Geological and other Reports
Wellington, March 17, 1862
Sir,—Although unconnected with the subject of minerals, an exploration of the Manawatu leads me to lay before you some remarks concerning the eventual settlement of that district, with a view to a thorough development of its resources.
I have long been impressed with the fact that the agricultural resouurces of New Zealand with not be appreciated until irrigation is understood and practised. With a comparatively warm climate, and an ample supply of water, the results of irrigation may be expected to be astonishing. I have already expressed an opinion that the broken forest country lying between the Rangitikei and the Whanganui rivers inclusive, can only be successfully worked in small or moderate holdings. I would now further remark that these rivers lie deep below the surrounding country; and, except perhaps near the mouth of the Rangitikei, are not adapted for irrigation.
The Manawatu, on the other hand, has quite a different character. It flows through comparatively low banks, and during floods, covers a large extent of the low country; while at the gorge, and for a considerable distance below it, there is evident to the eye a head of water, which could easily be directed to any lower point re-required.
From the sea to a considerable distance inland, say ten miles, the surface is covered by sand hills and sandy flats, which not only are very poor in their present state, but are a source of danger when broken into, to the neighbouring good land, as the sand blows and travels at a considerable rate.
This land by means of irrigation could be converted into fertile meadows; not only making a handsome return, but removing the previous danger of an irruption of sand.
On a moderate estimate there must be one hundred square miles of the above-named de-description between the Manawatu and the Rangitikei rivers; all of which, supposing the supply of water sufficient, might be brought into great fertility.
Between the Manawatu river and Wainui there is, perhaps, a larger extent of similar country, which would be immensely improved by irrigation, as far as the supply of water and the nature of the levels will permit. As the smaller rivers on this coast are useless for navigation, they might be employed, without compunction, on irrigation.
In connection with this subject the navigation of the Manawatu has to be considered; and I think the river might be made to serve both purposes. The navigation, except for canoes and rafting timber, is difficult and of little consequence, above Puketotara; and as all the water proposed to be abstracted for irrigation ought to be returned to the river, less by what is absorbed by extra evaporation, the scour at the mouth might not be much diminished, and the sediment which now goes to form sand banks at the bar, would to a great extent be spread over and fertilize the soil.
In the Manawatu district there are also swamps of very large area, which are probably beyond the power of private means to drain; so that, I would suggest, a great part of the district requires to be put in order, before it is settled. A combined system of drainage and irrigation, is what is required.
An irrigation canal, taken away from near the gorge, would relieve the present flooded lands.
It is evident that a large capital would require to be invested in the improvements which I propose, and that a great many details would have to be considered, such as the size of farms, whether the holders of the irrigation canal should have the land in freehold, or merely supply the water, &c.; but I do not here propose to enter into any details, as I consider it sufficient for the present, to put forward my views, so as to elicit discussion.
A consideration of the subject of irrigation may be deemed premature, as it may be considered that neither the present population of the Province, nor its state of advancement, would warrant the expenditure required; should this view be generally adopted, I would then advise that that the levels for irrigation canals should be taken, and that the necessary reserves should be made for their ultimate construction, with also a power to be retained to make use of the waters of the river when required.page 15
It may, however, be remarked that irrigation is practised successfully in so young a colony as Van Diemen's Land, and also in the Republic of Chilli, where the population is scanty.
Irrigation farms would require a more skilful husbandry than is usually practised in this Colony; but as there is no lack of intelligence among our farmers that difficulty might soon be got over.
The Manawatu is also evidently meant for the centre of a great timber trade, as the river is well adapted for floating timber down, both from the forests on the Western side of the range and from the seventy-mile bush on the East side—and, in the forest country at least, the lumberer should precede the settler.