'Mesopotamia' [‎31r] (61/152)

Mesopotamia] RIVERS AND CANALS
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(b) Rivers and Canals
The important rivers of Mesopotamia are the Tigris,
the Euphrates, and the river formed by the confluence
of these two at Kurna and known as the Shatt el-Arab.
Of less importance are the four tributaries which join
the Tigris from the Persian hills on its lett bank, the
Great and Lesser Zab, the Adheim between Mosul
and Baghdad, and the Diala just below the latter
town. The length of the Tigris between Mosul and
Kurna is about 723 miles, that of the Euphrates
between Meskene and Kurna about 1.002 miles; the
length of the Shatt el-Arab is 107 miles.
From the economic point of view, the main interest
in Mesopotamia centres round the Tigris and,!
Euphrates. Mesopotamia owes its past importance to
the wealth won from the rich soil of the Delta by means
of the ancient systems of irrigation, of which abundant
evidence exists even to-day, and the future progress ot
the country depends upon the proper utilisation of its
rivers for irrigation and navigation.
The Shatt el-Arah is navigable by ocean-going
steamers. At Eao the average width of the river is
1 mile, decreasing gradually to ^ mile at the mouth
of the Karun River, which flows in on the left bank
40 miles above Fao; above this point the river imme
diately decreases to a mean breadth of 600 yards.
Between Basra and Kurna the river gradually narrows
to 250 yards. Its utility ^cr navigation is at present
impeded by a bank of silt known as the Fao bar, which
lies across the mouth of the river at Fao, and gives at
low water a maximum depth of 11 feet only, with the
result that vessels of larger draught are compelled
either to wait for the tide or to trans-ship a portion of
their cargo to lighters outside the bar. The depth
of water over the bar at spring tides is 20 ft., at neap
tides 17 ft. Beyond the bar there is a depth of from
30 to 40 ft. up to Basra, except at two places, of which
the more serious is the Muhammera bar, just below
the confluence of the Karun River. Vessels drawing
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