1873..
DREW — UPPER-INDUS BASIN.
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vines of a uniform character, project fans that have coalesced together,
and now make a continuous spread of fan-deposits nearly two miles
in width, extending along the foot of the mountains for a distance of
30 miles. The fans, although touching, are still distinguishable one
from another ; the line of junction in the hollow between any two of
them is always marked, as well as the ending of the fan against the
main- stream alluvium. In fig. 7 is depicted a somewhat similar
Fig. 7. — Fans united (five miles south of Pamzalan, Changchenmo,
Ladakh).
succession of fans which have met. These are of a greater slope and
of a less area ; they occur by the side of a feeder of the Changchenmo
river, at a height of between 15,000 and 16,000 feet.
In Ladakh it is generally upon alluvial fans that cultivated ground
occurs. In that country nothing can be grown without irrigation ;
and the places are few where the waters of the main rivers, such as
the Indus and the Shayok, can be made available for it. The water
of the side streams is that which is made use of ; and this is led, for
these purposes, over the fan-stuff deposited by itself. Still, of the
whole fan-area, a very small proportion is tilled. Going along such
a space as was above described (opposite to Leh) we may find every
three or four miles a village or a hamlet with a cultivated area of
fifty to a hundred acres ; and the rest will be dry, bare, stony ground.
The reason varies for different cases. Sometimes it is that, from the
occurrence of ravines such as will be described further on, it is dif-
ficult to bring the water on to the surface of the fans ; sometimes
the quantity of water in the ravine is itself limited, and in summer
lessens to far below what would be necessary to irrigate any large
proportion of the area of the fan ; sometimes, again, the material is
such as to make an intractable surface.
Another combination of fans is when, projecting from ravines on
opposite sides of a large stream, they meet, or nearly meet, and the
river flows confined between them.