'Report on the Development of Mesopotamia with Special Reference to the Regeneration of the River Systems' [‎15] (21/50)

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Sir William V\ illcocks, in liis report, suggested that for provision against heavy-
floods the natural way was to follow the practice of ancient Egyptian and Babylo
nian engineers, and to confine attention to one bank of each river and ensure that
bank against inundation, the floods being allowed to waste their energies on the
other bank. With that object the left bank of his right Tigris canal (the water
for which was to be supplied from the Euphrates) was to act as a bund up to
Kut-el-Amara where it joined the proposed bank down the Hai.
I agree with Sir W illiam Willcocks's proposal so far as it goes, but I would
continue the process from Kut-el-Amara downward, and I assume that the Kut
barrage and Hai embankment are not works which will be carried out in the near
future.
(32) I am intimately acquainted with the country between Kut and Basra,
but have only travelled twice between Kut and Baghdad and am unable to ex
press any definite opinion as to the best method of flood control between those
points.
Between Kut and Amara, I am of the opinion that the following works should
be carried out:—
(i) General maintenance and improvement of existing bunds, and cons
truction of new bunds—especially on the right bank of the Fadiyah
reach, and the left bank of the Subadiah reach.
(ii) Eestriction of carrying capacity of all irrigation canals in accordance
with the requirements of agriculture.
{Hi) The closure of unimportant and useless channels.
Between Amara and Kurnah, the real work of regeneration will take place, as
it is from Amara downwards that the various branches take off to such an extent
as to threaten the existence of the river.
(33) Sir William Willcocks proposed to build regulating heads or weirs across
the Chahala, Majar Kabir and Michiriyah canals, which would allow that portion of
the high flood to escape which the river itself could in no wise carry, but would
pravent the escape of a large volume of water at low supply. I examined this project
with a view to the provision of temporary weir sin order to improve navigation for
military purposes, but decided against its expediency because the cutting off of the
low-water supply would throw large tracts of land out of cultivation and stop all
navigation on the canals, without any sufficient benefit to navigation on the main
river. I did, however, construct a weir across the Michiriyah canal putting in
bye-passes to provide sufficient water for irrigation, and the results were highly
satisfactory.
The Michiriyah carried oS about 40 per cent of the volume of the water of the
Tigris at that point, and a section taken after the closing of the canal shewed a
wonderful capacity on the part of the river for accommodating itself to increased
discharge, as, for some distance below where the Michiriyah canal takes off, the cross-
sectional area of the Tigris had increased by something like 25 per cent., and the
discharging capacity of the river in about the same proportion ; moreover, the
improvement was not merely local, but evidences were traceable for some thirty
or forty miles.
The experiment shews that the river, if encouraged to do so, will sink its bed,
lower its surface level, establish a better shaped channel, and maintain these general
improvements, which so far as can be seen are of a permanent character.