'HISTORY OF THE GREAT WAR BASED ON OFFICIAL DOCUMENTS. THE CAMPAIGN IN MESOPOTAMIA 1914-1918. VOLUME I.' [‎11v] (27/454)

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HISTORY OF THE WAR: MESOPOTAMIA
and forms the principal means of communication with Arabistan
and the Anglo-Persian oilfields. The delta below Mohammerah
is navigable by only one arm and for six months in the year
is generally a swamp caused by the melting of the snows and
occasionally by the action of the autumn rains.
At Kurmat Ali, five and three-quarter miles above Basra,
the Euphrates enters from the west by its new channel; while
its old channel comes in at Qurna, forty miles further up. The
course of this river is nowhere clearly defined in its lower
reaches ; for, in addition to the old and new channels of the
main stream, there are many subsidiary watercourses and
tracts of water. Navigation is consequently complicated,
especially during the flood season. The Hammar lake, about
thirty-five miles west of Ourna, offers the chief obstacle owing
to its shallowness and narrow entrance. In 1914 this lake was
navigable only by vessels of three feet draught and that only
during the high water season : in the time of low water all
navigation was suspended except for heliums*
From Qurna to this lake and beyond it to some seven miles
downstream of Nasiriya the channel runs through extensive
swamps. There is then some cessation of these to Samawa
(209 miles from Qurna), though the country adjoining the
river is liable to floods in the spring. Here two channels come
in. These are the branches into which the Euphrates divides
a short distance below Musaiyib (155 miles up-stream) and are
generally known as the Hindiya canal and Shatt Hilla. The
Hindiya barrage, one of the Willcocks irrigation projects, is
situated at the point of diversion of the two channels and
regulates the distribution of water between them. Between
the barrage and Samawa are considerable tracts of water and
marsh, including the Shinafiya lake.
From Musaiyib to Falluja, a distance of fifty-six miles, the
average width of the river is 270 yards. The depth of water
in this stretch averages six and a half feet at its lowest and
the stream-level is then some ten feet below the river-banks.
In the spring the floods increase the depth of water from six
and a half to about eighteen feet, and the country on the
right bank for some twenty miles upstream of Musaiyib is
then liable to flooding if the marginal bunds are not well
looked to. *
* Country sailing boats of one to seventy-five tonnage (freight) and with a
draught of one to five and a half feet when fully laden. On the Shatt al
Arab this term is applied to small rowing boats, while the larger boats are
termed mahailas.