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Appraisal of urban lake water quality through numerical index, multivariate statistics and earth observation data sets
Singh, S. K.; Singh, Prafull & Gautam, S. K.
Abstract
The earth observation data sets were employed
to study the land use/land cover change in study area from
year 2000–2010. Vegetation, built-up area and agriculture
classes had shown maximum changes. The lake water
samples were analyzed, and further, Water Quality Index
(WQI) was computed to categorize the lake water. The
average value of WQI is 64.52, 52.23 and 42.45 in premonsoon,
monsoon and post-monsoon seasons, respectively.
Generally, pre-monsoon samples have higher number
of polluted samples. Moreover, we applied the
multivariate statistical techniques for handling large and
complex data sets in order to get better information about
the lake water quality. Factor analysis and principal component
analysis are applied to understand the latent structure
of the data sets, and we have identified a total of four
factors in pre-monsoon, three factors in monsoon and three
factors in post-monsoon season, which are responsible for
the whole data structure. These factors have explained that
90.908, 89.078 and 85.456 % of the cumulative percentage
variance of the pre-monsoon, monsoon and post-monsoon
data sets. Overall analysis reveals that the agricultural
runoff, waste disposal, leaching and irrigation with
wastewater, land transformation in the surrounding areas
are the main causes of lake water pollution followed by
some degree of pollution from geogenic sources such as
rock weathering. Hence, there is an urgent need of proper
attention and management of resources.
Keywords
Lake; Land use/land cover change; Pollution; Earth observation data sets
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