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Fig. 8.17 Plantation along
first order channel
to sub-aerial processes. The on-site bene
t of afforestation include a marked
reduction in shallow landsliding (Pearce et al.
1987
; Phillips et al.
1990
),
substantially reduced rates of earth flow movement (Phillips et al.
1990
), and
cessation of gullying processes (Bay
eld and Meister
1998
; Phillips et al.
2000
).
Development of
first order stream and its flow through sub-surface soil over steep
mountain slope is the major cause of soil erosion and slope instability at several
places in the Shivkhola Watershed. For freshly-exposed slope surface created by
road cutting which is basically found on the way to Shiviter T.E. and Tindhariea
T.E. and of course aside the Hill Cart Road, the vegetative turfing (introduction of
fast growing grasses, bushes, trees and bamboos) can be most effective mitigation
measures in the vulnerable areas of Shivkhola Watershed. Sometimes sprays has to
be provided to the exposed slope surface to improve the moisture condition of the
soil and to facilitate vegetal tur
ng.
A preventive measure of soil erosion has been taken by saplings plantation along
first order channel at Gayabari Lower slope (Fig.
8.17
). In the slope failure prone
areas of the Shivkhola watershed, wild fern are to be grown profusely and can be
used for slope protection due to some unique taxonomic characters. The compound
leaves are 0.5
1 m long and convex upward and are arranged in successive vertical
layers. The rain drops falling on the convex leaves having a down slope trend are
conveyed down slope through the tips of the leaves and thus seldom get opportunity
to reach slope surface (Fig.
8.18
). Thus the thick fern cover is an essential slope
protector which restricts soil from being saturated and thus pore water pressure can
be controlled to restore slope stability (Maiti
2007
). The fern may be introduced to
the upper catchments of Paglajhora, 14 Mile landslide area etc.
-
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