‘Persia – especially Seistan’ [‎130v] (259/949)

16
If a fall of I’O per mile is assumed for the canal, and since it has been
shown in the last paragraph that the river falls 2*08 (say 2’0) a mile, the canal
head would be about 11 miles above Band-bKamal Khan or near Chahar
Burjak. This is about 4 miles above the present small Tarakun canal and about
6 miles above the small canal on the right bank which irrigates the plain
around Killa-i-Fath. So that the position of these two little canals shows that
a weir at or above Chahar Burjak would be high enough up the river to feed
canals which would command the big plains of Tarakun and Killa-i-Fath. On
the right bank of the river there is ample room for a big canal between the
present river and the toe of the clifts and the excavation would not be
excessive. On the left bank a big canal and a very large escape must be
carried along the left bank of the river, which, between Roden and Band-i-
Kamal Khan, has a set towards the cliffs on its south bank. At Band-i-Kamal
Khan village there is only about ^ a mile between the cliffs and the village.
So that it may prove necessary to excavate into the cliffs, which are of similar
soil to the valley. This would add to the expense of these channels. The
excavation would he deep (50 to 70 feet) wherever the cliffs were cut into, but
the length of such cutting is not likely to be long.
14. This note has dealt with the problem of irrigating the deltaic plain
on the supposition that all the land and all the water were under the complete
control of one authority. This is very far from being the case. The right bank
canal would irrigate only in Afghan territory, but the tails of the branches of
the left bank canal would end in Persian territory, whilst the middle canal
that would follow the present river bed would irrigate both Persian and Afghan
territory. The efficient distribution of the water between these interests w r ould
be an exceedingly difficult task, only to be achieved by engineers possessed of
the most advanced skill in canal engineering, controlled by an administration
that was quite impartial. It is easy to see that, if the existing small canals
on the right or left bank of the Helmand in Afghanistan were developed by
the present population, who are well-skilled in rough and ready methods for
leading water out on to the land, all the water of ordinary river could be
diverted into the canals, taking out above Chahar Burjak, leaving the
present cultivated tract in Seistan without water when most required, and to be
flooded at seasons of flood.
The present small canal in the old bed of the Tarakun channel could easily
he enlarged and extended to carry a large supply of water. It was originally
dug over a hundred years ago, it is said, and irrigated a large tract near Tarakun.
It then fell into disuse for a long period, and was re-opened as the present small
channel about 1894. Last year it was extended 4 miles by a small water
course 2 feet wide by 2 feet deep, which was in many places obliterated by
sand when I inspected the canal in February 1903. Although a scientifically
designed system would require a large and expensive escape, yet such canals,
as the Afghans are accustomed to make and use with skill, could easily be
developed by them in this part of the deltaic plain. The water could be
forced down the channel by boulder and tamarisk weirs, such as are constructed
for the present small canals along the Helmand Valley.
But the administration of canals to obtain the acreage that the water is
capable of irrigating needs to be energetic and just as well as highly trained.
These qualities can hardly be hoped for from the present administration of the
Helmand Valley.
Sufficient has been said to show that the river with the land at its com
mand in the deltaic valley is a very valuable property, which once supported
a large population. The experience acquired in India on irrigation works
could construct canals which would enable a large population to thrive on
these lands.