"نهر شط العرب ميناء البصرة" [ظ‎‎٢‎٣‎٦] (٤/٣)

Gulf ; and where the river currents have exhausted their energy, fluvial matter has
been deposited and a bar formed.
Although the Persian Gulf is not a tideless sea, the tidal currents are weak in*
comparison with those of the river, and the conditions at the mouth of the Shatt-eb
Arab river are similar to those obtaining at the mouth of the Mississippi and other
rivers of that class.
The immense amount of solid matter carried by the river in suspension, or
rolled along its bed, has been deposited at its mouth forming a delta through
which the river has found its way to the sea by one or more comparatively shallow
channels.
The delta is continually advancing seawards, the depth of the sea in front, and
the direction of the prevalent winds and currents being important factors in its
progress, and in the preparation of engineering schemes for increasing the depth
of water in the channel.
(19) The earliest survey of the Shatt-el-Arab of which there is any Earliest survey ol
record appears to be that made by Colonel Chesney’s expedition in 1837. This Shatt-el-Arab.
survey shewed two channels branching off near the mouth of the river ; the Western
channel was straight with an inner and outer bar, the former was situated at the
bifurcation and had only 16 feet of water over it at H. W. 0. S. T., whilst the channel
between the bars carried 34 feet, and the outer bar had 17 to 19 feet over it at high-
water and was about 4 miles broad. The Eastern channel carried from 17 to 20
feet for 8 miles, when it deepened rapidly to 30 and 40 feet.
(20) The first detailed chart is apparently that made by Lieutenant Gunn, First detailed
R.N., in November-December 1890, and it also shows two channels through the chart of Bar -
mud flats:—
One (the Eastern channel) running nearly due east from the Turkish fort
below Eao until it joined the mouth of the Bahmishir river, whilst the other, or
Western channel, ran in almost a straight line between the centre of the river at
Fao and the Turkish fort respectively. The Eastern channel carried the best
water, but had many bends and was not used.
The channel used for navigation was the Western channel; the whole length
of 10 miles was, however, one long bar or shallow channel carrying 18 to 20 feet of
water at H. W. O. S. T.
There was also a blind channel or gut midway between the Eastern and Western
channels, which started at the junction of the two channels and ran parallel to the
Western channel. This blind gut was 6 miles long and carried 20 to 24 feet of water
at H. W. O. S. T.
( 2 1) j n 1905, there was a partial survey of the entrance to the Shatt-el-Arab, Subsequent
which shewed that great changes were taking place ; the blind gut between the surve y s ‘
Eastern and Western channels was developing into the main channel, and the old
Eastern and Western channels had disappeared.
The date of the next completed survey was 1911. A further great improvement
was recorded : the new channel had been maintained and improved, the Inner Bar
carried a minimum of 23 feet of water at H. W. O. S. T., and the Outer Bar was
greatly curtailed in breadth and, with the exception of one small patch, carried
a minimum depth of 23 feet at H. W. O. S. T.
The last survey is the one that has just been completed under my direction,
and although the Inner Bar has entirely gone there being a minimum depth of 26 feet
71(w)AP