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28% is under low hydro-hazard frequency (below 20 events/year/km
2
).
Comparatively this frequency was quite low in all four zones during 1985-
1990 which suggested an increasing trend of hydro-hazard frequency in the
study area (Fig. 11.5d). On the basis of overall assessment of the watershed
it can be said that very high frequency is mostly found on the steep slopes
with the lithology of Lariakantha-Bhumiadhar Formation and along major
streams of the watershed and high frequency was found in moderately
steep areas and along major tributary streams whereas, moderate and low
frequency were confi ned to dense forests with the lithology of the Krol
Formation and human managed landscape, like agriculture and pasture
land, etc. (Fig. 11.5d).
Impacts of hydrological hazards on community food and livelihood
Farming is the main source of community food and livelihood throughout
the Himalaya but unfortunately it is the most susceptible sector of climate
change as the meteorological data shows that the trend of agro-ecology is
gearing toward hotter and a less humid environment. This is attributed
to the fact that climate change affects the two most important direct
agricultural production inputs, precipitation and temperature. Climate
change also indirectly affects agriculture by infl uencing the emergence and
distribution of crop pests and livestock diseases, exacerbating the frequency
and distribution of adverse weather conditions, reducing water supplies and
irrigation; and enhancing severity of soil erosion. The results suggested that
climate change accelerated land-use dynamics and hydrological hazards,
i.e., drought (decreasing underground water, drying up natural springs and
decreasing trends of stream discharge) in the no-monsoon period and fl ash
fl ood, river line fl ood, soil erosion and landslide in the monsoon period
which ultimately affected community food and livelihood as given below:
Dwindling Irrigation Facilities during Non-monsoon:
Check dams, spring
ponds, canals, gullies, water tanks and pipe lines are the main measures
for irrigation throughout the Himalaya as well as in the study area. The
results suggested that these measures are declining due to climate change
and its impacts on water resources, i.e., drying up of perennial springs and
streams (Fig.11.4 and Table 11.4). Twenty fi ve years back during 1985-1990
throughout the study area there were a total 86 check dams, 38 spring ponds
to provide water towards all irrigation canals and their gullies (Fig. 11.5
and Table 11.6). Consequently 90% agricultural land was under irrigation
due to very vigorous network of canal and their gullies (184 km). But at the
present time only 45% land is under irrigation due to very poor network of
canals (42 km), check dams (33) and spring ponds (12). The annual results
of the analysis concluded that the spring ponds, perennial streams, water
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