'IRAQ AND THE PERSIAN GULF' [‎44r] (92/862)

description of the land 49
below the Diyala confluence the Arch of Ctesiphon marks the Partho-
Sassanid capital, successor to Seleucia on the opposite bank (p. 232);
it remains in sight of a river steamer coming up-stream in the flood
season, sometimes ahead, sometimes astern, for the greater part of a
day. The river in this section has an average fall of 1 in 15,000
compared with 1 in 14,500 between Balad and Baghdad, and with
1 in 2,000 about Samarra. The width varies between 250 and 350
yards. The riverain belts are mainly irrigated by oil pumps, a
method which has developed at a very rapid rate since 1918. On
the left bank is the now barren plain, once fertile and watered by
the Nahrwan canal, and beyond that a low-lying area running at its
south end into the Haur Suwaiqiya, into which flow the waters of
many minor streams from the hills. The advance of the Tigris and
Diyala deltas has cut off these streams from direct access to the main
river, though some of their waters reach it by subsoil drainage in the
low-water season.
The country on the right bank is much more intersected by channels
and irrigation cuts than the left, and great care has to be exercised to
maintain the embankment in good order. The drainage channel of
the Aqarquf lake, which is fed by the Saqlawiya (p. 30), enters the
Tigris as the Mahsudiya or Nahr Washash at the first westward loop
south of Baghdad (fig. 13); even when not carrying water it forms
a considerable obstacle, with 9-foot banks. South of it the desert is
marked by the derelict banks of ancient canals, by numerous ruin-
mounds, and near the river by irrigation channels. Breaks in the
river embankment at the southern end of any loop in high flood
would almost invariably put large tracts of land under water and link
up the various marshes {haws) into a continuous sheet.
Kut al Imara to Amara (direct distance 90 miles; by river 126 miles)
The Tigris at Kut al Imara is particularly interesting because at or
just below the town there have been at least two great changes of
the river within historical times (fig. 9). Apart from minor changes
near the present bed where loops have been cut off and the river has
eaten into its banks, there are three clearly marked natural courses
with low marshy ground between them: the present channel, the
Shatt al Gharraf or Shatt al Hai, and the Shatt Dujaila the Dujafla
depression’ of the Kut campaign in 1916—which now ends in the
Haur Sanniya, but at one time flowed south by the Shatt al Khidr.
Some interesting geographical problems await solution here. It is
known that the Abbasid town of Madharaya stood on the Iigns
A 5195