Chapter V: The remedy consisted in keeping the gates of the (2)

If the discharge of a channel is increased, the waterways of bridges may need increasing. This can often be done (Chapter II., Art. 12) by making a floor at a low level. Or the waterway may be allowed to remain small, the floor being added at the bed level and the bridge then becoming an incomplete fall, (page 87). The fall in the water surface, though small, can be recognised and shown on the longitudinal section.

In remodelling schemes, the longitudinal section should give all possible information. It should show not only the levels of bed and banks, but the F.S. levels (in blue figures) above and below all falls or regulators, and the levels of floors and waterways of bridges. The plan should show all watercourses and the “chaks” or areas assigned to them.[34] On each chak the actual average irrigation can be shown in blue figures and the proposed irrigation in red. The “draw-off” for each proposed outlet can then be shown on the longitudinal section. The area actually irrigated, as shown on the map, should in each case be the mean of at least three years, and if possible of five years. The number of years should be mentioned in a note on the map. Cross-sections of channels should always be drawn to natural scale, and not with the horizontal scale differing from the vertical.

[34] The field maps mentioned on page 101 are prepared to a very large
scale and show all watercourses. The maps should always be corrected
up to date by the patwaris. The chak maps which are on a smaller
scale--say 4 inches to the mile--can thus be kept correct.

7. =Remodelling of outlets.= When a channel is remodelled, the remodelling of the outlets may consist in alterations of the number or sites or in alterations of their sizes.

Regarding the former, a map should be prepared showing all watercourses, chaks and contours.[35] On this map new lines for the watercourses can be shown, the principles enunciated in Chapter II., Art. 9, being generally followed, but in such a way as to utilise existing watercourses and outlets as far as possible. The work often consists in the abolition of a certain number of watercourses, when these are too close together and run parallel to one another. There may, however, be little gain in amalgamating two such watercourses if they serve two different villages. There is nothing to prevent the people from dividing the watercourse into two as soon as it gets away from the canal, and they are likely to do this in many cases. When one branch has a flatter slope than the other it would lose command if it took off further down. The people on the steeper branch might not agree to using the flatter one because of silt trouble, or increased height of embankment. In a new project it is not difficult to get the people to do what is needed, but when once irrigation has become established it is often difficult to get suitable changes made. The advantages of amalgamating watercourses, though appreciable, have been a good deal exaggerated. The chief advantage is gained by reduction in the sizes of outlets. Then, however many branches the watercourse may have, they can only run in turns and not all together. It may happen that two watercourses, though taking off near one another, run in different directions and that the chaks are of suitable shapes and sizes. In such a case the only advantage of amalgamating is that it saves an outlet in the canal bank. No saving in the length of watercourse will be effected because there will be a bifurcation as soon as the watercourse leaves the canal boundary. If both outlets are of suitable design and proper size or require only slight alteration, both can remain but otherwise amalgamation can be effected. In some cases amalgamation might give a discharge greater than that usually allowed for an outlet but this need form no obstacle. The chief reason for limiting the discharge is the alleged inability of the farmers to manage a large channel. This matter is exaggerated as already stated (page 74). In the case under consideration it obviously makes no difference whether there are two watercourses each discharging 5 c. ft. per second, or one discharging 10 c. ft. per second, and immediately dividing into two. Very small watercourses should, when possible, be joined to others but if there is no other near enough they must generally remain, however small they may be.

[35] In small remodelling schemes the lines of existing watercourses
show how the country slopes, and a contour plan is not a necessity.

Regarding the alterations in sizes of outlets, whether or not there are alterations in their number and position, information as to the actual duties on the watercourses should be obtained. The discharge of the watercourses should be observed several times and added up and checked with the discharge of the distributary. The areas irrigated are known from the irrigation register. If the duties are abnormal the causes can be gone into, and a judgement can be formed as to how far they will remain in existence, and whether any watercourse is often kept closed. If so the outlet is too large. The duties, modified so far as may seem desirable, can be used for calculating the sizes of the remodelled outlets. But alterations of the sizes after a year or two years’ working will probably be necessary. The above procedure is also applicable to a case where the old watercourses had no masonry heads but were merely open cuts as on some inundation canals.

A common case is that in which the channel is not remodelled--or at least its water level remains very much as before--but merely the outlets are altered in number, position or size, or in any or all of these. If the land irrigated by an outlet is high, the irrigation may be far short of what was expected, and the size of the outlet may have to be increased or its site shifted, generally upstream. This is often done at the request of the people, and at their expense.[36]

[36] On some of the more modern canals the people are not allowed to
pay for outlets, so that no question of ownership can arise.

Old outlets should always be removed when superseded by others. Otherwise they are apt to be reopened or claims set up regarding them.

Near the tail of a channel the discharge of an outlet may be an appreciable fraction of that of the channel. In such a case the adjustment of the size of the outlet, and that of the channel or of any weir or fall in the channel, should be considered together, the irrigation on the outlet and that on the channel downstream of it being compared. And similarly as to the sizes of any two or more tail outlets. Such outlets are sometimes left without masonry heads on the ground that this injures no one. It may injure an outlet upstream of them by drawing down the water. Tail outlets often need constructing or reducing in size to raise the water level in the reach upstream of them.

Whenever the size of an old outlet is altered the design should be altered if unsuitable. The parapets should be brought into proper line, the roadway corrected, the floor level adjusted and any splayed wing walls abolished. If the outlet is skew it should be made square. All this should also be done to all old outlets or heads of minors even if the sizes are correct, whenever remodelling of outlets on any channel is undertaken.[37]

[37] Wherever an outlet is built or altered, a template, made to the
exact size of barrel required, should be supplied to the subordinate
in charge of the work.

It was stated in Chapter II. that the construction of masonry outlets on a distributary is not usually a final settlement of the matter. In many cases a proper proportion of water does not reach the tail. Even in such a case matters have occasionally been left alone, or the old and pernicious system of closing the upper outlets has been resorted to. In such circumstances the irrigation of a group of tail villages will be found to be less than that of a group higher up, the people to some extent acquiescing in the old idea that a tail village must be a sufferer. Government, or at least the Irrigation Department, has no particular direct interest in the matter. The total area irrigated, will probably be very much the same in any case. But an engineer who takes an interest in this part of his work will not allow matters to remain long in the state described. He will, of his own accord, adjust the outlets and equalise, as far as possible, the irrigated percentages. The people will disturb matters to some extent by enlarging watercourses, but there is a limit to this and it can be met by an occasional reduction of an outlet. A distributary, when once its outlets have been carefully adjusted, attains to something approaching perfection in its working. Any excess in the supply is taken partly by the upper outlets but part of it gets to the tail. Similarly any deficiency in the supply is distributed over the channel. The outlets which have a poor command and small head are most affected in either case. On the whole they do not lose or gain more than the others. The working of such a distributary causes great satisfaction to the engineer and not the least ingredient in this is the knowledge that he has wholly destroyed the power of his native subordinate.

In an inundation canal division in the Punjab, some dozen distributaries, varying in length from 5 to 28 miles, and with discharges ranging up to 300 c. feet per second, were dealt with as above in one season. The engineer in charge being specially desirous that sufficient water should reach the tails, reduced the sizes of some outlets too much. When an outlet of 1 or 2 sq. feet has to be reduced to a small fraction of its size it is not easy to say what the fraction shall be. Water reached the tails of all the channels in sufficient quantity, in some cases in rather more quantity than was necessary. When the irrigation register was examined, it was found that the general results were entirely satisfactory. In a small proportion of cases outlets had irrigated too little and had to be re-enlarged somewhat. After a second season hardly any changes were needed. When any silt clearance or berm-cutting seemed necessary the irrigation register again came into play. If, for instance the tail outlets, as a whole, were receiving too little water, enlargement of the upstream reaches was effected with consequent lowering of the water level there.

In the case above described the channels flowed for only five months in the year. Some of them silted a good deal but as this silting was roughly the same every year, it did not greatly affect the question of outlet sizes. On a perennial distributary of which the head reach silts during part of the year and scours during the other part, a proper distribution of supply by adjustment of outlet sizes alone may be more difficult. If the silt was frequently cleared, this would cause needless expense and interference with irrigation. In cases where the distributary is not run constantly, something can be done by attending to the regulation. When there is silt in the head reach, the discharge can be reduced and the period of flow proportionately increased. The lowered water level reduces the supplies of the upper outlets, and increases the discharges of those lower down. Moreover the periodical silting and scour are not always serious. Also it is not essential that the supply to each watercourse should be exactly the same every year. There are always good and bad seasons. It is sufficient if a watercourse is not allowed to suffer on the whole, and is never allowed to suffer much. There is no doubt that it is possible to deal satisfactorily in the above manner with very many distributaries. It is frequently reported that “difficulty is experienced in getting water to the tail.” This is owing to timidity in reducing the sizes of outlets. The suitable plan is to reduce them to such an extent as to cause a proper supply to reach the tail and then, if necessary to enlarge some. It has been already remarked that only a short length of the barrel need be altered. The cost of this is very small. The real difficulty in the case is not the impossibility of securing good results, but the impracticability, in many cases, of securing the constant attention which the procedure demands.[38]

[38] See also Chapter V. Art 3.

8. =Miscellaneous Items.= At the headworks of a canal there is a permanent staff of men who work the gates and look after the works. They assist in discharge observations and in reading the gauges, and they may have to take soundings in the river to see what changes are taking place. Some one is on watch day and night and reads the gauges at frequent intervals. The officer in charge occasionally inspects the works at night without notice. Detailed rules regarding the above matters, and any others that are necessary owing to special local conditions, are drawn up. Sometimes there is difficulty in getting the staff to attend properly to the regulation of the supply in the canal at night. Probably some “tell-tale” watches would be useful. They would at least show the times at which the men concerned went to the gauges or other points.

At the headworks, and at all important regulators, a stock of concrete blocks should be kept ready for the execution of any urgent repairs.

Regarding the ordinary maintenance work on the channels, details are given in Appendices B and C. Appendix D, reprinted from _Punjab Rivers and Works_, contains rules for watching and protecting any banks or embankments which require it.

Silt clearances and berm cutting of channels have been mentioned in Art. 1. Special attention should be given to the accurate ranging of the centre line. Otherwise the channel may become crooked. The great defect in the earthwork ordinarily met with in the banks of canals and distributaries is that the clods are not broken. In consequence of this new banks are extremely liable to breach, and much trouble and expense result. Sometimes a dam is thrown across a new distributary, and the channel upstream of it is gradually filled with water, the bank being watched and leakages made good. The dam is then shifted to a place further down. In this way the banks are consolidated.

When a distributary is closed for silt clearance or other work, if the head regulator has planks and a double set of grooves, it is possible to stop all leakage by filling in earth between the two sets of planks and ramming it, but otherwise it is necessary to construct an earthen dam just below the regulator. Upstream of the dam the water, owing to the leakage through the planks, gates or needles, rises to the same level as the water in the canal. Native subordinates have a remarkable aptitude for allowing such dams to break while the work in the distributary is in progress or before it is measured. Now and then the dam is wilfully cut. The remedy is to make the dam of proper strength--the top should be 8 feet wide and a foot above the water,--and to have it watched day and night.

At a bend in a channel there is often a silt bank next the convex bank, and a hollow near the concave bank. The average bed level is probably very much the same as in the straight reaches. Removal of the silt bank is unnecessary, and if removed it quickly forms again.

Any length of channel in which the depth of silt to be cleared is small, say ·50 foot in a large channel and ·40 foot in a small one, should not be cleared, provided its length is considerable (say 1,000 feet), and that it is not close to (say within 3,000 or 2,000 feet from) the head of the channel. Estimates should be prepared accordingly, the shallow digging being struck out. Clearing a small depth of silt merely gives contractors a chance of cheating by scraping the bed.

If the watercourses at the tail of a distributary are silted, the people should be pressed to clear them. Otherwise there will be heading up of the water of the distributary, and silt deposit may result.

When a channel is scoured, any regulator in it can be kept partly closed so as to reduce the surface slope in the reach upstream of the regulator and encourage the deposit of silt. A table should, in such cases, be drawn up giving the gauge readings to be maintained at the tail of the reach corresponding to given readings at the head.

Various methods of protecting banks are described in _River and Canal Engineering_, Chapter VI. The growing of plants on the inner slopes of channels whose sides fall in, needs special attention. Some remarks on this are given in _Punjab Rivers and Works_, Chapter II., Art. 3. A specification for bushing is given in Appendix E of this volume.

A Subdivisional Officer generally receives a steady stream of applications from members of the irrigating community regarding--among other matters--outlets or watercourses. Generally these applications are made over to the zilladar to be reported on. In a large number of cases the applicant states that the irrigation of his land or “holding” is not satisfactory, or has fallen off, and sometimes he asks that it may be transferred, wholly or in part, to another watercourse which he thinks will give a better supply. In all such cases, and in some others, the first requirement is a statement of the irrigation figures. The irrigation register gives only the total for the watercourse. A printed form should be prepared with spaces for showing the name of the distributary, villages, watercourses, holdings and applicants concerned, and the nature of the application. Below this is a form, prepared somewhat as shown below. When this form is filled in, the state of affairs can at once be seen and much trouble is saved. The zilladar obtains the figures from the old field registers. The amount of detail required as to the applicant’s lands depends on the nature of his application. If it deals with only part of his land the other parts should also be shown. He may for instance be giving a disproportionate share of water to one part. If a transfer to another watercourse is asked for, the figures for that watercourse are also required.

-----------------+----------------------------------+--------+--------
Areas in Acres. | Applicant’s Holding. |Total of|Total of
|-------+---------+---------+------| Water- |Distrib-
| | | |Total.| course.| utary.
-----------------+-------+---------+---------+------+--------+--------
Culturable | | | | | |
commanded. | | | | | |
| | | | | |
Net {19...-19...| | | | | |
irri-{19...-19...| | | | | |
gated{19...-19...| | | | | |
| | | | | |
-----------------+-------+---------+---------+------+--------+--------
| | | | | |
Total of 3 years | | | | | |
| | | | | |
-----------------+-------+---------+---------+------+--------+--------
| | | | | |
Average | | | | | |
| | | | | |
-----------------+-------+---------+---------+------+--------+--------
| | | | | |
Per cent. of | | | | | |
culturable | | | | | |
commanded | | | | | |
| | | | | |
-----------------+-------+---------+---------+------+--------+--------

If an application refers to a whole watercourse, the Subdivisional Officer can frequently, with the aid of an irrigation register and a set of chak maps, both kept up to date, dispose personally of the case. A good plan is to settle cases when on tour near the place concerned, the applicant and the zilladar being present as well as any other persons concerned. A certain number of cases have to come up again on the following tour, but all are settled in less time than is occupied if the papers go up and down between the Subdivisional Officer and the zilladar, the “file” of papers in any particular case being constantly swollen by reminders from the applicant.[39] Moreover, the applicants know that their views are known to the Subdivisional Officer. If the outlets on a channel need a general remodelling, such applications as those under consideration receive attention in connection with the scheme. Otherwise all the applications concerning one distributary can be considered together. If, however, a case is pressing, or the steps to be taken obvious, it can be settled without reference to any other case.

[39] The plan of personal settlement is distasteful not only to the
subordinates, but to the _munshi_ who has charge of the “vernacular
files.” Ordinarily he can delay a case, or manipulate it to some
extent.

The general arrangements for the “revenue” work or assessment of water rates have been stated in Art. 1. In the Punjab the remissions for failed crops are a source of trouble. In some districts the failed areas are small, and no particular trouble arises, but in other districts such areas are often very large. On perennial canals the crop inspection is done by the zilladars, on most of the inundation canals by the subordinates of the District Magistrate.[40] In both cases the amount of labour involved is enormous, and the corruption to which the system gives rise is also enormous. In the case of the inundation canals the superior staff of the District Magistrate nominally make checks, but the time at their disposal is wholly inadequate. In the case of the perennial canals the Canal Engineers are able to exercise considerable checks, but nothing like enough. In fact the state of a crop and the proportion of the charge on it which should be remitted is a difficult thing to judge, even if the subordinates were without guile. It is understood that a new and statesmanlike system is now to be introduced, the District Magistrate deciding, in consultation with the Executive Engineer, whether the season is such as to call for any general remission for each kind of crop, and, if so, to what extent. The proportion to be remitted in that crop is then to be fixed, and it is to be the same for every one.

[40] Officially called the “Collector” in some provinces, and “Deputy
Commissioner” in others.

It has been mentioned that some irrigation is effected by lift. The simplest form of lift is a horizontal pole which rests, not far from its thick end, on a support. From its thick end is suspended a bucket, and from its thin end a weight. A man lifts the thin end so that the bucket then dips into the water and is filled. Pulling down the thin end he raises the bucket and empties it. A greatly improved lifting apparatus is the Persian wheel which is vertical and has slung from it, like the buckets of a dredger but moving vertically, a number of earthen jars, which scoop up the water. As each jar passes over the top of the wheel it assumes a horizontal position, discharges its water into a shoot, and descends in an inverted position. The wheel is moved by a simple cog-wheel arrangement actuated by a bullock which is driven round and round in a circular track. The Persian wheel is used for lifts of any height. The lift from a canal watercourse is a few feet, that from a well may be 50 feet or more.

Most persons consider that a system of charging for water by volume would be a very great advance on present methods. It has been said that if the water were wasted it would be difficult for the cultivators to bring home the responsibility to any individual. This objection does not seem to have great force. Every individual would have a direct interest in economising the water, and any cultivator who was habitually careless would soon be detected by the others. In all probability the result would be a great improvement in the duty of the water. But the justice of any very rigid system of charging by volume is somewhat doubtful. The great difference in the duty of water on different watercourses has been mentioned more than once. Many of the causes of this are beyond the control of the farmers, and it would probably be necessary to charge reduced rates to some of them.