engineering works in the world. On the East Indian line, are the great
iron bridges over the Jumna at Allahabad, and those over the Tonse
and Soane, besides very heavy embankments and severe rock cuttings
in the new chord line through the Rajmehal hills. On the Lahore and
Delhi line, are the heavy embankments between the Jumna and Sutlej,
and the bridging of the Jumna, Sutlej, Beas, and Markunda rivers. The
continuation of this line towards Peshawur by the Government engineers
will involve works of great difficulty and magnitude in the rocky
country between the Jhelum and Indus, and the bridging of those two
rivers, besides the Ranee and the Chenab. The passage of the last river
alone will task the highest engineering skill, as that of the Sutlej
has already, and for the same reasons,—the exceedingly capricious
character of the stream, the sandy nature of the bed and banks, and the
enormous quantities of silt brought down by the waters.
On the Great Indian Peninsula line are works of at least equal
magnitude, though of a different kind, foremost among which stand the
great inclines of the Bhore and Thull Ghats, by which the railway
ascends the steep barrier of the Western Ghats by a series of zigzags,
inclines, curves, and tunnels, which render those works unequalled
in the world. On the Thull Ghat, for five continuous miles there is a
grade of 1 in 37, in which occur many severe curves; while the Bhore
Ghat incline is 19 miles long, and in that distance has no less than
thirty tunnels.
The Rails on all these lines are of the usual double-headed pattern,
weighing from 66 to 90 lbs. per lineal yard, and laid generally in
chairs on transverse wooden sleepers. These sleepers are either of one
or other of the woods that I have already described, sometimes kyanized
or burnettized; but large numbers of creosoted fir sleepers have also
been imported from Europe, and a certain number from Australia. The
Punjab line is almost entirely laid on Greaves’s patent Pot sleepers,
with which doubtless you are acquainted. The advantage of such a
roadway is of course the indestructibility of its material (iron); its
disadvantage, that the cast-iron sleepers are apt to get broken, and
that the rigidity of the roadway is bad for the rolling-stock at high
speeds. But there is no doubt that the life of a timber sleeper in
India is very short, and that it is very expensive to renew them; and a
good wrought-iron permanent way, that shall not be absolutely ruinous
in first cost, is still a desideratum.
The Locomotives employed on the Northern lines more nearly resemble
those in America than in England, as they have to burn wood instead
of coal. A huge spark-catcher is hoisted over the chimney, as serious
accidents at one time were common from the blazing sparks of wood out
of the uncovered funnel; and a cow-catcher is placed just in front of
the smoke-box, to take up stray cows or buffaloes, who _will_ get on to
the line in spite of the fencing. The engine-drivers are all Europeans,
I think, at present.
Fences are made of cactus or other hedges, or of the usual wire line,
or often simply of a mud wall and ditch.
There is nothing particular to say about the Stations, which are
similar to those in England, with some adaptation to the requirements
of the climate.
The Passenger Carriages are a great deal too much like those in
England, and are generally very hot and uncomfortable. The best have
double roofs, with cane backs and seats; but none have punkahs or
tatties; and it is only lately, and at the instance of a very stern
reminder from Government, that any serious attempt has been made to
render passenger carriages for European travellers more comfortable in
the hot weather. On the Great Indian Peninsula line, however, there are
very comfortable saloon carriages, with movable berths, and bath-room
and W.C. attached. Considering that from Bombay to Calcutta or Lahore
is a journey of some seventy-five hours, it is evident that these
things are serious matters in India.
That the results of these railways have been of the greatest benefit to
India in both a political and military sense, it would be impossible
to deny. Their educational and social value, too, to the people at
large have been great, and indirectly they have doubtless added much
to the wealth of the country. But only one line, I think, pays more
than the guaranteed 5 per cent., so that for all the others, the
Government pays a heavy charge annually for the advantages offered by
the railways, and this charge has of course to be met by taxation. The
traffic, too, is increasing very slowly, and it seems that much is
still wanting to assist its development to a much larger extent than
heretofore. One reason for this is, doubtless, that a great portion of
the goods traffic consists of articles, such as grain, of large bulk
and small intrinsic value, which will not bear high transit charges.
Another cause is that the natives, though travelling far more than
was anticipated, have not yet learned to travel to the same extent as
Europeans.
One mode of increasing the inducement would, I suggest, be to make the
railway fares more uniform, and the tickets more easily procurable than
at present; and this mode, indeed, would apply to English, as well as
to Indian, lines. There seems no more reason that you should have to
buy your ticket for a railway journey five minutes before starting,
and all in a scramble in front of a little pigeon-hole, than that
you should be forced to purchase your postage-stamps at the General
Post-office only, and just five minutes before the post goes out. I
don’t see why all journeys, up to a certain number of miles, should not
be performed at one uniform rate of charge, and by tickets procurable
at the nearest stationer’s, and available for any line in the kingdom.
Such a measure would be a great convenience to the traveller, would
prevent him in India from being cheated, as he often is, by the native
railway clerks, would effect a considerable economy in the railway
office establishment, and, where the lines are all under Government
control, ought to be carried out with very little trouble.
* * * * *
But we must go on to the leading speciality of all Indian engineering,
I mean, the subject of _Irrigation Works_. Of course there are other
countries in which artificial irrigation is extensively developed,—more
indeed than in India,—notably, for instance, in the provinces of
Piedmont and Lombardy, in the kingdom of Italy, where they are in
advance of us both in the economical distribution of water, and in all
legislative questions affecting the administration and rights of, and
property in water. But in no other country but India have works been
undertaken on so gigantic a scale; and it is in the dealing with such
vast bodies of water, and their carriage over such great distances and
in the face of so many impediments, that the specialities of Indian
irrigation works really consist.
Now, in order to give you a clear idea of the subject, I must begin by
premising a few remarks of an agricultural and financial character.
India is almost entirely an agricultural country. It is true she has
great mineral resources, but these are as yet undeveloped. She has had
valuable manufactures, and there is no reason she should not have them
again; but for many ages past and for as many to come, she has been and
will be almost entirely agricultural.
Again, half of the whole Government revenue is derived from the land.
It is called a land _tax_, but is really a land _rent_; that is, rent
paid by the occupier or cultivator, as the case may be, to the State as
the great landlord. This has been the case all over the East from time
immemorial; the only ownership in the land belongs to the Government,
although the occupier or cultivator often has rights of occupancy which
are almost as inalienable as the right of the State.
This being the case, it is evident that the Government is as much
interested as the people in the productiveness of the harvest; for
if the harvests fail, the people not only starve, but cannot pay the
land rent, and the Government has to feed thousands of hungry people
with an empty exchequer. Owing to the absence of roads and railways in
years gone by, any failure of the rains in a province produced the most
appalling distress, and the people died by hundreds and thousands.
Hence, so long back as 300 years ago, the Mahomedan emperors,
commonly called the Great Moguls, took a great interest in artificial
irrigation, and under the direction of a Mahomedan “Royal Engineer,”
one Aliverdi Khan, several canals were opened out. Some of these,
after falling into disuse from various causes, have been re-opened and
improved under the British Government, and are now known as the East
and West Jumna Canals, the one being 110, the other 500 miles, long.
Then the Government commenced a great work of its own, the Ganges
Canal, of which the main channels alone are 700 miles long, and the
first-class distributaries 3000 miles more. Since then, the Bari Doab
Canal has been completed; the Sirhind, Soane, and Sardah canals are in
progress, and others are projected.
It will perhaps give you a better idea of this kind of works, which are
all similar in character, if I briefly describe the largest of all, and
the one with which I am best acquainted,—the Ganges Canal. This canal
takes out of the River Ganges at Hurdwar, where the river leaves the
hills and enters the plains, by an artificial channel 200 feet wide and
20 feet in depth, the water having a depth of 10 feet, and the fall of
the bed being 2 feet per mile. This gives a volume of water of nearly
7000 cubic feet per second,—rather more than the Thames at Richmond, I
think. The canal, flowing onwards, crosses three great hill torrents,
two at a lower level, and one by a level crossing, and finally reaches
the valley of the Solani, which it passes by an aqueduct three miles
long, revetted with masonry throughout, the Solani river itself being
passed by a bridge, which gives it 750 feet of waterway. After crossing
this valley, 20 miles from its head, the canal arrives on level and
comparatively easy ground, and pursues its way along the watershed of
the country between the Ganges and Jumna rivers for another 30 miles,
broken only by sundry falls and locks, and spanned by several bridges.
At 50 miles from its head, it divides into two branches, of which one
runs down to Futtehgurh, the main line continuing to Cawnpore, and
throwing off other branches to Bolundshuhr and Etawah. From these main
lines, the principal distributaries run on both sides, nearly parallel
to the channel, and throwing off in their turn other minor lines,—until
the whole country is covered with a network of irrigating channels,
conveying the water to every field.
Thus you will see that this and other irrigating canals differ from an
ordinary navigation canal, such as you have in England, in two very
important particulars. First, the irrigating canal has a running stream
of water which is gradually expended as we follow its course, and so
its channel diminishes in size; secondly, it is dug on the highest line
or watershed of the country, so as to secure a command of level for
irrigating the whole area.
Now, as to the use to which this water is applied; you will understand
that there are two harvests in Upper India: the _rubbee_, or spring
harvest, which is reaped in March or April, and consists mainly of
wheat; and the _khurreef_, or autumn harvest, which is gathered in
September, October, or November, and consists of rice, sugar, Indian
corn, and various tropical products. All these require steady and
constant irrigation, and they get it from the spring and autumnal
rains, or from wells, during the average normal seasons; but if the
rains fail and the wells run dry, they are dependent on the canals, and
even when the season is regular, the supplementary irrigation from the
canal greatly increases the yield of the crop.
The Soil of Upper India is generally a light friable clay, excellent
for wheat, but absorbing a great deal of water. In Bengal, they have
a rich mud extending to a great depth, and of such fertility that
three crops are often grown on it in a year. In the Central Provinces,
there is the black cotton soil, which is, I believe, disintegrated
trap or granite. Across the Indus, again, we have a hard stiff clay,
which, though not good for wheat, is valuable for many crops when well
watered. I notice this question of the soils here, because it is an
important point for the engineer when projecting a new canal, for all
these soils require different quantities of water.
In designing a canal such as has been described, we must fix the head
at a point high up on the course of the parent river, first to get a
command of level, so that our canal may run on high ground; and next
because, in the higher portion of its course, the river water is free
from silt, and the river bed is more stable and less liable to the
caprice of the stream, which, lower down, might abandon our canal mouth.
Having fixed on the point of departure, then comes the question, how
large is our channel to be? That depends, first, on the quantity of
water we can get out of the river when at its lowest; secondly, on the
slope or fall we give to the bed of the canal. The minimum quantity of
water is, of course, determined by observation, and this has hitherto
practically fixed the capacity of canals in Northern India, because the
spring crop grown in the dry season is so much the more valuable of
the two; but in later projects, an additional capacity of channel has
been allowed, so that an extra supply of water may be admitted in the
autumn, when the river has plenty to spare.
As to the fall of the bed, or the Velocity to be allowed to the
artificial waterway, that is a question depending chiefly on the nature
of the soil. Several of the Indian Canals have been designed with too
high velocities, and the consequence has been a cutting and scouring of
the banks and beds, which have seriously endangered the various masonry
works in their course. On the other hand, if you give too little
velocity, of course you have to go to a greater expense by making a
larger channel to carry the same quantity of water, and you won’t
have velocity enough to carry forward the silt held in suspension,
or to prevent the growth of weeds, a serious evil in the tropics. On
the whole, it seems now generally admitted that a velocity of 2½ feet
per second is about what should be aimed at, though a compromise of
conflicting interests, in this as in other cases, has often to be made.
When, owing to the slope of the bed being less than that of the
country, the slope, if continued, would bring the canal bed too high,
and embankments would have to be made, it is evident that the bed must
be lowered by an artificial Fall or Rapid, made of such material and
shape that the mass of water may flow over it without injury, and take
up a new level below. The best forms of falls and rapids have been
the subject of great discussion amongst Indian canal engineers. The
Ogee fall in use on the Ganges Canal is now superseded by the Vertical
fall of Colonel Dyas,—the principle of which is that the shock of the
falling water is received into a cistern sunk below the bed, so as
to act as an elastic cushion. A grating of wooden bars, inclined at
an angle, and fixed along the crest, is also generally added. These
bars act like the teeth of a comb, and, by dividing the water into
filaments, greatly reduce its force.
If you want to navigate your canal, Locks must be provided as well as
falls; but the difficulties of navigation up stream are very great, and
the traffic on all these canals, with a current of some three miles
an hour, is in a very undeveloped state. It is doubtful whether it
is not impossible to combine satisfactorily the requirements of both
irrigation and navigation in the same channel.
At the heads of your branches or main distributaries, Regulating gates
will be required with sluices, by which the supply of water may be
divided, increased, or diminished, as the case may be. A similar work
will be required at the head of the canal where it leaves the river.
The tail generally ends in a fall or rapid, by which the water is
discharged into a river or nullah with a scour to clear away the silt.
You will find details of all these works in the Roorkee C. E.
‘Treatise.’ Besides these, Bridges of communication will be wanted for
the roads crossing the canal; Rest-houses (_chokees_) for the use of
the establishment; Escape heads for discharging surplus water; Inlets
for the reception of cross-drainage; and other works.
One chief object of carrying the canal at a high level is that it
should interfere as little as possible with the natural Drainage lines
of the country; but it is occasionally indispensable that it should
cross some of them, and it may cross them under three cases:—1. When
the bed of the canal is higher than the bed of the drainage line. 2.
When it is lower. 3. When the two beds are on the same level.
In the first case, the canal is carried over by an Aqueduct, which
may be of masonry or iron, according to the size of the canal, and
which must allow sufficient waterway underneath for the passage of the
drainage line when in flood.
In the second case, the drainage line is carried over the canal by a
Super-passage, which is in effect an aqueduct, only that here you have
to provide waterway above the canal for the river in flood. The canal,
if necessary, may be carried below it by an artificial fall of the
usual construction.
The third case rarely occurs in practice, and never when it can
possibly be avoided—there are the same objections to it as in the
case of a Level crossing on a railway. When it _has_ to be done, the
method of doing it may be understood by an explanation of the Rutmoo
level-crossing on the Ganges Canal at Dhunowrie, six miles above
Roorkee. A regulating bridge, with sluices, is fixed across the Canal,
just below the junction. A series of flood-gates hung between piers is
fixed across the Rutmoo, on the down-stream side of the canal; these
gates fall outwards by a hinge at the bottom, and are held upright by
a catch, which can be easily knocked out, and when thus held up, they
retain the canal at its normal level. When the Rutmoo is in flood,
the Canal sluice-gates are lowered to prevent the flood water rushing
down the canal, and choking it with silt or débris. At the same time,
the Rutmoo flood-gates are lowered by knocking out the catches, and
the whole flood water pours across the canal, and flows down its own
channel. When the flood is over, the sluices are raised, and the
flood-gates also one by one, the pressure of the water being taken off
by dropping planks down grooves in front, provided for that purpose.
Such a work of course requires the presence of an establishment to
manage it, and is very liable to be damaged by carelessness on the
sudden occurrence of a flood.
Well—the canal having been made and filled with water, how are we
to get the water into the fields? First, it flows down the main
distributaries, and then into secondary channels, which are laid out
at proper slopes, and of a size varying according to the amount of
water and the area to be watered. From these it is passed by pipes of
wood, iron, or earthenware, under the banks on to the fields, which
are divided into squares (_kyarees_), into which the water is passed
_seriatim_.
As there is generally less water than is required, village watercourses
are all filled in their turns; thus one set will be filled on three
days of the week, and another set on three other days, and so on.
The water rate is levied by the canal officer according to the area
irrigated, and the kind of crop taking it, as some crops want more
water than others, and are also better able to pay for it. Such a
system is obviously open to many objections, for it entails endless
labour in measurement, perpetual watchfulness, and much dispute and
interference, besides great waste. Some system has therefore long
been sought by which the water should be measured out at the head of
the distributary channel or village watercourse, and charged off like
beer or wine. Hitherto, however, all attempts to do this in India have
failed; chiefly, because we cannot find any practical machine that will
not get out of order and cannot be tampered with, by which a uniform
discharge may be secured in a given time under a varying head of
pressure. Could this be done, it is obvious that if a head or opening
of a given capacity were left open for a certain time, we should know
exactly how many cubic feet of water had been sent to a particular
village. Lieut. Carroll, Royal Engineers, a very clever and promising
officer, invented a module (as it is called), which you will find
described in the ‘Treatise,’ and which has been the nearest approach to
a machine of the above kind.
By comparison of the discharge of his canal at different points and
measurement of his irrigated areas, it is obvious that the canal
officer can collect data for determining what is styled “the irrigating
duty per cubic foot.” This varies much with the soil, the rate of
evaporation and other data, but on the best-managed canals, will
amount to the irrigation of 300 acres for each cubic foot per second
of water discharged at the main head. This is the rate on the Eastern
Jumna Canals; on others it is not nearly so high, and in new projects
about 200 are usually assumed. There are various other statistical
data for canals of great value, which you will find treated of in the
‘Professional Papers’ and the Roorkee ‘Treatise.’
In Southern India, the canals are of less elaborate construction,
owing to the more permanent character of the rivers in the lower
portions of their course, and to the abundance of excellent stone found
there, while in Northern India we have to be content with brick. The
chief object of engineering skill in a Madras system of canals is the
_Anicut_ or Weir thrown across the river at the point of departure, by
which a head of water is secured for the supply of the canals. Many of
these weirs are elaborate and costly affairs—that over the Godavery
is a mile and a half long, and the weir over the Soane, now under
construction, is little less. I show you on the plan the one over the
Kistna, which is a good example of its kind. You will see that the body
is composed of rubble stone, defended by ashlar from the action of the
water, and resting partly on shallow wells, and partly on the bed of
the river itself. This shallow character of foundations on sandy beds,
to which I have already alluded in a former lecture, is certainly a
peculiarity of Southern Indian engineering; but you will see the long
slope or apron of stone in rear of the weir, where the action of the
water is most severely felt after being checked in its onward flow,
and caused to whirl and scour. Very severe action takes place here for
some time after the weir is built, and large quantities of loose rough
stone are thrown in from time to time to fill up all gaps in the slope,
until the whole work has become firm. Moreover, the sand in these
rivers is of a coarser texture than that in Upper India, which, when
saturated with water, becomes a mere quicksand, which would swallow up
a much greater quantity of stone than the other. The weir, you will
observe, is provided with sluices, by which the accumulated silt in
front of the heads of the canals may be scoured through the body of the
work, these sluice-heads for the supply of the canals on both banks
of the river being built at the two ends of the weir. This system has
generally been applied to the deltas of the Madras rivers, and the more
gentle slope of the country has enabled these canals to be largely used
for navigation as well, to the great advantage of the traffic; the fall
of the bed is often only six inches per mile, or even less.