Irrigation and Inter-Colonial Co-operation. 363 



small canals taken out from them will require headworks practically 

 as expensive as those of large ones, and will therefore fro rata, 

 be more expensive, while their benefit to the country will be much 

 less. Moreover, a large canal can carry water more economically 

 than a small one, and can more rapidly gain command of irrigable 

 land. 



In some cases it will be possible to construct the canal first, and 

 thereafter to provide storage for it when this development becomes 

 necessary ; such procedure in gradual stages will generally be the 

 most advantageous one to adopt, as irrigation is usually a plant of 

 slow growth. 



Taking both large reservoirs and large canals together, their 

 advantages are that they better utilise the natural assets of more 

 certain supply and of the flatter slopes of the country w'hich charac- 

 terise large catchments. The larger rivers have the further great 

 advantage that on them there are fewer established riparian rights, 

 so that more comprehensive schemes can be established on them, with 

 less interference with such rights. 



It is, moreover, an irrigation maxim that a scheme must be on 

 a scale having a direct relation to that of its source of supply, or 

 its cost will be unnecessarily great and its utility will be needlessly 

 diminished. 



Compared with small schemes, the cost of both the construction 

 and maintenance of fair-sized schemes per acre irrigated will gener- 

 ally be considerably less, and the charge for water-supply can 

 therefore be reduced. It is thus more economical for the State to 

 undertake such projects, and more beneficial to the country as a 

 whole to have large areas irrigated. 



The disadvantages of large works may be said to be their great 

 cost, the uncertainty of getting all irrigable land under them occupied, 

 and the chance of constructional failure. On the other hand, contrary 

 fears have been entertained of their too great success, whereby the 

 market will be swamped, and small farmers on dry lands will be 

 unable to compete with irrigators under them. The answer to the 

 first set of objections is that they should not carry weight in a 

 progressive country if the programme of construction is properly 

 adapted to its requirements, seeing that there is the experience of 

 many other countries available as a guide, and the successful comple- 

 tion of numerous schemes in them as an encouragement. The replies 

 to the second set are that even the enthusiast in irrigation in making 

 his proposals will surely be restrained by reason, and will not suggest 

 so many schemes as will wreck the financial prospects of all, and 

 that, as explained above, there is in this countrv ample scope for the 

 successful existence, side by side, of schemes of different magnitude 

 and for different classes of agriculture. 



II. First-Class Works. 



So much has just been written about the class of " large works '^ 

 that but little remains to be noted concerning " first-class works." 



