Accepted Papers - 3.pdf - UNESCO

Table 3. Probability and recurrence interval of seasonal rainfall during monsoon period at
Henwal watershed.
No. Year Seasonal Rainfall in P = T = 1/P P (%)
rainfall (mm) decreasing order N/(M+1)
1 1988 1000.24 1061.40 0.08 13.00 7.69
2 1989 718.60 1005.50 0.15 6.50 15.38
3 1990 787.00 1000.24 0.23 4.33 23.08
4 1991 698.30 995.40 0.31 3.25 30.77
5 1992 541.70 902.70 0.38 2.60 38.46
6 1993 995.40 866.30 0.46 2.17 46.15
7 1994 866.30 787.00 0.54 1.86 53.85
8 1995 1061.40 718.60 0.62 1.63 61.54
9 1998 1005.50 698.30 0.69 1.44 69.23
10 2000 902.70 664.40 0.77 1.30 76.92
11 2001 367.80 541.70 0.85 1.18 84.62
12 2002 664.40 367.80 0.92 1.08 92.31
The climate balance based on rainfall and
evapo-transpiration data showed that there were two
excess and two deficit periods (Fig 3). The first
excess period was from the 28 th week to 38 th week
and second from the 2 nd week to the 8 th week. It is
evident from Fig. 3 that crops face moisture stress
from 39 th to 1 st standard meteorological week and
from 9 th week to 27 th week. The first spell coincided
with the sowing of rabi crop and its first critical
stage of irrigation. Thus irrigation is required to
mitigate moisture stress in this critical period.
Rainfall, mm
2000
1800
1600
1400
1200
1000
800
600
400
200
0
Estimation and Analysis of Runoff : On the basis
of the daily runoff values for 14 years, estimated by
ANN model, the annual runoff and seasonal runoff
values were computed for each year and are shown
in Table 4. The annual runoff more than 500 mm
was observed in 4 years, between 400 mm and
500 mm in 5 years, and less than 400 mm in 4 years.
The average annual and seasonal runoff was found
to be 431.7 mm and 292.4 mm, respectively. The
average seasonal runoff was found to be 70 per cent
of annual runoff. The expected runoff and seasonal
runoff during the first excess period was 665000
m 3 and for second excess period was 175000 m 3 .
0 10 20 30 40 50 60 70 80 90 100
Probability (%)
Fig. 2 : Annual rainfall at different probability levels.
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