Food Sources: Earth, Water, and Air - Food Culture and Health in Pre-Modern Islamic Societies - page 44

under the Abbāsids, was situated near
the original capital of Rām · ahristān
(Abra ª ahriyār), which according to tra-
dition, had been abandoned when a dam
across the Hīrmand had burst and the
water had been permanently diverted
from the Rām · āhristān canal. From
the works of the Muslim geographers, it
would appear that Zaran ¡ was irrigated
by six dams on the Hīrmand near where
it enters Lake Zarab. Some of these may
have been of Sāsānid origin. The Muslims
added various water-wheels to the system.
In 785/1383 Zaran ¡ and its irrigation
works were destroyed by Tīmūr, as was
also the Band-i Rustam on the Hīrmand
River near Bust, the water of which had
served to irrigate all the western lands of
Sīstān. Failure to repair and maintain the
elaborate system of canals and dams on
the Hīrmand River resulted in much of
the land formerly irrigated and drained
being converted into reed beds and
swamps. The headwaters of the Hīrmand
and the main stream are at the present
day in Af ∞ ānistān. After entering Persian
Sīstān, the river divides into two branches,
the Pariyān and the Sīstān rivers. The
former flows in a northerly direction, and
with its tributaries waters northern Sīstān.
The latter flows through southern and
south-western Sīstān. Near the Af ∞ ān
frontier, the Kahak dam diverts water
into the Pariyān, while another dam
lower down, the Band-i Zahāk, diverts
more water for irrigation. The use of the
water of the Hīrmand and the construc-
tion of new dams has been the subject
of bitter controversy between Persia and
Af ∞ ānistān. The first award of the river
waters between them was made in 1872.
The water of the Mur ∞ āb River in
‡ urāsān was diverted by numerous
dams and canals for irrigation. Al-Ia ¶ rī
relates that one march south of Marw, its
bed was artificially dyked with embank-
ments faced by wooden works which kept

the river-bed from changing. Under the
Sal ¡ ūs, the number of dams and dykes
on the Mur ∞ āb was increased. These
were later destroyed by the Mongols
and the oasis of Marw converted into a
desert swamp, according to āfi Abrū.
He states that after Tīmūr's conquest of
‡ urāsān, various of the amīrs and pillars
of the state each made a canal leading off
from the Mur ∞ āb, in order to irrigate the
land, and that when he was writing, i.e.
at the beginning of the 9th/15th century,
twenty of these were in existence. He
describes the city as being in a flourishing
condition.
One of the most important periods in
mediaeval Persia in the construction of
dams appears to have been the Īl ¶ ān
period, when, in the late 7th/13th cen-
tury and early 8th/14th centuries, sev-
eral dams were constructed. The great
achievement of this period was the con-
struction of a number of arch dams. One
at Kibar (Kivar), some 15 miles south of
umm, is the oldest surviving example
of this type of structure so far located.
Built in a V-shaped gorge, which narrows
about halfway down to a deep gully, the
dam is 85 ft. high and 180 ft. long at the
crest, the thickness of which is between
15 and 16 ½ ft. The air-face, the radius
of curvature of which is 125 ft., is verti-
cal except near the face where there is a
slight slope in the downstream direction.
The dam has a core of rubble masonry set
in mortar ( sārū ¡ ) made from lime crushed
with the ash of some desert plant, which
makes it hydraulic and results in a strong,
hard and highly impervious mortar ideal
for dams. The dam has a vertical series of
openings on the water-face connected by
shafts and galleries to provide passage for
the water through the dam walls (though
their precise function is uncertain). Two
other arch dams, probably also belong-
ing to the Īl ¶ ān period are situated near
abas, the · āh Abbāsī, east-north-east