‘Persia – especially Seistan’ [‎87v] (173/949)

*
10
The nulla flows in a rather deep bed in a narrow valley between two high
ridges. These ridges are too close to permit of much development; the valley
is rough and fissured by streams from each side, so the descent is moderately
difficult, and the best grade obtainable will probably be little better than the
slope of the nulla bed, say, 1—50 to 1—55.
At Sagari Sing, where white quartz reefs among the rocks in the bed of
the river give the name to the place, the line leaves the valley and turns sharp
to the right. Thenceforth the country opens on either hand, and the work
gradually gets lighter till as the Rakshan valley is neared at Panjgur, R. L.
3,100, the last few miles are over the usual easy glacis.
The Rakshan River between the villages of Khodabadan Tasp and Isa
Kalat is a wide sprawling torrent without any apparent banks. . Its bed is, of
coarse shingle, and full of quicksands after floods. When I saw it, the surface
flow of water was considerable, quite 50 cubic feet per second, but that was
shortly after heavy rain.
The underground flow must be great. The width of the river varies
from J to ^ a mile, but its waters in flood are shallow. Perhaps the best site
for a bridge would be above the uppermost village, Khodabadan, where the
channel of the river might be confined.
If the direct route to Isa Kalat be taken, the bridge would be J mile long:
short spans, on low piers with shallow founds and a drop wall. (Training
works are not suited to the conditions here, and might lead to trouble with the
owners of the date groves.) The bed of the river slopes sufficiently for tail
races to be effective, so the foundations should not be troublesome. I paid
very little attention to the choice of a site for this bridge, for, as will be
realised when I describe the alternative route via the Gorandi Pass, it is not
by any means certain from which direction the line will approach Isa Kalat.
Gorandi Pass alternative .—Peeling dissatisfied with the line along the
caravan road from Palantak Thana over the Dambodim, I examined two passes
to the west leading from Panjgur into a depression or Kap called Dostanzai,
and thence to the Palantak defile. One of these, the Ghulam Shah, was barely
practicable and calls for no further remark; but the second, the Gorandi,
proved much easier than the Dambodim. There is little to choose in actual
cost between these two routes, for though the works on the Gorandi are much
lighter, and the grades somewhat better than via the Dambodim, the length
of the line is about 15 miles greater, that is, if we bring the railway to Isa
Kalat, as I think we should do [vide plan).
It will be observed that the Gorandi Kotal is 500 feet lower than the
Dambodim, but that, on the other hand, the alignment over the former has to
cross a subsidiary watershed The boundary between adjacent drainage basins. between the Bibi Lori and Palantak Rivers, so
that the total rise and fall of the two routes is practically identical. The 12
miles between these two Tangis is over glacis scarred with deepish nullas; in
fact, the action of the Tangis on the surrounding country resembles that of two
separate sluice gates draining a muddy pond. There will be a good deal of
small span bridging along this alignment, but the other works will be light
enough except near the Gorandi Kotal. Even there the heavy works only
extend for 7 or 8 miles and are not formidable. The descent to Panjgur is
much easier than would appear from the barometric section down the Gorandi
nulla, as development is comparatively simple [vide sketch).
I Set kcctcclr
-a*..*