IRRIGATION.

Ashburton Guardian, Volume V, Issue 1272, 24 June 1886, Page 3

IRRIGATION.

[From the Mail.]

The report of the Irrigation Committee of the Ashburton County Council, marks what we believe to be an important step in the progress and prosperity of this part of the colony. We have persistently urged the piacticability and value of the scheme which has recently occupied so much attention, and which now has assumed something like tangible form, and it ii with especial gratification we notice the confirmation, in every material point, of the figures and estimates we placed before the public some months ago. It is not our intention at present to again enlarge upon the many and obvious advantages which must accrue to this district from a complete and properly maintained system of irrigation. It has been estimated that such a system would double and treble the agricultural and pastoral capabilities of this county, and from observations \ve have made m other parts of the world, in Victoria, in California, in Great Britain and other European countries, we are disposed to 'think the most sanguine of these estimates would be more than borne out by the results in our own immediate neighborhood. But we have already discussed the probable results of the undertaking; we have succeeded in directing the attention of the public and the practical attention of the County Council to the matter, and we now propose to make a cursory examination of the scheme of irrigation proposed by Mr Baxter and adopted by ihe Irrigation Committee of the County Council. We may state at once that the proposals made by Mr Baxter are hardly in accord with our own preconceived idea of the work, and we notice several points in his scheme which are open to more or less serious objection, but, speaking generally, the plan and report submitted to the County Council on Tuesday re

fleet the very highest credit upon the Intelligence, industry, and professional skill of the Engineer. Perhaps the most remarkable feature of the report, certainly the one which first attracted our attention, is the comparatively small estimated cost of the proposed undertaking. If it be possible to effectually irrigate 396,000 acres of land by the expenditure of a trifle less than 2s id an acre, there should be no

hesitancy on the part of the ratepayers in adopting the scheme. This lessen-

ing of estimated cost, as compared with our own estimate, is mainly effected by taking advantage of several detached sources of supply. Thus, for blocks 1, 2, and 3, virtually one block, including

Rakaia, and parts of Mount Hutt,

Upper Ashburton, and Wakanui districts, there are three in-takes—one from the North Ashburton, near

Wincbmore, but primarily by a cutting near Valetla fiom the south branch, one

from the Rakaia near the township,

and a third from the head of the present water race supply. The adoption of this plan would save many miles of

large and costly main channe>» but it

pre-supposes three very essential conditions—the sufficiency, constancy, and safety of a supply drawn from rivers with shifting channels and wide shingle beds. As regards the last condition, a

controversy is now raging among the

residents in the Wakanui district, and

occupies some prominence in our cor

respondence columns this morning. The experience obtained in connection

with the intake tor the Canterbury Mill and Borough water supply goes to show that the expense and danger of

diverting water from the river do not increase proportionately with the

volume of water introduced, but that two small streams, together equal in magnitude to one larger one, are less

costly and less dangerous than the larger one. We may mention, in passing, that the supply at present intro-

duced into the Wakanui Creek from the north branch of the Ashburton

river is about 20,000 gallons a minute, equal to about one quarter of the quantity that will be required for irri-

gating the Wakanui division of the district. Mr Baxter is probably aware that not many years ago the great

volume of the Rakaia river was in the

north bed, and many chains in the

south bed, where water is now to be found, were covered with tussocks and

fern. We are not aware that any guarantee exists that an equally radical change of course will not take place in the near future, and against the saving of cost effected by these additional intakes must be set the in-

creased expense of supervision. By multiplying the headworks the

cost of regulation and maintenance must be increased. We gather from the report of the Committee, which was adopted by the Council, that it is proposed to first proceed with the scheme so far as it applies to blocks 1 and 2, which comprise the tract of land lying between a line drawn from Winchmore to Rakaia township, the Rakaia river, the sea, and the Wakanui Creek, and south branch of the river to Winchmore, the starting

point, an area of 148,000 acres. If the whole of this division were irrigated | it would receive water equal to an inch rainfall each three weeks; btu taking Mr Baxter's estimate, a fair one we think, that only one-third of the land would be under irrigation, it could receive equal to an inch rainfall each week, that is 500 cubic feet an acre a day on Block 1 and 470 cubic feet an acre a day on Block 2, exclusive of waste of water and percolation in , mains. Mr Baxter’s estimate of cost does not, apparently, include possible cost of land, compensation for severance, fencing, nor cost of bridges. We do not suppose the County Engineer has overlooked these items; he has, probably, assumed that the ratepayers, with but few exceptions, will give the land and bear the other expenses ; but, remembering that the main-channels with spoil on the banks will be nearly a chain in width, that severance will be an inconvenient feature of the system, and that the cost of bridges and fencing will be a very material item, we fear that his assumption will not be justified. In the case of the Wakanui Creek, the proprietor of the Canterbury Mill has been required by the Road Boards or ratepayers interested to erect a bridge at nearly every road it crosses. It is impossible to analyse or criticise the estimate of cost, as Mr Baxter has furnished very scanty particulars of construction and none of management or regulation. We have the fullest confidence in Mr

Baxter as an Engineer, we con side the Council and the ratepayers are singularly fortunate in having the services of a gentleman of such exceptional ability at their disposal, but before the question of the advisableness or otherwise of raising a loan for the initiation of the scheme be submitted to the ratepayers, it will be absolutely necessary to provide more detailed information with regard to some important features of the proposed system.

We should not close this notice without mentioning the names of two gentlemen who are entitled to especial credit for the part they have already borne in forwarding this scheme of irrigation. For nearly 21 years Mr C. E. Fooks, with professional skill and practical common sense, has consistently advocated the irrigation of the Ashburton plains, and during the last twelve months Mr E. F. Wright, of Gawlor Downs, has enthusiastically urged the same matter upon the attention of our local bodies, the ratepayers, and the Press. We trust these two gentlemen, and their fellow workers, may be spared to witness the triumph of their exertions.