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Study of
seasonal and spatial variation in surface water quality of
Cauvery river stretch in Karnataka
K. Venkatesharaju, R. K. Somashekar and K. L. Prakash
Department of Environmental Science, Bangalore University,
Bangalore-560 056, India.
*Corresponding author. E-mail:
klpenvi@rediffmail.com. Tel:
91-80-23213218,
91-0-9448684219. Fax: 91-80-23219295.
Accepted
3 December, 2009 |
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In this study, multivariate statistical
techniques, such as discriminant, factor /principal component and cluster analyses
were applied to water quality data set monitored in pre- and post- monsoon for twenty five locations during
three years to investigate seasonal and spatial variations
in river water quality. The variables were mainly divided
into two categories viz., non-conservative – DO, BOD, COD,
nitrates and phosphates and conservative parameters – TDS,
conductivity, alkalinity, hardness, calcium, magnesium,
sodium, potassium and sulfates. Trivial elevated values of
all non conservative Characteristics in pre-monsoon and some
conservative parameters (SO4, Cl) in post-monsoon period
reflected contribution on temporal effect on surface water.
Results of principal component analysis evinced that all the
parameters equally and significantly contribute to water
quality variations in the river basin for both the seasons.
Factor 1 and factor 2 analysis revealed the inverse relation
of DO, indicating the control of dissolved oxygen on organic
load and nutrients in different seasons. Hierarchical
cluster analysis grouped twenty five stations into three
clusters in pre-monsoon and six clusters in post- monsoon
with similar water quality features. Third clustered group
of former and sixth of latter consisted one station (St.25),
exhibiting significant spatial variation in physico-chemical
composition.
Key words: Multivariate analysis, cauvery, cluster, conservative
parameters, temporal and spatial variations. |
