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rise in groundwater levels during monsoon season, which results in increased
hydraulic connectivity among the sites.
Fig. 8.5.
Trends in post-monsoon groundwater levels based on
the three trend tests.
It is also evident from Fig. 8.4 that the sites with significant trends (
p
<
0.05) appear to be in three major clusters during pre-monsoon season over the
study area: (i) in northeast portion, (ii) in southwest portion, and (iii) in south
portion of the area. Of the three clusters, the first cluster falls in the residential
area, second in hillocks, and the third cluster falls in the cultivated command
area. Based on the type of land use/land cover in significant trend clusters, the
significant trends in the pre-monsoon groundwater levels of the first cluster
may be due to unsystematic and uncontrolled seasonal domestic groundwater
withdrawals. Similarly, the significant trends of the third cluster may be
attributed to the non-systematic and uncontrolled groundwater withdrawals
for irrigation during pre-monsoon season when surface water supply is not
adequate to meet the crop water requirements in the command area. Thus, the
significant trends in pre- and post-monsoon groundwater levels in the first and
third clusters are due to anthropogenic factors. However, the significant trends
in the second cluster could be attributed to geogenic factors (e.g., natural
geologic processes). It can be seen from Figs 8.4 and 8.5 that significant
increasing trends in post-monsoon groundwater level time series exist at less
number of sites than the number of sites having increasing trends in pre-
monsoon groundwater level time series.
8.5.2 Results of Homogeneity Tests
Results of the seven homogeneity tests indicating sites with presence/absence
of homogeneity in the time series of pre- and post-monsoon groundwater
levels are shown in Figs 8.6 and 8.7. Clearly, the number of sites with
homogeneity and non-homogeneity differs for different homogeneity tests in
both pre- and post-monsoon groundwater levels. For example, according to
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