Author(s): Dhundi Raj Pathak
Linked Author(s):
Keywords: Water quality; Seasonal variation; Anthropogenic process; Spatial variation; Statistical analysis; Kathmandu
Abstract: Statistical techniques were applied to analyze the water quality data sets including 10parameters at 40 sampling sites of upper Bagmati river basin in Kathmandu, Nepal to identify the major factors affecting water quality and to investigate the spatial and seasonal variations. The water quality parameters–temperature, p H, turbidity, conductivity, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), nitrate (NO3-N), ammonium (NH4+-N) and phosphate (PO4-N) were used as possible indicators to trace the impact of anthropogenic processes. Spatial variation was investigated using cluster analysis where, a total of 40 river monitoring sites were divided into two major clusters; low and high polluted zones. Principal component analysis (PCA) and factor analysis (FA) were subjected to water quality parameters to identify the pollution sources. Principal components (PCs) were extracted to distinguish the anthropogenic processes an the symmetrical correlation matrix computed with 10 variables for dry (winter), wet (monsoon) and post monsoon seasons of 2007 river water quality data set, respectively. The significant components extracted have eigen values greater than 1, and account for 79%, 68%and 77%of the total variance in the winter, monsoon and post monsoon data respectively. Non-parametric tests were applied for each parameter to identify their significance differences spatially and temporally.
Year: 2012