"كتيّب بلاد الرافدين. المجلد II. ١٩١٧" [‎٤‎٥‎٣] (٥٤٢/٤٦٤)

CONTROL OF TIGRIS WATER
453
that the Nahrawan would be safe from a flood caused by damming,
for the water might then perhaps find its way through gaps or
weak places in the high banks of the canal.
The available evidence from surveys is not full enough to
determine whether a dam on the Diyaleh near the head of the Beled-
ruz Canal could send water along, or close to, the line of that canal,
and thence into the depression of El-Merj and Suweiklyeh, so as to
cause the flooding of the right bank of the Tigris near Kut.
C onditions from K ut to K urna
The main features of the river in this part of its course can only
be very briefly sketched.
From Kut to Amara the river is about 850 yds. broad with
a depth of 26 ft. in flood and 5-7 ft. in low supply. The velocity
of the current is generally about 3^-4^ m.p.h. in flood, and 1-1-|
m.p.h. in low water. The river is navigable for steamers of 8-6 ft.
draught according to the season. There are shifting sand-banks in
the bed, especially between Sheikh Sa'ad and c Ali el-Gharbi. The
height of the banks steadily diminishes. At Kut they are about
16 ft. above low-water levels; at Ali el-Gharbi, about 18 ft. ; at
Amara, about 7 ft.
In flood-time the overflow water forms marshes just beyond the
immediate neigbourhood of the banks. These Mors become larger
and more continuous as one goes down-stream.
In a high flood there is an almost continuous line of marshes
several miles wide from Sheikh Sa'ad on the right bank, and from
Ali el-Gharbi to Amara on the left bank, where the Mors are also
fed by streams from the hills.
As the floods subside, the top of the water may filter back into
the river: more water drains southward into the marshes below
Amara, and much is lost by evaporation. The greater part of the
marshland dries up in the course of the summer.
On the right bank, 11 m. by river above Amara, is the large
Biteireh Canal, which deprives the Tigris of water even in the low
season, and may take perhaps rather more than a third of the river's
supply. On the left bank immediately above Amara town is the
common head of the Jehaleh (Chaheleh) and Musharreh canals. See
further below on this canal-head.
Beyond conservancy regulations to control canal-cutting, &c., by
the natives, there is little to be done to improve conditions on this
part of the river, short of training it thoroughly by works on a con
siderable scale. Merely local improvements might easily cause