'Handbook of Mesopotamia. Vol. I. 1918' [‎157] (166/568)

IRRIGATION OF IRAK
157
■ Nahrawan had several heads on the Tigris and took up the waters
"■< of the Adheim and the Diyaleh. Its tail entered the Tigris near
EI-Madayyah, in the neighbourhood of the modern Kut el-Amara.
In order that a sufficient head of waters might be obtained for the
' flip Nahrawan, the Tigris, at a point between four and five miles below
'% the El-Qaim head of the canal, and about ten miles below Samarra,
• Mil was turned by an earthen dam to flow over a natural weir of con-
Wlni glomerate. It seems that as this weir was gradually undermined
Wt attempts were made to keep the Nahrawan supplied by moving
its head farther and farther upstream till it reached the neighbour
hood of the Hamrln hills. Nevertheless the lower course of the
Nahrawan gradually silted up in the eleventh, twelfth, and thirteenth
Wi centuries.
The Nahrawan is still to be traced for the greater part of its
P original course, as a broad, high-lying dry channel between lofty
' earthen banks. In parts it has been breached or obliterated.
(&) On the right hank of the Ti the alluvial
- plain between the river and the desert was watered by the Dujeil
and its branches. The Dujeil took off from the Tigris above the
■li conglomerate weir already mentioned. It still carries some water
Jljiiii in the flood season as far as Sumeikeh.
*•1' (c)Behveen the rivers from the lin — ah out
lineDhvamyeh — Kut el-Amara irrigation was maintained through
mh a number of great canals which took off from the Euphrates or from
nek f what is now the Hilla arm of that river, and tailed into the Tigris
or into the present course of the Shatt el-Hai, which in the period
liatiiif the Caliphate was the main stream of the Tigris. These canals
jjtfE in part carry a certain amount of water, though not nearly so much,
nor generally so far, as they did a thousand years ago ; in part they
"' are high dry channels enclosed for long stretches between lofty
jjjjt- earthen banks ; and in part they have been almost obliterated,
iillf* The absence of barrages on the Euphrates above its bifurcation
ufcfe must have made it very difficult to keep up perennial irrigation
ii.ii on ^ese canals. (The Babylonian engineers seem to have used the
Abu Dibis depression as a reservoir, and it appears that another
Vi# Babylonian reservoir lay between the rivers near Sippara north of
Babylon.)
yl r ^ ie country between the rivers was protected against inundation
rial,* f rom the Tigris by the embankments of canals drawing their water
^ ' from the Euphrates, e .g. the Nahr Melcha, the high banks of which
(((jit are still to be traced for long distances between the neighbourhood
Kill# of Ctesiphon and that of Kut.
id) Below the neighbourhood of Ku the Tigris had, until