WAITAKEKEI WATER SCHEME.

New Zealand Herald, Volume XLIII, Issue 13214, 27 June 1906, Page 6

WAITAKEKEI WATER SCHEME.

PROGRESS OF THE WORKS.

The great works undertaken by the Auckland City Council for a water supply from the 'watershed of the Waitakerei Ranges are proceeding rapidly. All the benching for the pipe track lias been completed, "and the separate pieces from the break-pressure tank to the tunnel at George's Hill, and from the other end of the tunnel round to the Waitakerei Falls, including the small tunnel of 200 ft, have been finished. The pipe track from, the break-pressure tank down to Henderson Valley Road, including a small tunnel, has been finished for some time. The total distance of the George's Hill tunnel cut is now 2300 ft, and there are still 600 ft to cut, but the contractors are in rather better country, chiefly solid rock, and no timbering has been required so far. A number of men are now engaged on the excavation works at iho pressure tank, and the top surface has been removed. This tank will be 155 ft in length, 77ft wide, and 14ft deep, and will be in two compartments, each containing lialf-a-million gallons. The break-pressure tank, receiving its supply from the pipe lino from the Waitakerei Falls, will discharge into the 24in locking-bar steel pipes, and thus the water wilt flow by gravitation, to Titirangi Road, and then into the 27in locking-bar steel mains to Ponsonby reservoir, the breakpressure tank being 475 ft above sea level. Th- two miles between the tank' and the big impounding reservoir above the falls is to be covered by 21 in cast iron pipes, the supply of which is included in the MephanFerguson contract. Clearing operations at the impounding reservoir aro .low iu progress. In some respects this work is almost unique in the colony. All vegetation and roots are to be cleared off , to a depth of 9in, and as heavy standing bush covered tho site not long since tho labour is heavy. This is the slowest work of all the contracts, except the tunnelling. The useful timber is, of course, utilised, and the other vegetation is destroyed by fire. Mtessrs. E. H. Bennett, Limited, , have this contract in hand, aud are at present engaged in " logging up" or stacking the vegetation for firing. / The bigger timber is split with gelignite charges, fired by a battery. The great impounding reservoir will tap the stream above the falls, and will submerge an area of .about 65 acres, and contain upwards of 200,000,000 gallons of water, while a smaller dam, further up, will take 50,000,000 gallons. The artificial lakes which will thus be erected. in the heart of tho kauri forest should be well worth a visit as beauty spots. Tho rails for tho tramway, which is to run along the pipe track from the breakpressure tank, have just arrived by the s.s. Kaikoura, and will be sent up at once. The tramway will enable the cement, etc., to be conveyed up for tho big masoray wall at the falls. Tliis wall will rise 50ft above the present crest of Waitakerei Falls, and go down 15ft be law it, with a bottom thickness of 15ft, and a total length of 500 ft, the two ends locking into notches on either side of the creek. A large number of the cast iron pipes for the upper pipe line are now at Swanson railway station, and Mr. Moody has commenced the trenches for the locking-bar pipes at the Western Springs 2nd. At New Lynn the Me plum-Ferguson foundries are in. full operation, turning out iho 28l't locking-bar steel pipes at the rate of two per hour. Some slight delay has been , caused at the works by the burning of tho dipping tank, but this will soon bo righted. The watershed for the scheme comprises some 2920 acres, and the Waitakerei Fallswill give, with. tho various other creeks taken in, an almost unlimited supply of the purest drinking water. Over 11,000,000 gallons per diem have been recorded as going over the falls in winter, and this scheme will have 1,500,000 gallons per day of running water as the minimum flow during the estimated 90 days of dry weather per annum. Tho storage reservoirs will provide for 90 days, and give, together with the running water, a minimum • flow of 4,500,000 gallons daily. This, with the 1,500,000 gallons daily as the minimum from the Nihotupu Falls, will give a minimum of 6,000,000 gallons, while the consumption now is 3,400,000 gallons par diem, obtained from Nihotupu arid Western Springs.. An impounding reservoir at Nihotupu would add 3,000,000 gallons per day, so that there is ample room for expansion.