'Handbook of Mesopotamia. Vol. I. 1918' [‎164] (173/568)

164
IKEIGATION OF IRAK
west of the Tigris there is a trough which starts from the
neighbourhood of the river near Istablat, ahout 6 miles below
Samarra, and runs SW. to the large depression into which the
" Wadi A seasonal or intermittent watercourse, or the valley in which it flows. Tartar drains; and along this trough an escape-canal might
be carried, though at a considerable cost If the Tartar depression,
which has not yet been surveyed, should prove sufficiently large,
a reservoir might be established here, which could support the
irrigation of the country between the rivers from Baghdad to JBabylon.
If the depression is not large enough to store all the excess flood-
water of the Tigris, the escape could be carried on to the Euphrates
reservoir in the Habbaniyeh basin, with which would then be con
nected, for the purpose of storing the additional water fiom the
Tigris, the neighbouring depression of Abu Dibis.
Sir William Willcocks calculates the cost of a Tigris escape to
Habbaniyeh and of the reservoirs in connexion with it at £22,000,000.
If the Tartar depression should prove large enough to take the
whole of the water from the Tigris, the cost would fall, he considers,
to £12,000,000. But it would seem difficult to calculate what would
be the cost of such works in the new conditions which will have
been created by the war.
Other Proposals for Dealing with Tigr —In 1911 Sir William
Willcocks proposed that until an escape for the excess waters of the
Tigris could be constructed at the head of the delta, the following
measures should be adopted : that the inundations from the Tigris
at Baghdad should be reduced by an escape at Mo'adhdham, which
would allow the flood-waters to spill into the depression east of
Baghdad, whence they would return to the river by an outlet below
the city ; that the right bank of the Tigris above Baghdad should be
secured by an embankment from about opposite Mansuriyeh to
Kazimain; and that downstream of Baghdad towards Kut el-Amara
the country between the rivers (which was to be irrigated from the
Euphrates) should be protected by an embankment consisting of the
spoil of the 'right Tigris canal' (for which see below, p. 166), while
the floods were to be allowed to spill over the left bank. When Sir
William Willcocks wrote there were frequent spills from the Tigris
bend south of Ctesiphon. He proposed to make a cut across the neck
of the bend in order to induce the river to silt up its former channel,
and then, having allowed time for a gradual increase of water in the
Tigris below this point, to carry the right Tigris canal across the
bend so as to close it altogether. The cut across the neck of this
loop was subsequently dug by the Turks in 1915.