IRRIGATION.

Ashburton Guardian, Volume V, Issue 1312, 11 August 1886, Page 3

IRRIGATION.

In the current number of the New Zealand Country Journal Mr Edward Dobson, C.E, has an interesting paper on irrigation, a subject which at the present time is engaging a large amount of attention in various parts of the Australasian colonies. ' We have already touched at some length upon the irrigation proposals put forth by the Ashburton County Council, but we need make no apology for asking the attention of our readers for a few moments to the interesting and valuable notes on the collection, storage, and distribution of water with special regard to its use for irrigation purposes, whichjbave been prepared by Mr Dobson. It is unnecessary to follow the writer in his observations upon the results of irrigation in Italy, Spain, and France; our readers are familiar with the almost fabulous effects of the system in those countries; but an account of the operations in New South Wales and Victoria will be read with especial interest. In New South Wales the great present need is to supply the pastoral districts with drinkj ing water for stock, which is sought to be accomplished by impounding the water during flood time in tanks and in ponds formed by placing dims across the creeks and depressions in the country. The rivers are few aud far between, and their flow sluggish, whilst a great part of the Central Australian Plain is practically level. There are large areas which do not belong to any-river basin, and on which the rainfall disappears by evaporation or percolation through the soil, without reaching any river. In fact, with the exception of the Murray and the Murrumbidgee, the rivers on the west of the dividing range are more or .6 s intermittent in their flow, and their beds are dry for many months in each year. Accordingly, we find the title of .the New South Wales Commission to * be, not “ Irrigation,” or even “ Water Supply,” but “ Conservation of Water,” and it is to this object that the work of the Commission has been chiefly directed. In Victoria, a large area of the colony is occupied as farms, and there is a growing demand for water, not only for household use and for stock, but for irrigating purposes. A good deal of irrigation has recently been attempted; in some instances on a large scale, the water being raised from the adjacent rivers by pumping. Irrigation canals, taking their supply direct from jthe rivers, on a large scale as in America, are, as yet, things of the future in Victoria. Neither is there in Victoria the same normal want of water that prevails in the interior of New South Wales. Even the dry country to the north-west of the dividing range, where the rivers now lose themselves in swamps and lagoons in the flat plains, without ever reaching the Murray, might be fairly supplied with water, were the streams flowing from the hills confined and distributed in proper channels, instead of being allowed to spread and run to waste. In these two colonies —New South Wales and Victoria —the supplies of water used in irrigation are mostly pumped by steampower from dams or rivers lying below the level of the land to be irrigated, and a great deal of the distribution of the water is effected through canvas hose. In the Western Slates of America the

water is frequently brought many miles in canals from the sources of supply to the districts to be irrigated, the fluming and tunnelling to effect this being often on a very extensive scale; whilst in many districts water more or less artesian is lifted to the height required

for distribution over the surface 01 the mound by numerous windmills, As regards the proposed Irrigation o the Canterbury Plains, it |s gratifying to find that an engineer of Mr Dobson’s ability and reputation takes a most encouraging view of the scheme. He says: “If we now turn to the Canterbury Plains in their whole extent from the Waiau to the Waitaki, we shall find that, for the purposes of irrigation, they compare favorably in every respect with the above-named countries. We have a tolerably tegular rainfall; abundant permanent sources of water supply in our rivers; and a country sloping from the foot of the hills towards the sea in a way as to render it easy to lead she water to any part required, and at the same time presenting ample facilities for drainage. In fact, it would be difficult to imagine any engineering conditions more favorable for an extended system of irrigation than are here presented by these plains in their normal state.” It will be noticed that the opinion entertained by Mr Dobson is precisely in accord with what we have expressed as our own, and we have renewed pleasure in congratulating the settlers in this district upon the prospect of the early completion of a practical system of irrigation.— Mail,