SCHEMES FOR THE FUTURE
The completion of one programme by the construction of the Reservoir
and the works dependent upon it does not mean stagnation. Irrigation
is an ever-growing and ever-living science. There can be no standing
still. Even in the ordinary routine there are thousands of details
always pressing forward for fresh consideration. It takes but a few
years for a daring innovation to become old-fashioned. The system of
perennial irrigation in Egypt is so young that there is still much
to be learnt. It means a totally new style of agriculture. Nothing
but constant experiment and constant watchfulness will enable the
engineers to distribute the water to the best advantage. The best
methods of reclaiming new land, and of preventing the deterioration
of the old, the maintenance and improvement of existing locks,
weirs, regulators, barrages, and other masonry, the care of canals
and drains—these and an infinity of other matters fill the life of
the irrigation engineer, so that, always interesting, it is also at
times even exciting. Decisions of great and immediate importance have
to be constantly and promptly taken. Their duty touches very nearly
the lives of all who dwell and labour within their districts. There
can be no question of any folding of the hands to slumber. But beyond
all this, it is the peculiar good fortune of those whose care is the
water-supply of Egypt that they have to travel in thought or in fact
over half a great continent, and discuss schemes of a magnitude and
extent enough to stagger the imagination of the boldest dreamer. The
Anglo-Egyptian army at Omdurman opened an entirely new chapter in
the history of the control of the Nile.
No one can hold Egypt securely unless he holds also the whole
valley of the Nile. The sources of the river in hostile, or even
in indifferent, lands must always be a grave cause of danger, or,
at the best, anxiety. If tradition be correct, the Abyssinians on
more than one occasion made use of their position on the Nile as
a powerful lever in negotiations with Egypt. Vansleb, the Dutch
seventeenth-century traveller already quoted,[6] is not perhaps
perfectly trustworthy as to his facts, but at least he is evidence as
to the tradition. He had in his possession, he says, a copy in Arabic
of a letter written by David, King of Ethiopia (_i.e._, Abyssinia),
surnamed Constantine, to ‘Abu Seid Barcuk, King of Egypt, in the
year of martyrs 1193, in which he threatens in two distinct places
to turn aside the river Nilus and hinder it from entering into
Egypt,’ so as to cause all the inhabitants to perish with hunger,
if he ‘continues to vex the Copties.’ Vansleb also says that
‘the King of Ethiopia hindered the current of Nilus and turned
it out of Egypt in the days of Mostanser, one of the califfes of
Egypt, which obliged him to send the Patriarch of the Copties with
rich presents to the King of Ethiopia, to entreat him to take away
the bank, which he had raised to turn aside the river. The King of
Ethiopia having granted this request for the sake of the Patriarch,
the river increased in one night 3 cubits, which was sufficient to
water the fields.’ Doubtless the tradition is founded on fact;
if the country in question had been occupied by a Power with any
engineering skill, there is little doubt that this method of pressure
would have been oftener adopted.
The danger is by no means an imaginary one, and this is recognised in
the latest treaty between the Government of the Soudan and Abyssinia,
concluded May 15, 1902, in which it is laid down that no work shall
be constructed across the Blue Nile, Lake Tsana, or the river Sobat,
which shall arrest the flow of their waters into the Nile, except
by mutual agreement.
If even now it is thought necessary to make formal treaty
arrangements on the subject with Abyssinia, much more real would be
the apprehension if the Soudan Government were hostile to Egypt. But
quite apart from any hostility, an important question might arise. We
have seen what great efforts have been made in Egypt under the system
of perennial irrigation to secure a good supply of water in the
summer months; it is then that the river is at its lowest; the best
of reservoirs can only supplement the natural flow of the river. At
the very time that it would be easiest to do it, an interference with
that natural flow would be most disastrous. The mere employment of
a considerable amount of water on irrigation in the Soudan during
the summer months might have a very serious effect. The possession
of the Soudan practically guarantees to Egypt the safety of her
water-supply. The fact that the sources of the White Nile are in
purely British territory, and that in the Soudan itself the British
flag flies side by side with the Egyptian, gives thus a more and
more permanent aspect to the British position in Egypt.
It is calculated that at the present moment another 3,500,000,000
cubic metres of water over and above the present summer supply,
including the Assouan Reservoir, would amply suffice for all possible
requirements in Egypt. When the Dam is raised to its full height,
about 1,000,000,000 cubic metres more will be provided. If only
Egypt were to be considered, the remainder of the water required
could be stored in a similar reservoir built somewhere above Wadi
Halfa. Egypt could then be developed to its very fullest extent,
but ‘such a work,’ as Sir W. Garstin remarks, ‘would leave
untouched the countries bordering the river to the south. Their
interests must be safeguarded by such a scheme as will insure them
a proportional share in the prospective benefits.’
From every point of view the interests of the Soudan are vital
to Egypt. Bitterly has she suffered from the neglect of those
interests in the past. Misrule and oppression caused the Mahdi’s
rebellion, with all its burden of shame and suffering. With a more
intelligent enemy the loss of the control of the Nile might have meant
irretrievable disaster. She knows now that a prosperous and contented
Soudan is the best safeguard against rebellion. Upon England, too,
rests the responsibility for the welfare of those vast provinces,
once so shamefully abandoned to barbarism and ruin. English arms
have retrieved that disgrace. It would be impossible to allow the
Soudan to get nothing and Egypt everything, even if such a course
were not certain to be fatal to both.
At present far-reaching schemes are being carefully inquired into,
under the guidance of Sir W. Garstin. Fortunately for Egypt, she
possesses in him an adviser of unsurpassed experience, cool, careful,
and level-headed, upon whose final judgment she may confidently
rely. He has already made a report, after personal observation, upon
the White Nile and its main affluents, and he has recently returned
from a journey to Lake Victoria Nyanza and Lakes Albert and Albert
Edward, the results of which have not yet been published. Another
expedition was also sent in 1902-1903 to explore Lake Tsana and
the upper course of the Blue Nile. A mass of information is being
collected and quietly digested, and in due time the policy to be
pursued will be settled on. For the moment there is no occasion
for hurrying. It will take time for Egypt to make full use of the
advantages of the Assouan Reservoir. The Soudan, though rapidly
progressing, is hardly yet in a position to reap the advantage of
such changes on a great scale. When the engineers have completed
their observations, there will still be the financial aspect of
the question to take in hand. Schemes involving the regulation of
2,000 miles of river cannot be subjected to too great scrutiny before
arriving at a decision. It would be rash to speculate on what course
will be finally adopted, before all the data are known, but it will
not be out of place to give some indication of the rival projects
in view, and to glance at some of the arguments for and against.
All the schemes aim at establishing a control over the head-waters of
the Blue or the White Nile, and so increasing the supply in the river
when it is most scanty. Anyone can see that the Blue Nile depends
upon Lake Tsana, which is across the Abyssinian frontier, and the
White Nile upon the Lakes Victoria and Albert Nyanza. Proposals
have been made for regulating the outflow from each of these lakes,
or from them all, and also for preventing the waste of water which
now takes place in the swamp country south of Fashoda. Up till now
the plan of building a dam at the point where the Blue Nile emerges
from Lake Tsana has been most in favour.
It has several great advantages. This lonely lake is situated
some 6,000 feet above sea-level, in a wild and desolate country in
Northern Abyssinia. It is 3,300 square kilometers in extent, and very
deep. During six months in the year there are very heavy rains in the
area which drains into the lake. Between Lake Tsana and Khartoum, a
distance of 1,350 kilometres, the Blue Nile falls over 1,000 metres,
and its rocky bed makes it very suitable as a channel for carrying
the water. It is deep and narrow, with high, steep banks, and so the
less liable to evaporation. For every metre by which the level of
the lake was raised, 3,300,000,000 cubic metres would be stored,
and it is obvious that, if the level were raised 4 or 5 metres,
there would, after making a proper deduction for evaporation, be
ample water to supply the greatest demand in Egypt, and also plenty
besides available in the Soudan. There are also strong arguments for
irrigation works on the Blue Nile. After the Cataracts of Rosaires,
which are roughly speaking about halfway between Khartoum and Lake
Tsana, the river passes through fertile plains consisting of rich
alluvial soil, extending to a great distance on both sides. At
present these lands yield only small returns, dependent as they are
upon a somewhat capricious rainfall. With proper irrigation they
would be most productive, and the water coming down from Tsana might
be utilized, without any great difficulties, by a system of canals
starting from this point, assisted by barrages and weirs. Further,
the river would thus be rendered navigable at all seasons of the year,
and would thus become an effective trade route in the most promising
part of the Soudan. The great objection is that Lake Tsana lies wholly
within Abyssinian territory. Nothing could be done without some very
definite arrangement with the Emperor Menelik, and one that would
be irrevocable by any successor of his who might be less friendlily
disposed. Nothing, in fact, would be absolutely satisfactory unless
complete sovereignty over the Reservoir district were assured
to the Soudan Government. In view of the fact that the whole of
this region is perfectly valueless to Abyssinia, or, indeed, to
anybody else, except for purposes of water-storage, it does not seem
impossible that by some cession of territory, or other compensation
elsewhere, a satisfactory arrangement may be come to. But even so,
the remoteness of the lake and the difficulties of transport would
prevent the immediate realization of the scheme. Without a railway
from some point in the Nile Valley it would be practicably impossible
to collect the necessary materials and supplies, and such a railway
will not be an affair of this year or next.
Precisely on the points where the Lake Tsana scheme is weakest the
schemes for utilizing one or both of the great lakes of Uganda are
strongest. Precisely where it is strong they are weakest. Any works
damming the exits of Lake Victoria Nyanza or Lake Albert would be
wholly within British territory. They would also be in a region much
more easily accessible from the sea. Lake Victoria has already railway
communication with Mombasa, and the transport of material, and also
of coolie labour from India would be comparatively easy. In the case
of Lake Albert, a railway would have to be built from Lake Victoria;
but this would be of service to the country apart from any irrigation
works, and would, indeed, practically establish through communication
by boat and railway between Mombasa and Alexandria. But here their
advantages over Lake Tsana end. The whole region is very much subject
to earthquakes. The strain to which great masonry works would be
subjected might be very severe. The country through which the White
Nile passes is very unsuited to large irrigation works. Much of it is
swamp, and the low slope of the land is ill-adapted for canals. The
soil, too, is poor and light compared with the rich alluvial tracts on
the Blue Nile, which would of course receive no benefit. Practically
only the provinces north of Khartoum would receive any benefit from
the increased supply, and in them the cultivable land can never be
more than a mere strip along the river, so circumscribed are they
by the desert ridges. In any case they would be equally benefited by
water coming from the Blue Nile. Besides this, the negro population
living on the White Nile is very much less advanced, and less likely
to form an industrious agricultural population than the inhabitants
of the Eastern Soudan.
Nor is the bed of the White Nile well adapted for carrying the
water. From Lake Albert to Khartoum the distance is 2,100 kilometres,
and the total drop is only 300 metres. It flows slower through a
hotter country. Except between Duffile and Rejaf it is very wide
and shallow, without any banks to speak of, and with a sandy or
muddy bottom. For at least half its course it runs through swamps,
and between Bor and Lake No alone it is calculated to lose half its
volume by dissipation and evaporation in the marshes. But for the
important contribution made by the Sobat, the volume reaching Khartoum
would be very much smaller than it is. If, then, a considerable extra
supply of water is to be brought down from the equatorial lakes,
the scheme must involve a permanent improvement in the channel of
the Bahr el Gebel, as the upper portion of the White Nile is called.
This, according to Sir W. Garstin, can only be effected in one way,
by embanking the river for its whole length between Bor and Lake No,
a distance of 624 kilometres. When it is considered that all supplies
would have to be brought from Khartoum, 1,000 kilometres distant;
that during four months of the year work is impossible, owing to
the incessant rains; that the local tribes can never be relied upon
for labour; that the climate is exceedingly bad and unhealthy at all
seasons; and that the actual engineering difficulties in making the
banks would be by no means small, some idea may be formed of the cost
of such an undertaking. It is estimated that to complete it in five
years’ time would involve an expenditure of £3,700,000. Another
proposal, which is really independent of the Reservoir question, is
to use the Bahr el Zeraf to carry the extra summer supply at present
wasted in the marshes. The Bahr el Zeraf is a branch of the Nile,
taking off near Shambe, and entering the river again below Lake No
before the junction of the Sobat. The cost of preparing the Bahr
el Zeraf channel by means of dredging and embanking is estimated
at £1,250,000, and in addition certain supplementary works would
be required.
Until the result of Sir W. Garstin’s observations on the Albert Lake
are known, it will be impossible to make any accurate comparison of
the qualifications of the two lakes Victoria and Albert for being
utilized as reservoirs. Lake Victoria, which lies between the two
‘Rift Valleys,’ is encircled by a low and shelving shore. It
covers approximately about 70,000 square kilometres. The Somerset Nile
flows out of it, and finds its way into Lake Albert. Lake Albert is
the northernmost of the chain of lakes in the western Rift Valley, and
into it drains the Albert Edward Lake by means of the Semliki River,
partly fed by the glaciers of Mount Ruwenzori. The Nile issues from
it at the northern end, not so very far from where the Somerset Nile
enters. Lake Albert is surrounded by mountains and cliffs. There is
comparatively little flat shore round it. Its area is roughly about
5,000 square kilometres. For every metre that the surface of each lake
was raised, Lake Victoria would store 70,000,000,000 cubic metres,
and Lake Albert 5,000,000,000. These enormous figures are enough to
show that, even when the largest allowance has been made for loss by
evaporation, dams of no great height on either lake would suffice
to store quite sufficient water for all possible needs in Egypt,
and all of the Soudan that could be touched by water coming down
the White Nile.
A very small rise in the level of Lake Victoria would give a very
large reserve of water, and therefore the works regulating its outflow
would be of less dimensions, and so, presumably, less subject to
damage by earthquakes. Being nearer the sea, they would, moreover,
be easier of construction. But Sir W. Garstin so far totally rejects
the idea of Lake Victoria. He says:
‘The amount of water which could be stored even by a very small rise
in the levels would be far beyond any possible requirements. This
lake may consequently be omitted altogether from any projects for
water-storage. Much of the country adjoining Lake Victoria Nyanza
is densely populated, and the villages are situated close to the
shores. Any considerable rise in the water-levels would flood a large
and populous area of country. It must not, moreover, be forgotten
that about half the area covered by this lake falls within German
territory. As the inhabitants of the southern half of this lake would
derive no benefit from such a reservoir, it is quite conceivable
that they might view any such proposal with disfavour.’
He proceeds to argue that Lake Albert, on the other hand, is specially
adapted by its conformation for the purpose.
‘With a regulating dam at a point on the river below its exit,
the Albert Lake could well be used to store up water during the
rainy season, which would be discharged into the river during the
months of low supply. In this way a double purpose would be served:
the volume of the river in flood would be diminished, and in summer
would be largely increased. The lake has an enormous catchment area,
and it seems probable that its levels could be, without serious
difficulty, raised to the required height.’
In all probability the arguments will be found to be conclusive in
favour of a dam at the exit to Lake Albert, but the reasoning against
a regulator for Lake Victoria does not appear at first sight very
cogent. Sir W. Garstin tells us that three years ago the mean water
level of the lake averaged some 8 feet lower than it did twenty years
earlier. But between January 1 and June 1, 1901, the level rose 3
feet 3 inches. When such fluctuations already occur in the ordinary
course of Nature, it would seem that some very useful regulation
might be carried out without causing the least inconvenience to
any dwellers on the shore, German or otherwise. All these remarks,
however, were written quite tentatively by Sir W. Garstin before
he had personally examined these regions, and his next report will
be certain to give fuller information on the matter. Perhaps in the
end both lakes will be subjected to the yoke of the engineers.
Such in brief outline are the gigantic schemes which are now engaging
the attention of the irrigation authorities of Egypt. Great as are
the achievements of the past, they look almost petty before these
visions of the future.