Temporal variation of rainfall trends in parambikulam aliyar sub basin, Tamil Nadu
Table 4. Linear regression analysis of Aliyar sub basin
Aliyar Nagar
Anamalai
Attakatti
Chinnakallar
Rainfall Series
Slope
Intercept
Slope
Intercept
Slope
Intercept
Slope
Intercept
Annual
10.05
678.78
16.04
3308.10
17.24
834.44
94.88
3232.20
SWM
3.39
230.81
5.48
2543.90
5.66
395.57
73.91
2456.80
NEM
5.95
292.54
7.23
451.49
9.14
308.24
6.59
599.39
Winter
0.10
21.53
-0.38
31.36
-0.58
30.94
0.40
15.08
Summer
0.81
133.90
3.72
281.35
3.01
99.69
13.98
160.95
Pollachi
Topslip
Vettaikaranpudur
Weaverly
Rainfall Series
Slope
Intercept
Slope
Intercept
Slope
Intercept
Slope
Intercept
Annual
5.88
734.59
-5.21
1411.50
4.15
675.19
47.41
1001.90
SWM
-1.94
388.34
-8.09
885.91
-1.73
328.79
28.34
713.75
NEM
5.27
225.79
2.72
342.81
5.15
225.03
11.61
196.70
Winter
-0.01
15.86
-0.24
28.37
0.04
11.93
8.57
52.04
Summer
2.56
104.60
0.40
154.41
0.70
109.44
-1.09
39.35
Bold values indicate the existence of trend with the significance level of 0.05
Conclusion
of the distribution. The knowledge of temporal
The annual and seasonal trends of rainfall were
pattern of rainfall trends analyzed in this study is
investigated by the Mann-Kendall test, the Sen’s
a basic and important requirement for agricultural
Slope estimator and the linear regression in this
planning and management of water resources.
paper. For this purpose, records from eight rain-
Acknowledgments: I wish to acknowledge office
gauge stations of the Aliyar sub basin for the period
of State Surface and Ground Water Data Centre,
of 1982-2012 were analyzed. The results indicated
Public works Department, Chennai for providing me
that a significant upward trend was noticed at
with the essential data for conducting the studies.
Weaverly station during North East monsoon and
The Department of Soil and Water Conservation
summer rainfall series and significant downward
Engineering, Tamilnadu Agricultural University,
trend was noticed during the South West monsoon at
Coimbatore is sincerely acknowledged for facilitating
Topslip. The Negative trends could affect agriculture
and supporting the research.
and water supply of this region. However, the trends
in the South West monsoon and winter rainfall time
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