WATER SUPPLY ON THE GOLDFIELDS.

New Zealand Times, Volume XXX, Issue 4459, 5 July 1875, Page 5

WATER SUPPLY ON THE GOLDFIELDS.

THE THAMES tVATEII-EACE. The following very interesting article appears in a recent number of the Thames Evening Star ;— Now that the works in connection with our water supply are approaching completion, a good idea can be had of the magnitude of the undertaking, and a pleasant day may be spent by a ride up the Kauaeranga Valley. The first section, contracted for by Mr. Heron, is completed ; and that portion being constructed by Messrs. R, and A. Smith will be finished in a few months’ time. The race takes the water from, the Kauaeranga Creek, ten miles from Shortland ; and a very ingenious method has been adopted for preventing an over supply of water getting into the race during times of a flood in the river. A solid block of masonry, in which five sluice gates are formed, abuts into the stream from the entrance of the first tunnel, and to each of four of these gates an air-tight tank is attached. In the masonry, at .various distances from the bottom cavities are formed in which these tanks are placed, and upon the water entering the race rising to a certain height it will lift one of these tanks which will gradually close the gate to which it is attached. Upon rising higher it -will reach another tank, and so in turn until four gates are closed, leaving only one to supply the race, and this gate is regulated by a lever upon the top ■ of the structure. By these, self-acting arrangements the possibility of the race being injured by an over supply of water is avoided. The first portion of thfe race goes through a steep spur by a tunnel 800 feet long, which has been well carried out by Mr. Heron, the contractor. In-this section a great deal of extra work has been found necessary, owing to the bad nature of the ground through which the open cuttings passed. In several places the cuttings are boxed in with stout timbers like large open culverts. There have been none of the iron troughs used ■ in the first section, but in a great portion of Messrs. Smith’s section they are used. . An idea can scarcely be conveyed upon paper of the difficulties that had to be overcome in carrying out the line, but owing to the attention paid by the engineer, Mr. Aitken, many alterations in the original line surveyed have been made, effecting both a saving in distance and in the expense of construction. There will be, after the whole is completed, three or four hundred tons of material unused. In many places the line had to be carried round the face of precipices of solid rock, in which the greatest difficulty was found in even getting a footing. However, all the work of cutting and forming the bed of the race is now done in No. 2 section, and the rivetting of the iron plates is the principal'work. Messrs. Smith Bros, have no less than seven parties of rivetters at work, and the noise of the hammering can be heard issuing from the centre of the dense forest. The timber for the framework is all of kauri, cut in the bush along the course of the race. All the kauri is supposed to belong to the Shortland Sawmill Company. In fact the men complain that not only the kauri but all the timber on the ground is claimed by the company, and accounts may be expected for the firewood used. Whoever owns the timber, other than the kauri, it will be very valuable, and it is in sufficient quantities to supply a colony with firewood and mining timber. No doubt but the race will be- used as a means of floating it down to the township, and it can be done at a comparatively low price. The construction of the race, besides being of so much importance to the goldfield by supplying motive power for crushing machines, will have the greatest effect on the future of this portion of the province. Industries will no doubt be started, and large manufactories can be supplied with a cheap motive power. But the undertaking will also attract attention to the valley of the Kauaeranga, along which some good farms are to bo picked out. The land, although at present in the goldfield, freeholds are to be obtained from the native owners, and some portions have already been acquired. Opening up the Kauaeranga valley and the formation of a good track is due in some measure to Messrs. Smith Bros., who, to get up the iron troughs of the race, wore compelled to form a good track, and at a considerable expense, which is now used by gum packers and storekeepers. In No. 2 section the longest tunnel cut is 550 ft., and effects a considerable saving in the length of the race. In No. 3 section, constructed by Mr. Foughey, there is another tunnel somewhat about the same length. The highest trestle work will be that across the Maungakiriri Creek in No. 2 section, which, when erected, will be 65ft. high. In several places in this section there is trestle work over 50ft. in height. The timber used is heart of kauri, and the work seems very substantially erected. That a bettor idea may be formed of the undertaking we will give some of the details. No. 1 section, constructed by Mr. Heron, commenced with a tunnel over 800 ft. in length, and about 1000 ft. .of open cuttings, which are now completed. No. 2 section, under tender to Messrs. R. and A. Smith, is eight miles in length, and has three tunnels in it—one 550 ft. and two of about 250 ft. each. Of trestle work in this section there is 15,000 ft. in all, 13,000 ft. of Which is done. The rivetting of 8000 ft. of the troughing has been completed. There will bo used in the woodwork 400,000 ft. of kauri, and as beforementioned the highest flume will be 65ft. in height, and several of the spars will be 44ft. long. Some of the opening cuttings are 16ft. deep, and in many places nearly 40ft. wide at the top. No. 3 section, under tender to Mr. Foughey, is one and three-quarter J

miles long, in which there are no Ifes than seven tunnels, one over 550 ft. long, the total number of feet to be driven being 2065. In this section there are 1200 ft. of fiuming, and the remainder open cuttings. It is proposed to have oxxe reservoir iix the Waio-Karaka Creek, but it is probable that other reservoirs will be formed along the course of the race. The iron left will be utilised in forming the main pipes oaxaying the supply to the principal centres. Within a few months the tenders will be out' for reservoir and laying of the pipes, and by the first of next, year we may expect to have the supply at our command. Although Messrs. Smith Brothers have yet a considerable time before their contract time expires, their section is wejl advanced and could be finished in a few months,- and Mr. Foughey expects to, have his contract completed in the specified time.