DRAINING THE SWAMP.

New Zealand Herald, Volume LXI, Issue 18679, 8 April 1924, Page 4

DRAINING THE SWAMP.

©SEDGES FOB ALL JOBS. A CONTRAST IN TYPES. COMING OF ELECTRICITY. THE SPIRIT OF ENTERPRISE. No. vn. The Hauraki drainage scheme has been xevoluticnised by the introduction of modern dredges. As'has been already indicated, some of the work being performed, particularly by tho drag .line machines, oould not have been . attempted under old methods. The long Teach of these machines makes it possible to turn a canal bank, that is liable to slip into a long battel; not only reducing the possibility of obstructions occurring but greatly increasing the capacity of ,the channel in times of flood. It naturally follows that an excavation ot- this character makes it possible to build high embankments on top of which sound metal roads can be forme without the risk of the stone being squeezed down into tho ooze or washed away by an overflow. Before the introduction of the new typo of moving machinery —it was only three years ago—the floating grab dredge was the only mechanical aid the drainage engineers possessed, and, of course, the grab dredge remains an important unit of the plant. In some, classes of work the grab still holds first place and no engineer will accept any suggestion that it is out of date. It is affirmed that the grab can remove spoil at a cheaper rate jier yard than any of the new dredges, and drainage authorities wax enthusiastic over its enduring qualities. When it tomes to grading off the bank of a canal or river, however, and depositing the spoil a chain away from the water's edge to form a high stopbank and road, the Priestman must retire from the field. So also must the various classes of dipper dredge or steam navvies, although these are "priceless in their particular work, which .is that of rapidly excavating a «anaL Types of Dredges. A striking example of the efficiency of the Btncyrus drag-line is to be aeon atthe present time on the Puhanga ca#al that cuts through a bend in the Piako River at Kerepeehi. Tho machine is almost within .sight of Ngatea which is on the main road across the plains and anyone desiriag to investigate modern methods of excavation oauld not soe a better illustration of the value of the dragline on solid ground. It travels on caterpillars, and therefore would be useless on peat or spongy ground. On this class of ground- provided it is not too soft, the dipper machines that haul themselves along on two pairs of wide skids , hold the field. One type straddles the drain and its giant shovel eats upwards into the face ahead. Another goes ahead of the drain, the bucket moving in the reverse way by an inward sweep towards the dredge body. A New Machine. A new type of dredge, the largest on the swamp, -lias .-now made its appearance and is -about to start on the extension of the Awaiti Canal. This is an American steam dipper dredge that weights 90 tons and is erected on a huge pontoon. It will thus be able to tackle work in deep peat country where, up till now, only the grab dredge hi>s been able to go. It has a long arm and considerable reach through elevated discharge spouts and will be able to remove a far greater amount of matter than the grab. On account of its length of arm.the ordinary ballasting is not sufficient ; tomaintain , its balance. To enable it to stand the heavy leverage .strain three long steel ; uprights ' with wide bases to stop them sinking too far are necessary. There is one -on each side of the dredge and another at the stern that jests on -the : bottom .of the .canal or as much further as the weigh sinks it. Two ,of these dredges, are to be used on. the Piako, \he second being now in the course of erection at Kerepeehi. The pontoons, which measure aboilt 80ft. by 20st., were built by the Land Department's own staff at Xerepeehi, where there is also a complete engineering workshop that is able to carry out all repairs -for -the whole dredge plant, including the necessary attention to electrical apparatus.

Hydro-Electric Power. Thanks to the energy with which the Thames Valley Power Board has extended its lines, Horahora power drives the .machinery of the viockshopj charges batteries etc. Who would have dreamefi a generation ago, even 10 years ago, that hydro-electric power would to-day be turning the wheels of an engineering workshop in what was then the centre of a swamp, lighting the homes of settlers and driving milking plants? The introduction of the new dredges has marked a new era in swamp conquest, but so also has the distribution of electricity. It has been said before in these *>ages and should be said again, that thews is nothing that will so .cxtejyl settlement, increase production and makß for the happiness and contentment -of the rural population as cheap electric power on farms and as far as the drainage of the Hauraki swamp is concerned, who can say whesje the usefulness of electric power is to end ? If it is economically sound to extend transmission lines to the very frontiers of settlement, T*ho is to place a limit upon its future possibilities? There are no doubt "pockets" in the swamp that are un drainabic by ordinary means but is it going beyond the realm of practical affairs to picture electrically driven pumps pouring out the water for which there is no fall? On these flat lands is it inconceivable that traction agents, using electric power, may one day draw farmers' ploughs and cultivating implements? I* it not possible that one day the cleaning of drains, now done by hand, will be performed by some simple machine drawing its power from the overhead lines ?

Not only mechanical instruments have marked a new era of progress in the nost war period. On the swamp as everywhere else reinforced concrete is used more extensively and we see elaborate sluice gates in this material that are also bridges. Where the doors were formerly of wood they are now of concrete whicE cannot warp and jam. On the swamps the progress and enterprising spirit of the age is apparent in matters big and small and the Dominion will reap richly.