WAITOHI FLAT WATER SUPPLY

Temuka Leader, Issue 2293, 15 December 1891, Page 4

WAITOHI FLAT WATER SUPPLY

The Waitohi Flat water-races, the first mooted in the district, the last- to be undertaken, are now practically completed, and settlers already realise the advantage of a permanent surface water supply The scheme has involved a good "deal of trouble,' and has doubtless been a source of some anxiety to the engineers ; an inspection of it, however, will reveal • e ven to the unitiated observer that it is exceptionally complete. XHB HEAP WORKS, which have ; been carried out by Mr James Cartwright, are situated about half a mile above the road known as Coil’s cutting, the site selected being immediately beneath a steep sandstone bluff. The system adopted is that intoduced by Messrs Measou and Marchant, and known - a8 the filter box plan. This consists of a timber box very strongly constructed, but with a number of interstices, sunk beneath the bed of the river and secured there by heavy iron piles and covered with large blocks of Milestone wived together. From this a close-boarded intake culvert conveys the water, which filters through to an open race. At the opening to the race is a sluice, strongly constructed of timber and concrete. The t/ate of this is raised by means of a powerful screw working through a nut. To guard against the river overflowing into the race a high embankment has been made, and to protect this there runs at an angle from the cliff about 9 chains of fencing. This is constructed of iron piles 20 feet apart, and driven about 10 feet. Against these are bolted black pine studs, with 16 wires strained upon them. The whole line of this fence is planted with willows (now aR growing luxuriantly), and the embankment itself is planted with smaller ones. The open cutting is about 2 yards deep and a little over 2 yards wide at its commencement, and it gradually reduces in depth until Coil’s road is reached. At suitable places overflow channels have been cut, and there are a very substantial main sluice and regulating sluice, the former about 15 chains and the latter about 20 chains from the intake culvert. The regulating sluice has been patented by Messrs Meason and Marchant, the engineers, and ia a most ingenious contrivance. It is . regulated by means of a weight attached ' to a lever, and acts in such a manner that any undue pressure causes a gate to close and stop all water from flowing along the race. It can be adjusted to a nicety, and ;Works extremely well. At Coil’s road there is a concrete barrel culvert 39 feet long by 2 feet 6 inches diameter, with substantial face walls, and after passing this a sideling cutting commences at the Waitohi terrace. This has been the most troublesome job of the whole contract, but it has been splendidly carried out by the contractor. The terrace is of a very peculiar geological formation, and in the course of the work soils of various characters have been encountered. Some of these were particularly hard, others friable and porous, and others again of a soapy clay nature. The fall was only 4 feet to the mile, so that the work had to be carried on with the utmost care; The terrace cutting started with a depth of about 4 feet and a width of about 6 feet, and this was maintained pretty evenly until Mr Coil’s private road is reached where .an increased depth was required. The cutting has been taken out with a batter ”of a half to one, except for a short distance where the “batter” is a quarter to one, and this appears to be quite sufficient, for in only two places have slips occurred.' Above the race are catch-water drains with timber shoots. Where roads have had to be crossed concrete culverts have been erected. Of those there are 9, all of the same diameter, 2 feet 6 inches. Near Mr Pearce’s and also at Mr Hullen’s there are concrete overflows in the side of the race. These allow of the escape of surplus water, and also of the race being diverted if required. Overflow water is carried down the embankment by mean t of 12-inch pipes. The roadways over all culverts are faced up with hand-placed boulders. The headworks section of the contract terminates at Mr Bell’s, a distance of a little over two miles from the intake culvert. Some idea of the .excavation required in its construction may be gathered from the fact that the cubic content of the cutting is about 22,000 yards. It may be mentioned that wherever required at road crossings or elsewhere the race has been substantially fenced. Mr Cartwright, the contractor, has had by no means an easy job, and has suffered some inconvenience from winter ■ frost, &c. He has, however, made a capital job. The work is true to plan, j substantial, and neat. ! me DISTRIBUTING RACES, 3 The contract for which was let to Mr 1 R. Calvert, are of various sizes, but 1 require little comment. They serve to 8 r*riy. on the water from the main race

through the various paddocks comprised in the water supply district. The largest races are 3 feet in the bottom. Of this size there are 48 chains. There f.dlow 220 chains 2 feet 6 inches ; 440 chains 2 feet; and about 800 chains 15 inches. The majority of these are cut with a waterrace plough, which, where the ground has a proper natural fall completes the work, or nearly so, as it proceeds. In places the races has to be deepened. This is done by hand, and in other parts embankments or small aqueducts have to be constructed. Where the race crosses creeks, flumes of timber, supported upon iron piles have been put in. These flumes have all concrete “ lips.” Under banks, where necessary pipe, or concrete culverts have been put in of sizes according to the probable amount of drainage water to be carried. Where natural courses served they have been used in place of cut races, and the Raupo Creek has now a sufficient supply for the settlers whose lands are intersected by it. The more elevated part of the district, that is the Rangitira Valley, has also a good supply, which reaches it by way of the Waitohi school and township, and then through Mr Andrews’ land to Mr William Wright’s. Upon this section of the race a number of dams have had to be filled, and these have taken a considerable time, but every settler has now an ample supply. The races finally empty into the Raupo Creek, and the creek at Epworth Wool Works. A peculiar feature of this contract has been the peculiarly absorbent nature of the ground, which has soaked in water far more freely than more sandy soil. After a little time, however, as has invariably been the case, the steady flow of waterformed a secure bed, and loss by absorption is reduced to a minimum. This contract has also been neatly carried out, and appears very complete. The works throughout are a decided credit to the engineers and an acquisition to the district. To Mr James Radford, the clerk of the works is due the highest praise. He has had an arduous and important job, and has fulfilled it in a most creditable manner.