AREA ANALYSIS OF A PART OF THE UPPER TSANGPO VALLEY

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP63-00314R000200160053-7
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 12
• Document Creation Date: December 12, 2016
• Document Release Date: October 23, 1998
• Sequence Number: 53
• Publication Date: August 19, 1960
• Content Type: REPORT

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GEOGRAPHIC INTELLIGENCE REPORT
H PP
flEA.ANALYSIS O A P1s? T' OF T TS71tdGP(? VALLE`~
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WARNING
This material contains information affecting
the National Defense of the United States
within the meaning of the espionage laws,
Title 18, USC, Secs. 793 and 794, the trans-
mission or revelation of which in any manner
to an unauthorized person is prohibited by law.
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:IA/PR GP 60--4r7;
19 August 1960
This report analyzes that part of the upper Tsangpo (Bramnaputra)
Valley extending west to east from approximately 8209 to 860E and south
to north from the Nepal-Tibet border to the arestlines of the Trans-
Himalayan Mountains north of the Tsangpo River.' Emphasis is placed
25X1 X4 upon description
of the terrain, climate,
and vegetation that are characteristic of the area. Additional infor-
mation is given concerning population distribution, routes, and trade
and their relation to operational activities.
A. General Physical Description
The terrain of the upper Tsangpo area can be divided into three
major units: (1) the valley and associated river plains of the Tsangpo;
(2) the plains and mountains extending south of the Tsangpo Valley to
the Nepal border; and (3) the hill and mountain country north of the
Tsangpo, generally known as the Trans-Himalayan Mountains.
1. The Tsanano Valley and Plains
The Tsangpo headwaters rise in high valleys (elevation about 16,000
feet) at approximately 82?30'E. The valleys of the upper Tsangpo source
streams are very broad and this tributary characteristic persists as
far as Tradum, with the Tsangpo itself spread in numerous channel-3
This report should be used with MIS Map Series L500: sheets NB-4
and NH-45, scale 1:1,000,000; sheets NH-44-12 and NH-45-il, scale
1:250,000; and sheets 71C and H-45-T, scale 1:253,1+40. Data shown on
these map sheets for areas in Tibet were compiled from route surveys
made by travelers and explorers, mainly from 1870 to 1920. On the
1:1,000,000 sheets a few place names and route alignment; have been
updated as of 1958-59.
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(except during high water) and meandering over a wide, plain-like valley.
Great sand dunes and vast accumu:i.ations of alluvium are common --
particularly along the stretch of the river near 83030'! and at the
confluence of the Tsangpo and the Tea Chu (river), immediately west or
Tradum. East of Tradum the river, for the most part, is confined to e
single channel, the valley becomes narrower (although generally exceed-
ing one-half mile In width), and river depths are greater (see Table,
p. 8).
2. Plains and Mountains South of the T o
South of the Tsangpo the terrain can be divided into two major
types. West of 'T'radum., broad valleys open into the Tsangp~o. Through
these valleys flow tributaries that have their sources in the high
peaks (elevations 20,00 to 21,000 feet) marking the Nepal-Tibet border.
Difficult passes higher than 19,000 feet cross the border range.
East of Tradum the terrain is more broken and cottparttnentalixed,
with Nepalese streams -- the Buri, Trisuli, and Sun Kosi -- draining
considerable territory north of the Nepal-Tibet border. From about
850E to 860E, the Tsangpo-.Ganges water divide lies in a roughly east-west
aligned.. range that is only .10 to 15 miles south of the Ssangpo. :gib the
south, this range partially encloses a high plain of approximate!,--?r 15
by 25 miles in which several lakes, including Pekhu Too, are located.
Border passes west of the Gya Pass (84037'!) are at 18;000 feet and
higher; east of the Gya Pass the main transborder routes follow the
valleys of rivers that have out through the high border mountains.
To the south of '. "radunn is the 22-mile-wide Mustang area -- actually
a salient formed by the upper Kali River tributaries that rise north of
the mein water divide -- that extends the Nepal border to within 20 miles
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of the Tsangpo. Here the water divide is marked by the Kore Pass, a
mere rounded knoll at slightly more than 15,000 feet that is located
several miles north of the border. North of the Kore Pass a plain
about 15,000 feet high opens northward to the Tsangpo.
3. The Trans-Hi.melayan Mountains
North of the Tsangpo Valley rises a jumbled and complex mass of
hills and ridges of the Tans Himalayan Mountains, whose crests mark
the divide between the Tsangpo and the interior drainage basins of the
high plateau (Chang Thang) of northern Tibet. The Trans-Himalayan
passes leading to the northern plateau are at elevations of about 18,000
feet; they are relatively open and easy, however, with gentle der.3cents
to the 15,000-foot to 16,000-foot elevations of the Chang Thang. In
contrast to the generally rounded hills and open valleys south of the
Tsangpo, the complex ridges and spurs marking the southern slopes of
the Trans-Himalayan Mountains are cut by numerous streams, many of which
flow in part through ravines and gorges. The larger valleys, hot=ever,
are more open and fairly broad, and it is possible to travel through
them. In some sections, mainly east of Tradum, these side valleys are
used by the major east-west Lhasa to Ladakh caravan route.
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B. Climate
The climate of the upper Taangpo is characterized by great varia-
bility in both temperature and precipitation. Because weather records
for the area are lacking, only rough generalizations can be made. It
is likely, however, that freezing temperatures can be expected during
all but the warmest summer months. Average winter temperatures probably
range from 0?F to 10?F with minimum temperature estimated to be -15?F
or below and maxim= temperature somewhere around 20?F to 25?F. Some-
what higher and some bat lower temperatures than these can be expected
occasionally. Differences in elevation will tend to produce slightly
lower temperature readings to the west and higher ones in the east.
The heaviest precipitation in the area occurs during July and
August, primarily as rain although, occasionally, hail storms and
flurries of snow may occur even during this season. Total precipitation
varies greatly from year to year. Some summers have only occasional
showers, but in other years heavy rain storms occur during the summer.
Most of the area receives some snow by late October, and along the
upper tributaries of the Tsangpo snow may be expected by mid-September.
In general, less snow falls north of the Tsangpo Valley than to the
south, with the high plateau of Chang Thang receiving only light amounts
of extremely dry snow, which evaporates quickly. South of the Tsangpo,
however, anorwfalls appear to be more frequent, with greater and more
lasting accumulations. In the Kubi Valley (about 82?30VE) near the Nepal.
border at an, elevation of about 16,000 feet, snow accumulations of several
feet are said to last from November through Parch. Most of the Tsangpo
Valley is at lower elevations, however, and reportedly receives less
now, with little accumulation.
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Strong.westeriy winds sweep the open Tsangpo Valley during winter
and spring, and the combination of wind, dry snow, and a high evap-
oration rate normally limits any significant accumulation of snow to
lee slopes and depressions. To the east, in the areas of the Jongka
Dzong and Pekhu Tso Plain that are largely protected and compart-
mentalized by surrounding mountains, some snow accumulations have been
recorded. Harrer (author of Seven Years in Tibet) reported that heavy
snow blocked the exit from Jongka Dzong for approximately a month, from
mid-December through mid-January, 1944-45; similarly he found the Pekhu
Tso Plain covered by snow in early November. How typical these con-
ditions are is not known, although the general alignment of the terrain
features suggests that these areas would accumulate more snow than the
wind-swept Tsangpo Valley and adjoining plains. Little is known about
the high (18,000 to 19,000 feet) passes along the Nepal-Tibet frontier,
but their elevations suggest that they are snowbound during much of the
year. Considerable transborder movement takes place throughout most of
the year, however, over the much lower routes via the ICore Pass and
Mustang area and via the river valley tracks through I(yirong Dzong and
Nyalam Dzong. (See diacusaion of trade routes, p. 8.)
A typical feature of the Tibetan climate is the strong westerly
mind that prevails from November through April or May. The wind nor-
mally follows a daily rhythm in which strongest velocities are recorded
from early afternoon through early evening. The wind has been reported
as strong enough to hurl st.a1_i, pebbles before it, and the famed explorer
peen Hedin reported that "even with well-protected eyes it was some-
times impossible to look up" wwhen riding westward against this wind.
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Tibetan travelers usually plan their journeys to end in early afternoon
to avoid these winds. BUY atmosphere and dust storms are common in
the Tsangpo Valley, particularly during the comparatively dry spring
months. During the June-through-October period the winds generally
are Light and are mostly westerlies.
C. Vegetation
Most of the plains and valleys are covered by grass that supports
large numbers of sheep, goats, and yaks of the Tibetan nomads. large
herds of wild yaks, antelopes, and kiang (an animal akin to a wild horse)
are also found in this area. The nomads normally seek out the higher
v ,1 nY pastures (up to 36,000 feet) during summer and early autumn,
retreating to more sheltered lover valleys and plains during winter.
Except for the upper Trisuli Valley south of Jongka Nang, the area is
too high to permit the graving of small grains. During summer, some
meager dietary supplements such as wild onions, mushrooms., and wild
rhubarb may be available lv limited quantities.
Low shrubs occur occasionally in this area, and, in a very few
protected places, some dwarf willows may be found. The only trees in
the area grow, at elevations below 12,000 feet, in the small pocket of
25X9A1 the ICoai River Valley (a Triouli tributary) in which l vtrong Dzong is
25X9A 10 located
0. River Ubaractera
The Tsangpo generally is fordable above Tradum; below this point,
however, it is doubtful that the river can be crossed without using a
boat or a rope bridge. The fording of the river is affected by the
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considerable variations of the -;-u ?r rainy season. Cr. normal vears.
communications between the northern and southern banks are often Lev-
ered from July through early September by high water. Even after the
Tsangpo recedes, movement is hindered by an effective barrier of bogs,
pools, and alluvium that remains for some weeks. Summers with abnor-
mally light precipitation do occur, however, and river crossings under
such conditions probably can be made during much of the period that
would normally have high water.
Along the upper Tsangpo (near its sources) fording is related to
the time of day and daily weather conditions. Normally, water levels
rise in the afternoon. because of melting glacial ice and snow. There-
fore, river crossings normally are feasible only during the morning.
One or two sunny days in succession, however, may release enough water
to stop fording altogether for two or three days afterward. Conversely,
cool cloudy days tray permit fording at any time during the day.
normal years the Tsanglao is probably frozen solid above Tradum
from about December through March. As the river becomes narrower arxd
deeper east of Tradum, an open channel will be maintained throughout
the winter in an increasing Aber of places. At a point near 840451P.,
farrer found the river frozen in mid-Deceuber, but about 2 weeks earlier
it had been open some 100 miles downstream. At Pindzoling (880E) the
river is said never to freeze como,letely.
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`r=a rreterie ties rf "r-- '!ewr oat Selected 1?r i s a/
r:wzsS 2 #.t? T.oCanti.p i
820551E, near ' ns:ng
83?37'E, neeTr Dongh
4o1O'F. nesr " .dtam
W5?IV'E , !south of Salo
oti these rsv ,3a rem at ,, were tai in June and early July when
?r~?ater 1_eveis should be approaching their maximum,, the particular year,
(3-1,1071') -s aabno lly dry. T ae-re#ore,, these figures probably are amore
reedy repreaentative of the lcza unter conditions that normally should
be expected from late Oc4 bpr t:3tr. oa? h z'ty.
The most densely p< piAE ^. " t o the g x era area ?'. the upper
Trisu3.t Valley in the w3. 3.zs tt r t -v? J rg
and Ky1rorg Dzong, :accept
-for this rel ttve].y sai&' 1. :wen a c>.d. r*, :fie se ttereal v~.a