been dismissed, while work Las been found elsewhere for married mum i If the proposals for concreting the headrace and falls are carried out, tlero will be occupation for a. largo number of men for a lengthy period, but the experts have yet to finalise their j.-iaus •r and have- them sanctioned.