'Handbook of Mesopotamia. Vol. I. 1918' [‎22] (31/568)

22 BOUNDARIES AND PHYSICAL FEATURES
Armenian plateau from east to west, join their waters near its south
western corner, some 25 miles WNW. of Kharput. From the junction
of these two rivers the Euphrates cuts its way southwards through
the Taurus in a series of gorges, and, alter emerging from the moun
tains, flows, on a course of about 650 miles, in a shallow valley or trough
between the western edge of upper Mesopotamia on one side and
northern Syria and the Syrian Desert on the other. At Hit it enters
the alluvial bed in which it flows thence to the sea. It passes along
the western and southern sides of the alluvial plain of Irak, ap
proaching to within 25 miles of the Tigris in the neighbourhood of
Ctesiphon, but again diverging from that river. Its waters divide
into branches and spill over marshes and broads, until, about 400 miles
by river below Hit, what remains of them joins the waters of the
Tigris, partly at Kurna, partly at Gurmat c Ali a few miles above
Basra.
The streams forming the head-waters of the Tigris (the Arghana Su
and the Dibeneh Su) rise on the southern edge of the Armenian
plateau, just N. of the eastern Taurus and close to the Murad Su.
The Arghana Su has its sources S. of Kharput, within a few miles of
the Euphrates. The Arghana and the Dibeneh penetrate the barrier
of the Taurus and unite in the lowlands of Diarbekr, some 20 miles
N. of that town. The Tigris flows along the southern side of the
lowlands until, 60 miles below Diarbekr, it enters a succession of
gorges between the Tur Abdin plateau to the south and west, and
the mountains of central Kurdistan to the north and east. It leaves
the mountains near Jeziret-ibn-'Omar, 170 miles below Diarbekr,
and thence flows in a trough through the upper Mesopotamian
plains, passing by Mosul to Samarra, 340 miles below Jezlret-ibn-
'Omar. Some 15 miles below Samarra it enters its alluvial bed, and
follows a course through northern and eastern Irak for about
550 miles. As it proceeds southwards, more and more of its water
is spilt into marshes, and, though some of this returns to the main
channel, its volume is much reduced by the time a part of the
Euphrates is met at Kurna.
From Kurna downwards the united waters of the Euphrates and
the Tigris are known as the Shatt el-Arab, a large river about
125 miles long, which at Mohammareh, about 48 miles from its
mouth, is joined by the greater part of the waters of the Karun.
Drainage. —Outside the boundaries of this area the Euphrates
drains a large part of the Armenian plateau and the north-eastern
corner of Syria. Within this area it receives two large tributaries in
upper Mesopotamia, the Belikh and the Khabur. These drain the
western and central parts of the northern Jezlreh plain and the