The time taken by a rise in travelling down a canal is very much the same as that taken by a fall and each takes effect more or less gradually. When a branch receives, at any point, a temporary increase in its supply, owing to the closure of a distributary for, say, three days, there will be a rise lasting for three days at a point further down. The rise will take some time to come to its height, and some time to die away. There will be about three days from the commencement of the rise to the commencement of the fall, or from the end of the rise to the end of the fall. If, either in the main canal or in a branch, there is any distributary into which full supply cannot be got, its turn can be increased accordingly. Owing to the shortness of the turns, and to allowance having to be made for the time occupied by rises and falls in travelling down the branch, the fixing of the turns for distributaries near the tail of the branch requires a good deal of consideration. Matters are facilitated by making a sketch ([Fig. 25]) in which the widths of the channels, as drawn, are roughly in proportion to the full supply discharges. If 14 copies of the sketch are made the arrangements for each day can be shown on them, full supply being shown black and residuum hatched. Distributaries would be shown as well as the main channels.
Fig. 25.
The irrigation registers of course show how the irrigation of the different channels is going on from year to year and if changes in the turns become necessary they can be effected.
After the water has entered the watercourses the canal officials have nothing to do with its distribution. The people arrange among themselves a system of turns, each person taking the water for a certain number of “pahars”—a pahar is a watch of three hours—or fractions of a pahar. The zilladar can however be called in by any person who has a dispute with his neighbour. If the matter is not settled the person aggrieved can lodge a formal complaint and a canal officer then tries the case, and if necessary punishes the offender.
In former days it was usual, in some places, for no regular turns to be fixed for the distributaries, orders being issued regarding them from time to time. The weak point about any such plan is that in the event of the controlling officer delaying, owing to any accident, to issue an order, no one knows what to do. Orders were also sometimes issued to zilladars giving them discretionary powers in distribution. No one would now issue such orders. The essential principle is to remove power from the hands of the subordinates. The working of the main channels by turns and the construction of outlets of such a size that they never require closure, has resulted—in places where such matters are attended to—in the absolute destruction of such power.[32] The only way in which a zilladar can injure anyone is to say that water is not in demand. This would however result in damaging the whole of the villages in his charge. He is not likely to do this.
[32] In the printed form lately in use in the Punjab for reports on zilladars, one of the questions asked is whether “his arrangements” for the distribution of water are satisfactory, as if that was still considered to be the zilladar’s business.
In case the supply is wholly or partially interrupted owing to a breach or an accident at the headworks, or other cause, one particular branch or distributary may lose its turn or part of it. If its loss is not great it may be best to allow the turns to take their usual course, but otherwise they should be temporarily altered in such a way as to compensate the channels which have suffered.
On inundation canals the water at a regulator is sometimes headed up,—all branches being partially closed—in order to give more water to outlets in the upstream reach. There are even some regulators—or rather stop-dams—constructed solely for this purpose at places where there is no bifurcation of the canal or distributary. Any such heading up should be planned out beforehand and days for it fixed, and also the gauge reading. If the water, without any heading up, rises to the needful height on the gauge, nothing has to be done. There are also places on inundation canals where the land is high and is only irrigable during floods. At such places it is usual, on some canals, to allow the people to make cuts in the bank when the water attains a certain height. Owing to the high level of the country, nothing in the nature of a breach can occur. In one canal division where the above arrangement was in force, the people used to send applications to the Executive Engineer for leave to cut the banks. This resulted in much delay. A list was prepared showing exactly where the banks might be cut, the people were informed and the formalities were much reduced.