Accepted Papers - 3.pdf - UNESCO

the determination of specification for the (a) storage
capacity, (b) shape, (c) dimensions (top bottom,
depth, side slope), (d) inlet, and (e) outlet.
The monthly mean pan evaporation data
obtained from the Ranichauri meteorological
observatory was multiplied with a factor 0.7 to get
pond surface area and evaporation (Duggal and
Soni, 1996). The volume of the water evaporated
from the surface of the pond was determined by
multiplying the corrected evaporation with the
average surface area of the pond. 10% of storage
capacity was kept as provisions for the loss in
storage capacity due to siltation.
ii) Irrigation System Based on Very Low
Discharge Spring / Stream
It has been found that low discharge springs
and streams having discharge between 1 to 10 lpm
are very common in hills and they are either
unutilized or grossly under utilized for irrigation
because of a high proportion of application loss due
to low discharge. If the cost of storage tank is low,
this discharge can be stored in tanks and used when
required at a reasonably low cost.
The first and for most components in design
of any irrigation system is the determination of total
irrigation requirement. Since vegetable cultivation
is the most profitable, in the region under irrigation
conditions, only vegetable rotation was considered
for this system. The analysis showed that irrigation
was required during two seasons: (a). autumn
(October to December), and (b). summer (late March
to early June). Since these two irrigation seasons
are preceded by wet season i.e. rainy and winter,
the discharge during this period is surplus and goes
waste. If the water is carried over to deficit season
by storing, the command area can be increased.
RESULTS AND DISCUSSION
Hydrological Analysis
Rainfall : Rainfall data of Ranichauri for the years
1988 to 2002 were analyzed. The maximum annual
rainfall value during the period of study was found
to be 1840 mm in 1998 and the minimum was 719
mm in 2001. The maximum seasonal rainfall during
monsoon season was 1061 mm in 1995 and
minimum 367 in 2001. The highest rainfall was
found in the month of August and lowest rainfall
was in the month of November. The highest value
of weekly rainfall was observed in the 33 th standard
meteorological week and 43 rd had lowest rainfall in
the whole monsoon period. The seasonal rainfall in
terms of percent of annual rainfall is shown in Table
2. From this table, it is evident that the average
seasonal rainfall was about 63 per cent of annual
rainfall. The probabilities and recurrence interval
of annual, seasonal and maximum weekly rainfalls
for the period 1988-2002 are shown in Table 3. The
excepted annual rainfall at different per cent
probability levels are shown in Fig. 2.
Table 2. Seasonal rainfall in terms of percent of annual rainfall at Henwal watershed.
Year Annual Seasonal Seasonal Year Annual Seasonal Seasonal
rainfall rainfall rainfall as rainfall rainfall rainfall
(mm) (mm) % of annual (mm) (mm) as % of
rainfall annual rainfall
1988 1452.34 1000.24 68.87 1994 1175.50 866.30 73.70
1989 1185.00 718.60 60.64 1995 1386.80 1061.40 76.54
1990 1542.20 787.00 51.03 1998 1840.20 1005.50 54.64
1991 1056.70 698.30 66.08 2000 1334.40 902.70 67.65
1992 855.30 541.70 63.33 2001 719.10 367.80 51.15
1993 1452.20 995.40 68.54 2002 1255.40 664.40 52.92
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