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Environment
Avalanche Safe Township
for Holy Shrine
by VK Joshi
Avalanches always occur on the most beautiful spots on the earth.
Uttaranchal Himalayas are no exception. Apart from being a trekker's
paradise, some of the holiest Hindu shrines are situated here. Amongst
these the Kedarnath is an amazing spot. Despite proximity to several
avalanches the shrine has withstood the test of time. Several thousands
devotees visit this place to pay obeisance year after year. While
discussing the avalanches this story narrates how safe or otherwise is
Kedarnath area.
The
pressure of visitors to Kedarnath has increased enormously and the need
for the basic facilities like boarding and lodging has also
proportionately increased. The shrine and the township around need an in
depth survey to avoid mishaps due to avalanches. Kedarnath town and the
environs have been studied in detail by the glaciologists of the
Geological Survey Of India (GSI). Deepak Srivastava, Director and an
eminent glaciologist has extensively explored the region for avalanches
along with his team.
Much revered by the Hindus, the Kedarnath temple sits in the shadow of
Kedarnath massif. Though constructed by human artisans the temple looks
very much a part of the mountain eco-system. It is said that the temple
has been there in some or other form even before the Mahabharata. Since
8th century the present temple has been majestically standing where it
is and being worshipped.
The Mandakini River valley which houses the temple runs almost
north-south, bound by five peaks, viz., 5505m peak, Bharat Kunta
peak-6578m, Kedarnath peak-6940m, Mahalaya Paravat peak-5970m and
Hanuman top peak-5320m. These form a sort of amphitheatre called as a
cirque in the lingua of the glaciologists. A 5040m triangular peak, the
Brahma Gupha juts out majestically in the middle of the cirque. The
width of the valley in the cirque area (valley head) is six kilometer
and narrows down to three kilometer in the southern end.
Srivastava in one of his papers says that the Mandakini River valley is
unique because two glaciers that have separate regimen, orientation and
flow occupy this single valley. The two glaciers, Chaurabari and
Companion glaciers terminate at different elevations, at the same place.
From the moraines it appears that these two glaciers were unified in the
past and occupied the entire one kilometer wide valley at Kedarnath.
Moraines are the rock boulders of assorted sizes to rock flour produced
and carried by the glacier and left behind as they recede. These
moraines are well established and held at place by the vegetation for a
length of three kilometers up to the snout of the glaciers. The moraines
have lots of stories hidden in them. It appears that there were at least
four major episodes of glacier recession as marked by the traces of the
moraines throughout the valley. In other words, earlier the glaciers had
descended down to much lower levels than the present.
Kedarnath township is situated on a glacial outwash plain. Channels of
Mandakini River originate from Chaurabari and Companion glaciers and
encircle this plain to meet below the township. The erosion by the
stream has been such that it has cut through the water table in the
upper part of the plain. Thus constant oozing of water has made the
place marshy.
Avalanches in any area depend upon several factors like the nature of
the snow pack, physical and mechanical processes, slope conditions and
geomorphologic setting. The last condition many times comes as a savior
too. The geographical location of Kedarnath township is such that during
the winters a single snow storm can precipitate up to two meters of
snow. The density of fresh snow here is 0.01 to 0.02 gm/cc. The
amphitheatre at Kedarnath many times creates a wind tunnel, raising
cyclonic winds. Wind activity results in cornices and slabs. These slabs
lead to slab avalanches. Windborne avalanches are often quite
destructive. One such avalanche had uprooted micro-hydel generating unit
and damaged the Bharat Sewashram building. While planning construction
activity in air-borne avalanche prone areas protrusions in the path of
the avalanche should never be allowed. They create the effect of a
windblast and cause substantial damage.
A redeeming feature for Kedarnath is that the floor of the Mandakini
valley in the area remains buried under ten meters of snow. The density
of settled snow has been measured as 0.2 to 0.3 gm/cc by Srivastava and
his colleagues. The temperatures below freezing point leads to a
metamorphism of the snow and the grain size increases. Thus a crust of
high density snow is formed all over that protects the structures buried
therein.
The upper reaches of Mandakini valley are devoid of vegetation, except
alpine grass. In the valley portion around Garurchatti, Rhodendron
bushes and the area near Ghuinderpani have pine and birch trees. These
barren slopes are not able to hold the avalanches and this part is
maximum avalanche prone. Between the left morainic ridge and the wall of
the valley runs a nala. This provides a good barrier against avalanches
to the left side of the valley in Kedarnath township. The right side,
due to absence of any such barrier is however, not so safe. The terraces
formed by these moraines are fairly wide and people are tempted to start
construction on both sides. But the right side should be left untouched
warns Srivastava in his report. Moreover, the valley walls are very
steep with flat portions at the heads which provide ample space for
accumulation of snow. Generally such topographies do not generate
regular avalanches, but if there is one it can be of high order.
The avalanches of Kedarnath area have been classified as Chute and Slope
types depending on the nature of the zone of collection of snow.
Genetically they develop as loose snow or slab avalanche depending on
the climate and intensity of the snowstorm. The devastation caused by
these is enormous.
Altogether 28 probable avalanche zones have been identified by
Srivastava and his team mates situated between altitudes of 3800 to 4000
meters. One of them designated as R-13 has an average ice volume of
70891m3 with a chute length of 900m and impact force of 84.8tonnes/m3.
Here it worth knowing that while an impact force of 10tonnes/m3 can
uproot matured trees, an avalanche of 100tonnes/m3 can move reinforced
concrete structures. Therefore the planners must always remember that
there is no engineering solution against geohazards.
The temple has been safe from avalanches through the centuries. Even the
present township of Kedarnath has not been hit by a major avalanche. An
acute need for further expansion is being felt. For which the terraces
on the left side only, up to Lenchuri village have been recommended by
the glaciologists of GSI. Only drawback of this portion is the marshy
condition due to deep erosion of the terrace. Development of a proper
drainage can take care of the condition and habitats can be safely
constructed.
The science of glaciology is much recent compared to the site of
Kedarnath temple. Hats off to those saints who knew which is the safest
spot for the shrine to remain intact for the centuries to come. Or was
it the choice of the Lord Shiva himself!
October 15, 2006
Image: View of Kedarnath temple ensconced
in Mandakini valley.
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