8 



THE IEEIGATION AGE. 



LATERALS AND THEIR MANAGEMENT. 



BY E. II. PAHGITER, SUPERINTENDING ENGINEER, IRRIGA- 

 TION BRANCH, PUBLIC WORKS DEPARTMENT, 

 DELHI, INDIA. 



The natural method of irrigating a tract of land, 

 of conveying to it the life-giving streams of water from 

 one main source of supply, and distributing them to 

 every part, can best be learned from the similar proc- 

 esses we see in the vegetable and animal world. Here 

 the body or substance of a plant or animal is irrigated 

 by its sap or blood. The main source of supply is re- 

 peatedly subdivided into smaller and smaller channels, 

 until the network of these is spread over the whole 

 body, and every cell lias a supply brought to it. The 

 same principles will everywhere work out the same re- 

 sults. Consequently in all irrigating countries, we find 

 the same process of a canal branching off into a sys- 

 tem of distribiitaries or laterals, each of which in turn 

 gives off field water courses, to supply every little plot 

 of ground with the water it needs. This, obviously, is 

 the only plan on which a number of different interests 

 can combine, each in the first place seeking its own in- 



MR. EDWYN H. PARGITER, 

 DELHI, INDIA. 



terest; but in the combination mutually seeking the 

 best interests of all. 



But what is not so obvious is that this same prin- 

 ciple of mutual co-operation must be - carried out to 

 the very end, in order to ensure the truest economy 

 in the use of the water, and the highest efficiency 

 in most expeditiously conveying it to every plot of 

 ground to be irrigated. The same principles that 

 have, in India, worked out rules for the maintenance 

 and management of laterals and watercourses, are now 

 working out the same rules in America. Co-operation 

 has been found to be the necessary preliminary to 

 successful working of a lateral. The supply of water 

 required for several different farms or estates, can be 

 utilized to far greater advantage by each receiving the 

 whole supply for its share of a certain time, rather than 

 by each receiving its share of the supply continuously 

 for the whole of that time. The advisability of such 

 a system of rotation of supplies is now as clearly rec- 

 ognized in America, as in India. But the joint use of 

 a common channel by several owners necessarily in- 

 volves its maintenance by them jointly also; and it is 

 as to the best and fairest method of apportioning to 

 each user his proper share in the work of maintenance, 

 that differences of opinion arise, and shareholders dis- 

 agree; with the result, often, that the whole, or part, 

 of the common channel is not kept in proper order, and 

 some, or all, suffer by receiving a poorer supply of 



water than they might. This is due to a perverse 

 and short-sighted trait of selfish human nature, whereby 

 each irrigator fails to see why he should be called on 

 to do work which at first sight does not seem to benefit 

 himself, but only others. 



Now the management and maintenance of a lateral 

 is very rightly made over to the users of that lateral, 

 as they are most directly concerned in its being always 

 kept in good working order, and are always on the spot 

 to see to this being done. But what they often fail to 

 see, is the necessity of co-operation in the whole of 

 the work, in the maintenance of the whole of the com- 

 mon channel. The irrigators at the lower end, or tail, 

 can quite see the justice of their doing their share in 

 the maintenance of the whole lateral from its headgate 

 down to the end where they receive water. They will 

 help in clearing the whole channel of silt and weeds, 

 and in repairing breaches or strengthening weak banks 

 along its whole length. They quite acknowledge the 

 fairness of their bearing a share in the cost of bringing 

 the water they require from the canal to their land. 

 But an irrigator, who takes off water higher up the 

 course of the lateral, often cannot see why he should 

 do a single stroke of work for, or bear any part of the 

 cost of, clearing or repairing the lateral, below the 

 point where he takes off his water. In consequence he 

 fights hard against any rule requiring him to help in 

 this way; holding that it is other people's work, and 

 that it is none of his business to do work for them, 

 which does not benefit himself. 



?fow if each irrigator from a lateral were allowed 

 to neglect that portion of it beyond his own land, 

 the burden of maintenance would vary for each accord- 

 ing to the distance of his land from the head of the 

 lateral, and might come very heavily on those at the 

 lower end; so much so as to limit very soon the prac- 

 ticable working length of a lateral ; and consequently the 

 number of shareholders in it; and so, also, the quan- 

 tity of water carried in it. But the smaller the chan- 

 nel the less efficiently and economically it will work; 

 the greater will be the proportionate share of cost to 

 each shareholder, and the less the available supply of 

 water in times of scarcity. At such a time, indeed, 

 when the whole supply is taken in rotation by each irri- 

 gator, each has at his disposal a larger supply in the 

 case of a larger channel, and can irrigate more land in 

 a short time than he could with the smaller supply 

 of a smaller channel in a proportionately longer time. 

 The irrigators along the upper end of a lateral will thus 

 directly benefit by having many others as sharers lower 

 down; and in consequence they can fairly be expected 

 to help those others in maintaining the whole length of 

 the lateral, from which they thus benefit. Even if 

 each irrigator along the upper portion never requires 

 to take the whole supply, still he reaps the benefit of 

 using a larger and more efficient channel involving 

 a proportionately smaller cost and trouble to maintain. 



As it would be quite impossible to ascertain and 

 apportion correctly to each shareholder the exact length 

 of channel he should help to maintain, after calcu- 

 lating the exact benefit he derives from having so many 

 other shareholders using water beyond the point he 

 takes his off, the only reasonable and feasible plan is 

 to make all equally responsible for the maintenance of 

 all common channels; each baring his share allotted 

 proportionately to the area of land he irrigates; or to 

 the quantity of water he iises, where different crops re- 

 quire very different quantities of water. Every portion 



