'IRAQ AND THE PERSIAN GULF' [‎31r] (66/862)

DESCRIPTION OF THE LAND
31
times cities and towns have been built on its many channels, and in
times of a strong central government the waters have been mastered.
The principle behind this mastery appears generally to have been the
same, namely to distribute the water at various points along the
course into canals—often earlier channels of the river which had
silted up—and to control these canals for navigation or irrigation, or
both, for the use of cities abandoned by the river. A short history of
the canal system, so far as is known, is given in Chapter X. Here it is
only necessary to state that in the last great period of Mesopotamian
prosperity the problem was solved by the Abbasid caliphs by main
taining and regulating five great canals from the Euphrates to the
Tigris: (i) the Nahr Isa, probably part of a prehistoric course of the
river, which has been mentioned above; (ii) the Nahr Sarsar, roughly
parallel to it and about 10 miles farther south; (iii) the Nahr Malik,
successor to a far older ‘royal’ canal which entered the Tigris opposite
Ctesiphon; (iv) the Nahr Kutha, which left the Euphrates about 12
miles above the modern village of Musaiyib and entered the Tigris
a few miles below Ctesiphon; and (v) the Shatt an Nil, which also
dates back to very ancient times and took off water from near Babylon
and drained into the Tigris above and below the modern Kut al
Imara, at a time when that river flowed down the Shatt al Gharraf
(p. 50). The surplus waters of the Euphrates and of the Tigris
emptied into the ‘Great Swamp’ {Al Bataih), which extended from
near Kufa on the Euphrates to near Wasit on the Shatt al Gharraf,
and was drained by a single channel into the Shatt al Arab at Qurna.
Much of this Euphrates canal system survived the devastations of
the Mongols in the thirteenth century, but decayed gradually during
the last 300 years of the Ottoman Empire. The last of the great
canals to become unnavigable was the Nahr Isa (Saqlawiya).
Falluja to the Hindiya Barrage (direct distance 53 miles; by river
80 miles)
From Falluja to Musaiyib the Euphrates flows south-east on a
general course parallel to the Tigris (fig. 7). The river in September
is about 130 feet above sea-level at Falluja and 104 feet at Musaiyib.
Its breadth in the low-water season varies from 150 to 300 yards, the
current is then only 2 miles an hour and the depth between 3! and
7 feet; but the flood waters may rise as much as 18 feet, so that the
natural banks, rarely more than 15 feet high, have to be raised by
continuous embankments over long stretches. Four controlled peren
nial canals, remodelled since the British occupation of Baghdad in